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1

Dark radiation emerging after big bang nucleosynthesis?  

Science Conference Proceedings (OSTI)

We show how recent data from observations of the cosmic microwave background may suggest the presence of additional radiation density which appeared after big bang nucleosynthesis. We propose a general scheme by which this radiation could be produced from the decay of nonrelativistic matter, we place constraints on the properties of such matter, and we give specific examples of scenarios in which this general scheme may be realized.

Fischler, Willy; Meyers, Joel [Theory Group, Department of Physics, University of Texas, Austin, Texas 78712 (United States) and Texas Cosmology Center, University of Texas, Austin, Texas 78712 (United States)

2011-03-15T23:59:59.000Z

2

Dark/visible parallel universes and Big Bang nucleosynthesis  

Science Conference Proceedings (OSTI)

We develop a model for visible matter-dark matter interaction based on the exchange of a massive gray boson called herein the Mulato. Our model hinges on the assumption that all known particles in the visible matter have their counterparts in the dark matter. We postulate six families of particles five of which are dark. This leads to the unavoidable postulation of six parallel worlds, the visible one and five invisible worlds. A close study of big bang nucleosynthesis (BBN), baryon asymmetries, cosmic microwave background (CMB) bounds, galaxy dynamics, together with the Standard Model assumptions, help us to set a limit on the mass and width of the new gauge boson. Modification of the statistics underlying the kinetic energy distribution of particles during the BBN is also discussed. The changes in reaction rates during the BBN due to a departure from the Debye-Hueckel electron screening model is also investigated.

Bertulani, C. A.; Frederico, T.; Fuqua, J.; Hussein, M. S.; Oliveira, O.; Paula, W. de [Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce TX 75429 (United States); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP (Brazil); Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce TX 75429 (United States); Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05314-970 Sao Paulo, SP (Brazil); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP, Brazil and Departamento de Fisica, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP (Brazil)

2012-11-20T23:59:59.000Z

3

Quark mass variation constraints from Big Bang nucleosynthesis  

SciTech Connect

We study the impact on the primordial abundances of light elements created of a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN). In order to navigate through the particle and nuclear physics required to connect quark masses to binding energies and reaction rates in a model-independent way we use lattice QCD data and an hierarchy of effective field theories. We find that the measured {sup 4}He abundances put a bound of {delta}-1% {approx}< m{sub q}/m{sub 1} {approx}< 0.7%. The effect of quark mass variations on the deuterium abundances can be largely compensated by changes of the baryon-to-photon ratio {eta}. Including the bounds on the variation of {eta} coming from WMAP results and some additional assumptions narrows the range of allowed values of {delta}m{sub q}/m{sub q} somewhat.

Bedaque, P; Luu, T; Platter, L

2010-12-13T23:59:59.000Z

4

LiBeB and Big Bang Nucleosynthesis  

E-Print Network (OSTI)

The dual origin of population II Li7, in both big bang nucleosynthesis and galactic cosmic-ray nucleosynthesis is discussed. It is argued that with additional Li6 data, stringent limits on the degree of Li7 depletion can be obtained. Li7 depletion is also constrained by the concordance of big bang predictions with observational determinations of light element abundances. Stringent limits can also be obtained for a fixed primordial D/H abundance.

Keith A. Olive; Brian D. Fields

1999-02-20T23:59:59.000Z

5

Constraint on slepton intergenerational mixing from big-bang nucleosynthesis  

Science Conference Proceedings (OSTI)

We find constraint on intergenerational mixing of slepton from big-bang nucleosynthesis (BBN). Today, we know that there exist lepton flavor violation (LFV) from the observation of neutrino oscillation, though there do not exist LFV in the standard model of particle physics (SM). LFV in charged lepton sector (cLFV) have also been expected to exist. From theoretical point of view, the effects of long-lived stau on BBN have been investigated and it is known that the stau can solve the cosmological 7Li problem. However, in the study so far, tau flavor is exactly conserved and it contradict with the existence of cLFV. In this study, we generalize the flavor to be violated and call the stau as slepton. Even if the violation is tiny, it drastically changes the lifetime and the evolution of relic density of the slepton. Thus we analyze the effects of the long-lived slepton on BBN, and constrain the magnitude of the cLFV.

Kohri, Kazunori; Ohta, Shingo; Sato, Joe; Shimomura, Takashi; Yamanaka, Masato [Theory Center, Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801 (Japan); Department of Physics, Saitama University, Shimo-okubo, Sakura-ku, Saitama, 338-8570 (Japan); Department of Physics, Niigata University, Niigata, 950-8502 (Japan) and Max-Planck-Institut fur Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Maskawa Institute for Science and Culture, Kyoto Sangyo University, Kyoto 603-8555 (Japan)

2012-07-27T23:59:59.000Z

6

Refined scenario of standard Big Bang nucleosynthesis allowing for nonthermal nuclear reactions in the primordial plasma  

Science Conference Proceedings (OSTI)

The standard scenario of big bang nucleosynthesis (BBN) is generalized to take into account nonthermal nuclear reactions in the primordial plasma. These reactions are naturally triggered in the BBN epoch by fast particles generated in various exoergic processes. It is found that, although such particles can appreciably enhance the rates of some individual reactions, their influence on the whole process of element production is not significant. The nonthermal corrections to element abundances are obtained to be 0.1% ({sup 3}H), -0.03% ({sup 7}Li), and 0.34 %-0.63% (CNO group).

Voronchev, Victor T.; Nakao, Yasuyuki; Nakamura, Makoto; Tsukida, Kazuki [Institute of Nuclear Physics, Moscow State University, Moscow 119991 (Russian Federation); Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Motooka, Fukuoka 819-0395 (Japan); Division of Advanced Plasma Research, Japan Atomic Energy Agency, 2-166 Oaza-Obuchi-Aza-Omotedate, Rokkasho, Kamikita, Aomori 039-3212 (Japan); Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Motooka, Fukuoka 819-0395 (Japan)

2012-11-12T23:59:59.000Z

7

STANDARD BIG BANG NUCLEOSYNTHESIS UP TO CNO WITH AN IMPROVED EXTENDED NUCLEAR NETWORK  

SciTech Connect

Primordial or big bang nucleosynthesis (BBN) is one of the three strong pieces of evidence for the big bang model together with the expansion of the universe and cosmic microwave background radiation. In this study, we improve the standard BBN calculations taking into account new nuclear physics analyses and enlarge the nuclear network up to sodium. This is, in particular, important to evaluate the primitive value of CNO mass fraction that could affect Population III stellar evolution. For the first time we list the complete network of more than 400 reactions with references to the origin of the rates, including Almost-Equal-To 270 reaction rates calculated using the TALYS code. Together with the cosmological light elements, we calculate the primordial beryllium, boron, carbon, nitrogen, and oxygen nuclei. We performed a sensitivity study to identify the important reactions for CNO, {sup 9}Be, and boron nucleosynthesis. We re-evaluated those important reaction rates using experimental data and/or theoretical evaluations. The results are compared with precedent calculations: a primordial beryllium abundance increase by a factor of four compared to its previous evaluation, but we note a stability for B/H and for the CNO/H abundance ratio that remains close to its previous value of 0.7 Multiplication-Sign 10{sup -15}. On the other hand, the extension of the nuclear network has not changed the {sup 7}Li value, so its abundance is still 3-4 times greater than its observed spectroscopic value.

Coc, Alain [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), CNRS/IN2P3, Universite Paris Sud, UMR 8609, Batiment 104, F-91405 Orsay Campus (France); Goriely, Stephane; Xu, Yi [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, CP 226, Boulevard du Triomphe, B-1050 Bruxelles (Belgium); Saimpert, Matthias; Vangioni, Elisabeth [Institut d'Astrophysique de Paris, UMR 7095 CNRS, Universite Pierre et Marie Curie, 98 bis Boulevard Arago, Paris 75014 (France)

2012-01-10T23:59:59.000Z

8

Limits on Cosmological Variation of Strong Interaction and Quark Masses from Big Bang Nucleosynthesis, Cosmic, Laboratory and Oklo Data  

E-Print Network (OSTI)

Recent data on cosmological variation of the electromagnetic fine structure constant from distant quasar (QSO) absorption spectra have inspired a more general discussion of possible variation of other constants. We discuss variation of strong scale and quark masses. We derive the limits on their relative change from (i) primordial Big-Bang Nucleosynthesis (BBN); (ii) Oklo natural nuclear reactor, (iii) quasar absorption spectra, and (iv) laboratory measurements of hyperfine intervals.

V. V. Flambaum; E. V. Shuryak

2002-01-31T23:59:59.000Z

9

Primordial Lithium Abundance in Catalyzed Big Bang Nucleosynthesis  

E-Print Network (OSTI)

There exists a well known problem with the Li7+Be7 abundance predicted by standard big bang nucleosynthesis being larger than the value observed in population II stars. The catalysis of big bang nucleosynthesis by metastable, \\tau_X \\ge 10^3 sec, charged particles X^- is capable of suppressing the primordial Li7+Be7, abundance and making it consistent with the observations. We show that to produce the correct abundance, this mechanism of suppression places a requirement on the initial abundance of X^- at temperatures of 4\\times 10^8 K to be on the order of or larger than 0.02 per baryon, which is within the natural range of abundances in models with metastable electroweak-scale particles. The suppression of Li7+Be7, is triggered by the formation of (Be7X^-), compound nuclei, with fast depletion of their abundances by catalyzed proton reactions, and in some models by direct capture of X^- on Be7. The combination of Li7+Be7 and Li6 constraints favours the window of lifetimes, 1000s \\la tau_X \\leq 2000 s.

Chris Bird; Kristen Koopmans; Maxim Pospelov

2007-03-08T23:59:59.000Z

10

Lithium in cool stellar atmospheres: Big bang nucleosynthesis and extrasolar planets  

E-Print Network (OSTI)

Lithium in cool stellar atmospheres: Big bang nucleosynthesis and extrasolar planets Matthias Steffen and Elisabetta Caffau Sternphysik In metal-poor stellar atmospheres, the Lithium line at 6707 Ã?-NLTE, respectively. The accurate spectroscopic determination of the Lithium abundance and in particular the 6Li/7Li

11

Low-Energy Photodisintegration of the Deuteron and Big-Bang Nucleosynthesis  

E-Print Network (OSTI)

The photon analyzing power for the photodisintegration of the deuteron was measured for seven gamma-ray energies between 2.39 and 4.05 MeV using the linearly polarized gamma-ray beam of the High-Intensity Gamma-ray Source at the Duke Free-Electron Laser Laboratory. The data provide a stringent test of theoretical calculations for the inverse reaction, the neutron-proton radiative capture reaction at energies important for Big-Bang Nucleosynthesis. Our data are in excellent agreement with potential model and effective field theory calculations. Therefore, the uncertainty in the baryon density obtained from Big-Bang Nucleosynthesis can be reduced at least by 20%.

W. Tornow; N. G. Czakon; C. R. Howell; A. Hutcheson; J. H. Kelley; V. N. Litvinenko; S. Mikhailov; I. V. Pinayev; G. J. Weisel; H. Witala

2003-09-10T23:59:59.000Z

12

Big-bang nucleosynthesis with high-energy photon injection  

DOE Green Energy (OSTI)

The author discusses the photodissociation of light elements due to the radiative decay of a massive particle, and he has shown how to constrain the model parameters from the observed light-element abundances. He adopted two quasar absorption system (QAS) D/H values, as well as solar system data for D/H and {sup 3}He/H. For each of these, he used two {sup 4}He values. He presents his results in terms of the confidence level at which each theoretical parameter set (i.e., the set of properties of a radiatively decaying particle) is excluded by the observed abundances. His algorithm for computing the confidence level is consistent and general enough to apply not only to the scenarios investigated in this work, but also to many other non-standard theories of BBN.

Holtmann, Erich N.

1999-05-01T23:59:59.000Z

13

After the Big Bang  

NLE Websites -- All DOE Office Websites (Extended Search)

After the Big Bang After the Big Bang Golden Age of Cosmology Big Bang Timeline Big Bang? Standard Big Bang Cosmology Slide 6 Big Bang Nucleosynthesis Redshift and Doppler Shift Doppler Shift Cepheid variables and Nebulae Standard Candles Hubble Expansion Hubble Law Cosmic Microwave Background Cosmic Background Explorer (1989-1993) COBE data/DMR CMB Fluctuations What is inflation? Why believe in inflation? Horizon Problem No inflation With inflation Flatness Problem Slide 24 Wilkinson Microwave Anisotropy Probe (2001-present) Fluctuations and geometry Universe's Baby Pictures Compare to COBE CMB vs. Inflation WMAP angular power spectrum Dark Matter Galaxy Rotation Curves Hot gas in Galaxy Clusters Dark Matter Halo Old view: Density of the Universe determines its destiny Hubble Expansion revisited

14

Big-bang nucleosynthesis and the relic abundance of dark matter in a stau-neutralino coannihilation scenario  

E-Print Network (OSTI)

A scenario of the Big-Bang Nucleosynthesis is analyzed within the Minimal Supersymmetric Standard Model which is consistent with a stau-neutralino coannihilation scenario to explain the relic abundance of dark matter. We find that we can account for the possible descrepancy of the abundance of $\\mathrm{^{7}Li}$ between the observation and the prediction of the Big-Bang Nucleosynthesis by taking the mass of the neutralino as $300 \\mathrm{GeV}$ and the mass difference between the stau and the neutralino as $(100 -- 120) MeV$. We can therefore simultaneously explain the abundance of the dark matter and that of $\\mathrm{^{7}Li}$ by these values of parameters. The lifetime of staus in this scenario is predicted to be $O(100 -- 1000) sec$.

Toshifumi Jittoh; Kazunori Kohri; Masafumi Koike; Joe Sato; Takashi Shimomura; Masato Yamanaka

2008-05-22T23:59:59.000Z

15

An updated nuclear reaction network for BBN  

E-Print Network (OSTI)

The key Standard-Physics inputs of the Big Bang Nucleosynthesis (BBN) are the light nuclei reaction rates. Both the network and the nuclear rates have been recently reanalyzed and updated, and cosmological and New-Physics constraints (taking into account the WMAP Cosmic Microwave Background anisotropies measurement) obtained with a new code are presented.

P. D. Serpico

2004-01-07T23:59:59.000Z

16

Compilation and R-matrix analysis of Big Bang nuclear reaction rates  

E-Print Network (OSTI)

We use the R-matrix theory to fit low-energy data on nuclear reactions involved in Big Bang nucleosynthesis. A special attention is paid to the rate uncertainties which are evaluated on statistical grounds. We provide S factors and reaction rates in tabular and graphical formats.

Pierre Descouvemont; Abderrahim Adahchour; Carmen Angulo; Alain Coc; Elisabeth Vangioni-Flam

2004-07-06T23:59:59.000Z

17

BNL | QCD Matter, Big Bang Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

QCD Matter QCD Matter image Physicist Paul Sorensen next to the STAR detector at Brookhaven's Relativistic Heavy Ion Collider Exploring Matter at the Dawn of Time Brookhaven Lab leads the world in exploring how the matter that makes up atomic nuclei behaved just after the Big Bang. At that time, more than 13 billion years ago, there were no protons and neutrons-just a sea of "free" quarks and gluons, fundamental particles whose interactions are governed by nature's strongest force and described by the theory of quantum chromodynamics (QCD). More than 1,000 scientists from around the nation and the world come to Brookhaven to recreate this "quark-gluon plasma" by accelerating heavy ions (atoms stripped of their electrons) to nearly the speed of light and smashing them together at the Lab's

18

Using BBN in cosmological parameter extraction from CMB: a forecast for Planck  

E-Print Network (OSTI)

Data from future high-precision Cosmic Microwave Background (CMB) measurements will be sensitive to the primordial Helium abundance $Y_p$. At the same time, this parameter can be predicted from Big Bang Nucleosynthesis (BBN) as a function of the baryon and radiation densities, as well as a neutrino chemical potential. We suggest to use this information to impose a self-consistent BBN prior on $Y_p$ and determine its impact on parameter inference from simulated Planck data. We find that this approach can significantly improve bounds on cosmological parameters compared to an analysis which treats $Y_p$ as a free parameter, if the neutrino chemical potential is taken to vanish. We demonstrate that fixing the Helium fraction to an arbitrary value can seriously bias parameter estimates. Under the assumption of degenerate BBN (i.e., letting the neutrino chemical potential $\\xi$ vary), the BBN prior's constraining power is somewhat weakened, but nevertheless allows us to constrain $\\xi$ with an accuracy that rivals bounds inferred from present data on light element abundances.

Jan Hamann; Julien Lesgourgues; Gianpiero Mangano

2007-12-18T23:59:59.000Z

19

Primordial Nucleosynthesis: The Predicted and Observed Abundances and Their Consequences  

E-Print Network (OSTI)

For a brief time in its early evolution the Universe was a cosmic nuclear reactor. The expansion and cooling of the Universe limited this epoch to the first few minutes, allowing time for the synthesis in astrophysically interesting abundances of only the lightest nuclides (D, 3He, 4He, 7Li). For big bang nucleosynthesis (BBN) in the standard models of cosmology and particle physics (SBBN), the SBBN-predicted abundances depend on only one adjustable parameter, the baryon density parameter (the ratio by number of baryons (nucleons) to photons). The predicted and observed abundances of the relic light elements are reviewed, testing the internal consistency of primordial nucleosynthesis. The consistency of BBN is also explored by comparing the values of the cosmological parameters inferred from primordial nucleosynthesis for the standard model and for models with non-standard early Universe expansion rates with those determined from studies of the cosmic background radiation, which provides a snapshot of the Universe some 400 thousand years after BBN ended.

Gary Steigman

2010-08-27T23:59:59.000Z

20

Cosmic Rays during BBN as Origin of Lithium Problem  

E-Print Network (OSTI)

There may be non-thermal cosmic rays during big-bang nucleosynthesis (BBN) epoch (dubbed as BBNCRs). This paper investigated whether such BBNCRs can be the origin of Lithium problem or not. It can be expected that BBNCRs flux will be small in order to keep the success of standard BBN (SBBN). With favorable assumptions on the BBNCR spectrum between 0.09 -- 4 MeV, our numerical calculation showed that extra contributions from BBNCRs can account for the $^7$Li abundance successfully. However $^6$Li abundance is only lifted an order of magnitude, which is still much lower than the observed value. As the deuteron abundance is very sensitive to the spectrum choice of BBNCRs, the allowed parameter space for the spectrum is strictly constrained. We should emphasize that the acceleration mechanism for BBNCRs in the early universe is still an open question. For example, strong turbulent magnetic field is probably the solution to the problem. Whether such a mechanism can provide the required spectrum deserves further studies.

Ming-ming Kang; Yang Hu; Hong-bo Hu; Shou-hua Zhu

2011-10-02T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

John C. Mather, the Big Bang, and the COBE  

NLE Websites -- All DOE Office Websites (Extended Search)

John C. Mather, the Big Bang, and the COBE John C. Mather, the Big Bang, and the COBE Resources with Additional Information · Videos John C. Mather Courtesy of NASA "Dr. John C. Mather of NASA's Goddard Space Flight Center has won the 2006 Nobel Prize for Physics, awarded by the Royal Swedish Academy of Sciences. Mather shares the prize with George F. Smoot of the University of California for their collaborative work on understanding the Big Bang. Mather and Smoot analyzed data from NASA's Cosmic Background Explorer (COBE), which studied the pattern of radiation from the first few instants after the universe was formed. In 1992, the COBE team announced that they had mapped the primordial hot and cold spots in the cosmic microwave background radiation. These spots are related to the gravitational field in the early universe, only instants after the Big Bang, and are the seeds for the giant clusters of galaxies that stretch hundreds of millions of light years across the universe. ...

22

Pre-Big Bang, vacuum and noncyclic cosmologies  

E-Print Network (OSTI)

WMAP and Planck open the way to unprecedented Big Bang phenomenology, potentially allowing to test the standard Big Bang model as well as less conventional approaches including noncyclic pre-Big Bang cosmologies that would incorporate a new fundamental scale beyond the Planck scale and, possibly, new ultimate constituents of matter. Alternatives to standard physics can be considered from a cosmological point of view concerning vacuum structure, the nature of space-time, the origin and evolution of our Universe, the validity of quantum field theory and conventional symmetries, solutions to the cosmological constant problem, inflationary scenarios, dark matter and dark energy, the interpretation of string-like theories... Lorentz-like symmetries for the properties of matter (standard or superbradyonic) can then be naturally stable space-time configurations resulting from general cosmological scenarios that incorporate physics beyond the Planck scale and describe the formation and evolution of the present vacuum. But an even more primordial question seems to be that of the origin of half-integer spins, that cannot be generated through orbital angular momentum in the usual real space-time. It turns out that the use of a spinorial space-time with two complex coordinates instead of the conventional four real ones presents several attractive features. Taking the cosmic time to be the modulus of a SU(2) spinor leads by purely geometric means to a naturally expanding universe, with a ratio between cosmic relative velocities and distances equal to the inverse of the age of the Universe. No reference to standard matter, hidden fields, gravitation or relativity is required to get such a result that looks quite reasonable from an observational point of view. We discuss basic ideas and phenomenological issues for noncyclic pre-Big Bang cosmologies in the present context.

Luis Gonzalez-Mestres

2012-12-12T23:59:59.000Z

23

Supernova bangs as a tool to study big bang  

SciTech Connect

Supernovae and gamma-ray bursts are the most powerful explosions in observed Universe. This educational review tells about supernovae and their applications in cosmology. It is explained how to understand the production of light in the most luminous events with minimum required energy of explosion. These most luminous phenomena can serve as primary cosmological distance indicators. Comparing the observed distance dependence on red shift with theoretical models one can extract information on evolution of the Universe from Big Bang until our epoch.

Blinnikov, S. I., E-mail: Sergei.Blinnikov@itep.ru [Institute for Theoretical and Experimental Physics (Russian Federation)

2012-09-15T23:59:59.000Z

24

NERSC User Group 2013 Big Bang, Big Data, Big Iron Planck Satellite...  

NLE Websites -- All DOE Office Websites (Extended Search)

User Group 2013 Big Bang, Big Data, Big Iron Planck Satellite Data Analysis At NERSC Julian Borrill Computational Cosmology Center, Berkeley Lab & Space Sciences Laboratory, UC...

25

The problem of big bang matter vs. anti-matter symmetry  

Science Conference Proceedings (OSTI)

The Big Bang was symmetrical in the particles and radiation emitted from its singularity source, which implies its resulting in equal amounts of matter and anti-matter and their prompt mutual annihilation. But that did not take place. The favored explanation ... Keywords: anti-matter, big bang, gamma ray bursts, matter, mutual annihilation, universe

Roger Ellman

2011-02-01T23:59:59.000Z

26

The big bang and inflation united by an analytic solution  

SciTech Connect

Exact analytic solutions for a class of scalar-tensor gravity theories with a hyperbolic scalar potential are presented. Using an exact solution we have successfully constructed a model of inflation that produces the spectral index, the running of the spectral index, and the amplitude of scalar perturbations within the constraints given by the WMAP 7 years data. The model simultaneously describes the big bang and inflation connected by a specific time delay between them so that these two events are regarded as dependent on each other. In solving the Friedmann equations, we have utilized an essential Weyl symmetry of our theory in 3+1 dimensions which is a predicted remaining symmetry of 2T-physics field theory in 4+2 dimensions. This led to a new method of obtaining analytic solutions in the 1T field theory which could in principle be used to solve more complicated theories with more scalar fields. Some additional distinguishing properties of the solution includes the fact that there are early periods of time when the slow-roll approximation is not valid. Furthermore, the inflaton does not decrease monotonically with time; rather, it oscillates around the potential minimum while settling down, unlike the slow-roll approximation. While the model we used for illustration purposes is realistic in most respects, it lacks a mechanism for stopping inflation. The technique of obtaining analytic solutions opens a new window for studying inflation, and other applications, more precisely than using approximations.

Bars, Itzhak [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-2535 (United States); Chen, Shih-Hung [Department of Physics and School of Earth and Space Exploration, Arizona State University, Tempe, Arizona 85287-1404 (United States)

2011-02-15T23:59:59.000Z

27

Optical coherence in astrophysics: The powerful alternative of big bang  

E-Print Network (OSTI)

The coherence of the interaction of light with a collisionless gas (Einstein 1917) founds the theory of gas lasers. It is, for the understanding of universe, a simpler and more powerful tool than the big bang which requires questionable supplements (dark matter, MOND, etc..). The Impulsive Stimulated Raman Scattering (ISRS) redshifts gradually light pulses which cross excited atomic hydrogen H*, so that the redshift is a measure of the column density of H*. Thus, the distance of the hot stars, surrounded by much H*, is exaggerated by the use of Hubble's law. Local exaggerated distances create voids in the maps of galaxies which become spongy. The interpretation of spectra of quasars, the periodicity of galaxy redshifts introduce an experimental "Karlsson's constant" exactly computed by ISRS. The need for dark matter comes from the exaggeration of the distance, therefore the size of galaxies. Without dark matter, celestial mechanics provides a reliable distance of spiral galaxies. Coherence also introduces superradiance and mode competition that explain that only the limbs of Str\\"omgren spheres are visible as circles maybe punctuated by an even number of dots: Too numerous, the figures assigned to gravitational lenses can be such limbs. The coincidence of the ignition of the rings of SNR1987A with the extinction of the star is due to a multiphoton coherent scattering of star light, which amplifies the superradiant emission of the rings.. A blueshift of microwaves crossing H* resulting, between 10 and 15 AU, of the expansion of solar wind, explains the "anomalous acceleration" of Pioneer probes. All is obtained without any change in theories of standard spectroscopy.

Jacques Moret-Bailly

2013-05-03T23:59:59.000Z

28

DOE research makes big bang | OSTI, US Dept of Energy, Office of Scientific  

Office of Scientific and Technical Information (OSTI)

DOE research makes big bang DOE research makes big bang Feature Archive Saul Perlmutter Photo Courtesy of Lawrence Berkeley National Laboratory Saul Perlmutter has been awarded the 2011 Nobel Prize in Physics for his breakthrough research at Lawrence Berkeley National Laboratory. He cofounded the Supernova Cosmology Project (SCP) in 1988, with the breakthrough coming ten years later. The SCP pioneered the methods used to discover the accelerating expansion of the universe through observations of distant supernovae. For many years Perlmutter has been a leader in studies to determine the nature of dark energy. Explore the universe using Science Accelerator; check out the search results for big bang and supernovae. OSTI Homepage Mobile Gallery Subscribe to RSS OSTI Blog Get Widgets Get Alert Services

29

Supercomputing: A Toolbox to Simulate the Big Bang and Beyond | Department  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Supercomputing: A Toolbox to Simulate the Big Bang and Beyond Supercomputing: A Toolbox to Simulate the Big Bang and Beyond Supercomputing: A Toolbox to Simulate the Big Bang and Beyond September 19, 2013 - 1:30pm Addthis This image shows the barred spiral galaxy NGC 1398. | Image courtesy of the Dark Energy Survey. This image shows the barred spiral galaxy NGC 1398. | Image courtesy of the Dark Energy Survey. Rob Roser Rob Roser Head, Fermilab Scientific Computing Division What does this project do? A new project sponsored by three of the Energy Department's National Labs will allow scientists to study the evolution of our universe in greater detail with a new cosmological simulation analysis toolbox. This project takes advantage of the Energy Department's investments in supercomputers and specialized high-performance computing

30

CO2 and cost optimization of reinforced concrete footings using a hybrid big bang-big crunch algorithm  

Science Conference Proceedings (OSTI)

A procedure is developed for the design of reinforced concrete footings subjected to vertical, concentric column loads that satisfies both structural requirements and geotechnical limit states using a hybrid Big Bang-Big Crunch (BB-BC) algorithm. The ... Keywords: Big Bang-Big Crunch optimization, Computer aided design, Optimization, Reinforced concrete, Spread footings, Structural design, Sustainable design

Charles V. Camp; Andrew Assadollahi

2013-08-01T23:59:59.000Z

31

From the Big Bang to the Higgs Boson in Less Than an Hour  

E-Print Network (OSTI)

From the Big Bang to the Higgs Boson in Less Than an Hour Jeffrey D H Higgs boson Gauge bosons (force field quanta) Higgs boson and vacuum expectation value Strong) photon Z boson W bosons H Higgs boson Gauge bosons (force field quanta) Higgs boson and vacuum

Fygenson, Deborah Kuchnir

32

From the Big Bang to the Higgs Boson in Less Than an Hour  

E-Print Network (OSTI)

From the Big Bang to the Higgs Boson in Less Than an Hour Jeffrey D neutrino Z0 W + W -g gluon (8) photon Z boson W bosons Quarks Leptons H Higgs boson Gauge bosons (force field quanta) Higgs boson and vacuum expectation value Strong force EM force Weak force #12;Par7cles

Fygenson, Deborah Kuchnir

33

Neutrinos' Instant Identity Changes Could Mean Big Things for the Big Bang  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Neutrinos' Instant Identity Changes Could Mean Big Things for the Neutrinos' Instant Identity Changes Could Mean Big Things for the Big Bang Neutrinos' Instant Identity Changes Could Mean Big Things for the Big Bang July 11, 2011 - 12:23pm Addthis Scientists use the near detector to verify the intensity and purity of the muon neutrino beam leaving the Fermilab site. | Courtesy of Fermilab, photo by Peter Ginter Scientists use the near detector to verify the intensity and purity of the muon neutrino beam leaving the Fermilab site. | Courtesy of Fermilab, photo by Peter Ginter Charles Rousseaux Charles Rousseaux Senior Writer, Office of Science What are the key facts? Researchers at Fermilab have been studying neutrinos and how they might change, or oscillate, between their three different identities -- electron, muon and tau.

34

Birth of Supermassive Black holes and Star Formation after the Big Bang  

E-Print Network (OSTI)

Modern observations of star formation in different galaxies contradicts with the current star formation theories. There are few questions and observations where current star formation theories were not able to explain well. This paper proposes an alternative theory of Star formation and birth of Supermassive Black holes after the Big Bang, which can answer the contradictions without violating the physics laws and fit perfectly well with the modern observations.

A Paramashivam

2013-01-01T23:59:59.000Z

35

An origin of the universe: a model alternative to Big Bang  

E-Print Network (OSTI)

We propose a new approach to the model of an origin of the universe built by Oscar Klein and Hannes Alfv\\'{e}n. Some modifications of assumptions underlying the model result in a possible scenario of the universe creation consistent with observations. We explain the large scale structre of the universe and we estimate the Hubble constant value as well as the number of galaxies in the universe. The model does not require many assumptions made in the model based on the Big Bang idea.

Andrzej Mercik; Szymon Mercik

2006-04-04T23:59:59.000Z

36

The Problem of Big Bang Matter vs. AntiMatter Symmetry  

E-Print Network (OSTI)

-The favored Big Bang concept is that the original symmetry was skewed, the universe now being all matter, all antimatter having annihilated. -The mechanism of matter/antimatter annihilation is analyzed. A total annihilation of original antimatter could not have occurred; the skewing is unnecessary; and the universe must contain equally both forms of matter. -Current detection of cosmic matter/antimatter annihilations is Gamma Ray Bursts [GRB's]. However, the conviction that the universe is now all matter with no antimatter has left that possibility rejected and uninvestigated and left standing the massive supernovae core collapse hypothesis for GRB's. -It has recently been reported that the rate of GRB's increases with red shift z for z = 0 to 4 as (1 + z)^1.5. The indication is that the rate increases significantly with time into the past at least back to z = 4 [and probably back to the Big Bang]. -That finding is inconsistent with the massive supernovae core collapse hypothesis for GRB's and supports GRB's being cosmic matter/antimatter annihilations.

Roger Ellman

2000-07-17T23:59:59.000Z

37

Cosmic Hydrogen Was Significantly Neutral a Billion Years After the Big Bang  

E-Print Network (OSTI)

The ionization fraction of cosmic hydrogen, left over from the big bang, provides crucial fossil evidence for when the first stars and quasar black holes formed in the infant universe. Spectra of the two most distant quasars known show nearly complete absorption of photons with wavelengths shorter than the Ly-alpha transition of neutral hydrogen, indicating that hydrogen in the intergalactic medium (IGM) had not been completely ionized at a redshift z~6.3, about a billion years after the big bang. Here we show that the radii of influence of ionizing radiation from these quasars imply that the surrounding IGM had a neutral hydrogen fraction of tens of percent prior to the quasar activity, much higher than previous lower limits of ~0.1%. When combined with the recent inference of a large cumulative optical depth to electron scattering after cosmological recombination from the WMAP data, our result suggests the existence of a second peak in the mean ionization history, potentially due to an early formation episode of the first stars.

Stuart Wyithe; Abraham Loeb

2004-01-12T23:59:59.000Z

38

The Multiverse Origin of our Physics does without Strings, Big Bang, Inflation, or Parallel Universes  

E-Print Network (OSTI)

Evolution needs long times and large numbers of samples or species. Our finely tuned physics can therefore not have evolved during the fast changes of a single Big-Bang universe, but the cosmological scales for time and for the number of universes in the multiverse satisfy that condition. Planck and Chandrasekhar equations show that multiverse. A variety of observations show the origin of our physics. The multiverse is being fed by the debris of its decaying universes, which is transported on the accelerated expansion. New universes originate from clouds of that debris, which is re-energized by the gravity at the center of the cloud when the proton density is reached. That epoch occurs much later than a Big Bang. It marks the beginning of our universe with a photon burst, which may have been observed by spacecraft as the radiation signature with a wider curvature than that of the cosmic background radiation. A test for black holes, published by Karl Schwarzschild in 1916, also confirms that beginning.

Tom Gehrels

2009-12-29T23:59:59.000Z

39

bigbangnucrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

October 2013 by B.D. Fields, (Univ. of Illinois) P. Molaro (Trieste Observatory) and S. Sarkar (Univ. of Oxford & Niels Bohr Institute, Copenhagen). Big-Bang nucleosynthesis (BBN)...

40

Necessary and sufficient conditions for big bangs, bounces, crunches, rips, sudden singularities, and extremality events  

E-Print Network (OSTI)

The physically relevant singularities occurring in FRW cosmologies had traditionally been thought to be limited to the "big bang", and possibly a "big crunch". However, over the last few years, the zoo of cosmological singularities considered in the literature has become considerably more extensive, with "big rips" and "sudden singularities" added to the mix, as well as renewed interest in non-singular cosmological events such as "bounces" and "turnarounds". In this article we present a complete catalogue of such cosmological milestones, both at the kinematical and dynamical level. First, using generalized power series, purely kinematical definitions of these cosmological events are provided in terms of the behaviour of the scale factor a(t). The notion of a "scale-factor singularity'" is defined, and its relation to curvature singularities (polynomial and differential) is explored. Second, dynamical information is extracted by using the Friedmann equations (without assuming even the existence of any equation of state) to place constraints on whether or not the classical energy conditions are satisfied at the cosmological milestones. We use these considerations to derive necessary and sufficient conditions for the existence of cosmological milestones such as bangs, bounces, crunches, rips, sudden singularities, and extremality events. Since the classification is extremely general, the corresponding results are to a high degree model-independent: In particular, we provide a complete characterization of the class of bangs, crunches, and sudden singularities for which the dominant energy condition is satisfied.

Celine Cattoen; Matt Visser

2005-08-11T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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41

Problems of antimatter after Big Bang, dark energy and dark matter. Solutions in the frame of non-local physics  

E-Print Network (OSTI)

Quantum solitons are discovered with the help of generalized quantum hydrodynamics. The solitons have the character of the stable quantum objects in the self consistent electric field. The delivered theory demonstrates the great possibilities of the generalized quantum hydrodynamics in investigation of the quantum solitons. The theory leads to solitons as typical formations in the generalized quantum hydrodynamics. The principle of universal antigravitation is considered from positions of the Newtonian theory of gravitation and non-local kinetic theory. It is found that explanation of Hubble effect in the Universe and peculiar features of the rotational speeds of galaxies need not in introduction of new essence like dark matter and dark energy. Problems of antimatter after Big Bang are considered from positions of non-local physics. The origin of difficulties consists in total Oversimplification following from principles of local physics and reflects the general shortenings of the local kinetic transport theory. Keywords: Foundations of the theory of transport processes; generalized Boltzmann physical kinetics; plasma - gravitational analogy; antigravitation; dark energy; dark matter; the theory of solitons; antimatter after Big Bang. PACS: 67.55.Fa, 67.55.Hc

Boris V. Alexeev

2010-12-22T23:59:59.000Z

42

Primordial Nucleosynthesis for the New Millennium  

E-Print Network (OSTI)

The physics of the standard hot big bang cosmology ensures that the earlyUniverse was a primordial nuclear reactor, synthesizing the light nuclides (D,3He, 4He, and 7Li) in the first 20 minutes of its evolution. After an overviewof nucleosynthesis in the standard model (SBBN), the primordial abundanceyields will be presented, followed by a status report (intended to stimulatefurther discussion during this symposium) on the progress along the road fromobservational data to inferred primordial abundances. Theory will be confrontedwith observations to assess the consistency of SBBN and to constrain cosmologyand particle physics. Some of the issues/problems key to SBBN in the newmillenium will be highlighted, along with a wish list to challenge theoristsand observers alike.

Steigman, G

2000-01-01T23:59:59.000Z

43

Primordial Nucleosynthesis For The New Millennium  

E-Print Network (OSTI)

The physics of the standard hot big bang cosmology ensures that the early Universe was a primordial nuclear reactor, synthesizing the light nuclides (D, 3He, 4He, and 7Li) in the first 20 minutes of its evolution. After an overview of nucleosynthesis in the standard model (SBBN), the primordial abundance yields will be presented, followed by a status report (intended to stimulate further discussion during this symposium) on the progress along the road from observational data to inferred primordial abundances. Theory will be confronted with observations to assess the consistency of SBBN and to constrain cosmology and particle physics. Some of the issues/problems key to SBBN in the new millenium will be highlighted, along with a wish list to challenge theorists and observers alike.

G. Steigman

2000-02-14T23:59:59.000Z

44

Big-bang nucleosynthesis with a long-lived charged massive particle including {sup 4}He spallation processes in a bound state  

SciTech Connect

We propose helium-4 spallation processes induced by long-lived stau in supersymmetric standard models, and investigate an impact of the processes on light elements abundances. We show that, as long as the phase space of helium-4 spallation processes is open, they are more important than stau-catalyzed fusion and hence constrain the stau property.

Jittoh, Toshifumi; Kohri, Kazunori; Koike, Masafumi; Sato, Joe; Sugai, Kenichi; Yamanaka, Masato; Yazaki, Koichi [Department of Physics, Saitama University, Shimo-okubo, Sakura-ku, Saitama, 338-8570 (Japan); Theory Center, Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801 (Japan); Maskawa Institute for Science and Culture, Kyoto Sangyo University, Kyoto 603-8555 (Japan); Hashimoto Mathematical Physics Laboratory, Nishina Accelerator Research Center, RIKEN, Wako, Saitama 351-0198 and Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

2012-07-27T23:59:59.000Z

45

ARE THERE ECHOES FROM THE PRE-BIG-BANG UNIVERSE? A SEARCH FOR LOW-VARIANCE CIRCLES IN THE COSMIC MICROWAVE BACKGROUND SKY  

SciTech Connect

In a recent analysis of Wilkinson Microwave Anisotropy Probe (WMAP) seven-year temperature maps, Gurzadyan and Penrose claim to find concentric circular patterns in the sky with anomalously low variances. These circles are presented as observational evidence for violent processes in a universe preceding our big bang as predicted by Penrose's Conformal Cyclic Cosmology. We reassess the statistical significance of the detection of the claimed concentric low-variance circles by comparing the WMAP data with Monte Carlo simulations of the cosmic microwave background (CMB) sky plus realistic modeling of WMAP's anisotropic noise. We find no anomaly in the variances compared with the {Lambda}CDM cosmological model. The observed variances in the data are consistent with a Gaussian CMB sky as predicted by the inflationary cosmology model at better than 3{sigma}.

Hajian, Amir, E-mail: ahajian@cita.utoronto.ca [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada)

2011-10-20T23:59:59.000Z

46

Particle Data Group - Astrophysics and Cosmology  

NLE Websites -- All DOE Office Websites (Extended Search)

Astrophysical Constants and Parameters Experimental tests of gravitational theory Big-Bang cosmology Big-Bang nucleosynthesis Cosmological parameters Dark matter Cosmic...

47

Magnetically Trapped Neutron Lifetime Experiment  

Science Conference Proceedings (OSTI)

... the theory of Big Bang Nucleosynthesis. As well as in determinations of the expected neutrino flux from nuclear reactors. ...

2013-07-22T23:59:59.000Z

48

bigbangnucrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

7 7 by B.D. Fields (Univ. of Illinois) and S. Sarkar (Univ. of Oxford). Big-bang nucleosynthesis (BBN) offers the deepest reliable probe of the early universe, being based on well-understood Standard Model physics [1-4]. Predictions of the abundances of the light elements, D, 3 He, 4 He, and 7 Li, synthesized at the end of the "first three minutes," are in good overall agreement with the primordial abundances inferred from observational data, thus validating the standard hot big-bang cosmology (see [5] for a review). This is particularly impressive given that these abundances span nine orders of magnitude - from 4 He/H ∼ 0.08 down to 7 Li/H ∼ 10 -10 (ratios by number). Thus BBN provides powerful constraints on possible deviations from the standard cosmology [2], and on new physics beyond the Standard Model [3]. 20.1. Theory The synthesis of the light elements is sensitive

49

A fully quantum model of Big Bang  

E-Print Network (OSTI)

In the paper the closed Friedmann-Robertson-Walker model with quantization in the presence of the positive cosmological constant and radiation is studied. For analysis of tunneling probability for birth of an asymptotically deSitter, inflationary Universe as a function of the radiation energy a new definition of a "free" wave propagating inside strong fields is proposed. On such a basis, tunneling boundary condition is corrected, penetrability and reflection concerning to the barrier are calculated in fully quantum stationary approach. For the first time non-zero interference between the incident and reflected waves has been taken into account which turns out to play important role inside cosmological potentials and could be explained by non-locality of barriers in quantum mechanics. Inside whole region of energy of radiation the tunneling probability for the birth of the inflationary Universe is found to be close to its value obtained in semiclassical approach. The reflection from the barrier is determined for the first time (which is essentially differs on 1 at the energy of radiation close to the barrier height). The proposed method could be easily generalized on the cosmological models with the barriers of arbitrary shape, that has been demonstrated for the FRW-model with included Chaplygin gas. Result is stable for variations of the studied barriers, accuracy are found to be 11--18 digits for all coefficients and energies below the barrier height.

Sergei P. Maydanyuk; Antonino Del Popolo; Vladislav S. Olkhovsky

2013-01-19T23:59:59.000Z

50

PRIMORDIAL SOUNDS: BIG BANG ACOUSTICS Mark Whittle  

E-Print Network (OSTI)

like this: a descending scream, building into a deep rasping roar, and ending in a deafening hiss notes slowly dissolve to become the tapestry of galaxies which now fills all of space. The birth in high school that sound cannot exist in the vacuum of space? Well yes, but space wasn't so empty when

Whittle, Mark

51

Nucleosynthesis and Neutrinos  

SciTech Connect

Neutrinos play the critical roles in nucleosynthesis of light-to-heavy mass nuclei in core-collapse supernovae. We study the nucleosynthesis induced by neutrino interactions and find suitable average neutrino temperatures in order to explain the observed solar system abundances of several isotopes {sup 7}Li, {sup 11}B, {sup 138}La and {sup 180}Ta. These isotopes are predominantly synthesized by the supernova {nu}-process. We also study the neutrino oscillation effects on their abundances and propose a method to determine the unknown neutrino oscillation parameters, i.e. {theta}{sub 13} and mass hierarchy.

Kajino, Toshitaka [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan)

2011-05-06T23:59:59.000Z

52

Neutrino Nucleosynthesis in Supernovae  

Science Conference Proceedings (OSTI)

Neutrino nucleosynthesis is an important synthesis process for light elements in supernovae. One important physics input of neutrino nucleosynthesis is cross sections of neutrino-nucleus reactions. The cross sections of neutrino-{sup 12}C and {sup 4}He reactions are derived using new shell model Hamiltonians. With the new cross sections, light element synthesis of a supernova is investigated. The appropriate range of the neutrino temperature for supernovae is constrained to be between 4.3 MeV and 6.5 MeV from the {sup 11}B abundance in Galactic chemical evolution. Effects by neutrino oscillations are also discussed.

Yoshida, Takashi [Division of Theoretical Astronomy, National Astronomical Observatory of Japan (Japan); Suzuki, Toshio [Department of Physics, College of Humanities and Sciences, Nihon University (Japan); Chiba, Satoshi [Advanced Science Research Center, Japan Atomic Energy Agency (Japan); Kajino, Toshitaka [Division of Theoretical Astronomy, National Astronomical Observatory of Japan (Japan); Department of Astronomy, Graduate School of Science, University of Tokyo (Japan); Yokomakura, Hidekazu; Kimura, Keiichi [Department of Physics, Graduate School of Science, Nagoya University (Japan); Takamura, Akira [Department of Mathematics, Toyota National College of Technology (Japan); Hartmann, Dieter H. [Department of Physics and Astronomy, Clemson University (United States)

2009-05-04T23:59:59.000Z

53

Deuteron photodisintegration with polarized photons at astrophysical energies  

E-Print Network (OSTI)

Following precise experimental studies at the Duke Free-Electron Laser Laboratory, we discuss photodisintegration of deuterons with 100% linearly polarized photons using a model independent theoretical approach taking together $M1$ and $E1$ amplitudes simultaneously. The isoscalar $M1_s$ contribution is also taken exactly into account. From the existing experimental measurement on doubly polarized thermal neutron capture, it is seen that the isoscalar $M1_s$ contribution could be of the same order of magnitude as the experimentally measured cross sections at energies relevant to Big Bang Nucleosynthesis (BBN). Therefore appropriate measurements on deuteron photodisintegration are suggested to empirically determine the $M1_s$ contribution at astrophysical energies.

G. Ramachandran; S. P. Shilpashree

2006-06-12T23:59:59.000Z

54

--No Title--  

NLE Websites -- All DOE Office Websites (Extended Search)

Nuclear and Weak Physics in Big Bang Nucleosynthesis Christel Smith Arizona State University Abstract: I will discuss the current status of our understanding of primordial...

55

Supernova neutrinos and nucleosynthesis  

E-Print Network (OSTI)

Observations of metal-poor stars indicate that at least two different nucleosynthesis sites contribute to the production of r-process elements. One site is responsible for the production of light r-process elements Zproduction of these elements. We explore this possibility by performing nucleosynthesis calculations based on long term Boltzmann neutrino transport simulations. They are based on an Equation of State that reproduces recent constrains on the nuclear symmetry energy. We predict that the early ejecta is neutron-rich with Ye ~ 0.48, it becomes proton rich around 4 s and reaches Ye = 0.586 at 9 s when our simulation stops. The nucleosynthesis in this model produces elements between Zn and Mo, including 92Mo. The elemental abundances are consistent with the observations of the metal-poor star HD 12263. For the elements between Ge and Mo, we produce mainly the neutron-deficient isotopes. This prediction can be confirmed by observations of isotopic abundances in metal-poor stars. No elements heavier than Mo (Z=42) and no heavy r-process elements are produced in our calculations.

G. Martínez-Pinedo; T. Fischer; L. Huther

2013-09-21T23:59:59.000Z

56

CONSTRAINING PRIMORDIAL MAGNETIC FIELDS THROUGH LARGE-SCALE STRUCTURE  

Science Conference Proceedings (OSTI)

We study primordial magnetic field effects on the matter perturbations in the universe. We assume magnetic field generation prior to the big bang nucleosynthesis (BBN), i.e., during the radiation-dominated epoch of the universe expansion, but do not limit analysis by considering a particular magnetogenesis scenario. Contrary to previous studies, we limit the total magnetic field energy density and not the smoothed amplitude of the magnetic field at large (of the order of 1 Mpc) scales. We review several cosmological signatures, such as halo abundance, thermal Sunyaev-Zel'dovich effect, and Ly{alpha} data. For a cross-check, we compare our limits with that obtained through the cosmic microwave background faraday rotation effect and BBN. The limits range between 1.5 nG and 4.5 nG for n{sub B} in (- 3; -1.5).

Kahniashvili, Tina; Natarajan, Aravind; Battaglia, Nicholas [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Maravin, Yurii [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506 (United States); Tevzadze, Alexander G., E-mail: tinatin@andrew.cmu.edu [Faculty of Exact and Natural Sciences, Javakhishvili Tbilisi State University, 3 Chavchavadze Avenue, Tbilisi 0128 (Georgia)

2013-06-10T23:59:59.000Z

57

bigbangnucrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

August August 2011 by B.D. Fields (Univ. of Illinois) and S. Sarkar (Univ. of Oxford). Big-Bang nucleosynthesis (BBN) offers the deepest reliable probe of the early Universe, being based on well-understood Standard Model physics [1-8]. Predictions of the abundances of the light elements, D, 3 He, 4 He, and 7 Li, synthesized at the end of the 'first three minutes', are in good overall agreement with the primordial abundances inferred from observational data, thus validating the standard hot Big-Bang cosmology (see [9] for a review). This is particularly impressive given that these abundances span nine orders of magnitude - from 4 He/H ∼ 0.08 down to 7 Li/H ∼ 10 -10 (ratios by number). Thus BBN provides powerful constraints on possible deviations from the standard cosmology, and on new physics beyond the Standard Model [4-7]. 22.1. Theory The synthesis of the light elements is sensitive

58

Supercomputing: A Toolbox to Simulate the Big Bang and Beyond...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

of the Energy Department's investments in supercomputers and specialized high-performance computing codes. The team is developing an open platform with a web-based front end...

59

Turning big bang into big bounce. I. Classical dynamics  

SciTech Connect

The big bounce (BB) transition within a flat Friedmann-Robertson-Walker model is analyzed in the setting of loop geometry underlying the loop cosmology. We solve the constraint of the theory at the classical level to identify physical phase space and find the Lie algebra of the Dirac observables. We express energy density of matter and geometrical functions in terms of the observables. It is the modification of classical theory by the loop geometry that is responsible for BB. The classical energy scale specific to BB depends on a parameter that should be fixed either by cosmological data or determined theoretically at quantum level, otherwise the energy scale stays unknown.

Dzierzak, Piotr; Malkiewicz, Przemyslaw; Piechocki, Wlodzimierz [Theoretical Physics Department, Institute for Nuclear Studies, Hoza 69, 00-681 Warsaw (Poland)

2009-11-15T23:59:59.000Z

60

New Results on Nucleosynthesis in Massive Stars; Nuclear Data Needs for Nucleosynthesis  

DOE Green Energy (OSTI)

We review the current status of the nuclear reaction rates needed to study nucleosynthesis in massive stars. Results for the calculated nucleosynthesis of all stable species from Hydrogen to Bismuth in a completely evolved 25 M{sub {circle_dot}} star of initial solar metallicity will be presented. Special emphasis will be paid to two particular reactions, {sup 12}C({alpha}, {gamma}){sup 16}O and {sup 22}Ne({alpha},n){sup 25}Mg, and their effect on the structure of the star and resultant nucleosynthesis. Both have been measured many times, but the present range of experimental uncertainty translates into remarkable sensitivity of the calculated nucleosynthesis.

Hoffman, R; Rauscher, T; Heger, A; Woosley, S

2001-11-09T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Proton-rich nucleosynthesis and nuclear physics  

Science Conference Proceedings (OSTI)

Although the detailed conditions for explosive nucleosynthesis are derived from astrophysical modeling, nuclear physics determines fundamental patterns in abundance yields, not only for equilibrium processes. Focussing on the {nu}p- and the {gamma}-process, general nucleosynthesis features within the range of astrophysical models, but (mostly) independent of details in the modelling, are presented. Remaining uncertainties due to uncertain Q-values and reaction rates are discussed.

Rauscher, T.; Froehlich, C. [Dept. of Physics, University of Basel, 4056 Basel (Switzerland); Dept. of Physics, NCSU, Raleigh, NC 27695 (United States)

2012-11-12T23:59:59.000Z

62

Resonant high energy graviton to photon conversion at post recombination epoch  

E-Print Network (OSTI)

Resonant conversion of high energy gravitons into photons in large scale cosmological magnetic fields at the post recombination epoch is considered. It is shown that the probability of the resonance photon production is much higher than the non-resonant one. As a result an observable isotropic background of cosmic gamma rays might be created. As shown in our previous paper, an early population of primordial black holes (PBHs) prior to big bang nucleosynthesis (BBN) could be an efficient source of high frequency gravitational waves. For the primordial black hole mass about $10^8$ g the produced photons would be the dominant component of the soft to hard Cosmic X-ray Background (CXB) and for lower masses the spectrum is shifted down to the ultraviolet and optic.

Alexander D. Dolgov; Damian Ejlli

2013-03-06T23:59:59.000Z

63

s007.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

01 and CYBURT 03. 9 Limit on the number of neutrino types based on combination of WMAP data and big- bang nucleosynthesis. The limit from WMAP data alone is 8.3. See also...

64

Citation: W.-M. Yao  

NLE Websites -- All DOE Office Websites (Extended Search)

01 and CYBURT 03. 3 Limit on the number of neutrino types based on combination of WMAP data and big- bang nucleosynthesis. The limit from WMAP data alone is 8.3. See also...

65

NUCLEAR ASPECTS OF STELLAR AND EXPLOSIVE NUCLEOSYNTHESIS  

E-Print Network (OSTI)

NUCLEAR ASPECTS OF STELLAR AND EXPLOSIVE NUCLEOSYNTHESIS Thomas Rauscher 1 , Friedrich. of Astron. and Astroph., Univ. of California, Santa Cruz, CA 95064 Abstract The majority of nuclear­Feshbach). The global parametrizations of the nuclear properties needed for predictions far off stability probe our

Rauscher, Thomas

66

Integrated Nucleosynthesis in Neutrino Driven Winds  

E-Print Network (OSTI)

Although they are but a small fraction of the mass ejected in core-collapse supernovae, neutrino-driven winds (NDWs) from nascent proto-neutron stars (PNSs) have the potential to contribute significantly to supernova nucleosynthesis. In previous works, the NDW has been implicated as a possible source of r-process and light p-process isotopes. In this paper we present time-dependent hydrodynamic calculations of nucleosynthesis in the NDW which include accurate weak interaction physics coupled to a full nuclear reaction network. Using two published models of PNS neutrino luminosities, we predict the contribution of the NDW to the integrated nucleosynthetic yield of the entire supernova. For the neutrino luminosity histories considered, no true r-process occurs in the most basic scenario. The wind driven from an older $1.4 M_\\odot$ model for a PNS is moderately neutron-rich at late times however, and produces $^{87}$Rb, $^{88}$Sr, $^{89}$Y, and $^{90}$Zr in near solar proportions relative to oxygen. The wind fro...

Roberts, L F; Hoffman, R D

2010-01-01T23:59:59.000Z

67

Probing Primordial and Pre-Galactic Lithium with High Velocity Clouds  

E-Print Network (OSTI)

The pre-Galactic abundance of lithium offers a unique window into non-thermal cosmological processes. The primordial Li abundance is guaranteed to be present and probes big bang nucleosynthesis (BBN), while an additional Li component is likely to have been produced by cosmic rays accelerated in large scale structure formation. Pre-Galactic Li currently can only be observed in low metallicity Galactic halo stars, but abundance measurements are plagued with systematic uncertainties due to modeling of stellar atmospheres and convection. We propose a new site for measuring pre-Galactic Li: low-metallicity, high-velocity clouds (HVCs) which are likely to be extragalactic gas accreted onto the Milky Way, and which already have been found to have deuterium abundances consistent with primordial. A Li observation in such an HVC would provide the first extragalactic Li measurement, and could shed new light on the apparent discrepancy between BBN predictions and halo star Li abundance determinations. Furthermore, HVC Li could at the same time test for the presence of non-primordial Li due to cosmic rays. The observability of elemental and isotopic Li abundances is discussed, and candidate sites identified.

Tijana Prodanovic; Brian D. Fields

2004-12-09T23:59:59.000Z

68

Nucleosynthesis and the rp-process  

Science Conference Proceedings (OSTI)

Production of elements heavier than iron, their abundance and cite of production remain an active field of research to-date. In this paper I would present a brief review of the nucleosynthesis process and then focus further on the proton capture processes with particular emphasis on the nuclear physics aspects of the rp-process. The present calculation clearly shows that the electron capture rates on waiting point nuclei are at least of similar magnitude as the competing positron decay rates under rp-process conditions. The study strongly suggests that electron capture rates form an integral part of weak-interaction mediated rates under rp-process conditions and should not be neglected in nuclear reaction network calculations as done in past.

Nabi, Jameel-Un [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Swabi, Khyber Pakhtunkhwa (Pakistan)

2012-11-20T23:59:59.000Z

69

The Revival of Galactic Cosmic Ray Nucleosynthesis?  

E-Print Network (OSTI)

Because of the roughly linear correlation between Be/H and Fe/H in low metallicity halo stars, it has been argued that a ``primary'' component in the nucleosynthesis of Be must be present in addition to the ``secondary'' component from standard Galactic cosmic ray nucleosynthesis. In this paper we critically re-evaluate the evidence for the primary versus secondary character of Li, Be, and B evolution, analyzing both in the observations and in Galactic chemical evolution models. While it appears that [Be/H] versus [Fe/H] has a logarithmic slope near 1, it is rather the Be-O trend that directly arises from the physics of spallation production. Using new abundances for oxygen in halo stars based on UV OH lines, we find that the Be-O slope has a large uncertainty due to systematic effects, rendering it difficult to distinguish from the data between the secondary slope of 2 and the primary slope of 1. The possible difference between the Be-Fe and Be-O slopes is a consequence of the variation in O/Fe versus Fe: recent data suggests a negative slope rather than zero (i.e., Fe $\\propto$ O) as is often assumed. In addition to a phenomenological analysis of Be and B evolution, we have also examined the predicted LiBeB, O, and Fe trends in Galactic chemical evolution models which include outflow. Based on our results, it is possible that a good fit to the LiBeB evolution requires only traditional the Galactic cosmic ray spallation, and the (primary) neutrino-process contribution to B11. We thus suggest that these two processes might be sufficient to explain Li6, Be, and B evolution in the Galaxy, without the need for an additional primary source of Be and B.

Brian D. Fields; Keith A. Olive

1998-09-22T23:59:59.000Z

70

Primordial nucleosynthesis in conformal Weyl gravity  

DOE Green Energy (OSTI)

Recently conformal Weyl gravity has been considered as a candidate alternative gravity theory. This fourth-order theory is attractive because it is the only metric theory of gravity which is invariant under local conformal transformations of the metric. The authors calculate the primordial light element abundances in this theory. The major difference from the standard cosmology is that the universe expands far more slowly throughout the nucleosynthesis epoch. The production of {sup 4}He depends strongly on {eta}, the ratio of baryons to photons. For {eta} = 10{sup {minus}8} the mass fraction of {sup 4}He is X{sub 4} {approx_equal} 0.25 and the number densities relative to hydrogen for {sup 2}H, {sup 3}He and {sup 7}Li are n({sup 2}H)/n(H) {approx_equal} 9 {times} 10{sup {minus}20}, n({sup 3}He)/n(H) {approx_equal}4 {times} 10{sup {minus}18} and n({sup 7}Li)/n(H) {approx_equal} 10{sup {minus}13}. This value of {eta} corresponds to a baryon mass density close to the standard model critical density. However, adjusting {eta} to give a reasonable helium yield forces the deuterium and lithium yields to be small enough that the theory cannot be reconciled with observations.

Knox, L.; Kosowsky, A. [Univ. of Chicago, IL (United States). Enrico Fermi Inst.]|[Fermi National Accelerator Lab., Batavia, IL (United States)

1993-10-01T23:59:59.000Z

71

Challenges in explosive nucleosynthesis of heavy elements  

Science Conference Proceedings (OSTI)

We show that a treatment of charged-current neutrino interactions in hot and dense matter that is consistent with the nuclear equation of state has a strong impact on the spectra of the neutrinos emitted during the deleptonization period of a protoneutron star formed in a core-collapse supernova. We compare results of simulations including and neglecting mean field effects on the neutrino opacities. Their inclusion reduces the luminosities of all neutrino flavors and enhances the spectral differences between electron neutrino and antineutrino. The magnitude of the difference depends on the equation of state and in particular on the symmetry energy at sub-nuclear densities. These modifications reduce the proton-to-nucleon ratio of the neutrino-driven outflow, increasing slightly their entropy. They are expected to have a substantial impact on the nucleosynthesis in neutrino-driven winds, even though they do not result in conditions that favor an r-process. Contrarily to previous findings, our simulations show that the spectra of electron neutrinos remain substantially different from those of other (anti)neutrino flavors during the entire deleptonization phase of the protoneutron star. The obtained luminosity and spectral changes are also expected to have important consequences for neutrino flavor oscillations and neutrino detection on Earth.

Pinedo, Gabriel Martinez; Fischer, T.; Lohs, A.; Huther, L. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 2, 64289 Darmstadt, Germany and GSI Helmholtzzentrum fuer Schwerioneneforschung, Planckstrasse 1, 64291 Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerioneneforschung, Planckstrasse 1, 64291 Darmstadt, Germany and Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 2, 64289 Darmstadt (Germany); Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 2, 64289 Darmstadt (Germany)

2012-10-20T23:59:59.000Z

72

The big bang: An example of mobile media as new media  

Science Conference Proceedings (OSTI)

Over the last couple of years we have become used to the global media informing us about the revolutionary and democratic possibilities of mobile media. As a symbol of technological convergence, the multimedia possibilities of mobile media have become ... Keywords: Mobile media, South Korean online communities, mobile gaming, mobility

Larissa Hjorth

2009-06-01T23:59:59.000Z

73

A Survey of Big Bang Cosmology, Part I: Cosmic Geography ELEGANT CONNECTIONS IN PHYSICS I  

E-Print Network (OSTI)

decade-long struggle to develop the General Theory of Relativity (GR), in which he envisioned gravitation geometrically as the “curvature of spacetime. ” Immediate observational confirmation for the theory was significant but slim. In 1915 this consisted of the successful accounting of the anomalous precession of Mercury’s orbit. Tests of other early predictions, all on the solar system scale, would have to wait. Measurement of the deflection of light rays grazing the sun occurred with the 1919 solar total eclipse; measuring gravitational redshift and radar echo delay required high-speed electronics that appeared about 1960. Some measurements, such as gyroscope precession and gravitational waves, are only now being carried out for the first time.[1] Despite limited early opportunities to test the theory, in 1917 Einstein hitched his wagon to the stars and brazenly

unknown authors

1915-01-01T23:59:59.000Z

74

The Planck energy-mass source as an alternative to the Big Bang  

E-Print Network (OSTI)

The general theory of relativity is used to show that the total energy-mass of the visible Universe could be produced by an energy-mass source with the Planck power. The source was supposedly born at the phase of cosmic inflation and acts continuously throughout the lifetime of our Universe. The model allows one to treat dark energy as a real form of energy without using the hypothesis of anti-gravity.

Timashev, Serge F

2008-01-01T23:59:59.000Z

75

Long Fuse, Big Bang: Thomas Edison, Electricity, and the Locus of Innovation  

SciTech Connect

Calls for breakthroughs in science and technology have never been louder, and yet the demand for innovation is made more challenging by public and political misconceptions surrounding where, when, and how it happens. Professor Andrew Hargadon uses historical research to advance our current understanding of the innovation process. He discussed the social and technical context in which electric light, and the modern electric power infrastructure, were born and considers its implications for managing innovation in science and technology today.

Hargadon, Andrew [University of California, Davis

2012-10-22T23:59:59.000Z

76

n the Big Bang at the beginning of the Uni-verse, the lightest elements, hydrogen,  

E-Print Network (OSTI)

. Butlittlewasknownabouttheproductionof elements, and the associated history of star formation, in the most distant galaxies that formed window on the early formation of elements andstarsintheUniverse. A number of studies have explored throughtheradiationtheyabsorbfromeven more distant quasars. These studies probe the earliest chemical history of gas in the Universe

Cowan, John

77

What the latest discoveries tell us about the Big Bang, dark matter and multiple universes  

E-Print Network (OSTI)

The intriguing science behind moral judgements WHAT MAKES US DISGUSTED? Stephen Hawking New film: the verdict) of your bowl movements, is stuck with the Bluetooth pin 0000, making it an easy target. BLUETOOTH TOILETS

Bechtel, William

78

Fusion in first few minutes after Big Bang form lightest elements  

E-Print Network (OSTI)

the shortest lives. HIGH MASS and LUMINOUS LOW MASS and DIM Like a gas-guzzling car, big fuel tank but burns fuel fast, so the tank of gas does not last long. Like a fuel-efficient car, small fuel tank but burns and distance 10-4 LSun - 106 LSun Temperature: from color and spectral type 3,000 K - 50,000 K Mass: calculated

Shirley, Yancy

79

Fusion in first few minutes after Big Bang form lightest elements  

E-Print Network (OSTI)

-guzzling car, big fuel tank but burns fuel fast, so the tank of gas does not last long. Like a fuel LSun Temperature: from color and spectral type 3,000 K - 50,000 K Mass: calculated from period (p DIMMER #12;Massive stars have the shortest lives. HIGH MASS and LUMINOUS LOW MASS and DIM Like a gas

Shirley, Yancy

80

The Planck energy-mass source as an alternative to the Big Bang  

E-Print Network (OSTI)

The general theory of relativity is used to show that the total energy-mass of the visible Universe could be produced by an energy-mass source with the Planck power. The source was supposedly born at the phase of cosmic inflation and acts continuously throughout the lifetime of our Universe. The model allows one to treat dark energy as a real form of energy without using the hypothesis of anti-gravity.

Serge F. Timashev

2008-03-03T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


81

From Cavendish to PLANCK: Constraining Newton's gravitational constant with CMB temperature and polarization anisotropy  

SciTech Connect

We present new constraints on cosmic variations of Newton's gravitational constant by making use of the latest CMB data from WMAP, BOOMERANG, CBI and ACBAR experiments and independent constraints coming from big bang nucleosynthesis. We found that current CMB data provide constraints at the {approx}10% level, that can be improved to {approx}3% by including big bang nucleosynthesis data. We show that future data expected from the Planck satellite could constrain G at the {approx}1.5% level while an ultimate, cosmic variance limited, CMB experiment could reach a precision of about 0.4%, competitive with current laboratory measurements.

Galli, Silvia; Melchiorri, Alessandro; Smoot, George F.; Zahn, Oliver [Physics Department, Universita di Roma 'La Sapienza', Ple Aldo Moro 2, 00185, Rome, Italy, and Laboratoire Astroparticule et Cosmologie (APC), Universite' Paris Diderot - 75205 PARIS cedex 13 (Italy); Physics Department and INFN, Universita di Roma 'La Sapienza', Ple Aldo Moro 2, 00185, Rome (Italy); Lawrence Berkeley National Laboratory and Berkeley Center for Cosmological Physics Physics Department, University of California, Berkeley California 94720 (United States)

2009-07-15T23:59:59.000Z

82

On Non-Primordial Deuterium Production by Accelerated Particles  

E-Print Network (OSTI)

Deuterium plays a crucial role in cosmology because the primordial D/H abundance, in the context of big bang nucleosynthesis (BBN) theory, yields a precise measure of the cosmic baryon content. Observations of D/H can limit or measure the true primordial abundance because D is thought to be destroyed by stars and thus D/H monotonically decreases after BBN. Recently, however, Mullan & Linsky have pointed out that D arises as a secondary product of neutrons in stellar flares which then capture on protons via n+p \\to d + gamma, and that this could dominate over direct D production in flares. Mullan & Linsky note that if this process is sufficiently vigorous in flaring dwarf stars, it could lead to significant non-BBN D production. We have considered the production of D in stellar flares, both directly and by n capture. We find that for reasonable flare spectra, n/d < 10 and (n+d)/6Li < 400, both of which indicate that the n-capture channel does not allow for Galactic D production at a level which will reverse the monotonic decline of D. We also calculate the 2.22 MeV gamma-ray line production associated with n capture, and find that existing COMPTEL limits also rule out significant D production in the Galaxy today. Thus, we find flares in particular, and neutron captures in general, are not an important Galactic source of D. On the other hand, we cannot exclude that flare production might contribute to recent FUSE observations of large variations in the local interstellar D/H abundance; we do, however, offer important constraints on this possibility. Finally, since flare stars should inevitably produce some n-capture events, a search for diffuse 2.22 MeV gamma-rays by INTEGRAL can further constrain (or measure!) Galactic deuterium production via n-capture.

Tijana Prodanovic; Brian D. Fields

2003-07-09T23:59:59.000Z

83

Astrophysical models of r-process nucleosynthesis: An update  

SciTech Connect

An update on astrophysical models for nucleosynthesis via rapid neutron capture, the r process, is given. A neutrino-induced r process in supernova helium shells may have operated up to metallicities of {approx} 10{sup -3} times the solar value. Another r-process source, possibly neutron star mergers, is required for higher metallicities.

Qian Yongzhong [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2012-11-12T23:59:59.000Z

84

Nucleosynthesis in the accretion disks of Type II collapsars  

E-Print Network (OSTI)

We investigate nucleosynthesis inside the gamma-ray burst (GRB) accretion disks formed by the Type II collapsars. In these collapsars, the core collapse of massive stars first leads to the formation of a proto-neutron star and a mild supernova explosion is driven. However, this supernova ejecta lack momentum and falls back onto the neutron star which gets transformed to a stellar mass black hole. In order to study the hydrodynamics and nucleosynthesis of such an accretion disk formed from the fallback material of the supernova ejecta, we use the well established hydrodynamic models. In such a disk neutrino cooling becomes important in the inner disk where the temperature and density are higher. Higher the accretion rate (dot{M}), higher is the density and temperature in the disks. In this work we deal with accretion disks with relatively low accretion rates: 0.001 M_sun s^{-1} \\lesssim dot{M} \\lesssim 0.01 M_sun s^{-1} and hence these disks are predominantly advection dominated. We use He-rich and Si-rich abundances as the initial condition of nucleosynthesis at the outer disk, and being equipped with the disk hydrodynamics and the nuclear network code, we study the abundance evolution as matter inflows and falls into the central object. We investigate the variation in the nucleosynthesis products in the disk with the change in the initial abundance at the outer disk and also with the change in the mass accretion rate. We report the synthesis of several unusual nuclei like {31}P, {39}K, {43}Sc, {35}Cl, and various isotopes of titanium, vanadium, chromium, manganese and copper. We also confirm that isotopes of iron, cobalt, nickel, argon, calcium, sulphur and silicon get synthesized in the disk, as shown by previous authors. Much of these heavy elements thus synthesized are ejected from the disk via outflows and hence they should leave their signature in observed data.

Indrani Banerjee; Banibrata Mukhopadhyay

2013-05-08T23:59:59.000Z

85

Magnetic Protoneutron Star Winds and r-Process Nucleosynthesis  

E-Print Network (OSTI)

Because of their neutron-richness and association with supernovae, post-explosion protoneutron star winds are thought to be a likely astrophysical site for rapid neutron capture nucleosynthesis (the r-process). However, the most recent models of spherical neutrino-driven protoneutron star winds do not produce robust r-process nucleosynthesis for `canonical' neutron stars with a gravitational mass of 1.4M_sun and coordinate radius of 10km. These models fail variously; either the flow entropy is too low, the electron fraction is too high, or the dynamical expansion timescale is too long. To date, no models have included the effects of an ordered dipole magnetic field. We show that a strong magnetic field can trap the outflow in the neutrino heating region, thus leading to much higher matter entropy. We estimate both the trapping timescale and the resulting entropy amplification. For sufficiently large energy deposition rates, the trapped matter emerges dynamically from the region of closed magnetic field lines and escapes to infinity. We find that ordered dipoles with surface fields of greater than 6 times 10^14 Gauss increase the asymptotic entropy sufficiently for robust r-process nucleosynthesis.

Todd A. Thompson

2003-02-06T23:59:59.000Z

86

Cosmological bounds on neutrino degeneracy improved by flavor oscillations  

E-Print Network (OSTI)

We study three-flavor neutrino oscillations in the early universe in the presence of neutrino chemical potentials. We take into account all effects from the background medium, i.e. collisional damping, the refractive effects from charged leptons, and in particular neutrino self-interactions that synchronize the neutrino oscillations. We find that effective flavor equilibrium between all active neutrino species is established well before the big-bang nucleosynthesis (BBN) epoch if the neutrino oscillation parameters are in the range indicated by the atmospheric neutrino data and by the large mixing angle (LMA) MSW solution of the solar neutrino problem. For the other solutions of the solar neutrino problem, partial flavor equilibrium may be achieved if the angle theta_13 is close to the experimental limit tan^2(theta_13)radiation contribution from degenerate neutrinos is limited to such low values that it is neither observable in the large-scale structure of the universe nor in the anisotropies of the cosmic microwave background radiation. Existing limits and possible future measurements, for example in KATRIN, of the absolute neutrino mass scale will provide unambiguous information on the cosmic neutrino mass density, essentially free of the uncertainty of the neutrino chemical. potentials.

A. D. Dolgov; S. H. Hansen; S. Pastor; S. T. Petcov; G. G. Raffelt; D. V. Semikoz

2002-01-30T23:59:59.000Z

87

Search for new resonant states in 10C and 11C and their impact on the cosmological lithium problem  

E-Print Network (OSTI)

The observed primordial 7Li abundance in metal-poor halo stars is found to be lower than its Big-Bang nucleosynthesis (BBN) calculated value by a factor of approximately three. Some recent works suggested the possibility that this discrepancy originates from missing resonant reactions which would destroy the 7Be, parent of 7Li. The most promising candidate resonances which were found include a possibly missed 1- or 2- narrow state around 15 MeV in the compound nucleus 10C formed by 7Be+3He and a state close to 7.8 MeV in the compound nucleus 11C formed by 7Be+4He. In this work, we studied the high excitation energy region of 10C and the low excitation energy region in 11C via the reactions 10B(3He,t)10C and 11B(3He,t)11C, respectively, at the incident energy of 35 MeV. Our results for 10C do not support 7Be+3He as a possible solution for the 7Li problem. Concerning 11C results, the data show no new resonances in the excitation energy region of interest and this excludes 7Be+4He reaction channel as an explanation for the 7Li deficit.

F. Hammache; A. Coc; N. de Séréville; I. Stefan; P. Roussel; S. Ancelin; M. Assié; L. Audouin; D. Beaumel; S. Franchoo; B. Fernandez-Dominguez; S. Fox; C. Hamadache; J. Kiener; A. Laird; B. Le Crom; A. Lefebvre-Schuhl; L. Lefebvre; I. Matea; A. Matta; G. Mavilla; J. Mrazek; P. Morfouace; F. de Oliveira Santos; A. Parikh; L. Perrot; A. M. Sanchez-Benitez; D. Suzuki; V. Tatischeff; P. Ujic; M. Vandebrouck

2013-12-03T23:59:59.000Z

88

Gravitino Decays and the Cosmological Lithium Problem in Light of the LHC Higgs and Supersymmetry Searches  

E-Print Network (OSTI)

We studied previously the impact on light-element abundances of gravitinos decaying during or after Big-Bang nucleosynthesis (BBN). We found regions of the gravitino mass m_{3/2} and abundance zeta_{3/2} plane where its decays could reconcile the calculated abundance of Li7 with observation without perturbing the other light-element abundances unacceptably. Here we revisit this issue in light of LHC measurements of the Higgs mass and constraints on supersymmetric model parameters, as well as updates in the astrophysical measurements of light-element abundances. In addition to the constrained minimal supersymmetric extension of the Standard Model with universal soft supersymmetry-breaking masses at the GUT scale (the CMSSM) studied previously, we also study models with universality imposed below the GUT scale and models with non-universal Higgs masses (NUHM1). We calculate the total likelihood function for the light-element abundances, taking into account the observational uncertainties. We find that gravitino decays provide a robust solution to the cosmological Li7 problem along strips in the (m_{3/2}, zeta_{3/2}) plane along which the abundances of deuterium, He4 and Li7 may be fit with chi^2_min lithium abundance is taken from globular cluster data.

Richard H. Cyburt; John Ellis; Brian D. Fields; Feng Luo; Keith A. Olive; Vassilis C. Spanos

2013-03-03T23:59:59.000Z

89

Primordial magnetic field limits from cosmological data  

SciTech Connect

We study limits on a primordial magnetic field arising from cosmological data, including that from big bang nucleosynthesis, cosmic microwave background polarization plane Faraday rotation limits, and large-scale structure formation. We show that the physically relevant quantity is the value of the effective magnetic field, and limits on it are independent of how the magnetic field was generated.

Kahniashvili, Tina [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, Ontario P3E 2C (Canada); Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Tevzadze, Alexander G. [Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Faculty of Exact and Natural Sciences, Tbilisi State University, 1 Chavchavadze Avenue, Tbilisi, GE-0128 (Georgia); Sethi, Shiv K. [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Raman Research Institute, Sadashivanagar, Bangalore 560080 (India); Pandey, Kanhaiya [Raman Research Institute, Sadashivanagar, Bangalore 560080 (India); Ratra, Bharat [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States)

2010-10-15T23:59:59.000Z

90

Neutron capture rates and r-process nucleosynthesis  

E-Print Network (OSTI)

Simulations of r-process nucleosynthesis require nuclear physics information for thousands of neutron-rich nuclear species from the line of stability to the neutron drip line. While arguably the most important pieces of nuclear data for the r-process are the masses and beta decay rates, individual neutron capture rates can also be of key importance in setting the final r-process abundance pattern. Here we consider the influence of neutron capture rates in forming the A~80 and rare earth peaks.

Surman, R; McLaughlin, G C; Sinclair, R; Hix, W R; Jones, K L

2013-01-01T23:59:59.000Z

91

Neutron capture rates and r-process nucleosynthesis  

E-Print Network (OSTI)

Simulations of r-process nucleosynthesis require nuclear physics information for thousands of neutron-rich nuclear species from the line of stability to the neutron drip line. While arguably the most important pieces of nuclear data for the r-process are the masses and beta decay rates, individual neutron capture rates can also be of key importance in setting the final r-process abundance pattern. Here we consider the influence of neutron capture rates in forming the A~80 and rare earth peaks.

R. Surman; M. Mumpower; G. C. McLaughlin; R. Sinclair; W. R. Hix; K. L. Jones

2013-08-31T23:59:59.000Z

92

Cosmological scenario of the stop as the next lightest supersymmetric particle with the gravitino as the lightest supersymmetric particle, and the cosmic lithium problem  

SciTech Connect

The discrepancy on {sup 7}Li and {sup 6}Li abundances between the observational data and the standard big-bang nucleosynthesis theory prediction has been a nagging problem in astrophysics and cosmology, given the highly attractive and successful big-bang paradigm. One possible solution of this lithium problem is through hadronic decays of a massive metastable particle which alter the primordial element abundances. We explore this possibility using a gravitino dark matter framework in which the next lightest supersymmetric particle is typically long-lived. We found that the stop as the next lightest supersymmetric particle may provide an attractive solution to the lithium problem.

Kohri, Kazunori [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom); Santoso, Yudi [Institute for Particle Physics Phenomenology, Department of Physics, University of Durham, Durham DH1 3LE (United Kingdom)

2009-02-15T23:59:59.000Z

93

Nucleosynthesis: Stellar and Solar Abundances and Atomic Data  

E-Print Network (OSTI)

Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the earliest generations of stars in the Galaxy -- the progenitors of the halo stars -- responsible for neutron-capture synthesis. Comparisons of abundance trends can be used to understand the chemical evolution of the Galaxy and the nature of heavy element nucleosynthesis. In addition age determinations, based upon long-lived radioactive nuclei abundances, can now be obtained. These stellar abundance determinations depend critically upon atomic data. Improved laboratory transition probabilities have been recently obtained for a number of elements. These new gf values have been used to greatly refine the abundances of neutron-capture elemental abundances in the solar photosphere and in very metal-poor Galactic halo stars. The newly determined stellar abundances are surprisingly consistent with a (relative) Solar System r-process pattern, and are also consistent with abundance predictions expected from such neutron-capture nucleosynthesis.

John J. Cowan; James E. Lawler; Christopher Sneden; E. A. Den Hartog; Jason Collier

2006-05-04T23:59:59.000Z

94

Nucleosynthesis in the Outflow from Gamma Ray Burst Accretion Disks  

E-Print Network (OSTI)

We examine the nucleosynthesis products that are produced in the outflow from rapidly accreting disks. We find that the type of element synthesis varies dramatically with the degree of neutrino trapping in the disk and therefore the accretion rate of the disk. Disks with relatively high accretion rates such as 10 M_solar/s can produce very neutron rich nuclei that are found in the r process. Disks with more moderate accretion rates can produce copious amounts of Nickel as well as the light elements such as Lithium and Boron. Disks with lower accretion rates such as 0.1 M_solar/s produce large amounts of Nickel as well as some unusual nuclei such as Ti-49, Sc-45, Zn-64, and Mo-92. This wide array of potential nucleosynthesis products is due to the varying influence of electron neutrinos and antineutrinos emitted from the disk on the neutron-to-proton ratio in the outflow. We use a parameterization for the outflow and discuss our results in terms of entropy and outflow acceleration.

R. Surman; G. C. McLaughlin; W. R. Hix

2005-09-13T23:59:59.000Z

95

Explosive Nucleosynthesis in GRB Jets Accompanied by Hypernovae  

SciTech Connect

Two-dimensional hydrodynamic simulations are performed to investigate explosive nucleosynthesis in a collapsar using the model of MacFadyen and Woosley (1999). It is shown that {sup 56}Ni is not produced in the jet of the collapsar sufficiently to explain the observed amount of a hypernova when the duration of the explosion is {approx} 10 sec, which is considered to be the typical timescale of explosion in the collapsar model. Even though a considerable amount of {sup 56}Ni is synthesized if all explosion energy is deposited initially, the opening angles of the jets become too wide to realize highly relativistic outflows and gamma-ray bursts in such a case. From these results, it is concluded that the origin of {sup 56}Ni in hypernovae associated with GRBs is not the explosive nucleosynthesis in the jet. We consider that the idea that the origin is the explosive nucleosynthesis in the accretion disk is more promising. We also show that the explosion becomes bi-polar naturally due to the effect of the deformed progenitor. This fact suggests that the {sup 56}Ni synthesized in the accretion disk and conveyed as outflows are blown along to the rotation axis, which will explain the line features of SN 1998bw and double peaked line features of SN 2003jd. Some fraction of the gamma-ray lines from {sup 56}Ni decays in the jet will appear without losing their energies because the jet becomes optically thin before a considerable amount of {sup 56}Ni decays as long as the jet is a relativistic flow, which may be observed as relativistically Lorentz boosted line profiles in future. We show that abundance of nuclei whose mass number {approx} 40 in the ejecta depends sensitively on the energy deposition rate, which is a result of incomplete silicon burning and alpha-rich freezeout. So it may be determined by observations of chemical composition in metal poor stars which model is the proper one as a model of a gamma-ray burst accompanied by a hypernova.

Nagataki, Shigehiro; /Kyoto U., Yukawa Inst., Kyoto /KIPAC, Menlo Park; Mizuta, Akira; /Garching, Max Planck Inst.; Sato, Katsuhiko; /Tokyo U. /Tokyo U., RESCEU

2006-09-21T23:59:59.000Z

96

Fission Cycling in Supernova Nucleosynthesis: Active-Sterile Neutrino Oscillations  

E-Print Network (OSTI)

We investigate nucleosynthesis in the supernovae post-core bounce neutrino-driven wind environment in the presence of active-sterile neutrino transformation. We consider active-sterile neutrino oscillations for a range of mixing parameters: vacuum mass-squared differences of 0.1 eV^2 10^-4. We find a consistent r-process pattern for a large range of mixing parameters that is in rough agreement with the halo star CS 22892-052 abundances and the pattern shape is determined by fission cycling. We find that the allowed region for the formation of the r-process peaks overlaps the LSND and NSBL (3+1) allowed region.

J. Beun; G. C. McLaughlin; R. Surman; W. R. Hix

2006-02-01T23:59:59.000Z

97

Nucleosynthesis in the Outflow from Gamma Ray Burst Accretion Disks  

E-Print Network (OSTI)

We examine the nucleosynthesis products that are produced in the outflow from rapidly accreting disks. We find that the type of element synthesis varies dramatically with the degree of neutrino trapping in the disk and therefore the accretion rate of the disk. Disks with relatively high accretion rates such as ? M = 10 M?/s can produce very neutron rich nuclei that are found in the r process. Disks with more moderate accretion rates can produce copious amounts of Nickel as well as the light elements such as Lithium and Boron. Disks with lower accretion rates such as ? M = 1 M?/s produce large amounts of Nickel as well as some unusual nuclei such as 49 Ti,

R. Surman; G. C. Mclaughlin; W. R. Hix; Zn

2005-01-01T23:59:59.000Z

98

SFI Bulletinwinter 2006, vol. 21 #1 Beyond the Big Bang The Amazon's Lost Civilizations The Truth Behind Lying  

E-Print Network (OSTI)

at the level of excellence that it is, and that it has the sort of feedback and enthusiasm that it garnishes

99

MaxPlanckResearchMaxPlanckResearchScience Magazine of the Max Planck Society Big Bang in the  

E-Print Network (OSTI)

for Plasma Research - Bhat, Gandhinagar 382 428, India received 18 March 2011; accepted in final form 29 June

100

The r-process nucleosynthesis: Nuclear physics challenges  

SciTech Connect

About half of the nuclei heavier than iron observed in nature are produced by the socalled rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics. Another underlying difficulty associated with our understanding of the r-process concerns the uncertainties in the predictions of nuclear properties for the few thousands exotic neutron-rich nuclei involved and for which essentially no experimental data exist. The present contribution emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the nuclear structure properties of exotic neutron-rich nuclei as well as their radiative neutron capture rates and their fission probabilities. These quantities are particularly relevant to determine the composition of the matter resulting from the r-process. Their impact on the r-abundance distribution resulting from the decompression of neutron star matter is discussed.

Goriely, S. [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles Campus de la Plaine, CP 226, 1050 Brussels (Belgium)

2012-10-20T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
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101

Nucleosynthesis and Clump Formation in a Core Collapse Supernova  

E-Print Network (OSTI)

High-resolution two-dimensional simulations were performed for the first five minutes of the evolution of a core collapse supernova explosion in a 15 solar mass blue supergiant progenitor. The computations start shortly after bounce and include neutrino-matter interactions by using a light-bulb approximation for the neutrinos, and a treatment of the nucleosynthesis due to explosive silicon and oxygen burning. We find that newly formed iron-group elements are distributed throughout the inner half of the helium core by Rayleigh-Taylor instabilities at the Ni+Si/O and C+O/He interfaces, seeded by convective overturn during the early stages of the explosion. Fast moving nickel mushrooms with velocities up to about 4000 km/s are observed. This offers a natural explanation for the mixing required in light curve and spectral synthesis studies of Type Ib explosions. A continuation of the calculations to later times, however, indicates that the iron velocities observed in SN 1987 A cannot be reproduced because of a strong deceleration of the clumps in the dense shell left behind by the shock at the He/H interface.

K. Kifonidis; T. Plewa; H. -Th. Janka; E. Mueller

1999-11-10T23:59:59.000Z

102

Modeling Cosmic Nucleosynthesis | U.S. DOE Office of Science (SC)  

NLE Websites -- All DOE Office Websites (Extended Search)

Modeling Cosmic Nucleosynthesis Modeling Cosmic Nucleosynthesis Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » December 2013 Modeling Cosmic Nucleosynthesis First measurements of isotopes produced by Argonne's new CARIBU facility provide insight into the creation of the elements in the universe. Print Text Size: A A A Subscribe FeedbackShare Page Click to enlarge photo. Enlarge Photo Image courtesy of Argonne National Laboratory The Penning trap was used to precisely measure the masses of isotopes

103

Nucleosynthesis in a massive star associated with magnetohydrodynamical jets from collapsars  

SciTech Connect

We investigate the nucleosynthesis during the stellar evolution and the jet-like supernova explosion of a massive star of 70 M{sub Circled-Dot-Operator} having the solar metallicity in the main sequence stage. The nucleosynthesis calculations have been performed with large nuclear reaction networks, where the weak s-, p-, and r-processes are taken into account. As a result s-elements of 60 > A > 90 and r-elements of 90 > A > 160 are highly overproduced relative to the solar system abundances. We find that the Sr-Y-Zr isotopes are primarily synthesized in the explosive nucleosynthesis which could be one of the sites of the lighter element primary process (LEPP).

Ono, M.; Hashimoto, M.; Fujimoto, S.; Kotake, K.; Yamada, S. [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan and Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan); Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan); Kumamoto National College of Technology, Kumamoto 861-1102 (Japan); Division of Theoretical Astronomy/Center for Computational Astrophysics, National Astronomical Observatory of Japan, Tokyo 181-8588 (Japan); Advanced Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan)

2012-11-12T23:59:59.000Z

104

NEUTRINO SPECTRA FROM ACCRETION DISKS: NEUTRINO GENERAL RELATIVISTIC EFFECTS AND THE CONSEQUENCES FOR NUCLEOSYNTHESIS  

Science Conference Proceedings (OSTI)

Black hole (BH) accretion disks have been proposed as good candidates for a range of interesting nucleosynthesis, including the r-process. The presence of the BH influences the neutrino fluxes and affects the nucleosynthesis resulting from the interaction of the emitted neutrinos and hot outflowing material ejected from the disk. We study the impact of general relativistic effects on the neutrinos emitted from BH accretion disks. We present abundances obtained by considering null geodesics and energy shifts for two different disk models. We find that both the bending of the neutrino trajectories and the energy shifts have important consequences for the nucleosynthetic outcome.

Caballero, O. L.; McLaughlin, G. C. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Surman, R., E-mail: lcaballe@uw.edu, E-mail: olcaball@ncsu.edu, E-mail: gail_mclaughlin@ncsu.edu, E-mail: surmanr@union.edu [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States)

2012-02-01T23:59:59.000Z

105

Neutrino Spectra from Accretion Disks: Neutrino General Relativistic Effects and the Consequences for Nucleosynthesis  

E-Print Network (OSTI)

Black hole accretion disks have been proposed as good candidates for a range of interesting nucleosynthesis, including the r-process. The presence of the black hole influences the neutrino fluxes and affects the nucleosynthesis resulting from the interaction of the emitted neutrinos and hot outflowing material ejected from the disk. We study the impact of general relativistic effects on the neutrinos emitted from black hole accretion disks. We present abundances obtained by considering null geodesics and energy shifts for two different disk models. We find that both the bending of the neutrino trajectories and the energy shifts have important consequences for the nucleosynthetic outcome

O. L Caballero; G. C. McLaughlin; R. Surman

2011-05-31T23:59:59.000Z

106

Neutrino-induced nucleosynthesis of A>64 nuclei: The nu p-process  

E-Print Network (OSTI)

We present a new nucleosynthesis process, that we denote nu p-process, which occurs in supernovae (and possibly gamma-ray bursts) when strong neutrino fluxes create proton-rich ejecta. In this process, antineutrino absorptions in the proton-rich environment produce neutrons that are immediately captured by neutron-deficient nuclei. This allows for the nucleosynthesis of nuclei with mass numbers A >64. Making this process a possible candidate to explain the origin of the solar abundances of 92,94Mo and 96,98Ru. This process also offers a natural explanation for the large abundance of Sr seen in an hyper-metal-poor star.

C. Fröhlich; G. Martínez-Pinedo; M. Liebendörfer; F. -K. Thielemann; E. Bravo; W. R. Hix; K. Langanke; N. T. Zinner

2005-11-12T23:59:59.000Z

107

Radiation Dominated Universe for Jordan-Brans-Dicke Cosmology  

E-Print Network (OSTI)

Jordan-Brans-Dicke cosmology with a standard kinetic term for the scalar field and no mass term has the same radiation dominated solution as standard Einstein cosmology without the cosmological constant. Because of this, the primordial nucleosynthesis (Big - Bang nucleosynthesis) result obtained for standard cosmology remains the same for Jordan-Brans-Dicke cosmology. We show that Jordan-Brans-Dicke cosmology with a mass term for the scalar field as well as explaining dark energy for the present era, can also explain radiation dominated cosmology for the primordial nucleosynthesis era.

M. Arik; L. Amon Susam

2010-06-22T23:59:59.000Z

108

Extended quintessence with an exponential coupling  

E-Print Network (OSTI)

We study a class of extended quintessence cosmologies where the scalar field playing the role of the dark energy is exponentially coupled to the Ricci scalar. We find that the dynamics induced by the effective gravitational potential in the Klein-Gordon equation dominates the motion of the field in the early universe. The resulting "R-boost" trajectory is characterized by a kinetic dark energy density, given by [3\\rhomnr0(1+z)]^2 [ 32 rhor0 omegaJBD0]^(-1), where omegaJBD0, rhor0 and rhomnr0 are calculated at present, and represent the Jordan Brans Dicke parameter, the density of relativistic matter and of those species which are non-relativistic at redshift z, respectively. We show that such a trajectory represents an attractor, equivalent to a tracking solution with equation of state w=-1/3, providing a large basin of attraction for the initial dark energy density regardless of the properties of the potential energy yielding acceleration today. We derive the up to date constraints from Big Bang Nucleosynthesis (BBN) on the present scenario, and we show that they are largely satisfied for interesting trajectories of the dark energy scalar field in the early universe. We compute the cosmological perturbation spectra in these cosmologies. For a fixed value of omegaJBD0, the projection and Integrated Sachs-Wolfe effects on the cosmic microwave background anisotropy are considerably larger in the exponential case with respect to a quadratic non-minimal coupling, reflecting the fact that the effective gravitational constant depends exponentially on the dynamics of the field.

Valeria Pettorino; Carlo Baccigalupi; Gianpiero Mangano

2004-12-14T23:59:59.000Z

109

Varying couplings in the early universe: Correlated variations of {alpha} and G  

SciTech Connect

The cosmic microwave background anisotropies provide a unique opportunity to constrain simultaneous variations of the fine-structure constant {alpha} and Newton's gravitational constant G. Those correlated variations are possible in a wide class of theoretical models. In this brief paper we show that the current data, assuming that particle masses are constant, give no clear indication for such variations, but already prefer that any relative variations in {alpha} should be of the same sign of those of G for variations of {approx}1%. We also show that a cosmic complementarity is present with big bang nucleosynthesis and that a combination of current CMB and big bang nucleosynthesis data strongly constraints simultaneous variations in {alpha} and G. We finally discuss the future bounds achievable by the Planck satellite mission.

Martins, C. J. A. P. [Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); CTC, DAMTP, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Menegoni, Eloisa [ICRA, International Center for Relativistic Astrophysics, University of Rome, 'La Sapienza', Ple Aldo Moro 2, 00185 Rome (Italy); Galli, Silvia [Physics Department and INFN, University of Rome, 'La Sapienza', Ple Aldo Moro 2, 00185 Rome (Italy); Laboratoire Astroparticule et Cosmologie (APC), Universite Paris Diderot, 75205 Paris cedex 13 (France); Mangano, Gianpiero [INFN, Sezione di Napoli, and Physics Department, University of Naples 'Federico II', Via Cintia, 80126 Naples (Italy); Melchiorri, Alessandro [Physics Department and INFN, University of Rome, 'La Sapienza', Ple Aldo Moro 2, 00185 Rome (Italy)

2010-07-15T23:59:59.000Z

110

CMB  

NLE Websites -- All DOE Office Websites (Extended Search)

Hubble Diagram Hubble Diagram CMB BBN Cosmic Microwave Background One of the predictions that the Big Bang theory leads to, concerns some left over pieces that could tell us the temperature of the universe.. IF we believe that the Big Bang is how the universe began, then theorists predict that we should see a remnant microwave background. It is microwave because that is the area of the spectrum in which it is found. When we look out into space with our bare eyes, we see bright objects and a whole lot of "empty" space. However, if we examine the sky with a radio telescope, we see an almost perfect blackbody spectrum in the microwave spectrum. What is a blackbody and why is it radiating? How did we find the Cosmic Microwave Background? And can we fit a curve to the data taken for the Cosmic

111

The Primordial Abundance of $^6$Li and $^9$be  

E-Print Network (OSTI)

Light element ($^6$Li, $^7$Li and $^9$Be) depletion isochrones for halo stars have been calculated with standard stellar evolution models. These models include the latest available opacities and are computed through the sub-giant branch. If $^6$Li is not produced in appreciable amounts by stellar flares, then the detection of $^6$Li in HD 84937 by Smith, Lambert \\& Nissen (1993) is compatible with standard stellar evolution and standard big bang nucleosynthesis only if HD 84937 is a sub-giant. The present parallax is inconsistent with HD 84937 being a sub-giant star at the $2.5\\, \\sigma$ level. The most metal poor star with a measured $^9$Be abundance is HD 140283, which is a relatively cool sub-giant. Standard stellar evolution predict that $^9$Be will have been depleted in this star by $\\sim 0.3$ dex (for ${\\rm T_{eff}} = 5640$ K). Revising the abundance upward changes the oxygen-beryllium relation, suggesting incompatible with standard comic ray production models, and hence, standard big bang nucleosynthesis. However, an increase in the derived temperature of HD 140283 to 5740 K would result in no depletion of $^9$Be and agreement with standard big bang nucleosynthesis.

Brian Chaboyer

1994-05-31T23:59:59.000Z

112

NUCLEOSYNTHESIS IN CORE-COLLAPSE SUPERNOVA EXPLOSIONS TRIGGERED BY A QUARK-HADRON PHASE TRANSITION  

Science Conference Proceedings (OSTI)

We explore heavy-element nucleosynthesis in the explosion of massive stars that are triggered by a quark-hadron phase transition during the early post-bounce phase of core-collapse supernovae. The present study is based on general-relativistic radiation hydrodynamics simulations with three-flavor Boltzmann neutrino transport in spherical symmetry, which utilize a quark-hadron hybrid equation of state based on the MIT bag model for strange quark matter. The quark-hadron phase transition inside the stellar core forms a shock wave propagating toward the surface of the proto-neutron star. This shock wave results in an explosion and ejects neutron-rich matter from the outer accreted layers of the proto-neutron star. Later, during the cooling phase, the proto-neutron star develops a proton-rich neutrino-driven wind. We present a detailed analysis of the nucleosynthesis outcome in both neutron-rich and proton-rich ejecta and compare our integrated nucleosynthesis with observations of the solar system and metal-poor stars. For our standard scenario, we find that a 'weak' r-process occurs and elements up to the second peak (A {approx} 130) are successfully synthesized. Furthermore, uncertainties in the explosion dynamics could barely allow us to obtain the strong r-process which produces heavier isotopes, including the third peak (A {approx} 195) and actinide elements.

Nishimura, Nobuya; Thielemann, Friedrich-Karl; Hempel, Matthias; Kaeppeli, Roger; Rauscher, Thomas; Winteler, Christian [Department of Physics, University of Basel, CH-4056 Basel (Switzerland); Fischer, Tobias; Martinez-Pinedo, Gabriel [GSI, Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Froehlich, Carla [Department of Physics, North Carolina State University, NC 27695 (United States); Sagert, Irina, E-mail: nobuya.nishimura@unibas.ch [Department of Physics and Astronomy, Michigan State University, MI 48824 (United States)

2012-10-10T23:59:59.000Z

113

Sensitivity of r-Process Nucleosynthesis to Light-Element Nuclear Reactions  

E-Print Network (OSTI)

We study the efficiency and sensitivity of r-process nucleosynthesis to 18 light-element nuclear reaction rates. We adopt empirical power-law relations to parameterize the reaction sensitivities. We utilize two different hydrodynamic models for the neutrino-driven winds in order to study the dependence of our result on supernova wind models. We also utilize an exponential model to approximate a wide variety of other plausible conditions for the r-process. We identify several specific nuclear reactions among light neutron-rich nuclei that play a critical role in determining the final r-process nucleosynthesis yields. As an illustration, we examine ``semi-waiting'' points among the carbon isotopes. We show that not only neutron capture and $\\beta$-decay, but also $(\\alpha, \\mathrm{n})$ reactions are important in determining waiting points along the r-process path. Our numerical results from this sensitivity analysis serve foremost to clarify which light nuclear reactions are most influential in determining the final r-process abundances. We also quantify the effects of present nuclear uncertainties on the final r-process abundances. This study thus emphasizes and motivates which future determinations of nuclear reaction rates will most strongly impact our understanding of r-process nucleosynthesis.

T. Sasaqui; T. Kajino; G. J. Mathews; K. Otsuki; K. Nakamura

2005-04-24T23:59:59.000Z

114

R-Process Nucleosynthesis in Dynamically Ejected Matter of Neutron Star Mergers  

E-Print Network (OSTI)

Although the rapid neutron-capture process, or r-process, is fundamentally important for explaining the origin of approximately half of the stable nuclei with A > 60, the astrophysical site of this process has not been identified yet. Here we study r-process nucleosynthesis in material that is dynamically ejected by tidal and pressure forces during the merging of binary neutron stars (NSs) and within milliseconds afterwards. For the first time we make use of relativistic hydrodynamical simulations of such events, defining consistently the conditions that determine the nucleosynthesis, i.e., neutron enrichment, entropy, early density evolution and thus expansion timescale, and ejecta mass. We find that 10^{-3}-10^{-2} solar masses are ejected, which is enough for mergers to be the main source of heavy (A > 140) galactic r-nuclei for merger rates of some 10^{-5} per year. While asymmetric mergers eject 2-3 times more mass than symmetric ones, the exact amount depends weakly on whether the NSs have radii of ~15 km for a "stiff" nuclear equation of state (EOS) or ~12 km for a "soft" EOS. R-process nucleosynthesis during the decompression becomes largely insensitive to the detailed conditions because of efficient fission recycling, producing a composition that closely follows the solar r-abundance distribution for nuclei with mass numbers A > 140. Estimating the light curve powered by the radioactive decay heating of r-process nuclei with an approximative model, we expect high emission in the B-V-R bands for 1-2 days with potentially observable longer duration in the case of asymmetric mergers because of the larger ejecta mass.

Stephane Goriely; Andreas Bauswein; H. -Thomas Janka

2011-07-05T23:59:59.000Z

115

Nucleosynthesis in the outflows associated with accretion disks of Type II collapsars  

E-Print Network (OSTI)

We investigate nucleosynthesis inside the outflows from gamma-ray burst (GRB) accretion disks formed by the Type II collapsars. In these collapsars, massive stars undergo core collapse to form a proto-neutron star initially and a mild supernova explosion is driven. The supernova ejecta lack momentum and subsequently this newly formed neutron star gets transformed to a stellar mass black hole via massive fallback. The hydrodynamics and the nucleosynthesis in these accretion disks has been studied extensively in the past. Several heavy elements are synthesized in the disk and much of these heavy elements are ejected from the disk via winds and outflows. We study nucleosynthesis in the outflows launched from these disks by using an adiabatic, spherically expanding outflow model, to understand which of these elements thus synthesized in the disk survive in the outflow. While studying this we find that many new elements like isotopes of titanium, copper, zinc etc. are present in the outflows. 56Ni is abundantly synthesized in most of the cases in the outflow which implies that the outflows from these disks in a majority of cases will lead to an observable supernova explosion. It is mainly present when outflow is considered from the He-rich, 56Ni/54Fe rich zones of the disks. However, outflow from the Si-rich zone of the disk remains rich in silicon. Although, emission lines of many of these heavy elements have been observed in the X-ray afterglows of several GRBs by Chandra, BeppoSAX, XMM-Newton etc., Swift seems to have not detected these lines yet.

Indrani Banerjee; Banibrata Mukhopadhyay

2013-09-04T23:59:59.000Z

116

1997 Reviews, Tables, and Plots in the Review of Particle Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

Plots (Alphabetical List) Plots (Alphabetical List) in the 1997 Review of Particle Physics Cut-off date for this update was October 15, 1997. Please use this CITATION. See this same index logically ordered. Having trouble with PostScript files? We have a PostScript help file. Accelerator physics of colliders (8p, 89kb) Astrophysical constants (6p, 111kb) Atomic and nuclear properties of materials (2p, 80kb) Axions and other Very Light Bosons (6p, 59kb) b-flavored Hadrons, Production and Decay (13p, 130kb) B0-Bbar0 Mixing (5p, 86kb) Big-bang cosmology (3p, 65kb) Big-bang nucleosynthesis (8p, 302kb) Cabibbo-Kobayashi-Maskawa mixing matrix (10p, 219kb) Clebsch-Gordan coeff., sph. harmonics, and d functions (2p, 211kb) Collider parameters (high-energy colliders) (3p, 73kb) Compositeness, Searches for Quark and Lepton (5p, 59kb)

117

SHEDDING NEW LIGHT ON EXPLODING STARS: TERASCALE SIMULATIONS OF NEUTRINO-DRIVEN SUPERNOVAE AND THEIR NUCLEOSYNTHESIS  

SciTech Connect

This project was focused on simulations of core-collapse supernovae on parallel platforms. The intent was to address a number of linked issues: the treatment of hydrodynamics and neutrino diffusion in two and three dimensions; the treatment of the underlying nuclear microphysics that governs neutrino transport and neutrino energy deposition; the understanding of the associated nucleosynthesis, including the r-process and neutrino process; the investigation of the consequences of new neutrino phenomena, such as oscillations; and the characterization of the neutrino signal that might be recorded in terrestrial detectors. This was a collaborative effort with Oak Ridge National Laboratory, State University of New York at Stony Brook, University of Illinois at Urbana-Champaign, University of California at San Diego, University of Tennessee at Knoxville, Florida Atlantic University, North Carolina State University, and Clemson. The collaborations tie together experts in hydrodynamics, nuclear physics, computer science, and neutrino physics. The University of Washington contributions to this effort include the further development of techniques to solve the Bloch-Horowitz equation for effective interactions and operators; collaborative efforts on developing a parallel Lanczos code; investigating the nuclear and neutrino physics governing the r-process and neutrino physics; and exploring the effects of new neutrino physics on the explosion mechanism, nucleosynthesis, and terrestrial supernova neutrino detection.

Haxton, Wick

2012-03-07T23:59:59.000Z

118

The Evolution of Li6 in Standard Cosmic-Ray Nucleosynthesis  

E-Print Network (OSTI)

We review the Galactic chemical evolution of Li6 and compare these results with recent observational determinations of the lithium isotopic ratio. In particular, we concentrate on so-called standard Galactic cosmic-ray nucleosynthesis in which Li, Be, and B are produced (predominantly) by the inelastic scattering of accelerated protons and \\alpha's off of CNO nuclei in the ambient interstellar medium. If O/Fe is constant at low metallicities, then the Li6 vs Fe/H evolution-as well as Be and B vs Fe/H-has difficulty in matching the observations. However, recent determinations of Population II oxygen abundances, as measured via OH lines, indicate that O/Fe increases at lower metallicity; if this trend is confirmed, then the Li6 evolution in a standard model of cosmic-ray nucleosynthesis is consistent with the data. We also show that another key indicator of Li6BeB origin is the Li6/Be ratio which also fits the available data if O/Fe is not constant at low metallicity. Finally we note that Li6 evolution in this scenario can strongly constrain the degree to which Li6 and Li7 are depleted in halo stars.

Brian D. Fields; Keith A. Olive

1998-11-11T23:59:59.000Z

119

The Particle Adventure | Glossary  

NLE Websites -- All DOE Office Websites (Extended Search)

Big Bang Theory The theory that the expanding universe began as an infinitely dense and hot medium. The initial instant is called the Big Bang...

120

Beta-decay spectroscopy relevant to the r-process nucleosynthesis  

Science Conference Proceedings (OSTI)

A scientific program of beta-decay spectroscopy relevant to r-process nucleosynthesis has been started using high intensity U-beam at the RIBF. The first results of {beta}-decay half-lives of very neutron-rich Kr to Tc nuclides, all of which lie close to the r-process path, suggest a systematic enhancement of the the {beta}-decay rates of the Zr and Nb isotopes around A110 with respect to the predictions of the deformed quasiparticle-random-phase-approximation model (FRDM + QRPA). An impact of the results on the astrophysical r-process is discussed together with the future perspective of the {beta}-decay spectroscopy with the EURICA.

Nishimura, Shunji [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Collaboration: RIBF Decay Collaboration

2012-11-12T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

r-Process Nucleosynthesis in Hot Accretion Disk Flows from Black Hole - Neutron Star Mergers  

E-Print Network (OSTI)

We consider hot accretion disk outflows from black hole - neutron star mergers in the context of the nucleosynthesis they produce. We begin with a three dimensional numerical model of a black hole - neutron star merger and calculate the neutrino and antineutrino fluxes emitted from the resulting accretion disk. We then follow the element synthesis in material outflowing the disk along parameterized trajectories. We find that at least a weak r-process is produced, and in some cases a main r-process as well. The neutron-rich conditions required for this production of r-process nuclei stem directly from the interactions of the neutrinos emitted by the disk with the free neutrons and protons in the outflow.

R. Surman; G. C. McLaughlin; M. Ruffert; H. -Th. Janka; W. R. Hix

2008-03-12T23:59:59.000Z

122

Sensitivity studies for r-process nucleosynthesis in three astrophysical scenarios  

E-Print Network (OSTI)

In rapid neutron capture, or r-process, nucleosynthesis, heavy elements are built up via a sequence of neutron captures and beta decays that involves thousands of nuclei far from stability. Though we understand the basics of how the r-process proceeds, its astrophysical site is still not conclusively known. The nuclear network simulations we use to test potential astrophysical scenarios require nuclear physics data (masses, beta decay lifetimes, neutron capture rates, fission probabilities) for all of the nuclei on the neutron-rich side of the nuclear chart, from the valley of stability to the neutron drip line. Here we discuss recent sensitivity studies that aim to determine which individual pieces of nuclear data are the most crucial for r-process calculations. We consider three types of astrophysical scenarios: a traditional hot r-process, a cold r-process in which the temperature and density drop rapidly, and a neutron star merger trajectory.

R. Surman; M. Mumpower; J. Cass; I. Bentley; A. Aprahamian; G. C. McLaughlin

2013-08-31T23:59:59.000Z

123

GRB 130606A AS A PROBE OF THE INTERGALACTIC MEDIUM AND THE INTERSTELLAR MEDIUM IN A STAR-FORMING GALAXY IN THE FIRST Gyr AFTER THE BIG BANG  

SciTech Connect

We present high signal-to-noise ratio Gemini and MMT spectroscopy of the optical afterglow of the gamma-ray burst (GRB) 130606A at redshift z = 5.913, discovered by Swift. This is the first high-redshift GRB afterglow to have spectra of comparable quality to those of z Almost-Equal-To 6 quasars. The data exhibit a smooth continuum at near-infrared wavelengths that is sharply cut off blueward of 8410 A due to absorption from Ly{alpha} at redshift z Almost-Equal-To 5.91, with some flux transmitted through the Ly{alpha} forest between 7000 and 7800 A. We use column densities inferred from metal absorption lines to constrain the metallicity of the host galaxy between a lower limit of [Si/H] {approx}> -1.7 and an upper limit of [S/H] {approx}< -0.5 set by the non-detection of S II absorption. We demonstrate consistency between the dramatic evolution in the transmission fraction of Ly{alpha} seen in this spectrum over the redshift range z = 4.9-5.85 with that previously measured from observations of high-redshift quasars. There is an extended redshift interval of {Delta}z = 0.12 in the Ly{alpha} forest at z = 5.77 with no detected transmission, leading to a 3{sigma} upper limit on the mean Ly{alpha} transmission fraction of {approx}<0.2% (or {tau}{sub GP}{sup eff} (Ly{alpha}) > 6.4). This is comparable to the lowest-redshift Gunn-Peterson troughs found in quasar spectra. Some Ly{beta} and Ly{gamma} transmission is detected in this redshift window, indicating that it is not completely opaque, and hence that the intergalactic medium (IGM) is nonetheless mostly ionized at these redshifts. We set a 2{sigma} upper limit of 0.11 on the neutral fraction of the IGM at the redshift of the GRB from the lack of a Ly{alpha} red damping wing, assuming a model with a constant neutral density. GRB 130606A thus for the first time realizes the promise of GRBs as probes of the first galaxies and cosmic reionization.

Chornock, Ryan; Berger, Edo; Lunnan, Ragnhild; Drout, Maria R.; Fong Wenfai; Laskar, Tanmoy [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fox, Derek B. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Roth, Katherine C., E-mail: rchornock@cfa.harvard.edu [Gemini Observatory, 670 North Aohoku Place, Hilo, HI 96720 (United States)

2013-09-01T23:59:59.000Z

124

NUCLEOSYNTHESIS IN TWO-DIMENSIONAL DELAYED DETONATION MODELS OF TYPE Ia SUPERNOVA EXPLOSIONS  

SciTech Connect

For the explosion mechanism of Type Ia supernovae (SNe Ia), different scenarios have been suggested. In these, the propagation of the burning front through the exploding white dwarf (WD) star proceeds in different modes, and consequently imprints of the explosion model on the nucleosynthetic yields can be expected. The nucleosynthetic characteristics of various explosion mechanisms are explored based on three two-dimensional explosion simulations representing extreme cases: a pure turbulent deflagration, a delayed detonation following an approximately spherical ignition of the initial deflagration, and a delayed detonation arising from a highly asymmetric deflagration ignition. Apart from this initial condition, the deflagration stage is treated in a parameter-free approach. The detonation is initiated when the turbulent burning enters the distributed burning regime. This occurs at densities around 10{sup 7} g cm{sup -3}-relatively low as compared to existing nucleosynthesis studies for one-dimensional spherically symmetric models. The burning in these multidimensional models is different from that in one-dimensional simulations as the detonation wave propagates both into unburned material in the high-density region near the center of a WD and into the low-density region near the surface. Thus, the resulting yield is a mixture of different explosive burning products, from carbon-burning products at low densities to complete silicon-burning products at the highest densities, as well as electron-capture products synthesized at the deflagration stage. Detailed calculations of the nucleosynthesis in all three models are presented. In contrast to the deflagration model, the delayed detonations produce a characteristic layered structure and the yields largely satisfy constraints from Galactic chemical evolution. In the asymmetric delayed detonation model, the region filled with electron capture species (e.g., {sup 58}Ni, {sup 54}Fe) is within a shell, showing a large off-set, above the bulk of {sup 56}Ni distribution, while species produced by the detonation are distributed more spherically.

Maeda, K. [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Roepke, F.K.; Fink, M.; Hillebrandt, W.; Travaglio, C. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching (Germany); Thielemann, F.-K., E-mail: keiichi.maeda@ipmu.j [Department Physik, Universitaet Basel, CH-4056 Basel (Switzerland)

2010-03-20T23:59:59.000Z

125

Nuclear Astrophysics  

E-Print Network (OSTI)

Nuclear physics has a long and productive history of application to astrophysics which continues today. Advances in the accuracy and breadth of astrophysical data and theory drive the need for better experimental and theoretical understanding of the underlying nuclear physics. This paper will review some of the scenarios where nuclear physics plays an important role, including Big Bang Nucleosynthesis, neutrino production by our sun, nucleosynthesis in novae, the creation of elements heavier than iron, and neutron stars. Big-bang nucleosynthesis is concerned with the formation of elements with A nuclear physics inputs required are few-nucleon reaction cross sections. The nucleosynthesis of heavier elements involves a variety of proton-, alpha-, neutron-, and photon-induced reactions, coupled with radioactive decay. The advent of radioactive ion beam facilities has opened an important new avenue for studying these processes, as many involve radioactive species. Nuclear physics also plays an important role in neutron stars: both the nuclear equation of state and cooling processes involving neutrino emission play a very important role. Recent developments and also the interplay between nuclear physics and astrophysics will be highlighted.

Carl R. Brune

2005-02-28T23:59:59.000Z

126

A New Look At Carbon Abundances In Planetary Nebulae. IV. Implications For Stellar Nucleosynthesis  

E-Print Network (OSTI)

This paper is the fourth and final report on a project designed to study carbon abundances in a sample of planetary nebulae representing a broad range in progenitor mass and metallicity. We present newly acquired optical spectrophotometric data for three Galactic planetary nebulae IC 418, NGC 2392, and NGC 3242 and combine them with UV data from the IUE Final Archive for identical positions in each nebula to determine accurate abundances of He, C, N, O, and Ne at one or more locations in each object. We then collect abundances of these elements for the entire sample and compare them with theoretical predictions of planetary nebula abundances from a grid of intermediate mass star models. We find some consistency between observations and theory, lending modest support to our current understanding of nucleosynthesis in stars below 8 M_o in birth mass. Overall, we believe that observed abundances agree with theoretical predictions to well within an order of magnitude but probably not better than within a factor of 2 or 3. But even this level of consistency between observation and theory enhances the validity of published intermediate-mass stellar yields of carbon and nitrogen in the study of the abundance evolution of these elements.

R. B. C. Henry; K. B. Kwitter; J. A. Bates

1999-10-19T23:59:59.000Z

127

Deep-Ocean Crusts as Telescopes: Using Live Radioisotopes to Probe Supernova Nucleosynthesis  

E-Print Network (OSTI)

Live 60Fe has recently been detected in a deep-ocean ferromanganese crust, isolated in layers dating from about 3 Myr ago. Since 60Fe has a mean life of 2.2 Myr, a near-Earth supernova is the only likely source for such a signal, and we explore here the consequences of a supernova origin. We combine the 60Fe data with several supernova nucleosynthesis models to calculate the supernova distance as a function of progenitor mass, finding an allowed range of 15-120 pc. We also predict the signals expected for several other radioisotopes, which are independent of the supernova distance. Species likely to be present near or above background levels are 10Be, 26Al, 53Mn, 182Hf and 244Pu. Of these, 182Hf and 244Pu are nearly background-free, presenting the best opportunities to provide strong confirmation of the supernova origin of the 60Fe signal, and to demonstrate that at least some supernovae are the source for the r-process. The accuracies of our predictions are hampered by large uncertainties in the predicted 60Fe yields for supernovae of different masses, so the new crust data motivate a redoubled theoretical attack on this problem.

Brian D. Fields; Kathrin A. Hochmuth; John Ellis

2004-10-22T23:59:59.000Z

128

Roles of Supernova Ejecta in Nucleosynthesis of Light Elements, Li, Be, and B  

E-Print Network (OSTI)

Explosions of type Ic supernovae (SNe Ic) are investigated using a relativistic hydrodynamic code to study roles of their outermost layers of the ejecta in light element nucleosynthesis through spallation reactions as a possible mechanism of the "primary" process. We have confirmed that the energy distribution of the outermost layers with a mass fraction of only 0.001 % follows the empirical formula proposed by previous work when the explosion is furious. In such explosions, a significant fraction of the ejecta ($>$0.1 % in mass) have the energy greater than the threshold energy for spallation reactions. On the other hand, it is found that the outermost layers of ejecta become more energetic than the empirical formula would predict when the explosion energy per unit ejecta mass is smaller than $\\sim 1.3\\times 10^{51}{ergs/}\\Msun$. As a consequence, it is necessary to numerically calculate explosions to estimate light element yields from SNe Ic. The usage of the empirical formula would overestimate the yields ...

Shigeyama, K N T

2004-01-01T23:59:59.000Z

129

Roles of Supernova Ejecta in Nucleosynthesis of Light Elements, Li, Be, and B  

E-Print Network (OSTI)

Explosions of type Ic supernovae (SNe Ic) are investigated using a relativistic hydrodynamic code to study roles of their outermost layers of the ejecta in light element nucleosynthesis through spallation reactions as a possible mechanism of the "primary" process. We have confirmed that the energy distribution of the outermost layers with a mass fraction of only 0.001 % follows the empirical formula proposed by previous work when the explosion is furious. In such explosions, a significant fraction of the ejecta ($>$0.1 % in mass) have the energy greater than the threshold energy for spallation reactions. On the other hand, it is found that the outermost layers of ejecta become more energetic than the empirical formula would predict when the explosion energy per unit ejecta mass is smaller than $\\sim 1.3\\times 10^{51}{ergs/}\\Msun$. As a consequence, it is necessary to numerically calculate explosions to estimate light element yields from SNe Ic. The usage of the empirical formula would overestimate the yields by a factor of $\\gtsim 3$ for energetic explosions such as SN 1998bw and underestimate the yields by a similar factor for less energetic explosions like SN 1994I. The yields of light elements Li, Be, and B (LiBeB) from SNe Ic are estimated by solving the transfer equation of cosmic rays originated from ejecta of SNe Ic and compared with observations.

Ko Nakamura; Toshikazu Shigeyama

2004-04-15T23:59:59.000Z

130

Inhomogeneous primordial nucleosynthesis and new abundance constraints on {Omega}{sub b}h{sup 2}  

DOE Green Energy (OSTI)

We discuss the upper limit to the baryonic contribution to the closure density. We consider effects of new observational and theoretical uncertainties in the primordial light element abundances, and the effects of fluctuation geometry on the inhomogeneous nucleosynthesis yields. We also consider implications of the possible detection of a high D/H abundance in a Lyman-{alpha} absorption cloud at high redshift and the implied chemical evolution effects of a high deuterium abundance. We show that there exists a region of the parameter space for inhomogeneous models in which a somewhat higher baryonic contribution to the closure density is possible than that allowed in standard homogeneous models. This result is contrary to some other recent studies and is due to both geometry and recently revised uncertainties in primordial light-element abundances, particularly {sup 7}Li. We find that the presently adopted abundance constraints are consistent with a contribution of baryons to the closure density as high as {Omega}{sub b}h{sub 50}{sup 2} {le} 0.11 ({eta} {le} 7 {times} 10{sup {minus}10}). This corresponds to a 20% increase over the limit from standard homogeneous models ({Omega}{sub b}h{sub 50}{sup 2} {le} 0.08, {eta} {le} 5.8 {times} 10{sup {minus}10}). With a high deuterium abundance the upper limits for the inhomogeneous and homogeneous models would be {Omega}{sub b}h{sub 50}{sup 2} {le} 0.04 and 0.03 ({eta} {le} 2.6 {times} 10{sup {minus}10} and 1.9 {times} 10{sup {minus}10}), respectively. Even higher limits could be obtained by further relaxing the presently accepted primordial lithium abundance constraint as some have proposed.

Mathews, G.J. [Notre Dame Univ., IN (United States). Dept. of Physics]|[Lawrence Livermore National Lab., CA (United States)]|[National Astronomical Observatory of Japan, Tokyo (Japan); Kajino, T.; Orito, M. [National Astronomical Observatory of Japan, Tokyo (Japan)

1995-07-20T23:59:59.000Z

131

PHASE TRANSITION GENERATED COSMOLOGICAL MAGNETIC FIELD AT LARGE SCALES  

SciTech Connect

We constrain a primordial magnetic field (PMF) generated during a phase transition (PT) using the big bang nucleosynthesis bound on the relativistic energy density. The amplitude of the PMF at large scales is determined by the shape of the PMF spectrum outside its maximal correlation length scale. Even if the amplitude of the PMF at 1 Mpc is small, PT-generated PMFs can leave observable signatures in the potentially detectable relic gravitational wave background if a large enough fraction (1%-10%) of the thermal energy is converted into the PMF.

Kahniashvili, Tina [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, PA 15213 (United States); Tevzadze, Alexander G. [Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave., Tbilisi 0160 (Georgia); Ratra, Bharat, E-mail: tinatin@phys.ksu.edu, E-mail: aleko@tevza.org, E-mail: ratra@phys.ksu.edu [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506 (United States)

2011-01-10T23:59:59.000Z

132

The 3He + 4He --> 7Be Astrophysical S-factor  

E-Print Network (OSTI)

We present precision measurements of the 3He + 4He --> 7Be reaction in the range ECM = 0.33 to 1.23 MeV using a small gas cell and detection of both prompt gamma rays and 7Be activity. Our prompt and activity measurements are in good agreement within an experimental uncertainty of several percent. We find S(0) = 0.595 +/- 0.018 keV b from fits of the Kajino theory to our data. We compare our results with published measurements, and we discuss the consequences for Big Bang Nucleosynthesis and for solar neutrino flux calculations.

T. A. D. Brown; C. Bordeanu; K. A. Snover; D. W. Storm; D. Melconian; A. L. Sallaska; S. K. L. Sjue; S. Triambak

2007-10-05T23:59:59.000Z

133

The 3He + 4He --> 7Be Astrophysical S-factor  

E-Print Network (OSTI)

We present precision measurements of the 3He + 4He --> 7Be reaction in the range ECM = 0.33 to 1.23 MeV using a small gas cell and detection of both prompt gamma rays and 7Be activity. Our prompt and activity measurements are in good agreement within an experimental uncertainty of several percent. We find S(0) = 0.594 +/- 0.017 keV b from fits of the Kajino theory to our data. We compare our results with published measurements, and we discuss the consequences for Big Bang Nucleosynthesis and for solar neutrino flux calculations.

Brown, T A D; Snover, K A; Storm, D W; Melconian, D; Sallaska, A L; Sjue, S K L; Triambak, S

2007-01-01T23:59:59.000Z

134

Cosmological implications of light element abundances: Theory  

DOE Green Energy (OSTI)

Primordial nucleosynthesis provides (with the microwave background radiation) one of the two quantitative experimental tests of the hot Big Bang cosmological model (versus alternative explanations for the observed Hubble expansion). The standard homogeneous-isotopic calculation fits the light element abundances ranging from [sup 1]H at 76% and [sup 4]He at 24% by mass through [sup 2]H and [sup 3]He at parts in 10[sup 5] down to [sup 7]Li at parts in 10[sup 10]. It is also noted how the recent Large Electron Positron Collider (and Stanford Linear Collider) results on the number of neutrinos (N[sub [nu

Schramm, D.N. (Univ. of Chicago, IL (United States) Fermi National Accelerator Lab., Batavia, IL (United States))

1993-06-01T23:59:59.000Z

135

THE {sup 12}C + {sup 12}C REACTION AND THE IMPACT ON NUCLEOSYNTHESIS IN MASSIVE STARS  

SciTech Connect

Despite much effort in the past decades, the C-burning reaction rate is uncertain by several orders of magnitude, and the relative strength between the different channels {sup 12}C({sup 12}C, {alpha}){sup 20}Ne, {sup 12}C({sup 12}C, p){sup 23}Na, and {sup 12}C({sup 12}C, n){sup 23}Mg is poorly determined. Additionally, in C-burning conditions a high {sup 12}C+{sup 12}C rate may lead to lower central C-burning temperatures and to {sup 13}C({alpha}, n){sup 16}O emerging as a more dominant neutron source than {sup 22}Ne({alpha}, n){sup 25}Mg, increasing significantly the s-process production. This is due to the chain {sup 12}C(p, {gamma}){sup 13}N followed by {sup 13}N({beta} +){sup 13}C, where the photodisintegration reverse channel {sup 13}N({gamma}, p){sup 12}C is strongly decreasing with increasing temperature. Presented here is the impact of the {sup 12}C+{sup 12}C reaction uncertainties on the s-process and on explosive p-process nucleosynthesis in massive stars, including also fast rotating massive stars at low metallicity. Using various {sup 12}C+{sup 12}C rates, in particular an upper and lower rate limit of {approx}50,000 higher and {approx}20 lower than the standard rate at 5 Multiplication-Sign 10{sup 8} K, five 25 M {sub Sun} stellar models are calculated. The enhanced s-process signature due to {sup 13}C({alpha}, n){sup 16}O activation is considered, taking into account the impact of the uncertainty of all three C-burning reaction branches. Consequently, we show that the p-process abundances have an average production factor increased up to about a factor of eight compared with the standard case, efficiently producing the elusive Mo and Ru proton-rich isotopes. We also show that an s-process being driven by {sup 13}C({alpha}, n){sup 16}O is a secondary process, even though the abundance of {sup 13}C does not depend on the initial metal content. Finally, implications for the Sr-peak elements inventory in the solar system and at low metallicity are discussed.

Pignatari, M. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)] [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Hirschi, R.; Bennett, M. [Astrophysics Group, EPSAM Institute, Keele University, Keele, ST5 5BG (United Kingdom)] [Astrophysics Group, EPSAM Institute, Keele University, Keele, ST5 5BG (United Kingdom); Wiescher, M.; Beard, M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)] [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Gallino, R. [Universita' di Torino, Torino, Via Pietro Giuria 1, I-10126 Torino (Italy)] [Universita' di Torino, Torino, Via Pietro Giuria 1, I-10126 Torino (Italy); Fryer, C.; Rockefeller, G. [Computational Physics and Methods (CCS-2), LANL, Los Alamos, NM 87545 (United States)] [Computational Physics and Methods (CCS-2), LANL, Los Alamos, NM 87545 (United States); Herwig, F.; Timmes, F. X., E-mail: marco.pignatari@unibas.ch [The Joint Institute for Nuclear Astrophysics, Notre Dame, IN 46556 (United States)

2013-01-01T23:59:59.000Z

136

A resolution of the cosmic Lithium problem  

E-Print Network (OSTI)

In 1982, Monique and Francois Spite discovered that the 7Li abundance in the atmosphere of old metal-poor dwarf stars in the galactic halo was independent of metallicity and temperature. Since then, 7Li abundance in the Universe has become a subject of intrigue, because there is less of it in Population II dwarf stars (by a factor of 3) than standard big bang nucleosynthesis predicts; a discrepancy which is still far from being solved. The most challenging features of the plateau is the lack of variability in the -2.8 Lithium plateau in Pop II (low-mass) stars formed in the pristine cloud swept up by the mixed SN+QN ejecta. We also find an increase in the scatter as well as an eventual drop in A(Li) below the Spite plateau values for very low metallicity ([Fe/H] <-3) in excellent agreement with observations. We propose a solution to the discrepancy between the Big Bang Nucleosynthesis 7Li abundance and the Spite plateau and list some implications and predictions of our model.

Rachid Ouyed

2013-04-12T23:59:59.000Z

137

Production of Intermediate-Mass and Heavy Nuclei  

SciTech Connect

Nucleosynthesis is the science related to all astrophysical processes which are responsible for the abundances of the elements and their isotopes in the universe. The astrophysical sites are the big bang and stellar objects. The working of nucleosynthesis processes is presented in a survey of events which act as abundance sources. For intermediate-mass and heavy elements, these are stellar evolution, type Ia and core collapse supernovae as well as hypernovae. We discuss successes and failures of existing processes and possible solutions via new (hitherto unknown) processes. Finally an analysis of their role is given in the puzzle to explain the evolution of the elemental and isotopic compositions found in galaxies, and especially the mixture found in the solar system. Different timescales due to the progenitor mass dependence of the endpoints of stellar evolution (type II supernova explosions - SNe II vs. planetary nebulae) or single vs. binary stellar systems (the latter being responsible for novae, type Ia supernovae -- SNe Ia, or X-ray bursts) are the keys to understand galactic evolution. At very early times, the role of explosion energies of events, polluting pristine matter with a composition originating only from the big bang, might also play a role. We also speculate on the role of very massive stars not undergoing SN II explosions but rather causing 'hypernovae' after the formation of a central black hole via core collapse.

Hix, William Raphael [ORNL; Thielemann, Friedrich-Karl W. [Universitat Basel, Switzerland; Fr?hlich, Dr. Carla [Universitat Basel, Switzerland; Hirschi, Raphael [Universitat Basel, Switzerland; Liebendoerfer, Matthias [Universitat Basel, Switzerland; Dillmann, Iris [Universitat Basel, Switzerland; Mocelj, Darko [Universitat Basel, Switzerland; Rauscher, Thomas [Universitat Basel, Switzerland; Martinez-Pinedo, Gabriel [Gesellschaft fur Schwerionenforschung (GSI), Germany; Langanke, Karlheinz [Gesellschaft fur Schwerionenforschung (GSI), Germany; Farouq, Khalil [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Kratz, Karl-Ludwig [ORNL; Pfeiffer, Bernard [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Panov, Igor V. [Alikhanov Institute for Theoretical and Experimental Physics, Moscow, Russia; Nadyozhin, Dimitri K [Alikhanov Institute for Theoretical and Experimental Physics, Moscow, Russia; Blinnikov, Sergei I [Alikhanov Institute for Theoretical and Experimental Physics, Moscow, Russia; Bravo, Eduardo [Universitat Politecnica de Catalunya, Barcelona, Spain; H?flich, Peter [Florida State University, Tallahassee; Zinner, Nikolaj T [ORNL

2007-07-01T23:59:59.000Z

138

DEPENDENCE OF s-PROCESS NUCLEOSYNTHESIS IN MASSIVE STARS ON TRIPLE-ALPHA AND {sup 12}C({alpha}, {gamma}){sup 16}O REACTION RATE UNCERTAINTIES  

Science Conference Proceedings (OSTI)

We have studied the sensitivity of s-process nucleosynthesis in massive stars to {+-}2{sigma} variations in the rates of the triple-{alpha} and {sup 12}C({alpha}, {gamma}){sup 16}O reactions. We simulated the evolution of massive stars from H burning through Fe-core collapse, followed by a supernova explosion. We found that the production factors of s-process nuclides between {sup 58}Fe and {sup 96}Zr change strongly with changes in the He burning reaction rates; using the Lodders solar abundances rather than those of Anders and Grevesse reduces s-process nucleosynthesis; later burning phases beyond core He burning and shell C burning have a significant effect on post-explosive production factors. We also discuss the implications of the uncertainties in the helium burning rates for evidence of a new primary neutron capture process (LEPP) in massive stars.

Tur, Clarisse; Austin, Sam M. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Laboratory, East Lansing, MI 48824-1321 (United States); Heger, Alexander [School of Physics and Astronomy, University of Minnesota, Twin Cities, Minneapolis, MN 55455-0149 (United States)], E-mail: tur@nscl.msu.edu, E-mail: austin@nscl.msu.edu, E-mail: alex@physics.umn.edu

2009-09-10T23:59:59.000Z

139

On the Sensitivity of Massive Star Nucleosynthesis and Evolution to Solar Abundances and to Uncertainties in Helium Burning Reaction Rates  

E-Print Network (OSTI)

We explore the dependence of pre-supernova evolution and supernova nucleosynthesis yields on the uncertainties in helium burning reaction rates. Using the revised solar abundances of Lodders (2003) for the initial stellar composition, instead of those of Anders & Grevesse (1989), changes the supernova yields and limits the constraints that those yields place on the 12C(a,g)16O reaction rate. The production factors of medium-weight elements (A = 16-40) were found to be in reasonable agreement with observed solar ratios within the current experimental uncertainties in the triple alpha reaction rate. Simultaneous variations by the same amount in both reaction rates or in either of them separately, however, can induce significant changes in the central 12C abundance at core carbon ignition and in the mass of the supernova remnant. It therefore remains important to have experimental determinations of the helium burning rates so that their ratio and absolute values are known with an accuracy of 10% or better.

Clarisse Tur; Alexander Heger; Sam M. Austin

2007-05-30T23:59:59.000Z

140

On the Evoution of the Light Elements I. D, He-3, and He-4  

E-Print Network (OSTI)

The light elements D, \\he3, \\he4, and \\li7 are produced in big bang nucleosynthesis and undergo changes in their abundances due to galactic processing. Since one may observe most of these elements only in contemporary environments, knowledge of the intervening evolution is necessary for determining the observational constraints on primordial nucleosynthesis. Chemical and stellar evolution model dependences in light element evolution are systematically investigated via a comparison of 1460 possible chemical evolution scenarios and of stellar nucleosynthesis yields, all of which have been selected to fit solar neighborhood C, N, O, and Fe abundances as well as the observed local gas density and gas mass fraction. The light element evolution and solar system yields in these models are found to span a wide range, explicitly demonstrating the model dependence. The range of model dependence for D, \\he3, and \\he4 solar abundances is calculated, and its sensitivity to the heavy element constraints is noted. The chemical evolution contribution to the uncertainty in the observed primordial light element abundances is estimated, and the effects of this uncertainty on big bang nucleosynthesis results are discussed. The predictions for the light elements are found to be correlated; the extent and physical origin of these correlations is discussed. D and \\he3 evolution is found to have significant model dependence, however, the dominant factor determining their solar and interstellar abundances is their primordial abundance. In addition, \\he3 is found to be very sensitive to the details of processing in low mass stars. \\he4 yields are shown to be very model dependent; in particular, both the introduction of mass loss and the possibly very high \\he4 stellar yields in the

Brian Fields

1995-12-08T23:59:59.000Z

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141

Volume 5 Number 2 February 14, 2004 THE UNIVERSITY OF HONG KONG  

E-Print Network (OSTI)

), the big bang (the first moments of the universe), gamma ray bursts (the biggest explosions in the universe

Tam, Vincent W. L.

142

William Fowler and Elements in the Stars  

NLE Websites -- All DOE Office Websites (Extended Search)

William Fowler and Elements in the Stars Resources with Additional Information William A. Fowler Courtesy AIP Emilio Segrè Visual Archives 'William A. Fowler ... shared the 1983 Nobel Prize in physics for his research into the creation of chemical elements inside stars ... . During his career in nuclear physics and nuclear astrophysics, which spanned more that 60 years, Fowler was primarily concerned with studies of fusion reactions--how the nuclei of lighter chemical elements fuse to create the heavier ones in a process known as nucleosynthesis. In 1957, Fowler coauthored ... the seminal paper "Synthesis of the Elements in the Stars", [which] showed that all of the elements from carbon to uranium could be produced by nuclear processes in stars, starting only with the hydrogen and helium produced in the Big Bang.

143

Fermilab Today  

NLE Websites -- All DOE Office Websites (Extended Search)

3, 2007 3, 2007 Subscribe | Contact Fermilab Today | Archive | Classifieds Search GO Calendar Thurs., May 3 1:00 p.m. ALCPG ILC Physics and Detector Seminar - Hornets' Nest WH-8XO Speaker: J. Repond, Argonne National Laboratory Title: Status Report of RPC/GEM Vertical Slice Test 2:30 p.m. Theoretical Physics Seminar - Curia II Speaker: M. Pospelov, University of Victoria Title: Particle Physics Catalysis of Big Bang Nucleosynthesis 3:30 p.m. DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over THERE WILL BE NO ACCELERATOR PHYSICS AND TECHNOLOGY SEMINAR TODAY 6:00 p.m. UTeV Seminar - 1 West Speaker: A. Chou, Fermilab Title: Ultra High Energy Cosmic Rays Fri., May 4 3:30 p.m. DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over 4:00 p.m. Joint Experimental-Theoretical Physics Seminar - 1 West

144

Variation of fundamental constants in space and time: theory and observations  

E-Print Network (OSTI)

Review of recent works devoted to the temporal and spatial variation of the fundamental constants and dependence of the fundamental constants on the gravitational potential (violation of local position invariance) is presented. We discuss the variation of the fine structure constant $\\alpha=e^2/\\hbar c$, strong interaction and fundamental masses (Higgs vacuum), e.g. the electron-to-proton mass ratio $\\mu=m_e/M_p$ or $X_e=m_e/\\Lambda_{QCD}$ and $X_q=m_q/\\Lambda_{QCD}$. We also present new results from Big Bang nucleosynthesis and Oklo natural nuclear reactor data and propose new measurements of enhanced effects in atoms, nuclei and molecules, both in quasar and laboratory spectra.

Flambaum, V V

2008-01-01T23:59:59.000Z

145

KMN  

NLE Websites -- All DOE Office Websites (Extended Search)

Kenneth M. Nollett Kenneth M. Nollett Complete Curriculum Vitae available as PDF file Astrophysics at Argonne lunch seminar Biographical sketch 1995 S.B., Massachusetts Institute of Technology 2000 Ph.D., The University of Chicago 2000-02 Postdoctoral Scholar, California Institute of Technology 2002-03 Research Associate, Institute for Nuclear Theory, University of Washington 2003-08 Assistant Physicist, Argonne National Laboratory 2008-12 Physicist, Argonne National Laboratory Publications ADS Search Google Scholar Nuclear reaction rates and primordial 6Li Kenneth M. Nollett, Martin Lemoine, and David N. Schramm Phys. Rev. C 56, 1144 (1997) Sharpening the predictions of big-bang nucleosynthesis Scott Burles, Kenneth M. Nollett, James W. Truran, and Michael S. Turner Phys. Rev. Lett. 82, 4176 (1999)

146

Possible solution to the $^7$Li problem by the long lived stau  

E-Print Network (OSTI)

Modification of standard big-bang nucleosynthesis is considered in the minimal supersymmetric standard model to resolve the excessive theoretical prediction of the abundance of primordial lithium 7. We focus on the stau as a next-lightest superparticle, which is long lived due to its small mass difference with the lightest superparticle. It provides a number of additional decay processes of $\\mathrm{^{7}Li}$ and $\\mathrm{^{7}Be}$. A particularly important process is the internal conversion in the stau-nucleus bound state, which destroys the $\\mathrm{^{7}Li}$ and $\\mathrm{^{7}Be}$ effectively. We show that the modification can lead to a prediction consistent with the observed abundance of $\\mathrm{^{7}Li}$.

Toshifumi Jittoh; Kazunori Kohri; Masafumi Koike; Joe Sato; Takashi Shimomura; Masato Yamanaka

2007-04-23T23:59:59.000Z

147

Do primordial Lithium abundances imply there's no Dark Energy?  

E-Print Network (OSTI)

Explaining the well established observation that the expansion rate of the universe is apparently accelerating is one of the defining scientific problems of our age. Within the standard model of cosmology, the repulsive 'dark energy' supposedly responsible has no explanation at a fundamental level, despite many varied attempts. A further important dilemma in the standard model is the Lithium problem, which is the substantial mismatch between the theoretical prediction for 7-Li from Big Bang Nucleosynthesis and the value that we observe today. This observation is one of the very few we have from along our past worldline as opposed to our past lightcone. By releasing the untested assumption that the universe is homogeneous on very large scales, both apparent acceleration and the Lithium problem can be easily accounted for as different aspects of cosmic inhomogeneity, without causing problems for other cosmological phenomena such as the cosmic microwave background. We illustrate this in the context of a void model.

Marco Regis; Chris Clarkson

2010-03-04T23:59:59.000Z

148

{sup 3}He+{sup 4}He {yields} {sup 7}Be astrophysical S factor  

SciTech Connect

We present precision measurements of the {sup 3}He+{sup 4}He {yields} {sup 7}Be reaction in the range E{sub c.m.}=0.33 to 1.23 MeV using a small gas cell and detection of both prompt {gamma} rays and {sup 7}Be activity. Our prompt and activity measurements are in good agreement within the experimental uncertainty of several percent. We find S(0)=0.595{+-}0.018 keV b from fits of the Kajino theory to our data. We compare our results with published measurements, and we discuss the consequences for Big Bang Nucleosynthesis and for solar neutrino flux calculations.

Brown, T. A. D.; Bordeanu, C.; Snover, K. A.; Storm, D. W.; Melconian, D.; Sallaska, A. L.; Sjue, S. K. L.; Triambak, S. [Center for Experimental Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195 (United States)

2007-11-15T23:59:59.000Z

149

Effect of circular Unruh radiation on bound nucleons and a possible answer to the Lithium 7 puzzle  

E-Print Network (OSTI)

In the shell model of nuclei, protons and neutrons move in a phenomenological nuclear potential much in the same manner as electrons move in Coulomb based potential in the shell model of atoms. As in the atomic case, the protons and neutrons of certain nuclear energy levels will have a non-zero orbital angular momentum (i.e. l =/= 0) and will therefore experience a centripetal potential and a centripetal acceleration. We advance the hypothesis, based on justification via the path integral formalism, that if one associates an Unruh temperature with this quantum centripetal acceleration then there is a potentially experimentally observable effect on certain nuclei -- the shifting of the naive expectations of the relative occupation of the ground and lowest lying energy levels. In particular we find that this effect should be most prominent in Li-7 nuclei. We speculate that this effect of the Unruh temperature might offer an answer to the Li-7 problem in Big Bang Nucleosynthesis.

Navid Rad; Douglas Singleton; Triyanta

2013-07-13T23:59:59.000Z

150

Is there further evidence for spatial variation of fundamental constants?  

SciTech Connect

Indications of spatial variation of the fine-structure constant, {alpha}, based on study of quasar absorption systems have recently been reported [J. K. Webb, J. A. King, M. T. Murphy, V. V. Flambaum, R. F. Carswell, and M. B. Bainbridge, arXiv:1008.3907.]. The physics that causes this {alpha}-variation should have other observable manifestations, and this motivates us to look for complementary astrophysical effects. In this paper we propose a method to test whether spatial variation of fundamental constants existed during the epoch of big bang nucleosynthesis and study existing measurements of deuterium abundance for a signal. We also examine existing quasar absorption spectra data that are sensitive to variation of the electron-to-proton mass ratio {mu} and x={alpha}{sup 2{mu}}g{sub p} for spatial variation.

Berengut, J. C.; Flambaum, V. V.; King, J. A.; Curran, S. J.; Webb, J. K. [School of Physics, University of New South Wales, Sydney 2052 (Australia)

2011-06-15T23:59:59.000Z

151

Precision cosmology defeats void models for acceleration  

SciTech Connect

The suggestion that we occupy a privileged position near the center of a large, nonlinear, and nearly spherical void has recently attracted much attention as an alternative to dark energy. Putting aside the philosophical problems with this scenario, we perform the most complete and up-to-date comparison with cosmological data. We use supernovae and the full cosmic microwave background spectrum as the basis of our analysis. We also include constraints from radial baryonic acoustic oscillations, the local Hubble rate, age, big bang nucleosynthesis, the Compton y distortion, and for the first time include the local amplitude of matter fluctuations, {sigma}{sub 8}. These all paint a consistent picture in which voids are in severe tension with the data. In particular, void models predict a very low local Hubble rate, suffer from an ''old age problem,'' and predict much less local structure than is observed.

Moss, Adam; Zibin, James P.; Scott, Douglas [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada)

2011-05-15T23:59:59.000Z

152

DARK MATTER POWERED STARS: CONSTRAINTS FROM THE EXTRAGALACTIC BACKGROUND LIGHT  

SciTech Connect

The existence of predominantly cold non-baryonic dark matter is unambiguously demonstrated by several observations (e.g., structure formation, big bang nucleosynthesis, gravitational lensing, and rotational curves of spiral galaxies). A candidate well motivated by particle physics is a weakly interacting massive particle (WIMP). Self-annihilating WIMPs would affect the stellar evolution especially in the early universe. Stars powered by self-annihilating WIMP dark matter should possess different properties compared with standard stars. While a direct detection of such dark matter powered stars seems very challenging, their cumulative emission might leave an imprint in the diffuse metagalactic radiation fields, in particular in the mid-infrared part of the electromagnetic spectrum. In this work, the possible contributions of dark matter powered stars (dark stars, DSs) to the extragalactic background light (EBL) are calculated. It is shown that existing data and limits of the EBL intensity can already be used to rule out some DS parameter sets.

Maurer, A.; Raue, M.; Kneiske, T.; Horns, D. [Institut fuer Experimentalphysik, Universitaet Hamburg, Luruper Chaussee 149, D-22761 Hamburg (Germany); Elsaesser, D. [Institut fuer Theoretische Physik und Astrophysik, Am Hubland, D-97074 Wuerzburg (Germany); Hauschildt, P. H., E-mail: andreas.maurer@physik.uni-hamburg.de [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)

2012-02-01T23:59:59.000Z

153

Cosmology Favoring Extra Radiation and Sub-eV Mass Sterile Neutrinos as an Option  

SciTech Connect

Precision cosmology and big-bang nucleosynthesis mildly favor extra radiation in the Universe beyond photons and ordinary neutrinos, lending support to the existence of low-mass sterile neutrinos. We use the WMAP 7-year data, small-scale cosmic microwave background observations from ACBAR, BICEP, and QuAD, the SDSS 7th data release, and measurement of the Hubble parameter from HST observations to derive credible regions for the assumed common mass scale m{sub s} and effective number N{sub s} of thermally excited sterile neutrino states. Our results are compatible with the existence of one or perhaps two sterile neutrinos, as suggested by LSND and MiniBooNE, if m{sub s} is in the sub-eV range.

Hamann, Jan; Hannestad, Steen [Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C (Denmark); Raffelt, Georg G. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, 80805 Muenchen (Germany); Tamborra, Irene [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, 80805 Muenchen (Germany); Dipartimento Interateneo di Fisica 'Michelangelo Merlin', Via Amendola 173, 70126 Bari (Italy); INFN, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy); Wong, Yvonne Y. Y. [Institut fuer Theoretische Teilchenphysik und Kosmologie, RWTH Aachen, 52056 Aachen (Germany)

2010-10-29T23:59:59.000Z

154

The 3He(alpha,gamma)7Be S-factor at solar energies: the prompt gamma experiment at LUNA  

E-Print Network (OSTI)

The 3He(alpha,gamma)7Be process is a key reaction in both Big-Bang nucleosynthesis and p-p chain of Hydrogen Burning in Stars. A new measurement of the 3He(alpha,gamma)7Be cross section has been performed at the INFN Gran Sasso underground laboratory by both the activation and the prompt gamma detection methods. The present work reports full details of the prompt gamma detection experiment, focusing on the determination of the systematic uncertainty. The final data, including activation measurements at LUNA, are compared with the results of the last generation experiments and two different theoretical models are used to obtain the S-factor at solar energies.

H. Costantini; D. Bemmerer; F. Confortola; A. Formicola; Gy. Gyürky; P. Bezzon; R. Bonetti; C. Broggini; P. Corvisiero; Z. Elekes; Zs. Fülöp; G. Gervino; A. Guglielmetti; C. Gustavino; G. Imbriani; M. Junker; M. Laubenstein; A. Lemut; B. Limata; V. Lozza; M. Marta; R. Menegazzo; P. Prati; V. Roca; C. Rolfs; C. Rossi Alvarez; E. Somorjai; O. Straniero; F. Strieder; F. Terrasi; H. P. Trautvetter

2008-09-30T23:59:59.000Z

155

Numerical solutions to the cosmological 3-fluid problem  

E-Print Network (OSTI)

We show that, for the scalar field cosmology with exponential potential, the set of values of the coupling parameter for which the solutions undergo a transient period of acceleration is much larger than the set discussed in the literature. The gradual inclusion of ordinary and dark matters results in an everywhere, but near the origin, smoother and right shifted (along the time axis) acceleration curve. For the 3-fluid problem, the energy density need not exhibit a plateau during the acceleration period. Much excess in the dark matter and/or ordinary matter energy densities would lead the universe to undergo an eternal deceleration expansion. For the 3-fluid problem with a single exponential potential we conclude that the Big Bang Nucleosynthesis constraint is not fulfilled if the universe is to undergo a transient period of acceleration. The 3-fluid model remains a good approximation for the description of large scale structures.

Mustapha Azreg-Aïnou

2013-02-27T23:59:59.000Z

156

WIMP Dark Matter Limit-Direct Detection Data and Sensitivity Plots from the Cryogenic Dark Matter Search II and the University of California at Santa Barbara  

DOE Data Explorer (OSTI)

Expectations for non-baryonic dark matter are founded principally in Big Bang nucleosynthesis calculations, which indicate that the missing mass of the universe is not likely to be baryonic. The supersymmetric standard model (SUSY) offers a promising framework for expectations of particle species which could satisfy the observed properties of dark matter. WIMPs are the most likely SUSY candidate for a dark matter particle. The High Energy Physics Group at University of California, Santa Barbara, is part of the CDMSII Collaboration and have provided the Interactive Plotter for WIMP Dark Matter Limit-Direct Detection Data on their website. They invite other collaborations working on dark matter research to submit datasets and, as a result, have more than 150 data sets now available for use with the plotting tool. The published source of the data is provided with each data set.

157

Variation of fundamental constants in space and time: theory and observations  

E-Print Network (OSTI)

Review of recent works devoted to the temporal and spatial variation of the fundamental constants and dependence of the fundamental constants on the gravitational potential (violation of local position invariance) is presented. We discuss the variation of the fine structure constant $\\alpha=e^2/\\hbar c$, strong interaction and fundamental masses (Higgs vacuum), e.g. the electron-to-proton mass ratio $\\mu=m_e/M_p$ or $X_e=m_e/\\Lambda_{QCD}$ and $X_q=m_q/\\Lambda_{QCD}$. We also present new results from Big Bang nucleosynthesis and Oklo natural nuclear reactor data and propose new measurements of enhanced effects in atoms, nuclei and molecules, both in quasar and laboratory spectra.

V. V. Flambaum

2008-01-14T23:59:59.000Z

158

Dependence of hadronic properties on Quark Masses and Constraints on their Cosmological Variation  

E-Print Network (OSTI)

We follow our previous paper on possible cosmological variation of weak scale (quark masses) and strong scale, inspired by data on cosmological variation of the electromagnetic fine structure constant from distant quasar (QSO) absorption spectra. In this work we identify the {\\em strange quark mass} $m_s$ as the most important quantity, and the {\\em sigma meson mass} as the ingredient of the nuclear forces most sensitive to it. As a result, we claim significantly stronger limits on ratio of weak/strong scale ($W=m_s/\\Lambda_{QCD}$) variation following from our previous discussion of primordial Big-Bang Nucleosynthesis ($|\\delta W/W|nuclear reactor ($|\\delta W/W|<1.2 \\cdot 10^{-10}$; there is also a non-zero solution $\\delta W/W=(-0.56 \\pm 0.05) \\cdot 10^{-9}$) .

V. V. Flambaum; E. V. Shuryak

2002-12-31T23:59:59.000Z

159

Variation of fundamental constants  

E-Print Network (OSTI)

We present a review of recent works devoted to the variation of the fine structure constant alpha, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra, Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feschbach resonance.

V. V. Flambaum

2006-08-25T23:59:59.000Z

160

EXPLOSIVE NUCLEOSYNTHESIS IN THE NEUTRINO-DRIVEN ASPHERICAL SUPERNOVA EXPLOSION OF A NON-ROTATING 15 M{sub sun} STAR WITH SOLAR METALLICITY  

SciTech Connect

We investigate explosive nucleosynthesis in a non-rotating 15 M{sub sun} star with solar metallicity that explodes by a neutrino-heating supernova (SN) mechanism aided by both standing accretion shock instability (SASI) and convection. To trigger explosions in our two-dimensional hydrodynamic simulations, we approximate the neutrino transport with a simple light-bulb scheme and systematically change the neutrino fluxes emitted from the protoneutron star. By a post-processing calculation, we evaluate abundances and masses of the SN ejecta for nuclei with a mass number {<=}70, employing a large nuclear reaction network. Aspherical abundance distributions, which are observed in nearby core-collapse SN remnants, are obtained for the non-rotating spherically symmetric progenitor, due to the growth of a low-mode SASI. The abundance pattern of the SN ejecta is similar to that of the solar system for models whose masses range between (0.4-0.5) M{sub sun} of the ejecta from the inner region ({<=}10, 000 km) of the precollapse core. For the models, the explosion energies and the {sup 56}Ni masses are {approx_equal} 10{sup 51}erg and (0.05-0.06) M{sub sun}, respectively; their estimated baryonic masses of the neutron star are comparable to the ones observed in neutron-star binaries. These findings may have little uncertainty because most of the ejecta is composed of matter that is heated via the shock wave and has relatively definite abundances. The abundance ratios for Ne, Mg, Si, and Fe observed in the Cygnus loop are reproduced well with the SN ejecta from an inner region of the 15 M{sub sun} progenitor.

Fujimoto, Shin-ichiro [Kumamoto National College of Technology, 2659-2 Suya, Goshi, Kumamoto 861-1102 (Japan); Kotake, Kei [Division of Theoretical Astronomy, National Astronomical Observatory Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hashimoto, Masa-aki; Ono, Masaomi [Department of Physics, School of Sciences, Kyushu University, Fukuoka 810-8560 (Japan); Ohnishi, Naofumi, E-mail: fujimoto@ec.knct.ac.jp [Department of Aerospace Engineering, Tohoku University, 6-6-01 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8579 (Japan)

2011-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Distinguished Lecture Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Distinguished Lecture Series Distinguished Lecture Series Long Fuse, Big Bang: Thomas Edison, Electricity, and the Locus of Innovation Andrew Hargadon October 22, 2012 - 12:00pm...

162

universe.tex - CECM  

E-Print Network (OSTI)

?I think there is no longer any credible alternative to the Big Bang," said Dr. David ... that is being accelerated apart by an even more mysterious ?dark energy.".

163

bigbangnucrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

are in good overall agreement with the primordial abundances inferred from observational data, thus validating the standard hot big-bang cosmology (see 5 for a recent review)....

164

Symposium on the Nature of Science?Streaming Video Archive  

NLE Websites -- All DOE Office Websites (Extended Search)

VI: October 8, 2008 Jeffrey Berryhill Big Science's Next Big Bang: The Large Hadron Collider Carl Haber Imaging the Voices of the Past: Using Physics to Restore...

165

Events  

NLE Websites -- All DOE Office Websites (Extended Search)

Throughout the program physicists answer questions and explain everything from the Higgs boson and the Big Bang to how a particle accelerator works. Physics for Everyone lecture...

166

Public Activities  

NLE Websites -- All DOE Office Websites (Extended Search)

Throughout the program physicists answer questions and explain everything from the Higgs boson and the Big Bang to how a particle accelerator works. Check our recent...

167

Fermilab Today  

NLE Websites -- All DOE Office Websites (Extended Search)

billion building the Large Hadron Collider, in which the colliding protons will recreate energies and conditions last seen a trillionth of a second after the Big Bang. Researchers...

168

Microsoft Word - Friday Flyer - February 22.docx  

NLE Websites -- All DOE Office Websites (Extended Search)

after school extracurricular club that focuses on "quarknet" type topics: particle (Higgs boson) news, quantum science, relativity, big bang, and such. We meet weekly and use the...

169

Primordial nucleosynthesis and neutrino physics  

E-Print Network (OSTI)

16] R. V. Wagoner, W. A. Fowler and F. Hoyle, Astrophys. J.57] G. M. Fuller, W. A. Fowler and M. J. Newman, Astrophys.58] G. M. Fuller, W. A. Fowler and M. J. Newman, Astrophys.

Smith, Christel Johanna

2009-01-01T23:59:59.000Z

170

BRUSLIB and NETGEN: the Brussels nuclear reaction rate library and nuclear network generator for astrophysics  

E-Print Network (OSTI)

Nuclear reaction rates are quantities of fundamental importance in astrophysics. Substantial efforts have been devoted in the last decades to measure or calculate them. The present paper presents for the first time a detailed description of the Brussels nuclear reaction rate library BRUSLIB and of the nuclear network generator NETGEN so as to make these nuclear data packages easily accessible to astrophysicists for a large variety of applications. BRUSLIB is made of two parts. The first one contains the 1999 NACRE compilation based on experimental data for 86 reactions with (mainly) stable targets up to Si. The second part of BRUSLIB concerns nuclear reaction rate predictions calculated within a statistical Hauser-Feshbach approximation, which limits the reliability of the rates to reactions producing compound nuclei with a high enough level density. These calculations make use of global and coherent microscopic nuclear models for the quantities entering the rate calculations. The use of such models is utterly important, and makes the BRUSLIB rate library unique. A description of the Nuclear Network Generator NETGEN that complements the BRUSLIB package is also presented. NETGEN is a tool to generate nuclear reaction rates for temperature grids specified by the user. The information it provides can be used for a large variety of applications, including Big Bang nucleosynthesis, the energy generation and nucleosynthesis associated with the non-explosive and explosive hydrogen to silicon burning stages, or the synthesis of the heavy nuclides through the s-, alpha- and r-, rp- or p-processes.

M. Aikawa; M. Arnould; S. Goriely; A. Jorissen; K. Takahashi

2005-06-24T23:59:59.000Z

171

Gauss-Bonnet Quintessence: Background Evolution, Large Scale Structure and Cosmological Constraints  

E-Print Network (OSTI)

We investigate a string-inspired dark energy scenario featuring a scalar field with a coupling to the Gauss-Bonnet invariant. Such coupling can trigger the onset of late dark energy domination after a scaling matter era. The universe may then cross the phantom divide and perhaps also exit from the acceleration. We discuss extensively the cosmological and astrophysical implications of the coupled scalar field. Data from the Solar system, supernovae Ia, cosmic microwave background radiation, large scale structure and big bang nucleosynthesis is used to constrain the parameters of the model. A good Newtonian limit may require to fix the coupling. With all the data combined, there appears to be some tension with the nucleosynthesis bound, and the baryon oscillation scale seems to strongly disfavor the model. These possible problems might be overcome in more elaborate models. In addition, the validity of these constraints in the present context is not strictly established. Evolution of fluctuations in the scalar field and their impact to clustering of matter is studied in detail and more model-independently. Small scale limit is derived for the perturbations and their stability is addressed. A divergence is found and discussed. The general equations for scalar perturbations are also presented and solved numerically, confirming that the Gauss-Bonnet coupling can be compatible with the observed spectrum of cosmic microwave background radiation as well as the matter power spectrum inferred from large scale surveys.

Tomi Koivisto; David F. Mota

2006-09-22T23:59:59.000Z

172

Nuclear astrophysics: the unfinished quest for the origin of the elements  

E-Print Network (OSTI)

Half a century has passed since the foundation of nuclear astrophysics. Since then, this discipline has reached its maturity. Today, nuclear astrophysics constitutes a multidisciplinary crucible of knowledge that combines the achievements in theoretical astrophysics, observational astronomy, cosmochemistry and nuclear physics. New tools and developments have revolutionized our understanding of the origin of the elements: supercomputers have provided astrophysicists with the required computational capabilities to study the evolution of stars in a multidimensional framework; the emergence of high-energy astrophysics with space-borne observatories has opened new windows to observe the Universe, from a novel panchromatic perspective; cosmochemists have isolated tiny pieces of stardust embedded in primitive meteorites, giving clues on the processes operating in stars as well as on the way matter condenses to form solids; and nuclear physicists have measured reactions near stellar energies, through the combined efforts using stable and radioactive ion beam facilities. This review provides comprehensive insight into the nuclear history of the Universe and related topics: starting from the Big Bang, when the ashes from the primordial explosion were transformed to hydrogen, helium, and few trace elements, to the rich variety of nucleosynthesis mechanisms and sites in the Universe. Particular attention is paid to the hydrostatic processes governing the evolution of low-mass stars, red giants and asymptotic giant-branch stars, as well as to the explosive nucleosynthesis occurring in core-collapse and thermonuclear supernovae, gamma-ray bursts, classical novae, X-ray bursts, superbursts, and stellar mergers.

Jordi Jose; Christian Iliadis

2011-07-12T23:59:59.000Z

173

Cosmology Becomes Data-driven Science Cosmology, our study of the nature, formation, and evolution of  

E-Print Network (OSTI)

), two powerful but competing models were in the air: the big bang and the steady state models by the flood of data from telescopes on Earth and in space. Observations have amply and thoroughly confirmed the big bang model as essentially correct. The Hubble Space Telescope and many other instruments have now

Landweber, Laura

174

The first turbulent combustion  

E-Print Network (OSTI)

The first turbulent combustion arises in a hot big bang cosmological model Gibson (2004) where nonlinear exothermic turbulence permitted by quantum mechanics, general relativity, multidimensional superstring theory, and fluid mechanics cascades from Planck to strong force freeze out scales with gravity balancing turbulent inertial-vortex forces. Interactions between Planck scale spinning and non-spinning black holes produce high Reynolds number turbulence and temperature mixing with huge Reynolds stresses driving the rapid inflation of space. Kolmogorovian turbulent temperature patterns are fossilized as strong-force exponential inflation stretches them beyond the scale of causal connection ct where c is light speed and t is time. Fossil temperature turbulence patterns seed nucleosynthesis, and then hydro-gravitational structure formation in the plasma epoch, Gibson (1996, 2000). Evidence about formation mechanisms is preserved by cosmic microwave background temperature anisotropies. CMB spectra indicate hydro-gravitational fragmentation at supercluster to galaxy masses in the primordial plasma with space stretched by \\~10^50. Bershadskii and Sreenivasan (2002, 2003) CMB multi-scaling coefficients support a strong turbulence origin for the anisotropies prior to the plasma epoch.

Carl H. Gibson

2005-01-19T23:59:59.000Z

175

The Cosmological Foundation of Our World, seen in a Revised History of our Universe  

E-Print Network (OSTI)

This paper has two parts, for a specific multiverse, and for the origin of our universe as it resulted from that multiverse. The first is based on the Planck domain and a Chandrasekhar equation that have quantum, relativity, gravity, and atomic physics in unified operation. The multiverse is an evolutionary system whereby universes survive only when they have those physics, and near-critical mass such that they do not collapse, nor expand too fast. The second part is based on 15 sets of observations of nucleosynthesis and particle properties, aging and demise for our universe, as well as of its early stages. The multiverse is supplied by debris from the aging universes, arriving on the accelerated expansion of intergalactic space. New universes accrete from the debris, which is re-energized and re-constituted gravitationally. In the process, the basic particle properties appear to have been preserved such that our universe originated much later, than it would have done in a Big Bang. The limit of Schwarzschild provides a confirmation, and information on dark energy.

Tom Gehrels

2009-12-29T23:59:59.000Z

176

Nuclear Astrophysics of Worlds in the String Landscape  

E-Print Network (OSTI)

Motivated by landscape models in string theory, cosmic nuclear evolution is analyzed allowing the Standard Model Higgs expectation value w to take values different from that in our world (w=1), while holding the Yukawa couplings fixed. Thresholds are estimated, and astrophysical consequences are described, for several sensitive dependences of nuclear behavior on w. The dependence of the neutron-proton mass difference on w is estimated based on recent calculations of strong isospin symmetry breaking, and is used to derive the threshold of neutron-stable worlds, w ~ 0.6+/- 0.2. The effect of a stable neutron on nuclear evolution in the Big Bang and stars is shown to lead to radical differences from our world, such as a predominance of heavy r-process and s-process nuclei and a lack of normal galaxies, stars and planets. Rough estimates are reviewed of w thresholds for deuteron stability and the pp and pep reactions dominant in many stars. A simple model of nuclear resonances is used to estimate the w dependence of overall carbon and oxygen production during normal stellar nucleosynthesis; carbon production is estimated to change by a fraction ~15(1-w). Radical changes in astrophysical behavior seem to require changes in w of more than a few percent, even for the most sensitive phenomena.

Craig J. Hogan

2006-02-06T23:59:59.000Z

177

Why Are Neutrinos Light? -- An Alternative  

SciTech Connect

We review the recent proposal that neutrinos are light because their masses are proportional to a low scale, f, of lepton flavor symmetry breaking. This mechanism is testable because the resulting pseudo-Goldstone bosons, of mass m_G, couple strongly with the neutrinos, affecting the acoustic oscillations during the eV era of the early universe that generate the peaks in the CMB radiation. Characteristic signals result over a very wide range of (f, m_G) because of a change in the total relativistic energy density and because the neutrinos scatter rather than free-stream. Thermodynamics allows a precise calculation of the signal, so that observations would not only confirm the late-time neutrino mass mechanism, but could also determine whether the neutrino spectrum is degenerate, inverted or hierarchical and whether the neutrinos are Dirac or Majorana. The flavor symmetries could also give light sterile states. If the masses of the sterile neutrinos turn on after the MeV era, the LSND oscillations can be explained without upsetting big bang nucleosynthesis, and, since the sterile states decay to lighter neutrinos and pseudo-Goldstones, without giving too much hot dark matter.

Hall, Lawrence J.; Oliver, Steven J.

2004-09-23T23:59:59.000Z

178

Constraints on cosmological parameters from MAXIMA-1  

SciTech Connect

We set new constraints on a seven-dimensional space of cosmological parameters within the class of inflationary adiabatic models. We use the angular power spectrum of the cosmic microwave background measured over a wide range of l in the first flight of the MAXIMA balloon-borne experiment (MAXIMA-1) and the low-l results from the COBE Differential Microwave Radiometer experiment. We find constraints on the total energy density of the universe, Omega = 1.0(-0.30)(+0.15), the physical density of baryons, Omega (b)h(2) = 0.03 +/- 0.01, the physical density of cold dark matter, Omega (cdm)h(2) = 0.2(-0.1)(+0.2), and the spectral index of primordial scalar fluctuations, n(s) = 1.08 +/- 0.1,all at the 95 percent confidence level. By combining our results with measurements of high-redshift supernovae we constrain the value of the cosmological constant and the fractional amount of pressureless matter in the universe to 0.45<(Lambda)<0.75 and 0.25big bang nucleosynthesis.

Balbi, A.; Ade, P.; Bock, J.; Borrill, J.; Boscaleri, A.; DeBernardis, P.; Ferreira, P.G.; Hanany, S.; Hristov, V.; Jaffe, A.H.; Lee,A.T.; Oh, S.; Pascale; E.; Rabii, B.; Richards, R.L.; Smoot, G.F.; Stompor, R.; Winant, C.D.; Wu, J.H.P.

2006-05-08T23:59:59.000Z

179

Cosmological lepton asymmetry with a nonzero mixing angle $\\theta_{13}$  

E-Print Network (OSTI)

While the baryon asymmetry of the Universe is nowadays well measured by cosmological observations, the bounds on the lepton asymmetry in the form of neutrinos are still significantly weaker. We place limits on the relic neutrino asymmetries using some of the latest cosmological data, taking into account the effect of flavor oscillations. We present our results for two different values of the neutrino mixing angle \\theta_{13}, and show that for large \\theta_{13} the limits on the total neutrino asymmetry become more stringent, diluting even large initial flavor asymmetries. In particular, we find that the present bounds are still dominated by the limits coming from Big Bang Nucleosynthesis, while the limits on the total neutrino mass from cosmological data are essentially independent of \\theta_{13}. Finally, we perform a forecast for COrE, taken as an example of a future CMB experiment, and find that it could improve the limits on the total lepton asymmetry approximately by up to a factor 5.

Castorina, Emanuele; Lattanzi, Massimiliano; Lesgourgues, Julien; Mangano, Gianpiero; Melchiorri, Alessandro; Pastor, Sergio

2012-01-01T23:59:59.000Z

180

Particle Data Group - Errata 2008  

NLE Websites -- All DOE Office Websites (Extended Search)

8 Review of Particle Physics 8 Review of Particle Physics C. Amlser et al., Physics Letters B667, 1 (2008) During the time between editions of the Review of Particle Physics and the Particle Physics Booklet, we often find a number of errata. We correct most errata on our WWW pages. If you should find errata that are not known to us, please send mail to pdg @ lbl.gov. Pages 228, 1316 of the full Review (page 3 of the Web version below): Big-Bang Nucleosynthesis (December 18, 2008): The bottom horizontal axis label of Figure 20.1 should read: Baryon-to-photon ratio η x 1010 (and not η x 10-10); Pages 259, 1319 of the full Review (page 17 of the Web version below): Cosmic Rays (December 19, 2008): The vertical axis label of Figure 24.10 should read: E3dN/dE [m-2sr-1eV2] (and not eV-2)

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Bayesian Belief Network (BBN)-based advisory system development for steam generator replacement project management  

E-Print Network (OSTI)

The growing need for improved project management technique points to the usefulness of a knowledge-base advisory system to help project managers understand current and future project status and optimize decisions based ...

Kim, Dohyoung, 1970-

2002-01-01T23:59:59.000Z

182

Fermilab Today  

NLE Websites -- All DOE Office Websites (Extended Search)

happened less than a billion years after the Big Bang. Read more Safety Tip of the Week Tire failures Click on the image to watch an ABC news story on tire failures associated with...

183

Science and Technology Review, January-February 1997  

SciTech Connect

Table of contents: accelerators at Livermore; the B-Factory and the Big Bang; assessing exposure to radiation; next generation of computer storage; and a powerful new tool to detect clandestine nuclear tests.

NONE

1997-01-01T23:59:59.000Z

184

Microsoft Word - QNet Curriculum Guide.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

and the Energy Frontier, January 1997 9. Ripples in Space-time, April 2002 10. Gamma Ray Bursts, July 1997 11. Echoes from the Big Bang, October 2002 12. Low-Energy Ways to...

185

The SN Ia Rate in High-Redshift Galaxy Clusters  

NLE Websites -- All DOE Office Websites (Extended Search)

Lin, Y.-T. & Mohr, J. J. 2004, ApJ, 617, 879 Livio, M. 2001, in Supernovae and Gamma-Ray Bursts: the Greatest Explosions since the Big Bang, ed. M. Livio, N. Panagia, & K....

186

Faces of Science  

NLE Websites -- All DOE Office Websites (Extended Search)

he has worked on developing fully autonomous "thinking telescopes" that catch gamma-ray bursts-the biggest explosions since the Big Bang. Play video Read more x x PHYSICS...

187

The Universe Adventure - Origins of the CMB  

NLE Websites -- All DOE Office Websites (Extended Search)

Origins of the CMB Decoupling of Matter The first light radiated after decoupling is now known as the CMB. During the first 380,000 years after the Big Bang, the universe was so...

188

bigbangnucrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

are in good overall agreement with the primordial abundances inferred from observational data, thus validating the standard hot Big-Bang cosmology (see 2-6 for reviews). This is...

189

KrakenOverview  

NLE Websites -- All DOE Office Websites (Extended Search)

waves becoming "frozen" when the matter and radiation decouple in the Big Bang. Actual usage by discipline ('09) Total Users: 1451 Active Users: 400 Total Projects: 357 TG:291...

190

The Royal Observatory Edinburgh comprises the UK Astronomy Technology Centre of the Science and Technology Facilities Council, the Institute for Astronomy of the University of Edinburgh and the ROE Visitor Centre.  

E-Print Network (OSTI)

targets so that we can explore the most distant galaxies formed just after The E-ELT will study nearby. the Big Bang, study individual stars in distant galaxies for the first time, and directly observe planets

Tittley, Eric

191

Joel Rowland  

NLE Websites -- All DOE Office Websites (Extended Search)

he has worked on developing fully autonomous "thinking telescopes" that catch gamma-ray bursts-the biggest explosions since the Big Bang. Play video Read more x x PHYSICS...

192

Cosmological Variation of the Fine Structure Constant from an Ultra-Light Scalar Field: The Effects of Mass  

E-Print Network (OSTI)

Cosmological variation of the fine structure constant $\\alpha$ due to the evolution of a spatially homogeneous ultra-light scalar field ($m \\sim H_0$) during the matter and $\\Lambda$ dominated eras is analyzed. Agreement of $\\Delta \\alpha/\\alpha$ with the value suggested by recent observations of quasar absorption lines is obtained by adjusting a single parameter, the coupling of the scalar field to matter. Asymptotically $\\alpha(t)$ in this model goes to a constant value $\\bar{\\alpha} \\approx \\alpha_0$ in the early radiation and the late $\\Lambda$ dominated eras. The coupling of the scalar field to (nonrelativistic) matter drives $\\alpha$ slightly away from $\\bar{\\alpha}$ in the epochs when the density of matter is important. Simultaneous agreement with the more restrictive bounds on the variation $|\\Delta \\alpha/\\alpha|$ from the Oklo natural fission reactor and from meteorite samples can be achieved if the mass of the scalar field is on the order of 0.5--0.6 $H_\\Lambda$, where $H_\\Lambda = \\Omega_\\Lambda^{1/2} H_0$. Depending on the scalar field mass, $\\alpha$ may be slightly smaller or larger than $\\alpha_0$ at the times of big bang nucleosynthesis, the emission of the cosmic microwave background, the formation of early solar system meteorites, and the Oklo reactor. The effects on the evolution of $\\alpha$ due to nonzero mass for the scalar field are emphasized. An order of magnitude improvement in the laboratory technique could lead to a detection of $(\\dot{\\alpha}/\\alpha)_0$.

Carl L. Gardner

2003-05-06T23:59:59.000Z

193

{sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions at sub-coulomb energies  

SciTech Connect

The {sup 2}H({sup 3}He,p{sup 3}H){sup 1}H and {sup 2}H({sup 3}He,n{sup 3}He){sup 1}H processes have been measured in quasi free kinematics to investigate for the first time the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions by means of the Trojan Horse Method. The {sup 3}He+d experiment was performed at 18 MeV, corresponding the a d-d energy range from 1.5 MeV down to 2 keV. This range overlaps with the relevant region for Standard Big Bang Nucleosynthesis as well as with the thermal energies of future fusion reactors and deuterium burning in the Pre Main Sequence phase of stellar evolution. This is the first pioneering experiment in quasi free regime where the charged spectator is detected. Both the energy dependence and the absolute value of the bare nucleus S(E) factors have been extracted for the first time. They deviate by more than 15% from available direct data with new S(0) values of 57.4{+-}1.8 MeVb for {sup 3}H+p and 60.1{+-}1.9 MeVb for {sup 3}He+n. None of the existing fitting curves is able to provide the correct slope of the new data in the full range, thus calling for a revision of the theoretical description. This has consequences in the calculation of the reaction rates with more than a 25% increase at the temperatures of future fusion reactors.

Tumino, A.; Spitaleri, C.; Mukhamedzhanov, A. M.; Typel, S.; Sparta, R.; Aliotta, M.; Kroha, V.; Hons, Z.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Mrazek, J.; Pizzone, R. G.; Rapisarda, G. G.; Romano, S.; Sergi, M. L. [Universita degli Studi di Enna Kore, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Cyclotron Institute Texas A and M University - College Station, Texas (United States); Excellence Cluster Universe - Technische Universitaet Muenchen, Garching, Germany and GSI Helmholtzzentrum fuer Schwerionenforschung GmbH - Theorie Darmstadt (Germany); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); School of Physics and Astronomy - University of Edinburgh, SUPA (United Kingdom); Nuclear Physics Institute of ASCR - Rez near Prague (Czech Republic); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Nuclear Physics Institute of ASCR - Rez near Prague (Czech Republic); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy)

2012-11-20T23:59:59.000Z

194

LOS ALAMOS, N.M., Oct. 31, 2013-Los Alamos National Laboratory scientist  

NLE Websites -- All DOE Office Websites (Extended Search)

Matter, antimatter and surviving the big Matter, antimatter and surviving the big bang is topic of Lab's next Frontiers in Science lecture October 31, 2013 Talk begins at 7 p.m. and open to public LOS ALAMOS, N.M., Oct. 31, 2013-Los Alamos National Laboratory scientist Vincenzo Cirigliano asks the question, How did we survive the big bang? in a series of Frontiers in Science lectures beginning Monday, Nov. 4, in the Duane Smith Auditorium at Los Alamos High School. "Particles and antiparticles were produced in equal numbers in the aftermath of the big bang," according to Cirigliano. "As the primordial soup cooled, they should have completely destroyed each other, leaving behind a universe with no matter. Instead, an - 2 - imbalance of matter over antimatter developed, eventually leading to galaxies and stars

195

bigbangrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

3 3 by K.A. Olive (University of Minnesota) and J.A. Peacock (University of Edinburgh). 21.1. Introduction to Standard Big-Bang Model The observed expansion of the Universe [1,2,3] is a natural (almost inevitable) result of any homogeneous and isotropic cosmological model based on general relativity. However, by itself, the Hubble expansion does not provide sufficient evidence for what we generally refer to as the Big-Bang model of cosmology. While general relativity is in principle capable of describing the cosmology of any given distribution of matter, it is extremely fortunate that our Universe appears to be homogeneous and isotropic on large scales. Together, homogeneity and isotropy allow us to extend the Copernican Principle to the Cosmological Principle, stating that all spatial positions in the Universe are essentially equivalent. The formulation of the Big-Bang

196

Berkeley Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

Search 29 Breakthroughs Search 29 Breakthroughs At Berkeley Lab, we've: Discovered sixteen elements. The periodic table would be smaller without Berkeley Lab. Among the Lab's handiwork is an instrumental role in the discovery of technetium-99, which has revolutionized the field of medical imaging. There's also americium, which is widely used in smoke detectors. Identified good and bad cholesterol. The battle against heart disease received a boost in the 1960s when Lab research unveiled the good and bad sides of cholesterol. Today, diagnostic tests that detect both types of cholesterol save lives. Big Bang Confirmed the Big Bang, and discovered dark energy. Lab detectors aboard a NASA satellite revealed the birth of the galaxies in the echoes of the Big Bang. And dark energy - the mysterious something

197

bigbangrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

1 1 by K.A. Olive (University of Minnesota) and J.A. Peacock (University of Edinburgh). 21.1. Introduction to Standard Big-Bang Model The observed expansion of the Universe [1,2,3] is a natural (almost inevitable) result of any homogeneous and isotropic cosmological model based on general relativity. However, by itself, the Hubble expansion does not provide sufficient evidence for what we generally refer to as the Big-Bang model of cosmology. While general relativity is in principle capable of describing the cosmology of any given distribution of matter, it is extremely fortunate that our Universe appears to be homogeneous and isotropic on large scales. Together, homogeneity and isotropy allow us to extend the Copernican Principle to the Cosmological Principle, stating that all spatial positions in the Universe are essentially equivalent. The formulation of the Big-Bang

198

Neutrinos and Nucleosynthesis in Gamma-Ray Burst Accretion Disks  

E-Print Network (OSTI)

We calculate the nuclear composition of matter in accretion disks surrounding stellar mass black holes as are thought to accompany gamma-ray bursts (GRBs). We follow a mass element in the accretion disk starting at the point of nuclear dissociation and calculate the evolution of the electron fraction due to electron, positron, electron neutrino and electron antineutrino captures. We find that the neutronization of the disk material by electron capture can be reversed by neutrino interactions in the inner regions of disks with accretion rates of 1 M_solar/s and higher. For these cases the inner disk regions are optically thick to neutrinos, and so to estimate the emitted neutrino fluxes we find the surface of last scattering for the neutrinos (the equivalent of the proto-neutron star neutrinosphere) for each optically thick disk model. We also estimate the influence of neutrino interactions on the neutron-to-proton ratio in outflows from GRB accretion disks, and find it can be significant even when the disk is optically thin to neutrinos.

R. Surman; G. C. McLaughlin

2003-07-31T23:59:59.000Z

199

Calculations of fission rates for r-process nucleosynthesis  

E-Print Network (OSTI)

Fission plays an important role in the r-process which is responsible not only for the yields of transuranium isotopes, but may have a strong influence on the formation of the majority of heavy nuclei due to fission recycling. We present calculations of beta-delayed and neutron-induced fission rates, taking into account different fission barriers predictions and mass formulae. It is shown that an increase of fission barriers results naturally in a reduction of fission rates, but that nevertheless fission leads to the termination of the r-process. Furthermore, it is discussed that the probability of triple fission could be high for $A>260$ and have an effect on the formation of the abundances of heavy nuclei. Fission after beta-delayed neutron emission is discussed as well as different aspects of the influence of fission upon r-process calculations.

I. V. Panov; E. Kolbe; B. Pfeiffer; T. Rauscher; K. -L. Kratz; F. -K. Thielemann

2004-12-29T23:59:59.000Z

200

Nucleosynthesis in type Ia supernovae driven by asymmetric thermonuclear ignition  

Science Conference Proceedings (OSTI)

Type Ia Supernovae (SNe Ia) are believed to be thermonuclear explosions of a white dwarf. They can be used as mature cosmological standardized candles, leading to the discovery of the accelerating expansion of the Universe. However, the explosion mechanism has not yet been fully clarified. In this paper, we first present nucleosynthetic features of a leading explosion scenario, namely a delayed-detonation scenario. Based on this, we propose a new and strong observational constraint on the explosion mechanism through emission lines from neutron-rich Fe-peaks. Especially, we show that an asymmetry in the explosion is likely a generic feature. We further argue that the diversity arising from various viewing angles can be an origin of observational diversities of SNe Ia seen in their spectral features (suspected possible biases in cosmology) and colors (related to the extinction estimate in cosmology). Using these new insights could open up a possibility of using SNe Ia as more precise distance indicators than currently employed.

Maeda, Keiichi [Institute for the Physics and Mathematics of the Universe (IPMU), Todai Institutes for Advanced Study (TODIAS), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

2012-11-12T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

The CMBR and the Seeds of Galaxies  

E-Print Network (OSTI)

The Cosmic Microwave Background Radiation (CMBR) is the radiation left over from the hot Big Bang. Its blackbody spectrum and small anisotropy provide clues about the origin and early evolution of the Universe. In particular, the spectrum of the CMBR rules out many non-gravitational models of structure formation, and the anisotropy of the CMBR provides a measure of the gravitational potential at the time of last scattering, about 300,000 years after the Big Bang. The density inhomogeneities needed to produce the gravitational potential perturbations traced by the CMBR have grown to become the galaxies, clusters of galaxies, and superclusters that we see today.

Edward L. Wright

1997-11-19T23:59:59.000Z

202

Case study: visualization of particle track data  

Science Conference Proceedings (OSTI)

The Relativistic Heavy Ion Collider (RHIC) experiment at the Brookhaven National Lab is designed to study how the universe came into being. It is believed that after the Big Bang, the universe expanded and cooled, consisting of a soup of quarks, gluons, ...

Xiaoming Wei; Arie E. Kaufman; Timothy J. Hallman

2001-10-01T23:59:59.000Z

203

Anthony Cooke AST/EGL 389  

E-Print Network (OSTI)

, humanity were just a glimmer in the cosmic eye. Exactly how they survived in earth's roaring infancy with the Big Bang out of a one in a million chance, and remained exiled in space, waiting. "In fact, it is entirely possible that this organism, in its earliest form, was able to endure the extreme cold of space

Walter, Frederick M.

204

13Name ________________________________ In 2004, astronomer Immo Appenzeller and his colleagues from Germany and the United  

E-Print Network (OSTI)

a Deep Field image of a small piece of the sky. The goal of this research was to find the most distant-back time you found for a galaxy in Question 3? How long after the Big Bang did this galaxy form? Exploring Space Mathematics http://image.gsfc.nasa.gov/poetry #12;Teacher's Guide A Glimpse of the Most Distant

205

Magnetic Bianchi type II string cosmological model in loop quantum cosmology  

E-Print Network (OSTI)

The loop quantum cosmology of the Bianchi type II string cosmological model in the presence of a homogeneous magnetic field is studied. We present the effective equations which provide modifications to the classical equations of motion due to quantum effects. The numerical simulations confirm that the big bang singularity is resolved by quantum gravity effects.

Victor Rikhvitsky; Bijan Saha; Mihai Visinescu

2013-12-09T23:59:59.000Z

206

The origin of mass  

Science Conference Proceedings (OSTI)

The origin of mass is one of the deepest mysteries in science. Neutrons and protons, which account for almost all visible mass in the Universe, emerged from a primordial plasma through a cataclysmic phase transition microseconds after the Big Bang. However, ... Keywords: Gordon Bell Prize categories: scalability and time to solution, SC13 proceedings

Peter Boyle, Michael I. Buchoff, Norman Christ, Taku Izubuchi, Chulwoo Jung, Thomas C. Luu, Robert Mawhinney, Chris Schroeder, Ron Soltz, Pavlos Vranas, Joseph Wasem

2013-11-01T23:59:59.000Z

207

Limits on cosmological variation of quark masses and strong interaction  

E-Print Network (OSTI)

We discuss limits on variation of $(m_q/\\Lambda_{QCD})$. The results are obtained by studying $n-\\alpha$-interaction during Big Bang, Oklo natural nuclear reactor data and limits on variation of the proton $g$-factor from quasar absorpion spectra.

V. F. Dmitriev; V. V. Flambaum

2002-09-19T23:59:59.000Z

208

A search for particle dark matter using cryogenic germanium and silicon detectors in the one- and two- tower runs of CDMS-II at Soudan  

SciTech Connect

Images of the Bullet Cluster of galaxies in visible light, X-rays, and through gravitational lensing confirm that most of the matter in the universe is not composed of any known form of matter. The combined evidence from the dynamics of galaxies and clusters of galaxies, the cosmic microwave background, big bang nucleosynthesis, and other observations indicates that 80% of the universe's matter is dark, nearly collisionless, and cold. The identify of the dar, matter remains unknown, but weakly interacting massive particles (WIMPs) are a very good candidate. They are a natural part of many supersymmetric extensions to the standard model, and could be produced as a nonrelativistic, thermal relic in the early universe with about the right density to account for the missing mass. The dark matter of a galaxy should exist as a spherical or ellipsoidal cloud, called a 'halo' because it extends well past the edge of the visible galaxy. The Cryogenic Dark Matter Search (CDMS) seeks to directly detect interactions between WIMPs in the Milky Way's galactic dark matter halo using crystals of germanium and silicon. Our Z-sensitive ionization and phonon ('ZIP') detectors simultaneously measure both phonons and ionization produced by particle interactions. In order to find very rare, low-energy WIMP interactions, they must identify and reject background events caused by environmental radioactivity, radioactive contaminants on the detector,s and cosmic rays. In particular, sophisticated analysis of the timing of phonon signals is needed to eliminate signals caused by beta decays at the detector surfaces. This thesis presents the firs two dark matter data sets from the deep underground experimental site at the Soudan Underground Laboratory in Minnesota. These are known as 'Run 118', with six detectors (1 kg Ge, 65.2 live days before cuts) and 'Run 119', with twelve detectors (1.5 kg Ge, 74.5 live days before cuts). They have analyzed all data from the two runs together in a single, combined analysis, with sensitivity to lower-energy interactions, careful control of data quality and stability, and further development of techniques for reconstructing event location and rejecting near-surface interactions from beta decays. They also present a revision to the previously published Run 119 analysis, a demonstration of the feasibility of a low-threshold (1 or 2 keV) analysis of Soudan data, and a review of the literature on charge generation and quenching relevant to the ionization signal.

Ogburn, Reuben Walter, IV; /Stanford U., Phys. Dept.

2008-04-01T23:59:59.000Z

209

Jefferson Lab Science Series - The Origin of the Elements  

NLE Websites -- All DOE Office Websites (Extended Search)

You Already Know This Physics! You Already Know This Physics! Previous Video (You Already Know This Physics!) Science Series Video Archive Next Video (Guesstimating the Environment) Guesstimating the Environment The Origin of the Elements Dr. Edward Murphy - University of Virginia, Department of Astronomy November 13, 2012 The world around us is made of atoms. Did you ever wonder where these atoms came from? How was the gold in our jewelry, the carbon in our bodies, and the iron in our cars made? In this lecture, we will trace the origin of a gold atom from the Big Bang to the present day, and beyond. You will learn how the elements were forged in the nuclear furnaces inside stars, and how, when they die, these massive stars spread the elements into space. You will learn about the origin of the building blocks of matter in the Big Bang,

210

South Pole Telescope helps Argonne scientists study earliest ages of the  

NLE Websites -- All DOE Office Websites (Extended Search)

Related Content Related Content Employee Spotlight: Clarence Chang South Pole Telescope helps Argonne scientists study earliest ages of the universe By Louise Lerner * October 28, 2013 Tweet EmailPrint For physicist Clarence Chang at the U.S. Department of Energy's (DOE) Argonne National Laboratory, looking backward in time to the earliest ages of the universe is all in a day's work. Chang helped design and operate part of the South Pole Telescope, a project that aims a giant telescope at the night sky to track tiny bits of radiation that are still traveling across the universe from the period just after it was born. "Basically, what we're looking at is the afterglow light of the Big Bang," Chang said. In the wake of the Big Bang, all the matter in the universe was just hot,

211

Symposium on the Nature of Science—Rocky Kolb  

NLE Websites -- All DOE Office Websites (Extended Search)

FIRST SECOND IN THE LIFE OF THE UNIVERSE FIRST SECOND IN THE LIFE OF THE UNIVERSE Rocky Kolb Watch the talk (Running time 51:09) Video in Frame Detached Video Some users have reported problems with the "Video in Frame" option. If you have problems, please try the "Detached Video" option. Requires RealPlayer 7.0 or higher. Get RealPlayer Thirteen billion years ago our universe started with a bang. Today we are gathering the fossil evidence of the very earliest moments of the universe. Our picture of the very beginning of the universe is still incomplete, with outstanding questions like: What powered the big bang? What is the dark matter that binds together the universe? What is the dark energy that thrusts apart the universe? Are there hidden spacetime dimensions? What was before the big bang?

212

The Fluid Mechanics of Gravitational Structure Formation  

E-Print Network (OSTI)

The standard model for gravitational structure formation in astrophysics, astronomy, and cosmology is questioned. Cold dark matter (CDM) hierarchical clustering cosmology neglects particle collisions, viscosity, turbulence and diffusion and makes predictions in conflict with observations. From Jeans 1902 and CDMHC, the non-baryonic dark matter NBDM forms small clumps during the plasma epoch after the big bang that ``cluster'' into larger clumps. CDM halo clusters collect the baryonic matter (H and He) by gravity so that after 300 Myr of ``dark ages'', huge, explosive (Population III) first stars appear, and then galaxies and galaxy clusters. Contrary to CDMHC cosmology, ``hydro-gravitational-dynamics'' HGD cosmology suggests the diffusive NBDM material cannot clump and the clumps cannot cluster. From HGD, the big bang results from an exothermic turbulent instability at Planck scales (10^{-35} m). Turbulent stresses cause an inflation of space and fossil density turbulence remnants that trigger gravitational i...

Gibson, C H

2006-01-01T23:59:59.000Z

213

Inflationary Cosmology  

E-Print Network (OSTI)

The big bang model and the history of the early universe according to the grand unified theories are introduced. The shortcomings of big bang are discussed together with their resolution by inflationary cosmology. Inflation, the subsequent oscillation and decay of the inflaton, and the resulting "reheating" of the universe are studied. The density perturbations produced by inflation and the temperature fluctuations of the cosmic background radiation are discussed. The hybrid inflationary model is described. Two "natural" extensions of this model which avoid the disaster encountered in its standard realization from the overproduction of monopoles are presented. Successful "reheating" satisfying the gravitino constraint takes place after the end of inflation in all three versions of hybrid inflation. Adequate baryogenesis via a primordial leptogenesis occurs consistently with the solar and atmospheric neutrino oscillation data. The primordial lepton asymmetry is turned partly into baryon asymmetry via the sphalerons which are summarized.

G. Lazarides

2001-11-26T23:59:59.000Z

214

Demagnified gravitational waves from cosmological double neutron stars and gravitational wave foreground cleaning around 1 Hz  

Science Conference Proceedings (OSTI)

Gravitational waves (GWs) from cosmological double neutron star binaries (NS+NS) can be significantly demagnified by the strong gravitational lensing effect, and the proposed future missions such as the Big Bang Observer or Deci-hertz Interferometer Gravitational Wave Observatory might miss some of the demagnified GW signals below a detection threshold. The undetectable binaries would form a GW foreground, which might hamper detection of a very weak primordial GW signal. We discuss the outlook of this potential problem, using a simple model based on the singular isothermal sphere lens profile. Fortunately, it is expected that, for a presumable merger rate of NS+NSs, the residual foreground would be below the detection limit {omega}{sub GW,lim}{approx}10{sup -16} realized with the Big Bang Observer/Deci-hertz Interferometer Gravitational Wave Observatory by correlation analysis.

Seto, Naoki [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2009-11-15T23:59:59.000Z

215

Does the universe obey the energy conservation law by a constant mass or an increasing mass with radius during its evolution?  

E-Print Network (OSTI)

How the energy conservation law is obeyed by the universe during its evolution is an important but not yet unanimously resolved question. Does the universe have a constant mass during its evolution or has its mass been increasing with its radius? Here, we evaluate the two contending propositions within the context of the Friedmann equations and the standard big bang theory. We find that though both propositions appeal to the Friedmann equations for validity, an increasing mass with increasing radius is more in harmony with the thermal history of the big bang model. In addition, temperature and flatness problems that plague the constant mass proposal are mitigated by the increasing mass with radius proposal. We conclude that the universe has been increasing in mass and radius in obedience to the energy conservation law.

Akinbo Ojo

2008-10-09T23:59:59.000Z

216

Search for the Cosmic Neutrino Background and KATRIN  

E-Print Network (OSTI)

The Cosmic Microwave Background (CMB) has been detected in 1964 by Penzias and Wilson. It shows today a remarkable constant temperature of T ~ 2.7 K independent of the direction. Present density is about 370 photons per cubic-cm. The size of the hot spots, which deviates only in the fifth decimal of the temperature from the average value, tells us, that the universe is flat. About 300 000 years after the Big Bang at a temperature of T = 3000 K already in the matter dominated era the electrons combine with the protons and 4He and the photons move freely in the neutral universe. So the temperature and distribution of the photons give us information of the universe 300 000 years after the Big Bang. Information about earlier times can, in principle, be derived from the Cosmic Neutrino Background. The neutrinos decouple already 1 second after the Big Bang at a temperature of about 10^{10} K. Today their temperature is ~ 1.95 K and the average density is 56 electron-neutrinos per cubic-cm. Registration of these neutrinos is an extremely challenging experimental problem which can hardly be solved with the present technologies. On the other hand it represents a tempting opportunity to check one of the key element of the Big Bang cosmology and to probe the early stages of the universe evolution. The search for the cosmic relic neutrinos with the induced beta decay Electron-neutrino + 3H --> 3He + e- is the topic of this contribution. The signal would show up by a peak in the electron spectrum with an energy of the neutrino mass above the Q value. We discuss the prospects of this approach and argue that it is able to set limits on the relic neutrino density in our vicinity.

Amand Faessler; Rastislav Hodak; Sergey Kovalenko; Fedor Simkovic

2013-04-20T23:59:59.000Z

217

Adaptive fuzzy model based inverse controller design using BB-BC optimization algorithm  

Science Conference Proceedings (OSTI)

The use of inverse system model as a controller might be an efficient way in controlling non-linear systems. It is also a known fact that fuzzy logic modeling is a powerful tool in representing nonlinear systems. Therefore, inverse fuzzy model can be ... Keywords: Big Bang-Big Crunch optimization, Fuzzy logic controller, Fuzzy model inversion, Heat transfer process, Inverse model based control, pH process

Tufan Kumbasar; Ibrahim Eksin; Mujde Guzelkaya; Engin Yesil

2011-09-01T23:59:59.000Z

218

Constraints on primordial density perturbations from induced gravitational waves  

SciTech Connect

We consider the stochastic background of gravitational waves produced during the radiation-dominated hot big bang as a constraint on the primordial density perturbation on comoving length scales much smaller than those directly probed by the cosmic microwave background or large-scale structure. We place weak upper bounds on the primordial density perturbation from current data. Future detectors such as BBO and DECIGO will place much stronger constraints on the primordial density perturbation on small scales.

Assadullahi, Hooshyar; Wands, David [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom)

2010-01-15T23:59:59.000Z

219

Why Time is Future Oriented  

E-Print Network (OSTI)

We assume that the universe consists of clusters which in turns have sub-clusters and the sub-clusters have sub-subclusters and so on. Confining to three-dimensional space, it is shown that the universe is expanding if entropy of the universe increases. It is also shown that clocks slow down when time progresses towards future. Our model also justifies the big bang theory.

Shahid N. Afridi; M. Khalid Khan

2004-12-09T23:59:59.000Z

220

Cosmology, Thermodynamics and Matter Creation  

E-Print Network (OSTI)

Several approaches to the matter creation problem in the context of cosmological models are summarily reviewed. A covariant formulation of the general relativistic imperfect simple fluid endowed with a process of matter creation is presented. By considering the standard big bang model, it is shown how the recent results of Prigogine et alii \\cite{1} can be recovered and, at the same time their limits of validity are explicited.

J. A. S. Lima; M. O. Calvao; I. Waga

2007-08-24T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

The promise of the large collider  

E-Print Network (OSTI)

"In 2007, the most powerful particle accelerator ever built, CERN's new Large hadron Collider, will probe the secrets of matter in the energy states prevailing in the moments after the Big Bang. By colliding particles together when they are moving at close to the speed of ight, physicists hope to find out about matter in its earliest forms, using the energy produced by the collisions." (2 pages)

2007-01-01T23:59:59.000Z

222

New ekpyrotic cosmology  

SciTech Connect

In this paper, we present a new scenario of the early universe that contains a pre-big bang ekpyrotic phase. By combining this with a ghost condensate, the theory explicitly violates the null energy condition without developing any ghostlike instabilities. Thus the contracting universe goes through a nonsingular bounce and evolves smoothly into the expanding post-big bang phase. The curvature perturbation acquires a scale-invariant spectrum well before the bounce in this scenario. It is sourced by the scale-invariant entropy perturbation engendered by two ekpyrotic scalar fields, a mechanism recently proposed by Lehners et al. Since the background geometry is nonsingular at all times, the curvature perturbation remains nearly constant on superhorizon scales. It emerges from the bounce unscathed and imprints a scale-invariant spectrum of density fluctuations in the matter-radiation fluid at the onset of the hot big bang phase. The ekpyrotic potential can be chosen so that the spectrum has a red tilt, in accordance with the recent data from WMAP. As in the original ekpyrotic scenario, the model predicts a negligible gravity wave signal on all observable scales. As such ''new ekpyrotic cosmology'' provides a consistent and distinguishable alternative to inflation to account for the origin of the seeds of large-scale structure.

Buchbinder, Evgeny I.; Khoury, Justin [Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2L 2Y5 (Canada); Ovrut, Burt A. [Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6395 (United States)

2007-12-15T23:59:59.000Z

223

Liquid-Gas Phase Transition of Supernova Matter and Its Relation to Nucleosynthesis  

E-Print Network (OSTI)

We investigate the liquid-gas phase transition of dense matter in supernova explosion by the relativistic mean field approach and fragment based statistical model. The boiling temperature is found to be high (T_{boil} >= 0.7 MeV for rho_B >= 10^{-7} fm^{-3}), and adiabatic paths are shown to go across the boundary of coexisting region even with high entropy. This suggests that materials experienced phase transition can be ejected to outside. We calculated fragment mass and isotope distribution around the boiling point. We found that heavy elements at the iron, the first, second, and third peaks of r-process are abundantly formed at rho_B = 10^{-7}, 10^{-5}, 10^{-3} and 10^{-2} fm^{-3}, respectively.

C. Ishizuka; A. Ohnishi; K. Sumiyoshi

2002-08-12T23:59:59.000Z

224

nu-Process Nucleosynthesis in Population III Core-Collapse Supernovae  

E-Print Network (OSTI)

We investigate the effects of neutrino-nucleus interactions (the nu-process) on the production of iron-peak elements in Population III core-collapse supernovae. The nu-process and the following proton and neutron capture reactions produce odd-Z iron-peak elements in complete and incomplete Si burning region. This reaction sequence enhances the abundances of Sc, Mn, and Co in the supernova ejecta. The supernova explosion models of 15 M_sol and 25 M_sol stars with the nu-process well reproduce the averaged Mn/Fe ratio observed in extremely metal-poor halo stars. In order to reproduce the observed Mn/Fe ratio, the total neutrino energy in the supernovae should be 3 - 9 x 10^{53} ergs. Stronger neutrino irradiation and other production sites are necessary to reproduce the observed Sc/Fe and Co/Fe ratios, although these ratios increase by the nu-process.

Takashi Yoshida; Hideyuki Umeda; Ken'ichi Nomoto

2007-10-01T23:59:59.000Z

225

NUCLEOSYNTHESIS OF NICKEL-56 FROM GAMMA-RAY BURST ACCRETION DISKS  

Science Conference Proceedings (OSTI)

We examine the prospects for producing nickel-56 from black hole accretion disks, by examining a range of steady-state disk models. We focus on relatively slowly accreting disks in the range of M-dot = 0.05 M{sub Sun} s{sup -1} to M-dot = 1 M{sub Sun} s{sup -1}, as are thought to be appropriate for the central engines of long-duration gamma-ray bursts. We find that significant amounts of nickel-56 are produced over a wide range of parameter space. We discuss the influence of entropy, outflow timescale, and initial disk position on mass fraction of nickel-56 which is produced. We keep careful track of the weak interactions to ensure reliable calculations of the electron fraction, and discuss the role of the neutrinos.

Surman, R.; Sabbatino, N. [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States); McLaughlin, G. C. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States)

2011-12-20T23:59:59.000Z

226

NUCLEOSYNTHESIS AND THE INHOMOGENEOUS CHEMICAL EVOLUTION OF THE CARINA DWARF GALAXY  

Science Conference Proceedings (OSTI)

The detailed abundances of 23 chemical elements in nine bright red giant branch stars in the Carina dwarf spheroidal galaxy are presented based on high-resolution spectra gathered at the Very Large Telescope (VLT) and Magellan telescopes. A spherical model atmospheres analysis is applied using standard methods (local thermodynamic equilibrium and plane-parallel radiative transfer) to spectra ranging from 380 to 680 nm. Stellar parameters are found to be consistent between photometric and spectroscopic analyses, both at moderate and high resolution. The stars in this analysis range in metallicity from -2.9 Car-612, seems to have formed in a pocket enhanced in SN Ia/II products. This latter star provides the first direct link between the formation of stars with enhanced SN Ia/II ratios in dwarf galaxies to those found in the outer Galactic halo (Ivans et al.). Another important result is the potential evidence for SN II driven winds. We show that the very metal-poor stars in Carina have not been enhanced in asymptotic giant branch or SN Ia products, and therefore their very low ratios of [Sr/Ba] suggests the loss of contributions from the early SNe II. Low ratios of [Na/Fe], [Mn/Fe], and [Cr/Fe] in two of these stars support this scenario, with additional evidence from the low [Zn/Fe] upper limit for one star. It is interesting that the chemistry of the metal-poor stars in Carina is not similar to those in the Galaxy, most of the other dwarf spheroidal galaxies, or the ultra faint dwarfs, and suggests that Carina may be at the critical mass where some chemical enrichments are lost through SN II driven winds.

Venn, Kim A.; Divell, Mike [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 1A1 (Canada); Shetrone, Matthew D. [McDonald Observatory, University of Texas at Austin, HC75 Box 1337-McD, Fort Davis, TX 79734 (United States); Irwin, Mike J. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB03 0HA (United Kingdom); Hill, Vanessa [Laboratoire Cassiopee UMR 6202, Universite de Nice Sophia-Antipolis, CNRS, Observatoire de la Cote d'Azur (France); Jablonka, Pascale [GEPI, Observatoire de Paris, CNRS UMR 8111, Universite Paris Diderot, F-92125, Meudon, Cedex (France); Tolstoy, Eline; Lemasle, Bertrand; Starkenburg, Else; Helmi, Amina [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Letarte, Bruno [South African Astronomical Observatory, Observatory Road, 7935 Observatory (South Africa); Baldner, Charles [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Battaglia, Giuseppina; Primas, Francesca [European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching (Germany); Kaufer, Andreas, E-mail: kvenn@uvic.ca [European Southern Observatory, Alonso de Cordova 3107, Santiago (Chile)

2012-06-01T23:59:59.000Z

227

Bottlenecks and Waiting Points in Nucleosynthesis in X-ray bursts and Novae  

Science Conference Proceedings (OSTI)

To better understand the energy generation and element synthesis occurring in novae and X-ray bursts, we give quantitative definitions to the concepts of ''bottlenecks'' and ''waiting points'' in the thermonuclear reaction flow. We use these criteria to search for bottlenecks and waiting points in post-processing element synthesis explosion simulations. We have incorporated these into the Computational Infrastructure for Nuclear Astrophysics, a suite of nuclear astrophysics codes available online at nucastrodata.org, so that anyone may perform custom searches for bottlenecks and waiting points.

Smith, Michael S.; Hix, W. Raphael; Nesaraja, Caroline D. [Physics Division, Oak Ridge National Lab, Oak Ridge, Tennessee, 37831-6354 (United States); Sunayama, Tomomi [Knox College, 2 East South Street, Galesburg, Illinois, 61401-4999 (United States); Dept. of Physics and Astronomy, Yale University, New Haven, Connecticut, 06520 (United States); Lingerfelt, Eric J. [Computational Science and Mathematics Division, Oak Ridge National Lab, Oak Ridge, Tennessee, 37831-6354 (United States); Physics Division, Oak Ridge National Lab, Oak Ridge, Tennessee, 37831-6354 (United States)

2010-08-12T23:59:59.000Z

228

Nucleosynthesis of Nickel-56 from Gamma-Ray Burst Accretion Disks  

E-Print Network (OSTI)

We examine the prospects for producing Nickel-56 from black hole accretion disks, by examining a range of steady state disk models. We focus on relatively slowly accreting disks in the range of 0.05 - 1 solar masses per second, as are thought to be appropriate for the central engines of long-duration gamma-ray bursts. We find that significant amounts of Nickel-56 are produced over a wide range of parameter space. We discuss the influence of entropy, outflow timescale and initial disk position on mass fraction of Nickel-56 which is produced. We keep careful track of the weak interactions to ensure reliable calculations of the electron fraction, and discuss the role of the neutrinos.

R. Surman; G. C. McLaughlin; N. Sabbatino

2011-12-12T23:59:59.000Z

229

Impact of active-sterile neutrino mixing on supernova explosion and nucleosynthesis  

E-Print Network (OSTI)

We show that for the active-sterile flavor mixing parameters suggested by the reactor neutrino anomaly, substantial \\\

Meng-Ru Wu; Tobias Fischer; Lutz Huther; Gabriel Martínez-Pinedo; Yong-Zhong Qian

2013-05-10T23:59:59.000Z

230

The dynamics of scalar-tensor cosmology from RS two-brane model  

E-Print Network (OSTI)

We consider a Randall-Sundrum two-brane cosmological model in the low energy gradient expansion approximation by Kanno and Soda. It is a scalar-tensor theory with a specific coupling function and a specific potential. Upon introducing the FLRW metric and perfect fluid matter on both branes in the Jordan frame, the effective dynamical equation for the the A-brane (our Universe) scale factor decouples from the scalar field and B-brane matter leaving only a non-vanishing integration constant (the dark radiation term). We find exact solutions for the A-brane scale factor for four types of matter: cosmological constant, radiation, dust, and cosmological constant plus radiation. We perform a complementary analysis of the dynamics of the scalar field (radion) using phase space methods and examine convergence towards the limit of general relativity. In particular, we find that radion stabilizes at a certain finite value for suitable negative matter densities on the B-brane. Observational constraints from Solar system experiments (PPN) and primordial nucleosynthesis (BBN) are also briefly discussed.

Laur Jarv; Piret Kuusk; Margus Saal

2006-08-24T23:59:59.000Z

231

The Fluid Mechanics of Gravitational Structure Formation  

E-Print Network (OSTI)

The standard model for gravitational structure formation in astrophysics, astronomy, and cosmology is questioned. Cold dark matter (CDM) hierarchical clustering cosmology neglects particle collisions, viscosity, turbulence and diffusion and makes predictions in conflict with observations. From Jeans 1902 and CDMHC, the non-baryonic dark matter NBDM forms small clumps during the plasma epoch after the big bang that ``cluster'' into larger clumps. CDM halo clusters collect the baryonic matter (H and He) by gravity so that after 300 Myr of ``dark ages'', huge, explosive (Population III) first stars appear, and then galaxies and galaxy clusters. Contrary to CDMHC cosmology, ``hydro-gravitational-dynamics'' HGD cosmology suggests the diffusive NBDM material cannot clump and the clumps cannot cluster. From HGD, the big bang results from an exothermic turbulent instability at Planck scales (10^{-35} m). Turbulent stresses cause an inflation of space and fossil density turbulence remnants that trigger gravitational instability at protosupercluster masses (10^{46} kg) in the H-He plasma. These fragment along plasma turbulence vortex lines to form protogalaxy masses (10^{42} kg) just before the transition to gas. The gas has x10^{-13} smaller viscosity, so it fragments at planetary and globular-star-cluster masses (10^{25} and 10^{36} kg) to form the baryonic dark matter (BDM). Observations from the Hubble Space Telescope show protogalaxies (PGs) in linear clusters reflecting their likely fragmentation on plasma vortex lines. From merging BDM planets, these PGs gently form small stars in globular clusters <1 Myr after the big bang without the dark ages, superstars, or reionization of CDM cosmology.

Carl H. Gibson

2006-10-20T23:59:59.000Z

232

CMB Observational Techniques and Recent Results  

E-Print Network (OSTI)

The Cosmic Microwave Background (CMB) consists of photons that were last created about 2 months after the Big Bang, and last scattered about 380,000 years after the Big Bang. The spectrum of the CMB is very close to a blackbody at 2.725 K and upper limits on any deviations of the CMB from a blackbody place strong constraints on energy transfer between the CMB and matter at all redshifts less than 2,000,000. The CMB is very nearly isotropic, but a dipole anisotropy of +/-3.346(17) mK shows that the Solar System barycenter is moving at 368+/-2 km/sec relative to the observable Universe. The dipole corresponds to a spherical harmonic index l=1. The higher indices l geq 2 indicate intrinsic inhomogeneities in the Universe that existed at the time of last scattering. While the photons have traveled freely only since the time of last scattering, the inhomogeneities traced by the CMB photons have been in place since the inflationary epoch only 10^{-35} sec after the Big Bang. These intrinsic anisotropies are much smaller in amplitude than the dipole anisotropy, with Delta T leq 100 microK. Electron scattering of the anisotropic radiation field produces an anisotropic linear polarization in the CMB with amplitudes less than 5 microK. Detailed studies of the angular power spectrum of the temperature and linear polarization anisotropies have yielded precise values for many cosmological parameters. This paper will discuss the techniques necessary to measure signals that are 100 million times smaller than the emission from the instrument and briefly describe results from experiments up to WMAP.

E. L. Wright

2003-12-31T23:59:59.000Z

233

Physics | More Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics Physics ORNL Physics More Science Home | Science & Discovery | More Science | Physics SHARE Physics Bottom view of the 25 million volt tandem electrostatic accelerator of the Holifield Heavy Ion Research Facility. Physics researchers at ORNL seek to answer fascinating questions about our Universe: What are the nuclear reactions that drive stellar explosions? How does nuclear matter organize itself? What are the properties of nuclear interactions? Why is there more matter than antimatter in the universe? Is the neutrino its own antiparticle? What are the properties of matter that existed just after the Big Bang? Our research staff address these questions by developing experimental techniques and detector systems, performing experiments at national and

234

hepreqrev.pptx  

NLE Websites -- All DOE Office Websites (Extended Search)

Microwave Background Microwave Background Data Analysis Julian Borrill Computational Cosmology Center, LBNL Space Sciences Laboratory, UCB A History Of The Universe Planck CMB Science * Past: - Existence => evidence of Big Bang over Steady State - Temperature anisotropies => fundamental parameters of cosmology, complementary constraints (SN1a) * Present: - Temperature & E-mode polarization anisotropies => precision cosmology, complementary constraints (DE) * Future: - B-mode polarization anisotropies => measurement of lensing potential, evidence of & constraints on Inflation 2 Nobel Prizes awarded, 1 supported, 1 anticipated! The CMB Data Challenge * Extracting fainter signals (polarization, high resolution) from the data requires: - larger data volumes to provide higher signal-to-noise.

235

Distinguished Lecturers Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Videos Videos Lawrence Berkeley National Laboratory Environmental Energy Technologies Division Distinguished Lecture Series Environmental Energy Technologies Division Distinguished Lecture Series Videos Long Fuse, Big Bang: Thomas Edison, Electricity, and the Locus of Innovation Andrew Hargadon, October 22, 2012 Climate Change Hits Home: Impacts on the Built Environment and Health John Spengler, June 18, 2012 High Comfort-Low Impact, From Buildings to Cities Matthias Schuler, April 30, 2012 Emissions Trading and Climate Finance: Is 2012 the Dead End or the Crossroads? Marc Stuart, January 27, 2012 Advances in Global Climate Modeling for Scientific Understanding and Predictability V. Ramaswamy, October 7, 2011 How is Building Energy Use Related to Occupant Behaviors and Building Usage

236

Distinguished Lecturers Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Past Seminars Past Seminars Lawrence Berkeley National Laboratory Environmental Energy Technologies Division Distinguished Lecture Series Environmental Energy Technologies Division Distinguished Lecture Series Andrew Hargadon October 22, 2012 Long Fuse, Big Bang: Thomas Edison, Electricity, and the Locus of Innovation Andrew Hargadon Charles J. Soderquist Chair in Entrepreneurship Professor of Technology Management at the Graduate School of Management University of California, Davis John Spengler June 18, 2012 Climate Change Hits Home: Impacts on the Built Environment and Health John Spengler Akira Yamaguchi Professor of Environmental Health & Human Habitation Harvard School of Public Health and Director of the Sustainability and Environmental Management Program Harvard Extension School

237

Heavy Nuclei from RHIC to the Cosmos  

E-Print Network (OSTI)

Ultra-relativistic heavy ion collisions produce a high-temperature, thermalized system that may mimic the conditions present shortly after the big bang. This writeup will given an overview of early results from the Relativistic Heavy Ion Collider (RHIC), and discuss what we have learned about hot, strongly interacting nuclear systems. The thermal and chemical composition of the system will be discussed, along with observables that are sensitive to the early evolution of the system. I will also discuss the implications of the RHIC results for cosmic ray air showers.

Spencer R. Klein

2002-11-01T23:59:59.000Z

238

Strong Energy Condition in $R + R^2$ Gravity  

E-Print Network (OSTI)

In this paper, we study Raychaudhuri's equation in the background of $R + \\beta R^2$ gravity with a phenomenological matter ($\\rho \\propto a(t)^{-n}$). We conclude that even though the Strong Energy Condition (S.E.C.) for Einstein's gravity, which guarantees singularity, is $n\\geq 2$ for $\\rho \\propto a(t)^{-n}$, a perturbative analysis of Raychaudhuri's equation in the background of $R + \\beta R^2$ gravity reveals that the big bang singularity may not be guaranteed for $n > 4$. We derive the following Strong Energy Conditions for $R + \\beta R^2$ ($\\beta \

J. H. Kung

1995-10-04T23:59:59.000Z

239

Gravitational Collapse and Radiation of Grand Unified Theory  

E-Print Network (OSTI)

The infinite gravitational collapse of any supermassive stars should pass through an energy scale of the grand unified theory (GUT). After nucleon-decays, the supermassive star will convert nearly all its mass into energy, and produce the radiation of GUT. It may probably explain some ultrahigh energy puzzles in astrophysics, for example, quasars and gamma-ray bursts (GRB), etc. This is similar with a process of the Big Bang Universe with a time-reversal evolution in much smaller space scale and mass scale. In this process the star seems be a true white hole.

Yi-Fang Chang

2007-10-02T23:59:59.000Z

240

New directions for gravity-wave physics via "Millikan oil drops"  

E-Print Network (OSTI)

Pairs of Planck-mass--scale drops of superfluid helium coated by electrons (i.e., "Millikan oil drops"), when levitated in the presence of strong magnetic fields and at low temperatures, can be efficient quantum transducers between electromagnetic (EM) and gravitational (GR) radiation. A Hertz-like experiment, in which EM waves are converted at the source into GR waves, and then back-converted at the receiver from GR waves back into EM waves, should be practical to perform. This would open up observations of the gravity-wave analog of the CMB from the extremely early Big Bang, and also communications directly through the interior of the Earth.

Raymond Y. Chiao

2006-10-29T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

"Millikan oil drops" as quantum transducers between electromagnetic and gravitational radiation  

E-Print Network (OSTI)

Pairs of Planck-mass-scale drops of superfluid helium coated by electrons (i.e., "Millikan oil drops"), when levitated in the presence of strong magnetic fields and at low temperatures, can be efficient quantum transducers between electromagnetic (EM) and gravitational (GR) radiation. A Hertz-like experiment, in which EM waves are converted at the source into GR waves, and then back-converted at the receiver from GR waves back into EM waves, should be practical to perform. This would open up observations of the gravity-wave analog of the Cosmic Microwave Background from the extremely early Big Bang, and also communications directly through the interior of the Earth.

Raymond Y. Chiao

2007-02-19T23:59:59.000Z

242

Space Dynamics in Global Time as an Effective Alternative to General Relativity  

E-Print Network (OSTI)

The fundamental physical object of the Global Time Theory is a three-dimensional curved space dynamically developing in global time. The equations of its dynamics are derived from the Lagrangian, and the Hamiltonian of ravitation turns out to be nonzero. The General Relativity solutions are shown to be a subset of the GTT solutions with zero energy density. In Global time Theory, the quantum theory of gravitation can be built on the basis of the Schredinger equation, as for other fields. The quantum model of the Big Bang is presented in some detailes.

D. E. Burlankov

2005-09-14T23:59:59.000Z

243

Gamma-Ray Bursts from Primordial Quark Objects in Space  

E-Print Network (OSTI)

We investigate the possibility that gamma-ray bursts originate in a concentric spherical shell with a given average redshift and find that this is indeed compatible with the data from the third BATSE (3B) catalog. It is also shown that there is enough freedom in the choice of unknown burst properties to allow even for extremely large distances to the majority of bursts. Therefore, we speculate about an early, and very energetic, origin of bursts, and suggest that they come from phase transitions in massive objects of pure quark matter, left over from the Big Bang.

B. Anoushirvani; D. Enström; S. Fredriksson; J. Hansson; P. Ökvist; A. Nicolaidis; S. Ekelin

1997-11-28T23:59:59.000Z

244

"Millikan oil drops" as quantum transducers between electromagnetic and gravitational radiation  

E-Print Network (OSTI)

Pairs of Planck-mass-scale drops of superfluid helium coated by electrons (i.e., "Millikan oil drops"), when levitated in the presence of strong magnetic fields and at low temperatures, can be efficient quantum transducers between electromagnetic (EM) and gravitational (GR) radiation. A Hertz-like experiment, in which EM waves are converted at the source into GR waves, and then back-converted at the receiver from GR waves back into EM waves, should be practical to perform. This would open up observations of the gravity-wave analog of the Cosmic Microwave Background from the extremely early Big Bang, and also communications directly through the interior of the Earth.

Chiao, R Y

2007-01-01T23:59:59.000Z

245

Primordial origins of Earth's carbon  

E-Print Network (OSTI)

In this chapter we review the astrophysical origins of Earth's carbon, starting from the products of the Big Bang and culminating with the Earth's formation. We review the measured compositions of different primitive objects including comets, various classes of meteorites and interstellar dust particles. We discuss the composition of the Solar Nebula, especially with regards to the distribution of volatiles such as carbon. We discuss dynamical models of planetary formation from planetesimals and planetary embryos, and the timescale for volatile delivery to the growing Earth from different sources. Finally, we review Earth's carbon reservoirs. Throughout the chapter we highlight open questions related to planet formation, meteoritics, and geochemistry.

Marty, Bernard; Raymond, Sean N

2012-01-01T23:59:59.000Z

246

Unified Theory of Bivacuum, Particles Duality, Fields & Time. New Bivacuum Mediated Interaction, Overunity Devices, Cold Fusion & Nucleosynthesis  

E-Print Network (OSTI)

New concept of Bivacuum is introduced, as a dynamic matrix of the Universe, composed from sub-quantum particles and antiparticles, forming vortical structures. These structures are presented by continuum of dipoles, each dipole containing a pair of correlated torus and antitorus: V(+) and V(-) of the opposite energy/mass, spin, charge and magnetic moments, compensating each other. The rest mass and charge of sub-elementary fermions or antifermions is a result of Bivacuum dipoles opposite symmetry shifts. Their fusion to triplets follows by elementary particles and antiparticles origination. The [corpuscle (C) - wave (W)] duality is a result of correlated beats between the 'actual' and 'complementary' states of sub-elementary fermions of triplets. It is shown, that Principle of least action, the 2d and 3d laws of thermodynamics can be a consequences of forced combinational resonance between positive and negative virtual pressure waves (VPW+/-) of Bivacuum and [C-W] pulsation of elementary particles. The quantum entanglement, mediated by virtual microtubules, composed from Bivacuum dipoles, connecting remote particles, is a result of such Bivacuum-matter interaction. The pace of time for any closed system is determined by pace of kinetic energy change of this system. The proposed mechanism of overunity devices can be provided by the electrons acceleration, induced by their resonant interaction with high frequency positive and negative VPW+/- in pull-in range conditions. The latter can be excited by pulsing currents and fields. The mechanism of overheating and cold fusion in electrolytic cells without violation of energy conservation is proposed also.

Alex Kaivarainen

2002-07-06T23:59:59.000Z

247

Complete calculation of evaluated Maxwellian-averaged cross sections and their uncertainties for s-process nucleosynthesis  

Science Conference Proceedings (OSTI)

Present contribution represents a significant improvement of our previous calculation of Maxwellian-averaged cross sections and astrophysical reaction rates. Addition of newly-evaluated neutron reaction libraries, such as ROSFOND and Low-Fidelity Covariance Project, and improvements in data processing techniques allowed us to extend it for entire range of sprocess nuclei, calculate Maxwellian-averaged cross section uncertainties for the first time, and provide additional insights on all currently available neutron-induced reaction data. Nuclear reaction calculations using ENDF libraries and current Java technologies will be discussed and new results will be presented.

Pritychenko, B.

2010-07-19T23:59:59.000Z

248

Constraints on Dark Energy from Supernovae, Gamma Ray Bursts, Acoustic Oscillations, Nucleosynthesis and Large Scale Structure and the Hubble constant  

E-Print Network (OSTI)

The luminosity distance vs. redshift law is now measured using supernovae and gamma ray bursts, and the angular size distance is measured at the surface of last scattering by the CMB and at z = 0.35 by baryon acoustic oscillations. In this paper this data is fit to models for the equation of state with w = -1, w = const, and w(z) = w_0+w_a(1-a). The last model is poorly constrained by the distance data, leading to unphysical solutions where the dark energy dominates at early times unless the large scale structure and acoustic scale constraints are modified to allow for early time dark energy effects. A flat LambdaCDM model is consistent with all the data.

Edward L. Wright

2007-01-22T23:59:59.000Z

249

First Light  

E-Print Network (OSTI)

The first dwarf galaxies, which constitute the building blocks of the collapsed objects we find today in the Universe, had formed hundreds of millions of years after the big bang. This pedagogical review describes the early growth of their small-amplitude seed fluctuations from the epoch of inflation through dark matter decoupling and matter-radiation equality, to the final collapse and fragmentation of the dark matter on all mass scales above \\~10^{-4} solar masses. The condensation of baryons into halos in the mass range of ~10^5-10^{10} solar masses led to the formation of the first stars and the re-ionization of the cold hydrogen gas, left over from the big bang. The production of heavy elements by the first stars started the metal enrichment process that eventually led to the formation of rocky planets and life. A wide variety of instruments currently under design [including large-aperture infrared telescopes on the ground or in space (JWST), and low-frequency arrays for the detection of redshifted 21cm radiation], will establish better understanding of the first sources of light during an epoch in cosmic history that was largely unexplored so far. Numerical simulations of reionization are computationally challenging, as they require radiative transfer across large cosmological volumes as well as sufficently high resolution to identify the sources of the ionizing radiation. The technological challenges for observations and the computational challenges for numerical simulations, will motivate intense work in this field over the coming decade.

Abraham Loeb

2006-03-14T23:59:59.000Z

250

Black hole growth in the early Universe is self-regulated and largely hidden from view  

E-Print Network (OSTI)

The formation of the first massive objects in the infant Universe remains impossible to observe directly and yet it sets the stage for the subsequent evolution of galaxies. While some black holes with masses > billion solar masses? have been detected in luminous quasars less than one billion years after the Big Bang, these individual extreme objects have limited utility in constraining the channels of formation of the earliest black holes. The initial conditions of black hole seed properties are quickly erased during the growth process. From deep, optimally stacked, archival X-ray observations, we measure the amount of black hole growth in z=6-8 galaxies (0.7-1 billion years after the Big Bang). Our results imply that black holes grow in tandem with their hosts throughout cosmic history, starting from the earliest times. We find that most copiously accreting black holes at these epochs are buried in significant amounts of gas and dust that absorb most radiation except for the highest energy X-rays. This sugge...

Treister, Ezequiel; Volonteri, Marta; Natarajan, Priyamvada; Gawiser, Eric

2011-01-01T23:59:59.000Z

251

Subtraction-noise projection in gravitational-wave detector networks  

SciTech Connect

In this paper, we present a successful implementation of a subtraction-noise projection method into a simple, simulated data analysis pipeline of a gravitational-wave search. We investigate the problem to reveal a weak stochastic background signal which is covered by a strong foreground of compact-binary coalescences. The foreground, which is estimated by matched filters, has to be subtracted from the data. Even an optimal analysis of foreground signals will leave subtraction noise due to estimation errors of template parameters which may corrupt the measurement of the background signal. The subtraction noise can be removed by a noise projection. We apply our analysis pipeline to the proposed future-generation space-borne Big Bang Observer mission which seeks for a stochastic background of primordial gravitational waves in the frequency range {approx}0.1 Hz--1 Hz covered by a foreground of black-hole and neutron-star binaries. Our analysis is based on a simulation code which provides a dynamical model of a time-delay interferometer network. It generates the data as time series and incorporates the analysis pipeline together with the noise projection. Our results confirm previous ad hoc predictions which say that the Big Bang Observer will be sensitive to backgrounds with fractional energy densities below {omega}=10{sup -16}.

Harms, Jan; Mahrdt, Christoph; Otto, Markus; Priess, Malte [Institut fuer Gravitationsphysik, Universitaet Hannover and Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Callinstrasse 38, 30167 Hannover (Germany)

2008-06-15T23:59:59.000Z

252

Fluid Mechanics Explains Cosmology, Dark Matter, Dark Energy, and Life  

E-Print Network (OSTI)

Observations of the interstellar medium by the Herschel, Planck etc. infrared satellites throw doubt on standard {\\Lambda}CDMHC cosmological processes to form gravitational structures. According to the Hydro-Gravitational-Dynamics (HGD) cosmology of Gibson (1996), and the quasar microlensing observations of Schild (1996), the dark matter of galaxies consists of Proto-Globular-star-Cluster (PGC) clumps of Earth-mass primordial gas planets in metastable equilibrium since PGCs began star production at 0.3 Myr by planet mergers. Dark energy and the accelerating expansion of the universe inferred from SuperNovae Ia are systematic dimming errors produced as frozen gas dark matter planets evaporate to form stars. Collisionless cold dark matter that clumps and hierarchically clusters does not exist. Clumps of PGCs began diffusion from the Milky Way Proto-Galaxy upon freezing at 14 Myr to give the Magellanic Clouds and the faint dwarf galaxies of the 10^22 m diameter baryonic dark matter Galaxy halo. The first stars persist as old globular star clusters (OGCs). Water oceans and the biological big bang occurred at 2-8 Myr. Life inevitably formed and evolved in the cosmological primordial organic soup provided by 10^80 big bang planets and their hot oceans as they gently merged to form larger binary planets and small binary stars.

Carl H. Gibson

2012-11-02T23:59:59.000Z

253

Cosmology/COBE  

E-Print Network (OSTI)

Abbreviated abstract of an invited talk at the International Cosmic Ray Conference in Calgary, July 1993: The results from the COBE satellite are in close agreement with the predictions of the standard hot Big Bang model, suggesting that the Universe was once hot, dense and isothermal, giving a background radiation spectrum that is close to a perfect blackbody. The spectrum observed by the FIRAS instrument places strong limits on events and scenarios occurring later than 1 year after the Big Bang. The observation of intrinsic anisotropy of the microwave background by the DMR instrument provides a measurement of the magnitude of the gravitational potential fluctuations that existed at decoupling. These potential perturbations were either produced in an inflationary epoch, or else they are initial conditions dating from t = 0. The angular power spectrum of dT is compatible with the inflationary scenario. The observed amplitude of dT can be used to restrict theories of the fundamental structure of matter on micro-physical scales and at energies higher than that of the most energetic cosmic rays. The DIRBE instrument will provide greatly improved data on extragalactic IR backgrounds after the strong foreground emission is subtracted.

Edward L. Wright

1993-11-19T23:59:59.000Z

254

Measurement of the $^{90, 92}$Zr(p,$?$)$^{91,93}$Nb reactions for the nucleosynthesis of elements around A=90  

E-Print Network (OSTI)

Cross section measurements of the reactions $^{90, 92}$Zr(p,$\\gamma$)$^{91,93}$Nb were performed using the NSCL SuN detector at the University of Notre Dame. These reactions are part of the nuclear reaction flow for the synthesis of the light p nuclei. For the $^{90}$Zr(p,$\\gamma$)$^{91}$Nb reaction the new measurement resolves the disagreement between previous results. For the $^{92}$Zr(p,$\\gamma$)$^{93}$Nb reaction the present work reports the first measurement of this reaction cross section. Both reaction cross sections are compared to theoretical calculations and a very good agreement with the standard NON-SMOKER model is observed.

A. Spyrou; S. J. Quinn; A. Simon; T. Rauscher; A. Battaglia; A. Best; B. Bucher; M. Couder; P. A. DeYoung; A. C. Dombos; X. Fang; J. Gorres; A. Kontos; Q. Li; L. Y. Lin; A. Long; S. Lyons; B. S. Meyer; A. Roberts; D. Robertson; K. Smith; M. K. Smith; E. Stech; B. Stefanek; W. P. Tan; X. D. Tang; M. Wiescher

2013-10-21T23:59:59.000Z

255

NEW DETERMINATION OF THE {sup 13}C({alpha}, n){sup 16}O REACTION RATE AND ITS INFLUENCE ON THE s-PROCESS NUCLEOSYNTHESIS IN AGB STARS  

Science Conference Proceedings (OSTI)

We present a new measurement of the {alpha}-spectroscopic factor (S{sub {alpha}}) and the asymptotic normalization coefficient for the 6.356 MeV 1/2{sup +} subthreshold state of {sup 17}O through the {sup 13}C({sup 11}B, {sup 7}Li){sup 17}O transfer reaction and we determine the {alpha}-width of this state. This is believed to have a strong effect on the rate of the {sup 13}C({alpha}, n){sup 16}O reaction, the main neutron source for slow neutron captures (the s-process) in asymptotic giant branch (AGB) stars. Based on the new width we derive the astrophysical S-factor and the stellar rate of the {sup 13}C({alpha}, n){sup 16}O reaction. At a temperature of 100 MK, our rate is roughly two times larger than that by Caughlan and Fowler and two times smaller than that recommended by the NACRE compilation. We use the new rate and different rates available in the literature as input in simulations of AGB stars to study their influence on the abundances of selected s-process elements and isotopic ratios. There are no changes in the final results using the different rates for the {sup 13}C({alpha}, n){sup 16}O reaction when the {sup 13}C burns completely in radiative conditions. When the {sup 13}C burns in convective conditions, as in stars of initial mass lower than {approx}2 M{sub Sun} and in post-AGB stars, some changes are to be expected, e.g., of up to 25% for Pb in our models. These variations will have to be carefully analyzed when more accurate stellar mixing models and more precise observational constraints are available.

Guo, B.; Li, Z. H.; Li, Y. J.; Su, J.; Yan, S. Q.; Bai, X. X.; Chen, Y. S.; Fan, Q. W.; Jin, S. J.; Li, E. T.; Li, Z. C.; Lian, G.; Liu, J. C.; Liu, X.; Shu, N. C. [China Institute of Atomic Energy, P.O. Box 275(1), Beijing 102413 (China); Lugaro, M.; Buntain, J. [Monash Centre for Astrophysics, Monash University, Clayton 3800, Victoria (Australia); Pang, D. Y. [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Karakas, A. I. [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Weston Creek ACT 2611 (Australia); Shi, J. R., E-mail: wpliu@ciae.ac.cn, E-mail: guobing@ciae.ac.cn [National Astronomical Observatories, Chinese Academy of Science, Beijing 100012 (China); and others

2012-09-10T23:59:59.000Z

256

Fermilab | Science at Fermilab | Questions for the Universe | The Birth of  

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Tevatron, Fermilab, Batavia, IL Tevatron, Fermilab, Batavia, IL Large Hadron Collider, CERN, Geneva, Switzerland BaBar, SLAC, Menlo Park, CA Further reading courtesy of Symmetry magazine Explain it in 60 Seconds: Antimatter Explain it in 60 Seconds: CP violation BaBar's Window on the Weak Force Persis Drell Where has all the antimatter gone? Persis Drell, director of SLAC National Accelerator Laboratory, explains how answering questions about antimatter may shed light on what happened in the early universe. View the Video What happened to the antimatter? Experiments teach us that for every fundamental particle there exists an antiparticle. The big bang and its aftermath almost certainly produced particles and antiparticles in equal numbers. However, for as far out in the universe as we can probe, our observations indicate that we live in a

257

The Universe Adventure - The Modern Universe  

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Modern Universe Modern Universe Like astronomers throughout history, modern cosmologists are interested in making an accurate model of the Universe. Starting with the laws of physics which explain how fundamental particles and forces interact, physicists derive general equations describing the evolution of the Universe's structure. Cosmologists use experimental evidence to select a set of initial conditions enabling them to solve the general equations, and calculate the state of the Universe at times in the past, present, or future. This generates a possible model, which can be tested by comparing the phenomena it predicts with observational data. In this manner, following the rigorous scientific method, cosmologists work to build a successful Universal model. In the next section we will examine evidence for the current Big Bang

258

Sandia National Laboratories: News: Publications: Lab News  

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Sept. 21, 2012 Sept. 21, 2012 Sandia's Explosives Technology Group discovers key detonation behavior in common explosive NOT SO BIG BANG - Alex Tappan (left) and Rob Knepper (both 2554) watch the detonation of a Sandia critical thickness experiment. The experiment typically uses less explosive material than the size of one-tenth of an aspirin tablet to determine small-scale detonation properties. The bench-top experiment is so small, researchers can stand next to the firing chamber with eye and ear protection. (Photo by Randy Montoya) by Sue Major Holmes The explosive PETN (pentaerythritol tetranitrate) has been around for a century and is used by everyone from miners to the military, but it took new research by Sandia to begin to discover key mechanisms behind what causes it to fail at very small scales.

259

 

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Stellar Fusion Cross Sections Underground Stellar Fusion Cross Sections Underground Daniel Bemmerer Forschungszentrum Dresden-Rossendorf (FZD) Abstract: Due to the suppression by the Coulomb barrier, the cross sections of astrophysically relevant nuclear reactions are very low at the stellar energy. Therefore they can only be directly measured in a low-background environment. For more than a decade now, the LUNA collaboration has pursued this approach with a 0.4 MV accelerator in the Gran Sasso underground laboratory in Italy. It was highly successful in studying the nuclear physics of the Sun and of the Big Bang. However, the energy range of LUNA is not sufficient to address the nuclear reactions of stellar helium and carbon burning and the neutron source reactions for the astrophysical s-process. Therefore, in the 2010 NuPECC

260

DOE Research and Development Accomplishments RSS Archive 2005-2006  

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5-2006 5-2006 2007 · 2008 · 2009 George Smoot Courtesy of Lawrence Berkeley National Laboratory "Blackbody Form" Research Yields 2006 Nobel Prize George Smoot made an announcement in 1992 that "essentially silenced all the scientific critics of the Big Bang theory." (See the October 3, 2006 edition of Today at Berkeley Lab.) For research leading up to that announcement, Smoot was awarded the Nobel Prize in Physics 2006. Smoot, an astrophysicist at Berkeley Lab since 1974 and a UC Berkeley physics professor since 1994, shared the award with John C. Mather of NASA Goddard Space Flight Center. Together they discovered the blackbody form and anisotropy of the cosmic microwave background radiation. Read more on this discovery at the DOE R&D Accomplishments Featured Scientists page.

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261

Experiment Profile: COUPP NAME: Chicagoland Observatory for Underground Particle  

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COUPP COUPP NAME: Chicagoland Observatory for Underground Particle Physics, or COUPP WHAT WILL THIS TELL US ABOUT THE WORLD? Everything you see, visible matter, makes up 4 percent of the universe. Dark matter and dark energy makes up the rest of the universe. Physicists understand that dark matter acts as an invisible source of gravity, but little more. COUPP seeks to pinpoint what particles make up dark matter, which will help explain how the universe came to exist. Without the added gravitational attraction of dark matter, stars and galaxies would never have formed. The expansion of the universe after the Big Bang would have dispersed visible matter too quickly. WHY IS THIS EXPERIMENT NEEDED NOW? Physicists have narrowed the hunt for what particles constitute dark

262

COBE Sky Map  

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COBE sky map COBE sky map This map of the ancient sky shows the minute variations in the microwave background discovered by the team led by Lawrence Berkeley Laboratory astrophysicist George Smoot. As seen in the map, vast regions of space have minute variations in temperature. Over billions of years, gravity magnified these small differences into the clusters of galaxies we observe today. Displayed horizontally across the middle of the map is the Milky Way galaxy. The image, a 360-degree map of the whole sky, shows the relic radiation from the Big Bang. The map was derived from one year of data taken by the Differential Microwave Radiometers onboard NASA's Cosmic Background Explorer satellite. Using Galactic coordinates, the map shows the plane of the Milky Way galaxy horizontally and the center of our galaxy at its

263

Brookhaven National Laboratory The Relativistic Heavy Ion Collider (RHIC)  

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Relativistic Heavy Ion Collider (RHIC) Relativistic Heavy Ion Collider (RHIC) An Exciting Beginning and a Compelling Future At the Relativistic Heavy Ion Collider (RHIC), a world-class particle accelerator at Brookhaven National Laboratory, physicists are exploring the most fundamental forces and properties of matter and the early universe, with important implications for our understanding of the world around us. Operated with funding from the U.S. Department of Energy's Office of Science, the Relativistic Heavy Ion Collider (RHIC), was designed to recreate a state of matter thought to have existed immediately after the Big Bang some 13 billion years ago, and to investigate how the proton gets its spin and intrinsic magnetism from its quark and gluon constituents. Large detectors located

264

The Universe Adventure - Current Research  

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Current Research Current Research When launched, the Supernova Acceleration Probe (SNAP) will study the effects of dark energy by surveying distant type Ia supernovae and making detailed measurements of weak gravitational lensing. With the new Large Hadron Collider (LHC) at CERN nearing full completion, experimentalists will soon be able to test certain elements of String Theory. While not definitive, these tests will cast some light upon the theory's parameters and may even provide clues into the identity of dark matter. Meanwhile, theorists continue to investigate the implications of String Theory for Big Bang cosmology, particularly the effects of strings on cosmic inflation. As particle physicists eagerly await the results from the new LHC, observational cosmologists are busy developing astronomical experiments,

265

Fermilab Cultural Events in Chicago's Far West Side  

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Art Gallery Header Public Access current show schedule contact us cultural events archive General Information Art Gallery Header Public Access current show schedule contact us cultural events archive General Information "I have always felt that science, technology, and art are importantly connected, indeed science and technology seem to many scholars to have grown out of art." -Robert Rathbun Wilson This convergence of art and science occurs daily in the Fermilab Art Gallery. It is a space for art exhibitions, chamber music concerts and where the top quark and big bang are debated over coffee. It is also a quiet space for contemplation and beauty. Current Status of Access to Fermilab Fermilab Examined – a Juried Exhibition by members of the Fermilab Photography Club 11/18/13-1/26/14 Artist Reception 11/20/13 Current Exhibition Upcoming Exhibition

266

NEWTON, Ask a Scientist at Argonne National Labs  

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Number of Galaxies and Expansion Number of Galaxies and Expansion Name: Kurt Status: other Grade: other Location: CA Country: Austria Date: Fall 2011 Question: Our telescopes show us that in the far reaches of space seem to be more galaxies and they are moving away from each other with ever increasing speed. scientists say that the moving away from each other is actually "stretching of space," should we not see fewer galaxies for that reason? Replies: Dear Kurt, I think that Hubble's idea of the expanding Universe means that the superclusters of galaxies -- not the galaxies or clusters,. but the clusters of clusters, are actually moving apart from each other. They have been doing this since the Big Bang. We do not see the farthest galaxies because their light has not reached us yet,

267

Research Highlights | ORNL Neutron Sciences  

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Neutron/Proton Capture Neutron/Proton Capture Beam Line 13 Fuels Discovery Fever for Fundamental Physicists Research Contact: Geoff Greene June 2011, Written by Agatha Bardoel Serpil Kucuker Dogan (left) and Matthew Musgrave prepare a helium-3 cooling cell that is used to measure the angle at which the neutron beam strikes the liquid hydrogen sample. The simplest, most sensible " Big Bang" universe, theoretical physicists believe, would be one in which equal numbers of particles and antiparticles are formed in pairs. As the universe cools, most of these particles would encounter their antiparticles, and they would annihilate. "In many ways, the most reasonable universe would be one in which there is no matter," says the University of Tennessee's Dr. Geoff Greene.

268

The supernova that destroyed a galaxy  

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The supernova that destroyed a galaxy The supernova that destroyed a galaxy The supernova that destroyed a galaxy The research may solve the long-standing puzzle of how supermassive black holes were formed in the centers of some galaxies less then a billion years after the Big Bang. August 5, 2013 Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) The Los Alamos simulation is the most realistic cosmological supernova simulation ever performed of this process. New supercomputer simulations by Los Alamos scientists and collaborators capture in unprecedented detail extremely powerful supernovae explosions in the early universe and their effect on the nascent galaxies that gave birth

269

U.S. CMS - 2009 News Archive  

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9 News Archive 9 News Archive In This Section: CMS in the News Press Releases Press Kit CMS Result of the Month Other News Sources: US LHC Interactions.org U.S. CMS Past News Archives: 2012 News Archive 2011 News Archive 2010 News Archive 2009 News Archive 2008 News Archive 2007 News Archive Current news archive December 18, 2009 Interactions News Wire LHC ends 2009 run on a high note December 18, 2009 ABC News Big Bang Collider sets new record December 16, 2009 symmetry breaking Burst of LHC collision data a welcome birthday gift December 11, 2009 Fermilab Today CMS Result of the Month: Simply smashing December 9, 2009 New York Times Collider sets record, and Europe takes U.S.'s lead December 9, 2009 Fermilab Today CMS says hello to the π0 January 2010 Vanity Fair The Genesis 2.0 Project December 7, 2009

270

Page not found | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

11 - 11020 of 31,917 results. 11 - 11020 of 31,917 results. Article A Cure for the Valentine's Blues? Livermore Supercomputer Seeks to Mend Broken Hearts Cupid's arrows may help you find love, but an Energy Department supercomputer is working to help cure broken hearts. http://energy.gov/articles/cure-valentines-blues-livermore-supercomputer-seeks-mend-broken-hearts Article Sweet Sunbeams and Creative Catalysts Opening a new window on the way plants generate the oxygen we breathe, SLAC simultaneously looks at the structure and chemical behavior of photosynthesis. http://energy.gov/articles/sweet-sunbeams-and-creative-catalysts Article Supercomputing: A Toolbox to Simulate the Big Bang and Beyond Learn how three Energy Department National Labs are collaborating to peer deeper into the origins of our universe than ever before.

271

H O  

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O O I - * , TWl rrporl «lf pnpmd u u iccouni of work fponiortd by fbc Unfad Suirs Gomuncnl. KtHka U» Unllii s u m nor Ih. Vaiui SHIM Atomic EnotT Comminjon, oar cur or tncir cnptoynf. nor Mr of ihtk caatrutott, ubcoRtmuirB, or tlwk cmptorra. milMsuir w n a f r . «prM§orimp&cd.of iMnmauy _ { l i . UBl Ibbililr or raponiiMlitr ror Ui. n e o n , , cum- *** pUUuu or tmfol«B or W larornutloa. ippiniia. proaoct or procac rfiKlowd. or rtprucnu Out iu use would not fafrinf* pririirly owned rifntr. FAR INFRARED SPECTROMETRY OF THE COSMIC BACKGROUND RADIATION Contents Abstract iii I. Introduction 1 A. Theory of the Background Radiation 2 1. Big Bang Theory 2 2. Primeval Perturbations 3 3. Later Perturbations 5 4. Recent Perturbations 5 B. Observations 6 1. Long Wavelength Direct Observations 7

272

Argonne CNM: 2012 Colloquium Series  

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2 Colloquium Series 2 Colloquium Series 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | Date Title Special Colloquium December 13, 2012 "Pathways to Complex Matter Far-Away-From Equilibrium: Developing Spatiotemporal Tools," by Gopal Shenoy, Argonne National Laboratory, hostged by Daniel Lopez Abstract: From the Big Bang to the coming of humankind, every manifestation of nature has exhibited processes far-away-from equilibrium leading to increasingly complex structural orders from geological to atomic length and time scales. Examples include the evolution of galaxies, hurricanes, stars, and planets; prebiotic reactions; cyclical reactions; photosynthesis; and life itself. The organizational spatiotemporal evolution in soft, hard, and biological matter also follows the same path. It begins from a far-from-equilibrium state and develops over time into organizations with length scales between atoms and small molecules on the one hand and mesoscopic matter on the other.

273

Fermilab Today | Experiment Profiles Archive | DAMIC  

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DAMIC DAMIC photo FACT SHEET: Click here to download PDF. NAME: Dark Matter In CCDs, or DAMIC The ORIGIN OF THE NAME: DAMIC searches for dark matter using Charge Coupled Devices. These digital chips register light that gets converted into a digital value a computer can store. WHAT WILL THIS TELL? Everything you see, visible matter, makes up 4 percent of the universe. Dark matter and dark energy make up the rest of the universe. Physicists understand that dark matter acts as an invisible source of gravity, but little more. DAMIC seeks to pinpoint what particles make up dark matter, which will help explain how the universe came to exist. Without the added gravitational attraction of dark matter, stars and galaxies would have never formed. The expansion of the universe after the Big Bang would have dispersed visible

274

RHIC | Relativistic Heavy Ion Collider  

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Relativistic Heavy Ion Collider Relativistic Heavy Ion Collider Photo of LINAC The Relativistic Heavy Ion Collider (RHIC) is a world-class particle accelerator at Brookhaven National Laboratory where physicists are exploring the most fundamental forces and properties of matter and the early universe. RHIC accelerates beams of particles (e.g., the nuclei of heavy atoms such as gold) to nearly the speed of light, and smashes them together to recreate a state of matter thought to have existed immediately after the Big Bang some 13.8 billion years ago. STAR and PHENIX, two large detectors located around the 2.4-mile-circumference accelerator, take "snapshots" of these collisions to reveal a glimpse of the basic constituents of visible matter, quarks and gluons. Understanding matter at

275

Files for the 2012 booklet production  

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Files for the 2012 booklet production Files for the 2012 booklet production Name pages tar file PDF Comments Accelerator Physics of Colliders 1 accel.tar accel-db.pdf July 31, 2012 Big-Bang Cosmology 6 bigbang.tar bigbang-db.pdf July 31, 2012 CKM quark-mixing matrix 7 kmmix.tar kmmix-db.pdf July 31, 2012 Cosmic Microwave Background 3 microwave.tar microwave-db.pdf July 31, 2012 Cosmic Rays 1 cosmicray.tar cosmicray-db.pdf July 31, 2012 Cosmological Parameters, The 4 hubble.tar hubble-db.pdf July 31, 2012 CP violation 5 cpviol.tar cpviol-db.pdf July 31, 2012 Dark matter 3 darkmat.tar darkmat-db.pdf July 31, 2012 Electroweak model ... 9 stanmodel.tar stanmodel-db.pdf July 31, 2012 Grand Unified Theories 6 guts.tar guts-db.pdf August 14, 2012

276

Planetary formation theory developed, tested: predicts timeline for life  

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Planetary formation theory developed, tested: predicts timeline for Planetary formation theory developed, tested: predicts timeline for life After the Big Bang: Theory suggests first planets formed after first generations of stars The researchers' calculations predict properties of first planet and timeline for life. May 3, 2012 image description The researchers state that the formation of Earth-like planets is not itself a sufficient prerequisite for life. Early galaxies contained strong sources of life-threatening radiation, such as supernovae and black holes. Therefore, they conclude that the conditions for life emerged only after the earliest epoch of galaxy formation. Get Expertise Jarrett Johnson Nuclear and Particle Physics, Astrophysics and Cosmology Email Hui Li Nuclear and Particle Physics, Astrophysics and Cosmology

277

The supernova that destroyed a galaxy  

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August » August » The supernova that destroyed a galaxy The supernova that destroyed a galaxy The research may solve the long-standing puzzle of how supermassive black holes were formed in the centers of some galaxies less then a billion years after the Big Bang. August 5, 2013 Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) The Los Alamos simulation is the most realistic cosmological supernova simulation ever performed of this process. New supercomputer simulations by Los Alamos scientists and collaborators capture in unprecedented detail extremely powerful supernovae explosions in the early universe and their effect on the nascent galaxies that gave birth

278

Particle Physics Education Sites  

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쭺-¶ 쭺-¶ Particle Physics Education Sites ¡]¥H¤U¬°¥~¤åºô¯¸¡^ quick reference Education and Information - National Laboratory Education Programs - Women and Minorities in Physics - Other Physics Sites - Physics Alliance - Accelerators at National Laboratories icon Particle Physics Education and Information sites: top Introduction: The Particle Adventure - an interactive tour of particle physics for everyone: the basics of theory and experiment. Virtual Visitor Center of the Stanford Linear Accelerator Center. Guided Tour of Fermilab, - overviews of several aspects of Particle Physics. Also check out Particle Physics concepts. Probing Particles - a comprehensive and straight-forward introduction to particle physics. Big Bang Science - approaches particle physics starting from the theoretical origin of the universe.

279

BNL | Neutrino Research History  

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Brookhaven Neutrino Research Brookhaven Neutrino Research image of neutrinos Tens of billions of neutrinos are passing through every square centimeter of the Earth's surface right now. A Ghost-Particle Retrospective Neutrinos, ghostlike particles that flooded the universe just moments after the Big Bang, are born in the hearts of stars and other nuclear reactions. Untouched by electromagnetism and nearly as fast as light, neutrinos pass practically unhindered through everything from planets to people, only rarely responding to the weak nuclear force and the even weaker gravity. In fact, at any given moment, tens of billions of neutrinos are passing through every square centimeter of the Earth's surface. Neutrino Research News photomultiplier tubes New Results from Daya Bay: Tracking the Disappearance of Ghostlike

280

The Universe Adventure - Feedback  

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Contact Us Contact Us First Name (optional): Simpson Last Name (optional): Homer E-Mail Address (if you would like to hear back from us): How can we contact you? Occupation (high school student, physics teacher, cosmologist, et cetera): What is your occupation? Type: Type of Feedback Organization/Format Content Fundamentals of Cosmology Evidence for the Big Bang Eras of the Cosmos The Final Frontier Glossary Other Comments and Feedback: We appreciate your comments! - The Universe Adventure Team submit reset [ top ] Site Content National Science Foundation Department of Energy S.D. Bechtel, Jr. Foundation [ Site Map ] optimized for Firefox [ UC Berkeley ] [ UC Berkeley Physics ] [ Particle Adventure! ] [ Contact Us ] Copyright © 2005 Lawrence Berkeley National Laboratory Physics Division |

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281

Top Science of 2013  

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RAPTOR telescope witnesses black hole birth RAPTOR telescope witnesses black hole birth /science-innovation/_assets/images/icon-science.jpg Top Science of 2013 Our strong interdisciplinary teaming and unique research facilities allow us to develop solutions to complex problems, and to support partners and collaborators, all with the goal of strengthening national security and making a safer world. RAPTOR telescope witnesses black hole birth placeholder The first "thinking telescope" RAPTOR found the birth of big black holes, possibly the most powerful events since the big bang. This robotic array screens 100 million objects and runs real-time analysis-autonomously alerting us when there's a discovery or a threat. In 2006, RAPTOR was the first of its kind to make a discovery: the birth of

282

LHC Workshop 2011  

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Matter / Antimatter Asymmetry Matter / Antimatter Asymmetry The big bang should have created equal amounts of matter and antimatter in the early universe. But today, everything we see from the smallest life forms on Earth to the largest stellar objects is made almost entirely of matter. Comparatively, there is not much antimatter to be found. Something must have happened to tip the balance. One of the greatest challenges in physics is to figure out what happened to the antimatter, or why we see matter/antimatter asymmetry. Read More Antimatter particles share the same mass as their matter counterparts, but they carry an opposite electric charge. The positively charged positron, for example, is the anti-particle to the negatively charged electron. Matter and antimatter particles are always produced as a pair and, if they

283

On Climbing Scalars in String Theory  

E-Print Network (OSTI)

In string models with "brane supersymmetry breaking" exponential potentials emerge at (closed-string) tree level but are not accompanied by tachyons. Potentials of this type have long been a source of embarrassment in flat space, but can have interesting implications for Cosmology. For instance, in ten dimensions the logarithmic slope |V'/V| lies precisely at a "critical" value where the Lucchin--Matarrese attractor disappears while the scalar field is \\emph{forced} to climb up the potential when it emerges from the Big Bang. This type of behavior is in principle perturbative in the string coupling, persists after compactification, could have trapped scalar fields inside potential wells as a result of the cosmological evolution and could have also injected the inflationary phase of our Universe.

E. Dudas; N. Kitazawa; A. Sagnotti

2010-09-04T23:59:59.000Z

284

Cosmic Dawn: The First Star in the Universe  

SciTech Connect

What was the first thing in the Universe? A black hole or a star? How did it form? Even our biggest and best telescopes cannot tell us. Direct calculation with supercomputers, however, can. The first luminous objects in the Universe were very massive stars shining one million times as brightly as our sun. They died quickly and seeded the cosmos with the chemical elements necessary for life. One star at a time, galaxies started to assemble just one hundred million years after the Big Bang, and they are still growing now. Join Dr. Abel in a fascinating journey through the early universe, where he uses the latest computer animations of early star formation, supernovae explosions and the buildup of the first galaxies.

Abel, Tom

2008-04-29T23:59:59.000Z

285

Quantum Criticality and Black Holes  

SciTech Connect

I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.

Sachdev, Subir (Harvard)

2007-08-22T23:59:59.000Z

286

Trapped Quintessential Inflation in the context of Flux Compactifications  

E-Print Network (OSTI)

We present a model for quintessential inflation using a string modulus for the inflaton - quintessence field. The scalar potential of our model is based on generic non-perturbative potentials arising in flux compactifications. We assume an enhanced symmetry point (ESP), which fixes the initial conditions for slow-roll inflation. When crossing the ESP the modulus becomes temporarily trapped, which leads to a brief stage of trapped inflation. This is followed by enough slow roll inflation to solve the flatness and horizon problems. After inflation, the field rolls down the potential and eventually freezes to a certain value because of cosmological friction. The latter is due to the thermal bath of the hot big bang, which is produced by the decay of a curvaton field. The modulus remains frozen until the present, when it becomes quintessence.

J. C. Bueno Sanchez; K. Dimopoulos

2006-06-22T23:59:59.000Z

287

Gravitinos, the Lithium problem, and DM production: Is there a corresponding neutrino physics linkage?  

E-Print Network (OSTI)

Studies are cited indicating that gravitino production acts as a natural upper bound to Li6 and Li7 levels, based on what happens after hadronic decay of relic 1 TeV into 100 GeV gravitinos at 1000 s. after the Big Bang. The produced gravitinos contribute a large fraction of required dark matter density. Whether or not gravitinos can be linked to neutrino production depends on which model of dark matter (DM) is assumed or used. A model presented by the author in 2008 links DM of about 100 GeV -- based on a phenomenological Lagrangian creating different Neutrino masses without SUSY -- with a dark matter candidate of about 100 GeV. This may tie in 100 GeV gravitinos with neutrino physics.

A. W. Beckwith

2008-10-08T23:59:59.000Z

288

Extremely High Energy Neutrinos, Neutrino Hot Dark Matter, and the Highest Energy Cosmic Rays  

E-Print Network (OSTI)

Extremely high energy (up to 10**(22) eV) cosmic neutrino beams initiate high energy particle cascades in the background of relic neutrinos from the Big Bang. We perform numerical calculations to show that such cascades could contribute more than 10% to the observed cosmic ray flux above 10**(19) eV if neutrinos have masses in the electron volt range. The required intensity of primary neutrinos could be consistent with astrophysical models for their production if the maximum neutrino energy reaches to 10**(22) eV and the massive neutrino dark matter is locally clustered. Future observations of ultra high energy cosmic rays will lead to an indirect but practical search for neutrino dark matter.

Shigeru Yoshida; Guenter Sigl; Sangjin Lee

1998-08-14T23:59:59.000Z

289

Forecast Constraints on Inflation from Combined CMB and Gravitational Wave Direct Detection Experiments  

E-Print Network (OSTI)

We study how direct detection of the inflationary gravitational wave background constrains inflationary parameters and complements CMB polarization measurements. The error ellipsoids calculated using the Fisher information matrix approach with Planck and the direct detection experiment, BBO (Big Bang Observer), show different directions of parameter degeneracy, and the degeneracy is broken when they are combined. For a slow-roll parameterization, we show that BBO could significantly improve the constraints on the tensor-to-scalar ratio compared with Planck alone. We also look at a quadratic and a natural inflation model. In both cases, if the temperature of reheating is also treated as a free parameter, then the addition of BBO can significantly improve the error bars. In the case of natural inflation, we find that the addition of BBO could even partially improve the error bars of a cosmic variance-limited CMB experiment.

Sachiko Kuroyanagi; Christopher Gordon; Joseph Silk; Naoshi Sugiyama

2009-12-18T23:59:59.000Z

290

Thermodynamics of the Transformation of Gravitational Waves into Matter Quantums for a Vacuum Space Model  

E-Print Network (OSTI)

It is shown that the entropy of low density monochromatic gravitational waves, waves required for the stabilization of the crystalline structure of vacuum cosmic space, varies with the volume in the same manner as the entropy of an ideal gas formed by particles. This implies that close enough to the big-bang event the energy of all the 10 to the 120 power gravitational waves, under an adiabatic compression process, which stabilizes the crystalline structure of vacuum space behaves thermodynamically as though it is consisted of a number nB = 10 to the 80 power of independent energy or matter quanta (neutrons). PACS numbers: 03.50.De, 03.65.-w, 04.20.-q, 61.50.-f, 65.50.+m, 98.80.Ft, 97.60.Lf

J. A. Montemayor-Aldrete; M. Lopez de Haro; J. R. Morones-Ibarra; A. Morales-Mori; Mendoza-Allende; E. Cabrera-Bravo; A. Montemayor-Varela

2005-09-06T23:59:59.000Z

291

SciDAC Visualization and Analytics Center for EnablingTechnologies  

SciTech Connect

The Visualization and Analytics Center for EnablingTechnologies (VACET) focuses on leveraging scientific visualization andanalytics software technology as an enabling technology for increasingscientific productivity and insight. Advances in computational technologyhave resulted in an 'information big bang,' which in turn has created asignificant data understanding challenge. This challenge is widelyacknowledged to be one of the primary bottlenecks in contemporaryscience. The vision of VACET is to adapt, extend, create when necessary,and deploy visual data analysis solutions that are responsive to theneeds of DOE'scomputational and experimental scientists. Our center isengineered to be directly responsive to those needs and to deliversolutions for use in DOE's large open computing facilities. The researchand development directly target data understanding problems provided byour scientific application stakeholders. VACET draws from a diverse setof visualization technology ranging from production quality applicationsand application frameworks to state-of-the-art algorithms forvisualization, analysis, analytics, data manipulation, and datamanagement.

Bethel, E. Wes; Johnson, Chris; Joy, Ken; Ahern, Sean; Pascucci,Valerio; Childs, Hank; Cohen, Jonathan; Duchaineau, Mark; Hamann, Bernd; Hansen, Charles; Laney, Dan; Lindstrom, Peter; Meredith, Jermey; Ostrouchov, George; Parker, Steven; Silva, Claudio; Sanderson, Allen; Tricoche, Xavier.

2007-06-30T23:59:59.000Z

292

Supersymmetry, Dark Matter and the LHC  

Science Conference Proceedings (OSTI)

The conceptually simplest scenario for dark matter (DM) is that it is a stable thermal relic from standard Big Bang cosmology, in many SUSY models the lightest neutralino. The relic density determination selects special regions in SUSY model parameter space with concomitant implications for collider physics, dark matter searches and low energy measurements. By studying various one-parameter extensions of the much-studied mSUGRA model (where we relax the untested universality assumptions) constructed to be in accord with the measured relic density, we show that these implications are in general model-dependent, so that LHC and DM measurements will provide clues to how sparticles acquire their masses. We point out some relatively robust implications for LHC and DM searches and conclude with an outlook for the future.

Tata, Xerxes [Department of Physics and Astronomy, University of Hawaii, Honolulu, HI 96825 (United States) and Physics Department, University of Wisconsin, Madison, WI 53705 (United States)

2010-02-10T23:59:59.000Z

293

On the Cosmic Nuclear Cycle and the Similarity of Nuclei and Stars  

E-Print Network (OSTI)

Repulsive interactions between neutrons in compact stellar cores cause luminosity and a steady outflow of hydrogen from stellar surfaces. Neutron repulsion in more massive compact objects made by gravitational collapse produces violent, energetic, cosmological events (quasars, gamma ray bursts, and active galactic centers) that had been attributed to black holes before neutron repulsion was recognized. Rather than evolving in one direction by fusion, nuclear matter on the cosmological scale cycles between fusion, gravitational collapse, and dissociation (including neutron-emission). This cycle involves neither the production of matter in an initial Big Bang nor the disappearance of matter into black holes. The similarity Bohr noted between atomic and planetary structures extends to a similarity between nuclear and stellar structures.

O. Manuel; Michael Mozina; Hilton Ratcliffe

2005-11-18T23:59:59.000Z

294

Experiment Profile: DAMIC NAME: Dark Matter In CCDs, or DAMIC  

NLE Websites -- All DOE Office Websites (Extended Search)

DAMIC DAMIC NAME: Dark Matter In CCDs, or DAMIC ThE ORIGIN OF ThE NAME: DAMIC searches for dark matter using Charge Coupled Devices. These digital chips register light that gets converted into a digital value a computer can store. WHAT WILL THIS TELL? Everything you see, visible matter, makes up 4 percent of the universe. Dark matter and dark energy make up the rest of the universe. Physicists understand that dark matter acts as an invisible source of gravity, but little more. DAMIC seeks to pinpoint what particles make up dark matter, which will help explain how the universe came to exist. Without the added gravitational attraction of dark matter, stars and galaxies would have never formed. The expansion of the universe after the Big Bang would have dispersed visible

295

The Universe Adventure - Fundamental Particles  

NLE Websites -- All DOE Office Websites (Extended Search)

Fundamental Particles Fundamental Particles Chart of Fundamental Particles All matter in the universe is comprised of fundamental particles. So what exactly makes up this matter? All matter is made of fundamental particles that came into being at the birth of the Universe. Quarks experience the strong force which is carried by massless particles called gluons. They bond together in specific combinations to form protons, neutrons, and other hadrons. Leptons do not experience the strong force but may interact via the electromagnetic force, the weak force, or both. Anti-quarks and anti-leptons are exactly the same as their quark and lepton counterparts, but have an opposite charge. All massive particles are influenced by the force of gravity. Quark-Gluon Plasma: 10-12 Seconds After the Big Bang

296

Inquiring Minds - Questions About Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics of the universe Physics of the universe From the big bang to black holes, extra dimensions, space and time Centrifugal Force From smaller than atoms to larger than galaxies structures spin and in doing so the centrifugal force throws things outward. Might not the Universe as a whole be spinning on an axis and what we currently ascribe to a mysterious repulsive force be a centrifugal force throwing things outward? Thrown out rather than pushed or drawn? Motion in the Universe I have been attempting to calculate the speed at which an individual is traveling through the universe when standing 'still'. i.e., the rotation speed of the earth, the speed of the orbit of the earth around the sun, the solar system withing our galaxy, the galaxy...etc. Is there such a measurement or 'thing' as absolute STILL?

297

microwaverpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

microwave microwave background 1 26. COSMIC MICROWAVE BACKGROUND Revised September 2013 by D. Scott (University of British Columbia) and G.F. Smoot (UCB/LBNL). 26.1. Introduction The energy content in radiation from beyond our Galaxy is dominated by the cosmic microwave background (CMB), discovered in 1965 [1]. The spectrum of the CMB is well described by a blackbody function with T = 2.7255 K, this spectral form being one of the main pillars of the hot Big Bang model for the early Universe. The lack of any observed deviations from a blackbody spectrum constrains physical processes over cosmic history at redshifts z ∼ < 10 7 (see earlier versions of this review). All viable cosmological models predict a very nearly Planckian spectrum inside the current observational limits (although that could change with more sensitive spectral experiments in the future [2]). Currently the key CMB observable

298

Energy Blog | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

9, 2013 9, 2013 VIDEO: Watch the Solar Decathlon 2013 Google+ Hangout Miss the Solar Decathlon 2013 Google+ Hangout? Watch a recording of it now. September 19, 2013 This image shows the barred spiral galaxy NGC 1398. | Image courtesy of the Dark Energy Survey. Supercomputing: A Toolbox to Simulate the Big Bang and Beyond Learn how three Energy Department National Labs are collaborating to peer deeper into the origins of our universe than ever before. September 19, 2013 Innovating to Meet the Evolving Cyber Challenge Protecting the critical energy infrastructure that supports America's economy and security is vital -- and is a top Energy Department priority. September 17, 2013 An Update on Fisker Automotive and the Energy Department's Loan Portfolio The continued success of America's auto industry depends on innovation

299

KINEMATIC SPACES AND DE VRIES ALGEBRAS: TOWARDS POSSIBLE PHYSICAL MEANING OF DE VRIES ALGEBRAS  

E-Print Network (OSTI)

Traditionally, in physics, spacetimes are described by (pseudo)Riemann spaces, i.e., by smooth manifolds with a tensor metric field. However, in several physically interesting situations smoothness is violated: near the Big Bang, at the black holes, and on the microlevel, when we take into account quantum effects. In all these situations, what remains is causality — an ordering relation. To describe such situations, in the 1960s, geometers H. Busemann and R. Pimenov and physicists E. Kronheimer and R. Penrose developed a theory of kinematic spaces. Originally, kinematic spaces were formulated as topological ordered spaces, but it turned out that kinematic spaces allow an equivalent purely algebraic description as sets with two related orders: causality and “kinematic ” causality (possibility to influence by particles with nonzero mass, particles that travel with speed smaller than the speed of light). In this paper, we analyze the relation between kinematic spaces and de Vries algebras – another mathematical object with two similarly related orders.

O. Kosheleva; F. Zapata

2012-01-01T23:59:59.000Z

300

Emergent universe in spatially flat cosmological model  

E-Print Network (OSTI)

The scenario of an emergent universe provides a promising resolution to the big bang singularity in universes with positive or negative spatial curvature. It however remains unclear whether the scenario can be successfully implemented in a spatially flat universe which seems to be favored by present cosmological observations. In this paper, we study the stability of Einstein static state solutions in a spatially flat Shtanov-Sahni braneworld scenario. With a negative dark radiation term included and assuming a scalar field as the only matter energy component, we find that the universe can stay at an Einstein static state past eternally and then evolve to an inflation phase naturally as the scalar field climbs up its potential slowly. In addition, we also propose a concrete potential of the scalar field that realizes this scenario.

Kaituo Zhang; Puxun Wu; Hongwei Yu

2013-11-16T23:59:59.000Z

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301

A classification of spherically symmetric self-similar dust models  

E-Print Network (OSTI)

We classify all spherically symmetric dust solutions of Einstein's equations which are self-similar in the sense that all dimensionless variables depend only upon $z\\equiv r/t$. We show that the equations can be reduced to a special case of the general perfect fluid models with equation of state $p=\\alpha \\mu$. The most general dust solution can be written down explicitly and is described by two parameters. The first one (E) corresponds to the asymptotic energy at large $|z|$, while the second one (D) specifies the value of z at the singularity which characterizes such models. The E=D=0 solution is just the flat Friedmann model. The 1-parameter family of solutions with z>0 and D=0 are inhomogeneous cosmological models which expand from a Big Bang singularity at t=0 and are asymptotically Friedmann at large z; models with E>0 are everywhere underdense relative to Friedmann and expand forever, while those with E0 ones. The 2-parameter solutions with D>0 again represent inhomogeneous cosmological models but the Big Bang singularity is at $z=-1/D$, the Big Crunch singularity is at $z=+1/D$, and any particular solution necessarily spans both z0. While there is no static model in the dust case, all these solutions are asymptotically ``quasi-static'' at large $|z|$. As in the D=0 case, the ones with $E \\ge 0$ expand or contract monotonically but the latter may now contain a naked singularity. The ones with E<0 expand from or recollapse to a second singularity, the latter containing a black hole.

B. J. Carr

2000-03-02T23:59:59.000Z

302

Testing Bell's Inequality with Cosmic Photons: Closing the Settings-Independence Loophole  

E-Print Network (OSTI)

We propose a practical scheme to use photons from causally disconnected cosmic sources to set the detectors in an experimental test of Bell's inequality. In current experiments, detector settings are determined by local quantum random number generators. In such experiments, only a small amount of correlation between detector settings and some local hidden variables, established less than a millisecond before each experimental run, would suffice to mimic the predictions of quantum mechanics. By setting the detectors using cosmic sources instead, observed violations of Bell's inequality in our proposed "Cosmic Bell" experiment would require any such coordination to have been in place for billions of years rather than milliseconds -- an improvement of 20 orders of magnitude. Quasar pairs can be used as real-time triggers to establish detector settings using existing technology. For quasars on opposite sides of the sky with redshifts z > 3.65, there is no event after the hot big bang 13.8 billion years ago (following any period of inflation) that lies in the past light cones of both quasars. Alternatively, detector settings could be set by observing patches of the Cosmic Microwave Background (CMB, z ~ 1089). For CMB patches with angular separations > 2.3 degrees, the events determining the detector settings would have no shared causal past since the hot big bang. In the case of the CMB, noise from the receiver and atmosphere make it difficult to rule out local influences on causal grounds alone, but a specially designed balloon-based system using state-of-the-art detectors is a realistic near-term possibility.

Jason Gallicchio; Andrew S. Friedman; David I. Kaiser

2013-10-11T23:59:59.000Z

303

Abstract for Andrew W. Steiner  

NLE Websites -- All DOE Office Websites (Extended Search)

Two Acts: r-Process Nucleosynthesis in Neutrino-Driven Winds and the Nuclear Symmetry Energy In the first portion of this talk, we revisit the problem of r-process nucleosynthesis...

304

What have we learnt from using real parallel machines to solve real problems?  

Science Conference Proceedings (OSTI)

We briefly review some key scientific and parallel processing issues in a selection of some 84 existing applications of parallel machines. We include the MIMD hypercube transputer array, BBN Butterfly, and the SIMD ICL DAP, Goodyear MPP and Connection ...

G. C. Fox

1989-01-01T23:59:59.000Z

305

CRD Report  

E-Print Network (OSTI)

of supernovae, gamma ray bursts and nucleosynthesis. “HighBlack Holes to Gamma Ray Bursts. ” A book launch party is

Wang, Ucilia

2006-01-01T23:59:59.000Z

306

SNAP  

NLE Websites -- All DOE Office Websites (Extended Search)

Expansion Discovered Expansion Discovered - The Big Bang, Modified - Dark Energy - How Will SNAP do it? - Why Do This From Space? - Why Do We Want to Know? - Detailed Overview - Spacecraft / Instruments - Resources Dark Energy Expansion Discovered Astronomers in the early 20th Century got the shocks of their lives when they discovered that galaxies appeared to be rushing away from us. They did this by taking spectra of the galaxies, and then measuring the shift in their spectrum due to their motion. diagram of red shift from astronomynotes.com Credit: Astronomynotes.com You're probably already familiar with this phenomenon, called the Doppler Shift -it's the same principle that makes a car horn change in pitch from high to low as it approaches and passes you. The sound waves are compressed as the car approaches you (resulting in a higher pitch) and are stretched as it recedes (which lowers the pitch). With light, an object approaching you has its light waves compressed, shortening the wavelength. This is called a blue shift ("blue" in this sense doesn't necessarily mean the object gets bluer; astronomers the word as a kind of shorthand, since in visible light the shorter wavelengths are blue). If the object is moving away, the wavelengths are stretched, resulting in a red shift of the spectrum.

307

Special Event/Tour Detail: Ask-a-Scientist Guided Tour of Fermilab  

NLE Websites -- All DOE Office Websites (Extended Search)

Special Event/Tour Detail: Ask-a-Scientist Guided Tour of Fermilab Special Event/Tour Detail: Ask-a-Scientist Guided Tour of Fermilab Tour Info Public Tours Registrar Calendar Special Event/Tours Audience: Public, Teachers, Students, Grades 6 - Adult Description: Take science questions straight to experts. Physicists answer questions and explain everything from the Big Bang to how a particle accelerator works. Ask a Scientist is held from 1 PM to 4 PM on the first Sunday of the month (except holiday weekends when we delay by one week and in the month of the Family Open House). Each three-hour session includes a presentation by a scientist, a tour, and a Q & A period. The docent-led tour includes visiting the 1st and 15th floor of Wilson Hall, the Linac building with the first two accelerators, the neutron therapy area and the Main Control Room. There is no charge for the session, but advance registration is required. The minimum age for the tour is 10 years old. No exceptions.

308

Cosmological milestones and energy conditions  

E-Print Network (OSTI)

Until recently, the physically relevant singularities occurring in FRW cosmologies had traditionally been thought to be limited to the "big bang", and possibly a "big crunch". However, over the last few years, the zoo of cosmological singularities considered in the literature has become considerably more extensive, with "big rips" and "sudden singularities" added to the mix, as well as renewed interest in non-singular cosmological events such as "bounces" and "turnarounds". In this talk, we present an extensive catalogue of such cosmological milestones, both at the kinematical and dynamical level. First, using generalized power series, purely kinematical definitions of these cosmological events are provided in terms of the behaviour of the scale factor a(t). The notion of a "scale-factor singularity" is defined, and its relation to curvature singularities (polynomial and differential) is explored. Second, dynamical information is extracted by using the Friedmann equations (without assuming even the existence of any equation of state) to place constraints on whether or not the classical energy conditions are satisfied at the cosmological milestones. Since the classification is extremely general, and modulo certain technical assumptions complete, the corresponding results are to a high degree model-independent.

Celine Cattoen; Matt Visser

2006-09-18T23:59:59.000Z

309

SNAP  

NLE Websites -- All DOE Office Websites (Extended Search)

Mission Home Page Mission Home Page - Spacecraft / Instruments - Science - E/PO - People cutaway image of SNAP The Universe is a big place... and it's getting bigger every day. Our current model of the Universe, called the Big Bang Model, is that the Universe originated approximately 13.7 billion years ago and has been expanding ever since. It was always assumed that expansion was slowing, with the gravity of the Universe itself applying the brakes. But shortly before the end of the 20th century astronomers got a big surprise: the Universe was not slowing down, it was speeding up, the expansion ever accelerating. Very little is known about this accelerated expansion, and less is known about its cause. The SuperNova Acceleration Probe, or SNAP, will fill the wide gaps in our knowledge. It will study exploding stars called supernovae, as well as the gentle smearing of the light from distant galaxies due to gravity - called weak gravitational lensing - and put limits on what may or may not be the force driving the outward pull on the Universe. SNAP will investigate over one thousand square degrees of sky - more than 5000 times the size of the full Moon! - with a 500 megapixel camera.

310

Cosmological singularities in Bakry-Émery spacetimes  

E-Print Network (OSTI)

We consider spacetimes consisting of a manifold with Lorentzian metric and a weight function or scalar field. These spacetimes admit a Bakry-\\'Emery-Ricci tensor which is a natural generalization of the Ricci tensor. We impose an energy condition on the Bakry-\\'Emery-Ricci tensor and obtain singularity theorems of a cosmological type, both for zero and for positive cosmological constant. That is, we find conditions under which every timelike geodesic is incomplete. These conditions are given by "open" inequalities, so we examine the borderline (equality) cases and show that certain singularities are avoided in these cases only if the geometry is rigid; i.e., if it splits as a Lorentzian product or, for a positive cosmological constant, a warped product, and the weight function is constant along the time direction. Then the product case is future timelike geodesically complete while, in the warped product case, worldlines of conformally static observers are complete. Our results answer a question posed by J Case. We then apply our results to the cosmology of scalar-tensor gravitation theories. We focus on the Brans-Dicke family of theories in 4 spacetime dimensions, where we obtain "Jordan frame" singularity theorems for big bang singularities.

Gregory J Galloway; Eric Woolgar

2013-12-12T23:59:59.000Z

311

Quantum cosmology and late-time singularities  

E-Print Network (OSTI)

The development of dark energy models has stimulated interest to cosmological singularities, which differ from the traditional Big Bang and Big Crunch singularities. We review a broad class of phenomena connected with soft cosmological singularities in classical and quantum cosmology. We discuss the classification of singularities from the geometrical point of view and from the point of view of the behaviour of finite size objects, crossing such singularities. We discuss in some detail quantum and classical cosmology of models based on perfect fluids (anti-Chaplygin gas and anti-Chaplygin gas plus dust), of models based on the Born-Infeld-type fields and of the model of a scalar field with a potential inversely proportional to the field itself. We dwell also on the phenomenon of the phantom divide line crossing in the scalar field models with cusped potentials. Then we discuss the Friedmann equations modified by quantum corrections to the effective action of the models under considerations and the influence of such modification on the nature and the existence of soft singularities. We review also quantum cosmology of models, where the initial quantum state of the universe is presented by the density matrix (mixed state). Finally, we discuss the exotic singularities arising in the brane-world cosmological models.

A. Yu. Kamenshchik

2013-07-22T23:59:59.000Z

312

Inflation  

E-Print Network (OSTI)

The shortcomings of the Standard Big Bang Cosmological Model as well as their resolution in the context of inflationary cosmology are discussed. The inflationary scenario and the subsequent oscillation and decay of the inflaton field are then studied in some detail. The density perturbations produced during inflation and their evolution during the matter dominated era are presented. The temperature fluctuations of the cosmic background radiation are summarized. The non-supersymmetric as well as the supersymmetric hybrid inflationary model is introduced and the `reheating' of the universe is analyzed in the context of the latter and a left-right symmetric gauge group. The scenario of baryogenesis via a primordial leptogenesis is considered in some detail. It is, finally, pointed out that, in the context of a supersymmetric model based on a left-right symmetric gauge group, hybrid inflation, baryogenesis via primordial leptogenesis and neutrino oscillations are linked. This scheme, supplemented by a familiar ansatz for the neutrino Dirac masses and mixing of the two heaviest families and with the MSW resolution of the solar neutrino puzzle, implies that the tau-neutrino mass lies approximately between 1 and 9 eV. The mu-tau mixing angle is predicted to lie in a narrow range which will be partially tested by the Chorus/Nomad experiment.

G. Lazarides

1998-02-25T23:59:59.000Z

313

Hydro-Gravitational-Dynamics Interpretation of the Tadpole VV29 Merging Galaxy System: Dark-Matter-Halo-Planet Star-Cluster Wakes  

E-Print Network (OSTI)

Hubble Space telescope (HST) images of merging galaxy system VV29 reveal the 0.3 Mpc baryonic-dark-matter (BDM) halo composed of primordial protoglobularstarcluster (PGC) clumps of planets. Star-cluster-wakes trace the merger by formation of stars from the planets. Aligned young globular star clusters (YGCs), star-wakes and dust-trails show the frictional, spiral passage of galaxy fragments VV29cdef in a long tail-like galaxy (VV29b) as the fragments merge on the accretion disk plane of the central spiral galaxy VV29a. The observations confirm the hydro-gravitational-dynamics (HGD) prediction of Gibson 1996 and quasar microlensing inference of Schild 1996 that the dark matter of galaxies is dominated by planets (PFPs) in million-solar-mass clumps. Globular star clusters (YGCs, OGCs, PGCs) preserve the density of the plasma epoch 30,000 years after the big bang when viscous supercluster-fragmentation began. Tadpole images show linear galaxy clusters reflecting turbulent vortex lines of protogalaxy fragmentation at the 0.003 Mpc Kolmogorov-Nomura scale of the plasma before transition to gas. The halo size indicates strong diffusion of PGC primordial-planet-clumps from a cooling protogalaxy as its planets freeze.

Carl H. Gibson

2008-03-29T23:59:59.000Z

314

Mergers and Non-Thermal Processes in Clusters of Galaxies  

E-Print Network (OSTI)

Clusters of galaxies generally form by the gravitational merger of smaller clusters and groups. Major cluster mergers are the most energetic events in the Universe since the Big Bang. The basic properties of cluster mergers and their effects will be discussed. Mergers drive shocks in the intracluster gas, and these shocks heat the intracluster gas, and should also accelerate nonthermal relativistic particles. Mergers also produce distinctive features in the X-ray images of clusters, including "cold fronts" and cool trails. Chandra and XMM/Newton observations of the X-ray signatures of mergers will be discussed. X-ray observations of shocks and cold fronts can be used to determine the geometry and kinematics of the merger. As a result of particle acceleration in shocks and turbulent acceleration following mergers, clusters of galaxies should contain very large populations of relativistic electrons and ions. Observations and models for the radio, extreme ultraviolet, hard X-ray, and gamma-ray emission from nonthermal particles accelerated in these shocks will also be described.

Craig L. Sarazin

2004-06-07T23:59:59.000Z

315

The Formation of the First Low-Mass Stars From Gas With Low Carbon and Oxygen Abundances  

E-Print Network (OSTI)

The first stars in the Universe are predicted to have been much more massive than the Sun. Gravitational condensation accompanied by cooling of the primordial gas due to molecular hydrogen, yields a minimum fragmentation scale of a few hundred solar masses. Numerical simulations indicate that once a gas clump acquires this mass, it undergoes a slow, quasi-hydrostatic contraction without further fragmentation. Here we show that as soon as the primordial gas - left over from the Big Bang - is enriched by supernovae to a carbon or oxygen abundance as small as ~0.01-0.1% of that found in the Sun, cooling by singly-ionized carbon or neutral oxygen can lead to the formation of low-mass stars. This mechanism naturally accommodates the discovery of solar mass stars with unusually low (10^{-5.3} of the solar value) iron abundance but with a high (10^{-1.3} solar) carbon abundance. The minimum stellar mass at early epochs is partially regulated by the temperature of the cosmic microwave background. The derived critical abundances can be used to identify those metal-poor stars in our Milky Way galaxy with elemental patterns imprinted by the first supernovae.

Volker Bromm; Abraham Loeb

2003-10-21T23:59:59.000Z

316

The Revival of White Holes as Small Bangs  

E-Print Network (OSTI)

Black holes are extremely dense and compact objects from which light cannot escape. There is an overall consensus that black holes exist and many astronomical objects are identified with black holes. White holes were understood as the exact time reversal of black holes, therefore they should continuously throw away material. It is accepted, however, that a persistent ejection of mass leads to gravitational pressure, the formation of a black hole and thus to the "death of while holes". So far, no astronomical source has been successfully tagged a white hole. The only known white hole is the Big Bang which was instantaneous rather than continuous or long-lasting. We thus suggest that the emergence of a white hole, which we name a 'Small Bang', is spontaneous - all the matter is ejected at a single pulse. Unlike black holes, white holes cannot be continuously observed rather their effect can only be detected around the event itself. Gamma ray bursts are the most energetic explosions in the universe. Long gamma-ray bursts were connected with supernova eruptions. There is a new group of gamma-ray bursts, which are relatively close to Earth, but surprisingly lack any supernova emission. We propose identifying these bursts with white holes. White holes seem like the best explanation of gamma-ray bursts that appear in voids. We also predict the detection of rare gigantic gamma-ray bursts with energies much higher than typically observed.

Alon Retter; Shlomo Heller

2011-05-13T23:59:59.000Z

317

Observational evidence favors a static universe  

E-Print Network (OSTI)

The common attribute of all Big Bang cosmologies is that they are based on the assumption that the universe is expanding. However examination of the evidence for this expansion clearly favours a static universe. The major topics considered are: Tolman surface brightness, angular size, type 1a supernovae, gamma ray bursts, galaxy distributions, quasar distributions, X-ray background radiation, cosmic microwave background radiation, radio source counts, quasar variability and the Butcher--Oemler effect. An analysis of the best raw data for these topics shows that they are consistent with expansion only if there is evolution that cancels the effects of expansion. An alternate cosmology, curvature cosmology, is in full agreement with the raw data. This tired-light cosmology predicts a well defined static and stable universe and is fully described. It not only predicts accurate values for the Hubble constant and the temperature of cosmic microwave background radiation but shows excellent agreement with most of the topics considered. Curvature cosmology also predicts the deficiency in solar neutrino production rate and can explain the anomalous acceleration of {\\it Pioneer} 10.

David F. Crawford

2010-09-05T23:59:59.000Z

318

Spin-Torsion, Braneworlds and Changing Symmetry in the Universe  

E-Print Network (OSTI)

In this thesis, we explore three phenomenological alternatives to the current paradigm of the standard inflationary big bang scenario. The three alternative themes are spin torsion (or Einstein-Cartan-Kibble-Sciama) theories, extra dimensions (braneworld cosmology) and changing global symmetry. In the spin torsion theories, we found new cosmological solutions with a cosmological constant as alternative to the standard scalar field driven inflationary scenario and we conclude that these toy models do not exhibit an inflationary phase. In the theme of extra dimensions, we discuss the dynamics of linearized scalar and tensor perturbations in an almost Friedmann-Robertson-Walker braneworld cosmology of Randall-Sundrum type II using the 1+3 covariant approach. We derive a complete set of frame-independent equations for the total matter variables, and a partial set of equations for the non-local variables, which arise from the projection of the Weyl tensor in the bulk. The latter equations are incomplete since there is no propagation equation for the non-local anisotropic stress. In the simplest approximation, we show the braneworld imprint as a correction to the power spectra for standard temperature and polarization anisotropies and similarly show that the tensor anisotropies are also insensitive to the high energy effects. Finally in the theme of changing global symmetry, we constructed a bounded isothermal solution embedded in an expanding Einstein de Sitter universe and showed that there is a possible phase transition in the far future.

Bernard Leong

2003-11-05T23:59:59.000Z

319

A stellar relic from the early Milky Way  

E-Print Network (OSTI)

The chemical composition of the most metal-deficient stars reflects the composition of the gas from which they formed. These old stars provide crucial clues to the star formation history and the synthesis of chemical elements in the early Universe. They are the local relics of epochs otherwise observable only at very high redshifts; if totally metal-free (``population III'') stars could be found, this would allow the direct study of the pristine gas from the Big Bang. Earlier searches for such stars found none with an iron abundance less than 1/10,000 that of the Sun, leading to the suggestion that low-mass stars could only form from clouds above a critical iron abundance. Here we report the discovery of a low-mass star with an iron abundance as low as 1/200,000 of the solar value. This discovery suggests that population III stars could still exist, that is, that the first generation of stars also contained long-lived low-mass objects. The previous failure to find them may be an observational selection effect.

Norbert Christlieb; Michael S. Bessell; Timothy C. Beers; Bengt Gustafsson; Andreas Korn; Paul S. Barklem; Torgny Karlsson; Michelle Mizuno-Wiedner; Silvia Rossi

2002-11-13T23:59:59.000Z

320

The Physics of the Intergalactic Medium  

E-Print Network (OSTI)

Intergalactic space is filled with a pervasive medium of ionized gas, the Intergalactic Medium (IGM). A residual neutral fraction is detected in the spectra of Quasi-Stellar Objects at both low and high redshifts, revealing a highly fluctuating medium with temperatures characteristic of photoionized gas. The statistics of the fluctuations are well-reproduced by numerical gravity-hydrodynamics simulations within the context of standard cosmological structure formation scenarios. As such, the study of the IGM offers an opportunity to probe the nature of the primordial density fluctuations on scales unavailable to other methods. The simulations also suggest the IGM is the dominant reservoir of baryons produced by the Big Bang, and so the principal source of the matter from which galaxies formed. The detection of metal systems within the IGM shows that it was enriched by evolved stars early in its history, demonstrating an intimate connection between galaxy formation and the IGM. The author presents a comprehensive review of the current understanding of the structure and physical properties of the IGM and its relation to galaxies, concluding with comments on prospects for furthering the study of the IGM using future ground-based facilities and space-based experiments.

Avery A. Meiksin

2007-11-21T23:59:59.000Z

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321

The role of the Higgs meson in the cosmological constraint on the mass of very heavy neutrinos  

Science Conference Proceedings (OSTI)

According to LEP experiments of the measurement of the width and height of a Z-boson peak, there are three neutrino species. However, this constraint applies only to light neutrinos with mass m 44 GeV. Because the experimental search for neutrinos on accelerators at very high energies ({ge}M{sub Z}) is a difficult problem, the investigation of indirect astrophysical effects becomes an important source of information on the properties of new particles. According to the Big Bang theory, the background of relic neutrinos also containing new species of very heavy neutrinos (if they exist) should exist in the Universe, and their annihilation in the halo of the Galaxy could lead to peculiarities in the spectrum of cosmic rays. The astrophysical constraints on the mass of heavy neutrinos were obtained by analyzing the spectra of cosmic electrons and photons and by using the idea about neutrino condensation in the time-dependent gravitational field of collapsing matter. In this paper, the authors take into account a finite mass of a Higgs meson and show how neutrino annihilation into a Higgs meson, which decays to a W pair modifies the restriction on heavy neutrino mass.

Konoplich, R.V.; Sorokina, E.V.; Khlopov, M.Yu. [Moscow Institute of Engineering Physics (Russian Federation)

1994-07-01T23:59:59.000Z

322

New Cosmological Model and Its Implications on Observational Data Interpretation  

E-Print Network (OSTI)

The paradigm of \\Lambda CDM cosmology works impressively well and with the concept of inflation it explains the universe after the time of decoupling. However there are still a few concerns; after much effort there is no detection of dark matter and there are significant problems in the theoretical description of dark energy. We will consider a variant of the cosmological spherical shell model, within FRW formalism and will compare it with the standard \\Lambda CDM model. We will show that our new topological model satisfies cosmological principles and is consistent with all observable data, but that it may require new interpretation for some data. Considered will be constraints imposed on the model, as for instance the range for the size and allowed thickness of the shell, by the supernovae luminosity distance and CMB data. In this model propagation of the light is confined along the shell, which has as a consequence that observed CMB originated from one point or a limited space region. It allows to interpret the uniformity of the CMB without inflation scenario. In addition this removes any constraints on the uniformity of the universe at the early stage and opens a possibility that the universe was not uniform and that creation of galaxies and large structures is due to the inhomogeneities that originated in the Big Bang.

B. Vlahovic

2013-03-03T23:59:59.000Z

323

Review of Particle Physics  

SciTech Connect

This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2158 new measurements from 551 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on neutrino mass, mixing, and oscillations, QCD, top quark, CKM quark-mixing matrix, V{sub ud} and V{sub us}, V{sub cb} and V{sub ub}, fragmentation functions, particle detectors for accelerator and non-accelerator physics, magnetic monopoles, cosmological parameters, and big bang cosmology. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.

Particle Data Group; Nakamura, Kenzo; al., et

2010-06-30T23:59:59.000Z

324

Conformal Structures Admitted by a Class of FRW Cosmologies  

E-Print Network (OSTI)

In this paper we demonstrate that there are large classes of Friedmann-Robertson-Walker (FRW) cosmologies that admit isotropic conformal structures of Quiescent Cosmology. FRW models have long been known to admit singularities such as Big Bangs and Big Crunches [1, 2] but recently it has been shown that there are other cosmological structures that these solutions contain. These structures are Big Rips, Sudden Singularities and Extremality Events [1, 2]. Within the Quiescent Cosmology framework [3] there also exist structures consistent with a cosmological singularity known as the Isotropic Past Singularity (IPS) [4, 5]. There also exists a cosmological final state known as a Future Isotropic Universe (FIU) [4], which strictly speaking, doesn't fit with the fundamental ideals of Quiescent Cosmology. In this paper, we compare the cosmological events of a large class of FRW solutions to the conformal structures of Quiescent Cosmology [4]. In the first section of this paper we present the relevant background information and our motivation. In the second section of this paper we construct conformal relationships for relevant FRW models. The third section contains a thorough discussion of a class of FRW solutions that cannot represent any of the previously constructed isotropic conformal structures from Quiescent Cosmology. The final section contains our remarks and future outlook for further study of this field.

Philip Threlfall; Susan M. Scott

2012-11-26T23:59:59.000Z

325

Order of Magnitude Smaller Limit on the Electric Dipole Moment of the Electron  

E-Print Network (OSTI)

The Standard Model (SM) of particle physics fails to explain dark matter and why matter survived annihilation with antimatter following the Big Bang. Extensions to the SM, such as weak-scale Supersymmetry, may explain one or both of these phenomena by positing the existence of new particles and interactions that are asymmetric under time-reversal (T). These theories nearly always predict a small, yet potentially measurable ($10^{-27}$-$10^{-30}$ $e$ cm) electron electric dipole moment (EDM, $d_e$), which is an asymmetric charge distribution along the spin ($\\vec{S}$). The EDM is also asymmetric under T. Using the polar molecule thorium monoxide (ThO), we measure $d_e = (-2.1 \\pm 3.7_\\mathrm{stat} \\pm 2.5_\\mathrm{syst})\\times 10^{-29}$ $e$ cm. This corresponds to an upper limit of $|d_e| < 8.7\\times 10^{-29}$ $e$ cm with 90 percent confidence, an order of magnitude improvement in sensitivity compared to the previous best limits. Our result constrains T-violating physics at the TeV energy scale.

ACME Collaboration; Jacob Baron; Wesley C. Campbell; David DeMille; John M. Doyle; Gerald Gabrielse; Yulia V. Gurevich; Paul W. Hess; Nicholas R. Hutzler; Emil Kirilov; Ivan Kozyryev; Brendon R. O'Leary; Cristian D. Panda; Maxwell F. Parsons; Elizabeth S. Petrik; Ben Spaun; Amar C. Vutha; Adam D. West

2013-10-28T23:59:59.000Z

326

Search for Heavy Resonances Decaying to Taus in 7 TeV Proton-Proton Collisions at the Large Hadron Collider  

E-Print Network (OSTI)

Over the last few decades, the Standard Model (SM) of particle physics has been used as a means of understanding the world around us. However, there is an increasing amount of data that suggests the SM of particle physics only describes nature up to energies of the electroweak scale. Extensions to the SM have been developed as a means of explaining experimental observation. If these extensions are indeed the correct mathematical descriptions of nature, the Large Hadron Collider (LHC), located at the European Center for Nuclear Research (CERN) near Geneva, Switzerland, is expected to produce new and exciting physics signatures that can shed light on the evolution of our universe since the early hypothesized Big Bang. Of particular interest are models that may lead to events with highly energetic tau lepton pairs. In this dissertation, focus is placed on a possible search for new heavy gauge bosons decaying to highly energetic tau pairs using a data sample corresponding to an integrated luminosity of 36 pb^-1 of proton-proton collisions at sqrt(s) = 7 TeV collected with the CMS detector at the CERN LHC. The number of observed events in the data is in good agreement with the predictions for SM background processes. In the context of the Sequential SM, a Z0 with mass less than 468 GeV/c^2 is excluded at 95 percent credibility level, exceeding the sensitivity by the Tevatron experiments at the Fermi National Accelerator Laboratory.

Gurrola, Alfredo

2011-08-01T23:59:59.000Z

327

Cosmology, Time's Arrow, and That Old Double Standard  

E-Print Network (OSTI)

It is widely accepted that temporal asymmetry is largely a cosmological problem; the task of explaining temporal asymmetry reduces in the main to that of explaining an aspect of the condition of the early universe. However, cosmologists who discuss these issues often make mistakes similar to those that plagued nineteenth century discussions of the statistical foundations of thermodynamics. In particular, they are often guilty of applying temporal "double standards" of various kinds---e.g., in failing to recognise that certain statistical arguments apply with equal force in either temporal direction. This paper aims to clarify the issue as to what would count as adequate explanation of cosmological time asymmetry. A particular concern is the question whether it is possible to explain why entropy is low near the Big Bang without showing that it must also be low near a Big Crunch, in the event that the universe recollapses. I criticise some of the objections raised to this possibility, showing that these too oft...

Price, Huw

2009-01-01T23:59:59.000Z

328

The Fluid Nature of Quark-Gluon Plasma  

E-Print Network (OSTI)

Collisions of heavy nuclei at very high energies offer the exciting possibility of experimentally exploring the phase transformation from hadronic to partonic degrees of freedom which is predicted to occur at several times normal nuclear density and/or for temperatures in excess of $\\sim 170$ MeV. Such a state, often referred to as a quark-gluon plasma, is thought to have been the dominant form of matter in the universe in the first few microseconds after the Big Bang. Data from the first five years of heavy ion collisions of Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) clearly demonstrate that these very high temperatures and densities have been achieved. While there are strong suggestions of the role of quark degrees of freedom in determining the final-state distributions of the produced matter, there is also compelling evidence that the matter does {\\em not} behave as a quasi-ideal state of free quarks and gluons. Rather, its behavior is that of a dense fluid with very low kinematic viscosity exhibiting strong hydrodynamic flow and nearly complete absorption of high momentum probes. The current status of the RHIC experimental studies is presented, with a special emphasis on the fluid properties of the created matter, which may in fact be the most perfect fluid ever studied in the laboratory.

W. A. Zajc

2008-02-25T23:59:59.000Z

329

Generation and detection of gravitational waves at microwave frequencies by means of a superconducting two-body system  

E-Print Network (OSTI)

The 2-body system of a superconducting sphere levitated in the magnetic field generated by a persistent current in a superconducting ring, can possibly convert gravitational waves into electromagnetic waves, and vice versa. Faraday's law of induction implies that the time-varying distance between the sphere and the ring caused by the tidal force of an incident gravitational wave induces time-varying electrical currents, which are the source of an electromagnetic wave at the same frequency as the incident gravitational wave. At sufficiently low temperatures, the internal degrees of freedom of the superconductors are frozen out because of the superconducting energy gap, and only external degrees of freedom, which are coupled to the radiation fields, remain. Hence this wave-conversion process is loss-free and therefore efficient, and by time-reversal symmetry, so is the reverse process. A Hertz-like experiment at microwave frequencies should therefore be practical to perform. This would open up observations of the gravitational-wave analog of the Cosmic Microwave Background from the extremely early Big Bang, and also communications directly through the interior of the Earth.

Raymond Y. Chiao

2007-10-08T23:59:59.000Z

330

Studying High Redshift Star Forming Galaxies at Centimeter and Millimeter Wavelengths  

E-Print Network (OSTI)

We discuss various aspects of centimeter and millimeter wavelength continuum and line observations of high redshift star forming galaxies. Perhaps the most important lesson is that sensitive observations at submm through cm wavelengths reveal a population of active star forming galaxies at high redshift which are unseen in deep optical surveys due to dust obscuration. Current models suggest that this population represents the formation of the spheroidal components of galaxies at z between 2 and 5, constituting about half of the total amount of cosmic star formation from the big bang to the present. High resolution imaging at cm wavelengths provides sub-arcsecond astrometry, and can be used to search for gravitational lensing and/or for the presence of an AGN. Radio continuum observations provide unique information on the magnetic fields in early galaxies, and give a gross indication of the star formation rate, while the radio-to-submm spectral index provides a rough indication of source redshift. Low J transitions of CO are redshifted into the cm bands for z > 2, allowing for sensitive searches for CO emission over large volumes at high redshift. We present recent results from the Very Large Array (VLA), and from the new 230 GHz MPIfR bolometer array at the IRAM 30m telescope. A wide field survey with the bolometer array indicates a cut-off in the source distribution function at FIR luminosities > 3e12 L_sun. Lastly, we summarize the scientific promise of the New VLA.

C. L. Carilli; K. M. Menten; M. S. Yun; F. Bertoldi; F. Owen; A. Dey

1999-07-30T23:59:59.000Z

331

Polarimeter Receiver Prototyping and Testing for the South Pole Telescope Upgrade  

E-Print Network (OSTI)

Experimental evidence has so far been supportive for the inflationary Big Bang model of cosmology, while imposing other mysteries, such as the fact that dark matter and dark energy actually consist of 95 % of the observable universe. The forthcoming upgrade of the South Pole Telescope, planned for 2010, will include a polarimeter with increased sensitivity. Measurements of the CMB polarization anisotropy to a high accuracy will describe the angular power spectrum of the B-mode polarization, which will help unravel some of the mysteries. We prototype and test a digital frequency multiplexed readout system for the SPT upgrade. The digital system has the advantage of being able to reconstruct the phase of the signals. We characterize the performance of the readout and we compare it to the theoretical expectations. The noise is found to be statistically insignificant (insert quantitative proof), and the system performs as expected, significantly better than the previous implementation. We conclude that the digital fMux readout system should be sent to the South Pole Telescope. 1

Constantinos Melachrinos

2009-01-01T23:59:59.000Z

332

Dark Energy in Perturbative String Cosmology  

E-Print Network (OSTI)

The apparent observation of dark energy poses problems for string theory. In de Sitter space, or in quintessence models, one cannot define a gauge-invariant S-matrix. We argue that eternal quintessence does not arise in weakly coupled string theory, but point out that it is difficult to define an $S$-matrix even in the presence of perturbative potentials for the moduli. The solutions of the Fischler-Susskind equations all have Big Bang or Big Crunch Singularities. We believe that an S-matrix (or S-vector) exists in this context but cannot be calculated by purely perturbative methods. We study the possibility of metastable de Sitter vacua in such weakly coupled scenarios, and conclude that the S-matrix of the extreme weak coupling region cannot probe de Sitter physics. We also consider proposed explanations of the dark energy from the perspective of string theory, and find that most are implausible. We note that it is possible that the axion constitutes both the dark matter and the dark energy.

Tom Banks; Michael Dine

2001-06-28T23:59:59.000Z

333

Is Hubble's Expansion due to Dark Energy  

E-Print Network (OSTI)

{\\it The universe is expanding} is known (through Galaxy observations) since 1929 through Hubble's discovery ($V = H D$). Recently in 1999, it is found (through Supernovae observations) that the universe is not simply expanding but is accelerating too. We, however, hardly know only $4\\%$ of the universe. The Wilkinson Microwave Anisotropy Probe (WMAP) satellite observational data suggest $73\\%$ content of the universe in the form of dark-energy, $23\\%$ in the form of non-baryonic dark-matter and the rest $4\\%$ in the form of the usual baryonic matter. The acceleration of the universe is ascribed to this dark-energy with bizarre properties (repulsive-gravity). The question is that whether Hubble's expansion is just due to the shock of big-bang & inflation or it is due to the repulsive-gravity of dark-energy? Now, it is believed to be due to dark-energy, say, by re-introducing the once-discarded cosmological-constant $\\Lambda$. In the present paper, it is shown that `the formula for acceleration due to dark-energy' is (almost) exactly of same-form as `the acceleration formula from the Hubble's law'. Hence, it is concluded that: yes, `indeed it is the dark-energy responsible for the Hubble's expansion too, in-addition to the current on-going acceleration of the universe'.

R. C. Gupta; Anirudh Pradhan

2010-10-19T23:59:59.000Z

334

Dark energy, exotic matter and properties of horizons in black hole physics and cosmology  

E-Print Network (OSTI)

We summarize recent results on the properties of near-horizon metrics in different spherically symmetric space-times, including Kantowski-Sachs cosmological models whose evolution begins with a horizon (the so-called Null Big Bang) and static metrics related to black holes. We describe the types of matter compatible with cosmological and black-hole horizons. It turns out, in particular, that a black hole horizon can be in equilibrium with a fluid of disordered cosmic strings ("black holes can have curly hair"). We also discuss different kinds of horizons from the viewpoint of the behavior of tidal forces acting on an extended body and recently classified as "usual", "naked" and "truly naked" ones; in the latter case, tidal forces are infinite in a freely falling reference frame. It is shown that all truly naked horizons, as well as many of those previously characterized as naked and even usual ones, do not admit an extension and therefore must be considered as singularities. The whole analysis is performed locally (in a neighborhood of a candidate horizon) in a model-independent manner. Finally, the possible importance of some of these models in generating dynamic, perturbatively small vacuum fluctuation contributions to the cosmological constant (within a cosmological Casimir-effect approach to this problem) is discussed.

K. A. Bronnikov; E. Elizalde; O. B. Zaslavskii

2008-10-28T23:59:59.000Z

335

The Nature and Origin of Time-asymmetric Spacetime Structures  

E-Print Network (OSTI)

Time-asymmetric spacetime structures, in particular those representing black holes and the expansion of the universe, are intimately related to other arrows of time, such as the second law and the retardation of radiation. The nature of the quantum arrow, often attributed to a collapse of the wave function, is essential, in particular, for understanding the much discussed "black hole information loss paradox". This paradox assumes a new form and can possibly be avoided in a consistent causal treatment that may be able to avoid horizons and singularities. The master arrow that would combine all arrows of time does not have to be identified with a direction of the formal time parameter that serves to formulate the dynamics as a succession of global states (a trajectory in configuration or Hilbert space). It may even change direction with respect to a fundamental physical clock such as the cosmic expansion parameter if this was formally extended either into a future contraction era or to negative "pre-big-bang" values.

H. D. Zeh

2010-12-21T23:59:59.000Z

336

The spin-dependent nd scattering length - a proposed high-accuracy measurement  

E-Print Network (OSTI)

The understanding of few-nucleon systems at low energies is essential, e.g. for accurate predictions of element abundances in big-bang and stellar fusion. Novel effective field theories, taking only nucleons, or nucleons and pions as explicit degrees of freedom, provide a systematic approach, permitting an estimate of theoretical uncertainties. Basic constants parameterising the short range physics are derived from only a handful of experimental values. The doublet neutron scattering length a_2 of the deuteron is particularly sensitive to a three-nucleon contact interaction, but experimentally known with only 6% accuracy. It can be deduced from the two experimentally accessible parameters of the nd scattering length. We plan to measure the poorly known "incoherent" nd scattering length a_{i,d} with 10^{-3} accuracy, using a Ramsey apparatus for pseudomagnetic precession with a cold polarised neutron beam at PSI. A polarised target containing both deuterons and protons will permit a measurement relative to the incoherent np scattering length, which is know experimentally with an accuracy of 2.4\\times 10^{-4}.

B. van den Brandt; H. W. Griesshammer; P. Hautle; J. Kohlbrecher; J. A. Konter; O. Zimmer

2004-01-23T23:59:59.000Z

337

The Failure of Black Holes to Explain Quasars  

E-Print Network (OSTI)

Abstract: The scientific consensus, (religious dogma), that quasars are powered by supermassive black holes or black holes of any size is mathematically and observationally false. The consensus that quasars are powered by super-massive black holes is wrong because black holes do not exist as proven mathematically by Mr. Stephen Crothers. [1][2] Since black holes do not exist they can never “power ” anything. This means that an actual explanation of the real mechanisms that power quasars is wide open, and that discovery as to the actual nature of these objects is open to amateurs and scientists who have not been brainwashed to believe in black holes. The author agrees with Mr. Halton Arp concerning them, as they probably eject from the location of active galaxies to become galaxies themselves. [3] It also should be mentioned that redshift as a determinate of quasar distance has also been falsified observationally by Mr. Halton Arp, as quasars are vastly closer than what the Big Bang Religion allows for. [4][5] References

Jeffrey J Wolynski

2013-01-01T23:59:59.000Z

338

The Inevitable Universe---Parker-Rhodes' peculiar mixture of ontology and physics  

Science Conference Proceedings (OSTI)

When asked to give a lecture on Parker-Rhodes' physics, I was somewhat non-plused. I almost replied What physics '' --- a point of view that Frederick expresses himself more than once in the book he was working on when he died. But that would be unjust. Whatever his view, I assert that the discovery of the Combinational Hierarchy is one of the most important discoveries'' --- or whatever you want to call it --- in physics made in this century. His calculation of the proton-electron mass ratio is also a fantastic result that we are still trying to come to grips with. And his insight into early cosmology --- what he called a cold big bang'' --- which appeared in an early version of the Theory of Indistinguishables, also had merit. His early universe is a lot closer to my own views now than I realized when I first encountered it. We will mention other insights as I go along. But his views are so different from those of anyone I know or knew, that I have decided to let him speak for himself by reading passages from his manuscript The Inevitable Universe, or TIU, which was still unpublished at the time of his death, and add a few comments on them.

Noyes, H.P.

1989-12-01T23:59:59.000Z

339

Cosmic String constraints from WMAP and the South Pole Telescope  

E-Print Network (OSTI)

The predictions of the inflationary LCDM paradigm match today's high-precision measurements of the cosmic microwave background anisotropy extremely well. The same data put tight limits on other sources of anisotropy. Cosmic strings are a particularly interesting alternate source to constrain. Strings are topological defects, remnants of inflationary-era physics that persist after the big bang. They are formed in a variety of models of inflation, including string theory models such as brane inflation. We assume a "Nambu-Goto" model for strings, approximated by a collection of unconnected segments with zero width, and show that measurements of temperature anisotropy by the South Pole Telescope break a parameter degeneracy in the WMAP data, permitting us to place a strong upper limit on the possible string contribution to the CMB anisotropy: the power sourced by zero-width strings must be <1.75% (95% CL) of the total or the string tension Gmu <1.7x10^{-7}. These limits imply that the best hope for detecting strings in the CMB will come from B-mode polarization measurements at arcminute scales rather than the degree scale measurements pursued for gravitational wave detection.

Cora Dvorkin; Mark Wyman; Wayne Hu

2011-09-22T23:59:59.000Z

340

Cosmic String constraints from WMAP and SPT  

E-Print Network (OSTI)

The predictions of the inflationary LCDM paradigm match today's high-precision measurements of the cosmic microwave background anisotropy with remarkable precision. The same data put tight limits on other sources of anisotropy. Cosmic strings are a particularly interesting alternate source to constrain. Strings are topological defects, remnants of inflationary-era physics that persist after the big bang. They are formed in a variety of models of inflation, including popular string theory models such as brane inflation. In this paper, we show that measurements of temperature anisotropy by the South Pole Telescope break a parameter degeneracy in the WMAP data, permitting us to place a strong upper limit on the possible string contribution to the CMB anisotropy: the power sourced by zero-width strings must be <1.75% (95% CL) of the total. In the model we use, this translates to an upper limit on the string tension of Gmu < 1.7x10^{-7}. These limits imply that the best hope for detecting strings in the CMB ...

Dvorkin, Cora; Hu, Wayne

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

SKA Key science project: Radio observations of cosmic reionization and first light  

E-Print Network (OSTI)

I update the SKA key science program (KSP) on first light and cosmic reionization. The KSP has two themes: (i) Using the 21cm line of neutral hydrogen as the most direct probe into the evolution of the neutral intergalactic medium during cosmic reionization. Such HI 21cm studies are potentially the most important new window on cosmology since the discovery of the CMB. (ii) Observing the gas, dust, star formation, and dynamics, of the first galaxies and AGN. Observations at cm and mm wavelengths, provide an unobscured view of galaxy formation within 1 Gyr of the Big Bang, and are an ideal complement to the study of stars, ionized gas, and AGN done using near-IR telescopes. I summarize HI 21cm signals, challenges, and telescopes under construction. I also discuss the prospects for studying the pre-galactic medium, prior to first light, using a low frequency telescope on the Moon. I then review the current status of mm and cm observations of the most known distant galaxies (z > 6). I make the simple argument that even a 10% SKA-high demonstrator will have a profound impact on the study of the first galaxies. In particular, extending the SKA to the 'natural' atmospheric limit (set by the O_2 line) of 45 GHz, increases the effective sensitivity to thermal emission by another factor four.

C. L. Carilli

2008-02-12T23:59:59.000Z

342

Slowly fading super-luminous supernovae that are not pair-instability explosions  

E-Print Network (OSTI)

Super-luminous supernovae that radiate more than 10^44 ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-30 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of 56Ni are synthesized; this isotope decays to 56Fe via 56Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae...

Nicholl, M; Jerkstrand, A; Inserra, C; McCrum, M; Kotak, R; Fraser, M; Wright, D; Chen, T -W; Smith, K; Young, D R; Sim, S A; Valenti, S; Howell, D A; Bresolin, F; Kudritzki, R P; Tonry, J L; Huber, M E; Rest, A; Pastorello, A; Tomasella, L; Cappellaro, E; Benetti, S; Mattila, S; Kankare, E; Kangas, T; Leloudas, G; Sollerman, J; Taddia, F; Berger, E; Chornock, R; Narayan, G; Stubbs, C W; Foley, R J; Lunnan, R; Soderberg, A; Sanders, N; Milisavljevic, D; Margutti, R; Kirshner, R P; Elias-Rosa, N; Morales-Garoffolo, A; Taubenberger, S; Botticella, M T; Gezari, S; Urata, Y; Rodney, S; Riess, A G; Scolnic, D; Wood-Vasey, W M; Burgett, W S; Chambers, K; Flewelling, H A; Magnier, E A; Kaiser, N; Metcalfe, N; Morgan, J; Price, P A; Sweeney, W; Waters, C

2013-01-01T23:59:59.000Z

343

Hydro-Gravitational-Dynamics Interpretation of the Tadpole VV29 Merging Galaxy System: Dark-Matter-Halo-Planet Star-Cluster Wakes  

E-Print Network (OSTI)

Hubble Space telescope (HST) images of merging galaxy system VV29 reveal the 0.3 Mpc baryonic-dark-matter (BDM) halo composed of primordial protoglobularstarcluster (PGC) clumps of planets. Star-cluster-wakes trace the merger by formation of stars from the planets. Aligned young globular star clusters (YGCs), star-wakes and dust-trails show the frictional, spiral passage of galaxy fragments VV29cdef in a long tail-like galaxy (VV29b) as the fragments merge on the accretion disk plane of the central spiral galaxy VV29a. The observations confirm the hydro-gravitational-dynamics (HGD) prediction of Gibson 1996 and quasar microlensing inference of Schild 1996 that the dark matter of galaxies is dominated by planets (PFPs) in million-solar-mass clumps. Globular star clusters (YGCs, OGCs, PGCs) preserve the density of the plasma epoch 30,000 years after the big bang when viscous supercluster-fragmentation began. Tadpole images show linear galaxy clusters reflecting turbulent vortex lines of protogalaxy fragmentatio...

Gibson, Carl H

2008-01-01T23:59:59.000Z

344

Observation of the submillimeter cosmic background spectrum  

SciTech Connect

An experimental measurement of the spectrum of the submillimeter cosmic background radiation is described. The experiment consists of measuring the night sky emission at an altitude of 39 km, correcting for the atmospheric molecular line emission, and placing limits on the contamination from sources of continuum radiation such as the apparatus itself and the earth. The observations were made on 24 July 1974 using a fully calibrated liquid-helium-cooled balloon- borne spectrophotometer. Important features of the apparatus include a cooled antenna, a polarizing interferometer, and a germanium bolometric detector. The characterization of the spectrophotometer includes the large angle response and emission of the antenna. The calibration of the instrument and corrections to the observed sky spectrum are based on measurements made during the flight. A simple model of the molecular line emission is used to determine the atmospheric contribution. The resulting spectrum covers the frequency range from 4 to 17 cm$sup -1$ and establishes that the cosmic background radiation follows the high frequency quantum cutoff for a 3K blackbody. A blackbody temperature of 2.99/sub -.$sub 14$/$sup +$.$sup 07$/K is deduced from our data. The present status of the cosmic background observations, which span more than three decades in frequency, is analyzed and it is concluded that they are all consistent with a blackbody temperature of 2.90 +- .04K (+- 1 SIGMA). This firmly supports the Big Bang cosmological model of the universe. (auth)

Woody, D.P.

1975-11-13T23:59:59.000Z

345

Hydro-Gravitational-Dynamics of Planets and Dark Energy  

E-Print Network (OSTI)

Self-gravitational fluid mechanical methods termed hydro-gravitational-dynamics (HGD) predict plasma fragmentation 0.03 Myr after the turbulent big bang to form protosuperclustervoids, turbulent protosuperclusters, and protogalaxies at the 0.3 Myr transition from plasma to gas. Linear protogalaxyclusters fragment at 0.003 Mpc viscous-inertial scales along turbulent vortex lines or in spirals, as observed. The plasma protogalaxies fragment on transition into white-hot planet-mass gas clouds (PFPs) in million-solar-mass clumps (PGCs) that become globular-star-clusters (GCs) from tidal forces or dark matter (PGCs) by freezing and diffusion into 0.3 Mpc halos with 97% of the galaxy mass. The weakly collisional non-baryonic dark matter diffuses to > Mpc scales and frag-ments to form galaxy cluster halos. Stars and larger planets form by binary mergers of the trillion PFPs per PGC on 0.03 Mpc galaxy accretion disks. Star deaths depend on rates of planet accretion and internal star mixing. Moderate accretion rates p...

Gibson, Carl H

2008-01-01T23:59:59.000Z

346

A Causal Model of Human Error for Safety Critical User Interface Design  

E-Print Network (OSTI)

This paper describes a method of assessing the implications for human error on user interface design of safety-critical software. In previous work we have proposed taxonomy of influencing factors that contribute to error. In this paper, components of the taxonomy are combined into a mathematical and causal model for error, represented as a Bayesian Belief Net (BBN). The BBN quantifies error influences arising from user knowledge, ability and the task environment, combined with factors describing the complexity of user action and user interface quality. The BBN model predicts probabilities of different types of error, slips and mistakes, for each component action of a task involving user-system interaction. We propose an Impact Analysis Method that involves running test scenarios against this causal model of error in order to determine those user actions that are prone to different types of error. Applying the proposed method will enable the designer to determine the combinations of inf...

Alistair G. Sutcliffe; Julia Galliers; Julia Galliers; Shailey Minocha; Shailey Minocha; Alistair Sutcliffe

1998-01-01T23:59:59.000Z

347

Halo Star Abundances and r-Process Synthesis  

E-Print Network (OSTI)

We review recent observational studies of heavy element abundances in low metallicity stars and explore some implications of these results for nucleosynthesis and early Galactic chemical evolution.

J. W. Truran; J. J. Cowan; B. D. Fields

2001-01-24T23:59:59.000Z

348

Stewardship Science Academic Alliances Annual  

National Nuclear Security Administration (NNSA)

to improve stellar nucleosynthesis models, criticality safety codes and nuclear fission theory. Our research is concentrated on the three topics discussed below. Neutron-induced...

349

ven as the National Academy of Engineering (NAE) announced its  

E-Print Network (OSTI)

updated version of the answer keys . With respect to the latter, there were more updates made to TST4 than of updating existin g answer key templates and documentation. The compromise reached for MUC-4 wa . These veteran groups are BBN Systems and Technologies (Cambridge, MA), General Electric (Schenectady, NY), Hughe

Simaan, Nabil

350

Graphical Framework for Action Recognition using Temporally Dense STIPs Pradeep Natarajan  

E-Print Network (OSTI)

Graphical Framework for Action Recognition using Temporally Dense STIPs Pradeep Natarajan BBN and recognize a se- quence of actions. More recently, Spatio-temporal Interest Points (STIPs) have been proposed hand, Bag-of-words approaches using Spatio- temporal Interest Points (STIP) as the basic features

Southern California, University of

351

A covariant causal set approach to discrete quantum gravity  

E-Print Network (OSTI)

A covariant causal set (c-causet) is a causal set that is invariant under labeling. Such causets are well-behaved and have a rigid geometry that is determined by a sequence of positive integers called the shell sequence. We first consider the microscopic picture. In this picture, the vertices of a c-causet have integer labels that are unique up to a label isomorphism. This labeling enables us to define a natural metric $d(a,b)$ between time-like separated vertices $a$ and $b$. The time metric $d(a,b)$ results in a natural definition of a geodesic from $a$ to $b$. It turns out that there can be $n\\ge 1$ such geodesics. Letting $a$ be the origin (the big bang), we define the curvature $K(b)$ of $b$ to be $n-1$. Assuming that particles tend to move along geodesics, $K(b)$ gives the tendency that vertex $b$ is occupied. In this way, the mass distribution is determined by the geometry of the c-causet. We next consider the macroscopic picture which describes the growth process of c-causets. We propose that this process is governed by a quantum dynamics given by complex amplitudes. At present, these amplitudes are unknown. But if they can be found, they will determine the (approximate) geometry of the c-causet describing our particular universe. As an illustration, we present a simple example of an amplitude process that may have physical relevance. We also give a discrete analogue of Einstein's field equations.

Stan Gudder

2013-11-15T23:59:59.000Z

352

Flux  

NLE Websites -- All DOE Office Websites (Extended Search)

5000 5000 6000 7000 8000 Wavelength (Angstroms) Flux (in arbitrary units) SN 1990N SN 1989B SN 1993O SN 1981B SN 1994D SN 1997ap Iron Peak Blends Ca II Si II & Co II Fe II & III Day -7 Day -5 Day -4 Day -2 ± 2 Day 0 Day +2 * -50 0 50 100 150 Observed days from peak Observed I magnitude 27 26 25 24 23 Observed R magnitude 27 26 25 24 Observed I magnitude 27 26 25 24 23 R band Ground-based I band HST I band (b) (c) (a) Pre-SN observation 3.5 4.0 4.5 5.0 5.5 log(cz) 14 16 18 20 22 24 26 effective m B 0.02 0.05 0.1 0.2 0.5 1.0 redshift z Hamuy et al (A.J. 1996) Supernova Cosmology Project 6 8 % 9 0 % 0.5 1.0 1.5 2.0 2.5 3.0 ! M Age < 9.6 Gyr (H = 50 km s -1 Mpc -1 ) No Big Bang 0.0 0.5 1.0 1.5 2.0 2.5 3.0 -3 -2 -1 0 1 2 3 -3 -2 -1 0 1 2 3 ! " z ~ 0 . 4 z = 0 . 8 3 6 8 % 9 0 % 0.5 1.0 1.5 2.0 2.5 3.0 ! M Age < 9.6 Gyr (H=50 km/s/Mpc)

353

On Dark Energy, Weyl Geometry and Brans-Dicke-Jordan Scalar Field  

E-Print Network (OSTI)

We review firstly why Weyl’s Geometry, within the context of Friedman-Lemaitre-Robertson-Walker cosmological models, can account for both the origins and the value of the observed vacuum energy density (dark energy). The source of dark energy is just the dilaton-like Jordan-Brans-Dicke scalar field that is required to implement Weyl invariance of the most simple of all possible actions. A nonvanishing value of the vacuum energy density of the order of 10 ?123 M 4 P lanck is derived in agreement with the experimental observations. Next, a Jordan-Brans-Dicke gravity model within the context of ordinary Riemannian geometry, yields also the observed vacuum energy density (cosmological constant) to very high precision. One finds that the temporal flow of the scalar field ?(t) in ordinary Riemannian geometry, from t = 0 to t = to, has the same numerical effects (as far as the vacuum energy density is concerned) as if there were Weyl scalings from the field configuration ?(t), to the constant field configuration ?o, in Weyl geometry. Hence, Weyl scalings in Weyl geometry can recapture the flow of time which is consistent with Segal’s Conformal Cosmology, in such a fashion that an expanding universe may be visualized as Weyl scalings of a static universe. The main novel result of this work is that one is able to reproduce the observed vacuum energy density to such a degree of precision 10 ?123 M 4 P lanck, while still having a Big-Bang singularity at t = 0 when the vacuum energy density blows up. This temporal flow of the vacuum energy density, from very high values in the past, to very small values today, is not a numerical coincidence but is the signal of an underlying Weyl geometry (conformal invariance) operating in cosmology, combined with the dynamics of a Brans-Dicke-Jordan scalar field.

Carlos Castro

2008-01-01T23:59:59.000Z

354

Sources of cosmic microwave radiation and dark matter identified: millimeter black holes (m.b.h.)  

E-Print Network (OSTI)

The universe is filled with blackbody millimeter radiation (CMBR), temperature 2.7{\\deg} Kelvin[1]. Big-bang cosmology explains this by the initial thermalization of photons scattered by electrons[2]. This explanation requires ad hoc previous existence of photons and thermal electrons. On the other hand most of the mass of the universe is unknown dark matter3. It explains anomalous dynamical properties, like that of stars in galaxies[4,5,6] . Alternatively the anomalies have been explained by adjusting and modifying well known laws ("Modified Newtonian dynamics"[7]). Here we show that millimeter black holes (m.b.h.) explain both: the background radiation, by its partial "evaporation", and the dark matter. Black holes emit blackbody radiation (Hawking[8] evaporation), and this is what is observed in the CMBR. Millimeter size black holes emit blackbody radiation at a temperature of 2.7{\\deg} Kelvin, and this is the resulting CMBR . Partial evaporation of ~10^30 m.b.h. gives the observed background field of photons being emitted and absorbed at the same rate by the m.b.h. The number of photons is constant, as observed. Their temperature decreases with time because the mass of the m.b.h. (and therefore its size) increases with time (the mass-boom effect[9]). The total mass of the m.b.h. is the dark matter. Hence dark matter is not so "dark" after all. Two important cosmological items are here identified by only one source: millimeter black holes.

Antonio Alfonso-Faus; Marius Josep Fullana i Alfonso

2010-04-13T23:59:59.000Z

355

Improving the design and analysis of superconducting magnets for particle accelerators  

Science Conference Proceedings (OSTI)

High energy particle accelerators are now the primary means of discovering the basic building blocks of matter and understanding the forces between them. In order to minimize the cost of building these machines, superconducting magnets are used in essentially all present day high energy proton and heavy ion colliders. The cost of superconducting magnets is typically in the range of 20--30% of the total cost of building such machines. The circulating particle beam goes through these magnets a large number of times (over hundreds of millions). The luminosity performance and life time of the beam in these machines depends significantly on the field quality in these magnets. Therefore, even a small error in the magnetic field shape may create a large cumulative effect in the beam trajectory to throw the particles of the magnet aperture. The superconducting accelerator magnets must, therefore, be designed and constructed so that these errors are small. In this thesis the research and development work will be described 3which has resulted in significant improvements in the field quality of the superconducting magnets for the Relativistic Heavy Ion Collider (RHIC). The design and the field quality improvements in the prototype of the main collider dipole magnet for the Superconducting Super Collider (SSC) will also be presented. RHIC will accelerate and collide two counter rotating beams of heavy ions up to 100 GeV/u and protons up to 250 GeV. It is expected that RHIC will create a hot, dense quark-gluon plasma and the conditions which, according to the Big Bang theory, existed in the early universe.

Gupta, R.C. [Univ. of Rajasthan, Jaipur (India). Dept. of Physics]|[Brookhaven National Lab., Upton, NY (United States). Magnet Div.

1996-11-01T23:59:59.000Z

356

Spitzer Imaging of i'-drop Galaxies: Old Stars at z~6  

E-Print Network (OSTI)

We present new evidence for mature stellar populations with ages >100Myr in massive galaxies (M_stellar>10^10M_sun) seen at a time when the Universe was less than 1Gyr old. We analyse the prominent detections of two z~6 star-forming galaxies (SBM03#1 & #3) made at wavelengths corresponding to the rest-frame optical using the IRAC camera onboard the Spitzer Space Telescope. We had previously identified these galaxies in HST/ACS GOODS images of Chandra Deep Field South through the "i-drop" Lyman break technique, and subsequently confirmed spectroscopically with the Keck telescope. The new Spitzer photometry reveals significant Balmer/4000Ang discontinuities, indicative of dominant stellar populations with ages >100Myr. Fitting a range of population synthesis models (for normal initial mass functions) to the HST/Spitzer photometry yields ages of 250-650Myr and implied formation redshifts z~7.5-13.5 in presently-accepted world models. Remarkably, our sources have best-fit stellar masses of 1.3-3.8x10^10M_sun (95% confidence) assuming a Salpeter initial mass function. This indicates that at least some galaxies with stellar masses >20% of those of a present-day L* galaxy had already assembled within the first Gyr after the Big Bang. We also deduce that the past average star formation rate must be comparable to the current observed rate (SFR_UV~5-30M_sun/yr), suggesting that there may have been more vigorous episodes of star formation in such systems at higher redshifts. Although a small sample, limited primarily by Spitzer's detection efficiency, our result lends support to the hypothesis advocated in our earlier analyses of the Ultra Deep Field and GOODS HST/ACS data. The presence of established systems at z~6 suggests long-lived sources at earlier epochs (z>7) played a key role in reionizing the Universe.

Laurence Eyles; Andrew Bunker; Elizabeth Stanway; Mark Lacy; Richard Ellis; Michelle Doherty

2005-02-18T23:59:59.000Z

357

Intensity-Frontier Antiproton Physics with The Antiproton Annihilation Spectrometer (TAPAS) at Fermilab  

SciTech Connect

The Fermilab Antiproton Source is the world's most intense source of antimatter. With the Tevatron program now behind us, this unique facility can help make the case for Fermilab's continued accelerator operations. The Antiproton Source can be used for unique, dedicated antimatter studies, including medium-energy {bar p}-annihilation experiments. We propose to assemble a powerful, yet cost-effective, solenoidal magnetic spectrometer for antiproton-annihilation events, and to use it at the Fermilab Antiproton Accumulator to measure the charm production cross section, study rare hyperon decays, search for hyperon CP asymmetry, precisely measure the properties of several charmonium and nearby states, and make the first measurements of the Drell-Yan continuum in medium-energy antiproton annihilation. Should the charm production cross section be as large as some have proposed, we will also be able to measure D{sup 0}-{bar D}{sup 0} mixing with high precision and discover (or sensitively limit) charm CP violation. The observation of charm or hyperon CP violation would be evidence for physics beyond the Standard Model, with possible implications for the origin of the baryon asymmetry of the universe - the question of what happened to all the antimatter that must have been produced in the Big Bang. The experiment will be carried out by an international collaboration and will require some four years of running time. As possibly the sole hadron experiment in progress at Fermilab during that time, it will play an important role in maintaining a broad particle physics program at Fermilab and in the U.S. It will thus help us to continue attracting creative and capable young people into science and technology, and introducing them to the important technologies of accelerators, detectors, and data acquisition and analysis - key roles in society that accelerator-based particle physics has historically played.

Apollinari, Giorgio; /Fermilab; Asner, David M.; /PNL, Richland; Baldini, Wander; /INFN, Ferrara; Bartoszek, Larry; Broemmelsiek, Daniel R.; Brown, Charles N.; /Fermilab; Chakravorty, Alak; /St. Xavier U., Chicago; Colas, Paul; /Saclay; Derwent, Paul; /Fermilab; Drutskoy, Alexey; /Moscow, ITEP; Fortner, Michael; /Northern Illinois U. /Saclay /Indian Inst. Tech., Hyderabad

2011-11-01T23:59:59.000Z

358

EVIDENCE FOR A CLUMPY, ROTATING GAS DISK IN A SUBMILLIMETER GALAXY AT z = 4  

SciTech Connect

We present Karl G. Jansky Very Large Array observations of the CO(2-1) emission in the z = 4.05 submillimeter galaxy (SMG) GN20. These high-resolution data allow us to image the molecular gas at 1.3 kpc resolution just 1.6 Gyr after the big bang. The data reveal a clumpy, extended gas reservoir, 14 {+-} 4 kpc in diameter, in unprecedented detail. A dynamical analysis shows that the data are consistent with a rotating disk of total dynamical mass 5.4 {+-} 2.4 Multiplication-Sign 10{sup 11} M {sub Sun }. We use this dynamical mass estimate to constrain the CO-to-H{sub 2} mass conversion factor ({alpha}{sub CO}), finding {alpha}{sub CO} = 1.1 {+-} 0.6 M {sub Sun }(K km s{sup -1} pc{sup 2}){sup -1}. We identify five distinct molecular gas clumps in the disk of GN20 with masses a few percent of the total gas mass, brightness temperatures of 16-31K, and surface densities of >3200-4500 Multiplication-Sign ({alpha}{sub CO}/0.8) M {sub Sun} pc{sup -2}. Virial mass estimates indicate they could be self-gravitating, and we constrain their CO-to-H{sub 2} mass conversion factor to be <0.2-0.7 M {sub Sun }(K km s{sup -1} pc{sup 2}){sup -1}. A multiwavelength comparison demonstrates that the molecular gas is concentrated in a region of the galaxy that is heavily obscured in the rest-frame UV/optical. We investigate the spatially resolved gas excitation and find that the CO(6-5)/CO(2-1) ratio is constant with radius, consistent with star formation occurring over a large portion of the disk. We discuss the implications of our results in the context of different fueling scenarios for SMGs.

Hodge, J. A.; Walter, F. [Max-Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Carilli, C. L. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801-0387 (United States); De Blok, W. J. G. [ASTRON, P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Riechers, D. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Daddi, E. [CEA, Laboratoire AIM-CNRS-Universite Paris Diderot, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Lentati, L., E-mail: hodge@mpia.de [Astrophysics Group, Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

2012-11-20T23:59:59.000Z

359

The advanced computational testing and simulation toolkit (ACTS)  

DOE Green Energy (OSTI)

During the past decades there has been a continuous growth in the number of physical and societal problems that have been successfully studied and solved by means of computational modeling and simulation. Distinctively, a number of these are important scientific problems ranging in scale from the atomic to the cosmic. For example, ionization is a phenomenon as ubiquitous in modern society as the glow of fluorescent lights and the etching on silicon computer chips; but it was not until 1999 that researchers finally achieved a complete numerical solution to the simplest example of ionization, the collision of a hydrogen atom with an electron. On the opposite scale, cosmologists have long wondered whether the expansion of the Universe, which began with the Big Bang, would ever reverse itself, ending the Universe in a Big Crunch. In 2000, analysis of new measurements of the cosmic microwave background radiation showed that the geometry of the Universe is flat, and thus the Universe will continue expanding forever. Both of these discoveries depended on high performance computer simulations that utilized computational tools included in the Advanced Computational Testing and Simulation (ACTS) Toolkit. The ACTS Toolkit is an umbrella project that brought together a number of general purpose computational tool development projects funded and supported by the U.S. Department of Energy (DOE). These tools, which have been developed independently, mainly at DOE laboratories, make it easier for scientific code developers to write high performance applications for parallel computers. They tackle a number of computational issues that are common to a large number of scientific applications, mainly implementation of numerical algorithms, and support for code development, execution and optimization. The ACTS Toolkit Project enables the use of these tools by a much wider community of computational scientists, and promotes code portability, reusability, reduction of duplicate efforts, and tool maturity. This paper presents a brief introduction to the functionality available in ACTS.

Drummond, L.A.; Marques, O.

2002-05-21T23:59:59.000Z

360

The Apparent Age of the Time Dilated Universe I: Gyrochronology, Angular Momentum Loss in Close Solar Type Binaries  

E-Print Network (OSTI)

In creation time-dilation cosmologies (e.g., those proposed by Humphreys, 1994, and Hartnett, 2007), one major question is: What maximum apparent age should be used to characterize the universe? The 14.7-billion-year answer provided by the Big Bang community should not be accepted due to its false assumptions, which are at odds with biblical history. There are many age-bearing processes (astrochronometers) that we can glean from today’s astronomy. Astrochronometers include wind-up times of spiral galaxies, rates of decrease rotation and magnetic activity, and spin-down and coalescence times of binary stars (magnetic braking), star cluster ages (isochron age) and nuclear burning ages (stellar aging on the H-R diagram), rates of visual binary orbital circularization, stellar kinematic ages, white dwarf cooling ages, pulsar spin-down ages (due to gravitational radiation), radio isochron ages from stellar spectra, and others. In this study, we will explore the subject of gyrochronology: the precise derivation of stellar ages from the rotational period of single solar-type stars and the orbital periods of interacting binaries. As stars and binaries age, magnetic braking steadily steals away angular momentum, and magnetic activity decreases. We seek to include original research from our astronomical observations. In this regard, we present a preliminary analysis of an asynchronous, fastrotating and near solar-type double contact eclipsing binary (Wilson and Twigg, 1980), AC Piscium from a recent observing run. We also include pertinent interferometric results of fast-spinning single stars. Finally, we attempt a first-ever age estimate of short period solar-type binaries apart from evolutionary time constraints. Figure 1. Magnetic braking on single stars. P is the period of rotation. AML is an acronym for Angular Momentum Loss. Figure 2. The definitions of angular momentum, L, and angular velocity, W.

Ronald G. Samec; Evan Figg

2012-01-01T23:59:59.000Z

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361

Redshift of photons penetrating a hot plasma  

E-Print Network (OSTI)

A new interaction, plasma redshift, is derived, which is important only when photons penetrate a hot, sparse electron plasma. The derivation of plasma redshift is based entirely on conventional axioms of physics. When photons penetrate a cold and dense plasma, they lose energy through ionization and excitation, Compton scattering on the individual electrons, and Raman scattering on the plasma frequency. But in sparse hot plasma, such as in the solar corona, the photons lose energy also in plasma redshift. The energy loss per electron in the plasma redshift is about equal to the product of the photon's energy and one half of the Compton cross-section per electron. In quiescent solar corona, this heating starts in the transition zone to the corona and is a major fraction of the coronal heating. Plasma redshift contributes also to the heating of the interstellar plasma, the galactic corona, and the intergalactic plasma. Plasma redshift explains the solar redshifts, the redshifts of the galactic corona, the cosmological redshifts, the cosmic microwave background, and the X-ray background. The plasma redshift explains the observed magnitude-redshift relation for supernovae SNe Ia without the big bang, dark matter, or dark energy. There is no cosmic time dilation. The universe is not expanding. The plasma redshift, when compared with experiments, shows that the photons' classical gravitational redshifts are reversed as the photons move from the Sun to the Earth. This is a quantum mechanical effect. As seen from the Earth, a repulsion force acts on the photons. This means that there is no need for Einstein's Lambda term. The universe is quasi-static, infinite, and everlasting.

Ari Brynjolfsson

2004-01-21T23:59:59.000Z

362

Science Videos from the SLAC Public Lecture Series  

DOE Data Explorer (OSTI)

The SLAC Public Lecture Series is sponsored several times a year by the SLAC Users Association and the SSRL. Distinguished scientists from SLAC, from SSRL, and from other arenas of High Energy Physics present lectures packed with scientific information that even laypeople can understand. A sampling of video titles includes: 1) Hunting the Elusive Higgs Boson and the Origin of Mass, Lance Dixon; 2) Dark Energy. What the…? Dr. Risa Wechsler; 3) The Dark Side of the Universe, Marusa Bradac; 4) The Large Hadron Collider: Redefining High Energy, Dr. Sarah Demers; 5) Robots: Fantasy and Reality, Dr. David Grossman; 6) Hydrogen: Fueling the Future, Jennifer Leisch; 7) Making Molecular Movies: 10,000,000,000,000 Frames per Second, Kelly Gaffney; 8) The Violent Universe, Dr. Eduardo do Couto e Silva; 9) A Comet on Earth: Results from the Stardust Mission, Sean Brennan; 10) Whispers of the Big Bang, Sarah Church; 11) Space: The Hunt for Hidden Dimensions, Dr. JoAnne Hewett; 12) Arsenic: The Silent Killer, Andrea Foster; 13)Archimedes: Accelerator Reveals Ancient Text, Uwe Bergmann; 14) Neutrinos Get Under Your Skin, Boris Kayser; 15) The Physics of Super Lasers, Dr. Philip Bucksbaum; 16) Smarter Drugs: How Protein Crystallography Revolutionizes Drug Design, Clyde Smith; 17) Profiling the Invisible: Quantum Mechanics and the Unseen Universe, Dr. Michael Peskin; 18) Physical Attraction: The Mysteries of Magnetism, Dr. Joachim Stohr; 19) The Runaway Universe, Dr. Roger Blandford; 20) Metals, Molecules, Life and Death, Dr. Graham George; 21) Our Lopsided Universe: The Matter with Anti-Matter; 22) Synchrotron Radiation: The Light Fantastic, Herman Winick; 23) All About SLAC: What Goes on in the World’s Longest Building, Neil Calder.

363

Vacuum quantum fluctuation energy in expanding universe and dark energy  

E-Print Network (OSTI)

This article is based on the Planckon densely piled vacuum model and the principle of cosmology. With Planck era as initial conditions and including early inflation, we have solved the Einstein-Friedmann equations to describe the evolution of the universe, a reasonable relation between dark energy density and vacuum quantum fluctuation energy density is obtained. The main results are : 1) the solution of Einstein-Friedmann equations has yielded the result $\\frac{{{\\rho}_{de}}}{{{\\rho}_{vac}}}\\sim{{(\\frac{{{t}_{P}}}{{{T}_{0}}})}^{2}}\\sim{{10}^{-122}} $ (Planck time ${{t}_{P}}={{10}^{-43}}s$ and universe age ${{T}_{0}}={{10}^{18}}s$);2) at inflation time ${{t}_{\\inf}}={{10}^{-35}}s$, the calculated universe radiation energy density is $\\rho ({{t}_{\\inf}})\\sim{{10}^{-16}}{{\\rho}_{vac}}$ and the corresponding temperature is ${{E}_{c}}\\sim{{10}^{15}}GeV$ consistent with GUT phase transition temperature;3) it is showed that the expanding universe is a non-equilibrium open system constantly exchanging energy with vacuum; during its expanding, the Planckons in universe lose quantum fluctuation energy and create cosmic expansion quanta-cosmons, the energy of cosmons is the lost part of vacuum quantum fluctuation energy and contributes to the total energy of the universe with the calculated value ${{E}_{\\cos mos}}={{10}^{22}}{{M}_{\\otimes}}{{c}^{2}}$ (${{M}_{\\otimes}}$ is solar mass) agreed with astronomic data; 4) the gravity potential and gravity acceleration of cosmons are derived with the nature of repulsive force, indicating that the cosmon may be the candidate of dark energy quantum; 5) solution to three well known cosmic problems of Big Bang model is presented.

Shun-Jin Wang

2013-01-02T23:59:59.000Z

364

MADCAP - The Microwave Anisotropy Dataset Computational Analysis Package  

E-Print Network (OSTI)

In the standard model of cosmology the universe starts with a hot Big Bang. As the universe expands it cools, and after 300,000 years it drops below the ionisation temperature of hydrogen. The previously free electrons become bound to protons, and with no electrons for the photons to scatter off they continue undeflected to us today. This image of the surface of last-scattering is what we call the Cosmic (because it fills the universe) Microwave (because of the frequency at which its black body spectrum peaks today) Background (because it originates behind all other light sources). Despite its stunning uniformity - isotropic to a few parts in a million - it is the tiny perturbations in the CMB that give us an unprecedented view of the early universe. First detected by the COBE satellite in 1991, these anisotropies are an imprint of the primordial density fluctuations needed to seed the development of gravitationally bound objects in the universe, and are potentially the most powerful discriminant between cosmological models. Realizing the extraordinary scientific potential of the CMB requires precise measurements of these tiny anisotropies over a significant fraction of the sky at very high resolution. The analysis of the resulting datasets is a serious computational challenge. Existing algorithms require terabytes of memory and hundreds of years of CPU time. We must therefore both maximize our resources by moving to supercomputers and minimize our requirements by algorithmic development. Here we will outline the nature of the challenge, present our current optimal algorithm, discuss its implementation - as the MADCAP software package - and its application to data from the North American test flight of the joint Italian-U.S. BOOMERanG experiment on the Cray T3E at NERSC...

Julian Borrill

1999-01-01T23:59:59.000Z

365

Institutional plan. FY 1998--2003  

SciTech Connect

This Institutional Plan for Argonne National Laboratory contains central elements of Argonne`s strategic plan. Chapter II of this document discusses the Laboratory`s mission and core competencies. Chapter III presents the Science and Technology Strategic Plan, which summarizes key features of the external environment, presents Argonne`s vision, and describes how the Laboratory`s strategic goals and objectives map onto and support DOE`s four business lines. The balance of the chapter comprises the science and technology area plans, organized by the four DOE business lines. Chapter IV describes the Laboratory`s ten major initiatives, which cover a broad spectrum of science and technology. Our proposal for an Exotic Beam Facility aims at, among other things, increased understanding of the processes of nuclear synthesis during and shortly after the Big Bang. Our Advanced Transportation Technology initiative involves working with US industry to develop cost-effective technologies to improve the fuel efficiency and reduce the emissions of transportation systems. The Laboratory`s plans for the future depend significantly on the success of its major initiatives. Chapter V presents our Operations and Infrastructure Strategic Plan. The main body of the chapter comprises strategic plans for human resources; environmental protection, safety, and health; site and facilities; and information management. The chapter concludes with a discussion of the business and management practices that Argonne is adopting to improve the quality and cost-effectiveness of its operations. The structure and content of this document depart from those of the Institutional Plan in previous years. Emphasis here is on directions for the future; coverage of ongoing activities is less detailed. We hope that this streamlined plan is more direct and accessible.

1997-07-01T23:59:59.000Z

366

Bayesian Methods and Universal Darwinism  

E-Print Network (OSTI)

Bayesian methods since the time of Laplace have been understood by their practitioners as closely aligned to the scientific method. Indeed a recent champion of Bayesian methods, E. T. Jaynes, titled his textbook on the subject Probability Theory: the Logic of Science. Many philosophers of science including Karl Popper and Donald Campbell have interpreted the evolution of Science as a Darwinian process consisting of a 'copy with selective retention' algorithm abstracted from Darwin's theory of Natural Selection. Arguments are presented for an isomorphism between Bayesian Methods and Darwinian processes. Universal Darwinism, as the term has been developed by Richard Dawkins, Daniel Dennett and Susan Blackmore, is the collection of scientific theories which explain the creation and evolution of their subject matter as due to the operation of Darwinian processes. These subject matters span the fields of atomic physics, chemistry, biology and the social sciences. The principle of Maximum Entropy states that systems will evolve to states of highest entropy subject to the constraints of scientific law. This principle may be inverted to provide illumination as to the nature of scientific law. Our best cosmological theories suggest the universe contained much less complexity during the period shortly after the Big Bang than it does at present. The scientific subject matter of atomic physics, chemistry, biology and the social sciences has been created since that time. An explanation is proposed for the existence of this subject matter as due to the evolution of constraints in the form of adaptations imposed on Maximum Entropy. It is argued these adaptations were discovered and instantiated through the operations of a succession of Darwinian processes.

John Campbell

2010-01-04T23:59:59.000Z

367

Hydro-Gravitational-Dynamics of Planets and Dark Energy  

E-Print Network (OSTI)

Self-gravitational fluid mechanical methods termed hydro-gravitational-dynamics (HGD) predict plasma fragmentation 0.03 Myr after the turbulent big bang to form protosuperclustervoids, turbulent protosuperclusters, and protogalaxies at the 0.3 Myr transition from plasma to gas. Linear protogalaxyclusters fragment at 0.003 Mpc viscous-inertial scales along turbulent vortex lines or in spirals, as observed. The plasma protogalaxies fragment on transition into white-hot planet-mass gas clouds (PFPs) in million-solar-mass clumps (PGCs) that become globular-star-clusters (GCs) from tidal forces or dark matter (PGCs) by freezing and diffusion into 0.3 Mpc halos with 97% of the galaxy mass. The weakly collisional non-baryonic dark matter diffuses to > Mpc scales and frag-ments to form galaxy cluster halos. Stars and larger planets form by binary mergers of the trillion PFPs per PGC on 0.03 Mpc galaxy accretion disks. Star deaths depend on rates of planet accretion and internal star mixing. Moderate accretion rates produce white dwarfs that evaporate surrounding gas planets by spin-radiation to form planetary nebulae before Supernova Ia events, dimming some events to give systematic distance errors misinterpreted as the dark energy hypothesis and overestimates of the universe age. Failures of standard LCDM cosmological models reflect not only obsolete Jeans 1902 fluid mechanical assumptions, but also failures of standard turbulence models that claim the cascade of turbulent kinetic energy is from large scales to small. Because turbulence is always driven at all scales by inertial-vortex forces the turbulence cascade is always from small scales to large.

Carl H. Gibson; Rudolph E. Schild

2008-08-24T23:59:59.000Z

368

New Hubble Space Telescope Observations of Heavy Elements in Four Metal-Poor Stars  

E-Print Network (OSTI)

Elements heavier than the iron group are found in nearly all halo stars. A substantial number of these elements, key to understanding neutron-capture nucleosynthesis mechanisms, can only be detected in the near-ultraviolet. ...

Roederer, Ian U.

369

Detection of the Second R-Process Peak Element Tellurium in Metal-Poor Stars  

E-Print Network (OSTI)

Using near-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, we detect neutral tellurium in three metal-poor stars enriched by products of r-process nucleosynthesis, ...

Roederer, Ian U.

370

Making Galaxies: One Star at a Time  

DOE Green Energy (OSTI)

In the age of precision cosmology the fundamental parameters of our world model are being measured to unprecedented accuracy. In particular, measurements of the cosmic microwave background radiation detail the state of the universe only 400,000 years after the big bang. Unfortunately, we have no direct observational evidence about the following few hundred million years, the so called dark ages. However, we do know from the composition of the highest redshift galaxies that it is there where the earliest and first galaxies are being formed. From a physics point of view these earliest times are much easier to understand and model because the chemical composition of the early gas is simpler and the first galaxies are much smaller than the ones found nearby. The absence of strong magnetic fields, cosmic rays, dust grains and UV radiation fields clearly also helps. The first generation of structure formation is as such a problem extremely well suited for direct ab initio calculations using supercomputers. In this colloquium I will discuss the rich physics of the formation of the first objects as computed via ab initio Eulerian cosmological adaptive mesh refinement calculations. We find the first generation of stars to be massive and to form in isolation with mass between 30 and 300 times the mass of the sun. Remarkably the relevant mass scales can all be understood analytically from the microscopic properties of atomic and molecular hydrogen. The UV radiation from these stars photo-evaporates their parent clouds within their lifetimes contributing significantly to cosmological reionization. Their supernovae distribute the first heavy elements over thousands of light years and enrich the intergalactic medium. As we are beginning to illuminate these earliest phases of galaxy formation many new questions arise and become addressable with our novel numerical techniques. How and where are the earliest magnetic fields made? How do the first super-massive black holes form? When and how can the first planets form in the universe? Algorithmic breakthroughs and large supercomputers enable these studies. Hence I will close with discussing how the expanding computing infrastructure at SLAC and scientific visualization at the Schwob Computing and Information Center at the Fred Kavli building allow us to find answers to the fundamental questions about the beginning of structure in the universe.

Abel, Tom

2006-09-18T23:59:59.000Z

371

I  

Gasoline and Diesel Fuel Update (EIA)

I 0'^TM^^^^^^^^^^^^^^^^^BBn~fi^H(iA w _ __--^^^^^^^^^^r I A ^^^^^^H^^^^fnffA^ ^^^^^^^^^^5!ii53^^^^^^^^^H~~~~f ^^^^^^^^^^^*^^^^^^^^^^^^^1~~~~A ^^^^^^^^^^^^^j^^^^^^^^^^^^^^^^^ ^^^^^^^^^HB|^B^^BI^^^^^^^^^H ^^^^^^^^^^^^^^^H xe^ ^^^^^^A^ This publication is available from the Superintendent of Documents, U.S. Government Printing Office (GPO). Ordering information and purchase of this and other Energy Information Administration (EIA) publications may be obtained from the GPO or the EIA's National Energy Information Center (NEIC). Questions on energy statistics should be directed to the NEIC. Addresses and telephone numbers appear below. National Energy Information Center, El-20 Energy Information Administration Forrestal Building Room 1 F-048 Washington, D C 20585

372

July 28, 2010, Partnerships of academia, industry, and government labs  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED * Interdisciplinary nature of research * Rapid transition from research to products One size does not fit all Partnerships of academia, industry, and government labs UNCLASSIFIED UNCLASSIFIED Network Science Collaborative Technology Alliance: an Interdisciplinary Collaboration Model Social/Cognitive Network ARC * Principal Member - Rensselaer Polytechnic Institute * General Members - CUNY, Northeastern Univ, IBM Communication Networks ARC * Principal Member - Penn State * General Members - CUNY, USC, UC-Davis, UC-Santa Cruz Information Networks ARC * Principal Member - Univ of Illinois, Urbana Champaign * General Members - CUNY, UC-Santa Barbara, IBM Interdisciplinary Research Center * Principal Member - BBN Tech * General Members - UC-Riverside,

373

Right-Handed Neutrinos as the Dark Radiation: Status and Forecasts for the LHC  

E-Print Network (OSTI)

Precision data from cosmology (probing the CMB decoupling epoch) and light-element abundances (probing the BBN epoch) have hinted at the presence of extra relativistic degrees of freedom, the so-called "dark radiation." We present a model independent study to account for the dark radiation by means of the right-handed partners of the three, left-handed, standard model neutrinos. We show that milli-weak interactions of these Dirac states (through their coupling to a TeV-scale Z' gauge boson) may allow the \

Luis A. Anchordoqui; Haim Goldberg; Gary Steigman

2012-11-01T23:59:59.000Z

374

List of weekly accessions Journals and Proceedings  

E-Print Network (OSTI)

) 012005. Virgo gravitational wave detector: Results and perspectives. T. Accadia, et al. Nuovo Cim. C034­cycle reactions and AGB nucleosynthesis. M. La Cognata Nuovo Cim. C034N06 (2011) 139­143. Talk: Perugia 2011/04/27 Status of AMS­02 experiment on the international space station. S. Di Falco Nuovo Cim. C034N06 (2011) 120

375

The Nuclear Physics of Solar and Supernova Neutrino Detection  

E-Print Network (OSTI)

This talk provides a basic introduction for students interested in the responses of detectors to solar, supernova, and other low-energy neutrino sources. Some of the nuclear physics is then applied in a discussion of nucleosynthesis within a Type II supernova, including the r-process and the neutrino process.

W. C. Haxton

1999-01-15T23:59:59.000Z

376

Chemical Evolution  

E-Print Network (OSTI)

In this series of lectures we first describe the basic ingredients of galactic chemical evolution and discuss both analytical and numerical models. Then we compare model results for the Milky Way, Dwarf Irregulars, Quasars and the Intra-Cluster- Medium with abundances derived from emission lines. These comparisons allow us to put strong constraints on the stellar nucleosynthesis and the mechanisms of galaxy formation.

Francesca Matteucci

2007-04-05T23:59:59.000Z

377

Short-lived isotopes and 23Na production in low mass AGB Stars  

E-Print Network (OSTI)

We discuss the synthesis of some short-lived isotopes and of 23Na in thermally pulsing AGB stars with initial mass of 2 Msun and two different metallicities (Z=1.5e-2, corresponding to the metal amount in the Sun, and Z=1e-4), representative of disk and halo stars, respectively. The different nucleosynthesis channels are illustrated in some details. As previously found, the 13C formed after each third dredge up episode is usually completely consumed by alpha captures before the onset of the subsequent thermal pulse, releasing neutrons. This is the most efficient neutron source in low mass AGB stars and the resulting s-process nucleosynthesis is at the origin of the solar main component. However, in the solar metallicity model, we find that the temperature of the first formed 13C pocket remains too low during the interpulse and the 13C is not completely burnt, being partially engulfed in the convective zone generated by the following thermal pulse. Due to the rapid convective mixing in this zone, the 13C is exposed to a larger temperature and a nucleosynthesis characterized by a relatively high neutron density develops. The main effect is the strong enhancement of isotopes located beyond some critical branching in the neutron-capture path, like 60Fe, otherwise only marginally produced during a standard s-process nucleosynthesis.

S. Cristallo; R. Gallino; O. Straniero; L. Piersanti; I. Dominguez

2006-06-15T23:59:59.000Z

378

Radioactive ion beam research at LLNL  

DOE Green Energy (OSTI)

In this paper we discuss efforts underway at LLNL to develop the technology for the measurement of proton and alpha-particle reactions with unstable nuclei which are necessary for understanding the nucleosynthesis and energy generation in hot hydrogen-burning environments. 16 refs., 5 figs.

Mathews, G.J.; Bauer, R.W.; Haight, R.C.; Sale, K.E.

1985-08-01T23:59:59.000Z

379

CEMP-s and CEMP-s/r stars: last update  

E-Print Network (OSTI)

We provide an updated discussion of the sample of CEMP-s and CEMP-s/r stars collected from the literature. Observations are compared with the theoretical nucleosynthesis models of asymptotic giant branch (AGB) stars presented by Bisterzo et al. (2010, 2011, 2012), in the light of the most recent spectroscopic results.

Bisterzo, S; Straniero, O; Cristallo, S; Kaeppeler, F; Wiescher, M

2013-01-01T23:59:59.000Z

380

[Experimental physics at Yale University: Research proposal and budget Proposal, 1 January 1992--31 December 1996  

SciTech Connect

This report reviews the following topics: nuclear and quark matter; correlated pairs from heavy ion collisions-search for new low mass resonances coupled to electron-positron collisions; proposed light ion research program; experimental nuclear astrophysics (explosive nucleosynthesis); search for rare decay modes and rare processes in nuclei; and nuclear spectroscopy at the extremes of spin, isospin, and temperature. (LSP).

Not Available

1992-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

(Experimental physics at Yale University: Research proposal and budget Proposal, 1 January 1992--31 December 1996)  

Science Conference Proceedings (OSTI)

This report reviews the following topics: nuclear and quark matter; correlated pairs from heavy ion collisions-search for new low mass resonances coupled to electron-positron collisions; proposed light ion research program; experimental nuclear astrophysics (explosive nucleosynthesis); search for rare decay modes and rare processes in nuclei; and nuclear spectroscopy at the extremes of spin, isospin, and temperature. (LSP).

Not Available

1992-01-01T23:59:59.000Z

382

Opportunities for Neutrino Physics at the Spallation Neutron Source (SNS)  

E-Print Network (OSTI)

In this paper we discuss opportunities for a neutrino program at the Spallation Neutrons Source (SNS) being commissioning at ORNL. Possible investigations can include study of neutrino-nuclear cross sections in the energy rage important for supernova dynamics and neutrino nucleosynthesis, search for neutrino-nucleus coherent scattering, and various tests of the standard model of electro-weak interactions.

Yu Efremenko; W R Hix

2008-07-17T23:59:59.000Z

383

Algebraic stabilization of explicit numerical integration for extremely stiff reaction networks  

Science Conference Proceedings (OSTI)

In contrast to the prevailing view in the literature, it is shown that even extremely stiff sets of ordinary differential equations may be solved efficiently by explicit methods if limiting algebraic solutions are used to stabilize the numerical integration. ... Keywords: Combustion, Nucleosynthesis, Ordinary differential equations, Reaction networks, Reactive flows, Stiffness

Mike Guidry

2012-06-01T23:59:59.000Z

384

Astron. Nachr. / AN 335, No. 1, 1 9 (2014) / DOI This.is/not.aDOI High resolution study of the abundance pattern of the heavy elements in  

E-Print Network (OSTI)

of the abundance pattern of the heavy elements in very metal-poor field stars. M. Spite1, and F. Spite1 GEPI, Nucleosynthesis. The abundances of heavy elements in EMP stars are not well explained by the simple view of the r-poor matter. The abundances found in the CEMP- r+s stars reflect the transfer of heavy elements

Recanati, Catherine

385

B Flavour Tagging with Artificial Neural Networks for the CDF II Experiment  

SciTech Connect

One of the central questions arising from human curiosity has always been what matter is ultimately made of, with the idea of some kind of elementary building-block dating back to the ancient greek philosophers. Scientific activities of multiple generations have contributed to the current best knowledge about this question, the Standard Model of particle physics. According to it, the world around us is composed of a small number of stable elementary particles: Electrons and two different kinds of quarks, called up and down quarks. Quarks are never observed as free particles, but only as bound states of a quark-antiquark pair (mesons) or of three quarks (baryons), summarized as hadrons. Protons and Neutrons, the constituents forming the nuclei of all chemical elements, are baryons made of up and down quarks. The electron and the electron neutrino - a nearly massless particle without electric charge - belong to a group called leptons. These two quarks and two leptons represent the first generation of elementary particles. There are two other generations of particles, which seem to have similar properties as the first generation except for higher masses, so there are six quarks and six leptons altogether. They were around in large amounts shortly after the beginning of the universe, but today they are only produced in high energetic particle collisions. Properties of particles are described by quantum numbers, for example charge or spin. For every type of particle, a corresponding antiparticle exists with the sign of all charges swapped, but similar properties otherwise. The Standard Model is a very successful theory, describing the properties of all known particles and the interactions between them. Many of its aspects have been tested in various experiments at very high precision. Although none of these experimental tests has shown a significant deviation from the corresponding Standard Model prediction, the theory can not be complete yet: Cosmological aspects like gravity, dark matter and dark energy are not described, and open questions remain in the sector of neutrino masses and neutrino oscillations. Also no answer has been given to the question of matter-antimatter asymmetry observed in the contemporary universe. Assuming that the Big Bang created equal amounts of matter and antimatter, there must be effects where nature treats matter and antimatter somehow different. This can happen through a mechanism called CP violation, which has been observed within the Standard Model, but not in the necessary order of magnitude. For all these reasons, the search for New Physics - theories beyond the Standard Model - is one of the main objectives of modern particle physics. In this global effort, flavour physics is the field of transitions between the different types of quarks, called quark flavours, wherein the examination of B meson oscillations and the search for CP violation in B{sub s}{sup 0} meson decays set the stage for the work presented in this thesis.

Schmidt, Andreas; /Karlsruhe U., EKP

2010-01-01T23:59:59.000Z

386

An Anticipatory and Deceptive AI Utilizing Bayesian Belief Networks  

Science Conference Proceedings (OSTI)

The U.S. military defines antiterrorism as the defensive posture taken against terrorist threats. Antiterrorism includes fostering awareness of potential threats, deterring aggressors, developing security measures, planning for future events, interdicting an event in progress, and ultimately mitigating and managing the consequences of an event. Recent events highlight the need for efficient tools for training our military and homeland security officers for anticipating threats posed by terrorists. These tools need to be easy enough so that they are readily usable without substantial training, but still maintain the complexity to allow for a level of deceptive reasoning on the part of the opponent. To meet this need, we propose to integrate a Bayesian Belief Network (BBN) model for threat anticipation and deceptive reasoning into training simulation environments currently utilized by several organizations within the Department of Defense (DoD). BBNs have the ability to deal with various types of uncertainties; such as identities, capabilities, target attractiveness, and the combinations of the previous. They also allow for disparate types of data to be fused in a coherent, analytically defensible, and understandable manner. A BBN has been developed by ORNL uses a network engineering process that treats the probability distributions of each node with in the broader context of the system development effort as a whole, and not in isolation. The network will be integrated into the Research Network Inc,(RNI) developed Game Distributed Interactive Simulation (GDIS) as a smart artificial intelligence module. GDIS is utilized by several DoD and civilian organizations as a distributed training tool for a multiplicity of reasons. It has garnered several awards for its realism, ease of use, and popularity. One area that it still has room to excel in, as most video training tools do, is in the area of artificial intelligence of opponent combatants. It is believed that by utilizing BBN as the backbone of the artificial intelligence code, a more realistic and helpful training experience will be available and enemy combatants that move and strategize with purpose will be obtained.

Lake, Joe E [ORNL; Allgood, Glenn O [ORNL; Olama, Mohammed M [ORNL; Saffold, JAy [Research Network, Inc

2009-01-01T23:59:59.000Z

387

The Universe Adventure - Galaxial Motion  

NLE Websites -- All DOE Office Websites (Extended Search)

Bulk Motions of Galaxies Bulk Motions of Galaxies Galaxy Diagram The Structure of a typical Spiral Galaxy. Galaxies are most often found in clusters and are thus subject to gravitational forces from their neighbors. The relative motion that results from these interactions causes deviations from the cosmological principle called bulk flow. Measuring the peculiar velocities enables cosmologists to calculate the masses of interacting galaxies. Using this technique scientists can estimate the total density of matter in the Universe. During the recombination epoch, the Universe had cooled sufficiently for nucleosynthesis to occur. However, this process produces only a few elements, and looking at the abundance of these elements today is indicative of the rate of nucleosynthesis and the amount of baryonic mass

388

Abstract for Khalil Farouqi  

NLE Websites -- All DOE Office Websites (Extended Search)

Farouqi Farouqi University of Chicago and Argonne Explosive nucleosynthesis in the high-entropy wind of core-collapse supernovae In an attempt to constrain the astrophysical conditions for the nucleosynthesis of the classical r-process elements beyond Fe, we have performed large-scale dynamical network calculations within the model of an adiabatically expanding high-entropy wind (HEW) of type II supernovae (SN II). A superposition of several entropy-components (S) with model-inherent weighting results in an excellent reproduction of the overall Solar System (SS) isotopic r-process residuals, as well as the more recent observations of elemental abundances of metal-poor, r-process-rich halo-stars in the early Galaxy. For the heavy r-process elements beyond Sn, our HEW model

389

Abstract for Carla Froehlich  

NLE Websites -- All DOE Office Websites (Extended Search)

Carla Froehlich Carla Froehlich University of Basel, Switzerland Core Collapse Supernovae: New Aspects of Nucleosynthesis and their Imprint on Galactic Evolution In 1D, a self-consistent treatment of core collapse supernovae with presently known input physics and computer simulations does not yet lead to successful explosions, while 2D models show promise. On the other hand there is a need to provide correct nucleosynthesis abundances for the quickly evolving field of galactic evolution and observations of low metallicity stars. The innermost ejecta are directly affected by the explosion mechanism, most strongly the yields of Fe-group nuclei for which an induced piston or thermal bomb treatment will not provide the correct yields because the neutrino interactions are not included. I will show how

390

Protoneutron Star Winds  

E-Print Network (OSTI)

Neutrino-driven winds are thought to accompany the Kelvin-Helmholtz cooling phase of nascent protoneutron stars in the first seconds after a core-collapse supernova. These outflows are a likely candidate as the astrophysical site for rapid neutron-capture nucleosynthesis (the r-process). In this chapter we review the physics of protoneutron star winds and assess their potential as a site for the production of the heavy r-process nuclides. We show that spherical transonic protoneutron star winds do not produce robust $r$-process nucleosynthesis for `canonical' neutron stars with gravitational masses of 1.4 M_sun and coordinate radii of 10 km. We further speculate on and review some aspects of neutrino-driven winds from protoneutron stars with strong magnetic fields.

Todd A. Thompson

2003-09-03T23:59:59.000Z

391

Neutrino-driven wind and wind termination shock in supernova cores  

E-Print Network (OSTI)

The neutrino-driven wind from a nascent neutron star at the center of a supernova expands into the earlier ejecta of the explosion. Upon collision with this slower matter the wind material is decelerated in a wind termination shock. By means of hydrodynamic simulations in spherical symmetry we demonstrate that this can lead to a large increase of the wind entropy, density, and temperature, and to a strong deceleration of the wind expansion. The consequences of this phenomenon for the possible r-process nucleosynthesis in the late wind still need to be explored in detail. Two-dimensional models show that the wind-ejecta collision is highly anisotropic and could lead to a directional dependence of the nucleosynthesis even if the neutrino-driven wind itself is spherically symmetric.

A. Arcones; L. Scheck; H. -Th. Janka

2006-12-21T23:59:59.000Z

392

Reaction rate uncertainties and the {nu}p-process  

Science Conference Proceedings (OSTI)

Current hydrodynamical simulations of core collapse supernovae find proton-rich early ejecta. At the same time, the models fail to eject neutron-rich matter, thus leaving the origin of the main r-process elements unsolved. However, the proton-rich neutrino-driven winds from supernovae have been identified as a possible production site for light n-capture elements beyond iron (such as Ge, Sr, Y, Zr) through the {nu}p-process. The detailed nucleosynthesis patterns of the {nu}p-process depend on the hydrodynamic conditions and the nuclear reaction rates of key reactions. We investigate the impact of reaction rate uncertainties on the {nu}p-process nucleosynthesis.

Froehlich, C.; Rauscher, T. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Dept. of Physics, University of Basel, 4056 Basel (Switzerland)

2012-11-12T23:59:59.000Z

393

Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances  

SciTech Connect

Semidirect capture, a two-step process that excites a giant-dipole resonance followed by its radiative de-excitation, is a dominant process near giant-dipole resonances, that is, for incoming neutron energies within 5 20 MeV. At lower energies such processes may affect neutron capture rates that are relevant to astrophysical nucleosynthesis models. We implement a semidirect capture model in the coupled-channel reaction code Fresco and validate it by comparing the cross section for direct-semidirect capture 208Pb(n,g)209Pb to experimental data. We also investigate the effect of low-energy electric dipole strength in the pygmy resonance. We use a conventional single-particle direct-semidirect capture code Cupido for comparison. Furthermore, we present and discuss our results for direct-semidirect capture reaction 130Sn(n,g)131Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.

Thompson, I J [Lawrence Livermore National Laboratory (LLNL); Escher, Jutta E [ORNL; Arbanas, Goran [ORNL

2013-01-01T23:59:59.000Z

394

Stars as thermonuclear reactors: their fuels and ashes  

E-Print Network (OSTI)

Atomic nuclei are transformed into each other in the cosmos by nuclear reactions inside stars: -- the process of nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars and how they manage to burn their fuel so slowly most of the time are discussed. Thermonuclear reactions involving protons in the hydrostatic burning of hydrogen in stars are discussed first. This is followed by triple alpha reactions in the helium burning stage and the issues of survival of carbon and oxygen in red giant stars connected with nuclear structure of oxygen and neon. Advanced stages of nuclear burning in quiescent reactions involving carbon, neon, oxygen and silicon are discussed. The role of neutron induced reactions in nucleosynthesis beyond iron is discussed briefly, as also the experimental detection of neutrinos from SN 1987A which confirmed broadly the ideas concerning gravitational collapse leading to a supernova.

A. Ray

2004-05-28T23:59:59.000Z

395

Fermilab Today  

NLE Websites -- All DOE Office Websites (Extended Search)

, 2006 , 2006 Calendar Monday, May 1 11:00 a.m. Academic Lecture Series - Curia II Speaker: S. Dodelson, Fermilab Title: The Clumpy Universe - Course 6b (3rd Lecture) 2:30 p.m. Particle Astrophysics Seminar - Curia II Speaker: G. Steigman, Ohio State University Title: Schrammfest: BBN: Successes and Challenges 3:30 p.m. DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over 4:00 p.m. All Experimenters' Meeting - Curia II Special Topics: Recent Activity at the Test Beam; NuMI Horn Repair Tuesday, May 2 12:30 p.m. Lunchtime Video Presentation - Curia II Chernobyl: A BBC Dramatization 2:00 p.m. Research Techniques Seminar - West Wing (WH-10NW) Speaker: G. Deptuch, Brookhaven National Laboratory Title: Monolithic Active Pixel Sensors for Not Visible Light Applications: Advantages and Limitations

396

Cosmological and astrophysical constraints on superconducting cosmic strings  

E-Print Network (OSTI)

We investigate the cosmological and astrophysical constraints on superconducting cosmic strings (SCSs). SCS loops emit strong bursts of electromagnetic waves, which might affect various cosmological and astrophysical observations. We take into account the effect on the CMB anisotropy, CMB blackbody spectrum, BBN, observational implications on radio wave burst and X-ray or gamma-ray events, and stochastic gravitational wave background measured by pulsar timing experiments. We then derive constraints on the parameters of SCS from current observations and estimate prospects for detecting SCS signatures in on-going observations. As a result, we find that these constraints exclude broad parameter regions, and also that on-going radio wave observations can probe large parameter space.

Koichi Miyamoto; Kazunori Nakayama

2012-12-30T23:59:59.000Z

397

Progress in the physics of massive neutrinos  

E-Print Network (OSTI)

The current status of the physics of massive neutrinos is reviewed with a forward-looking emphasis. The article begins with the general phenomenology of neutrino oscillations in vacuum and matter and documents the experimental evidence for oscillations of solar, reactor, atmospheric and accelerator neutrinos. Both active and sterile oscillation possibilities are considered. The impact of cosmology (BBN, CMB, leptogenesis) and astrophysics (supernovae, highest energy cosmic rays) on neutrino observables and vice versa, is evaluated. The predictions of grand unified, radiative and other models of neutrino mass are discussed. Ways of determining the unknown parameters of three-neutrino oscillations are assessed, taking into account eight-fold degeneracies in parameters that yield the same oscillation probabilities, as well as ways to determine the absolute neutrino mass scale (from beta-decay, neutrinoless double-beta decay, large scale structure and Z-bursts). Critical unknowns at present are the amplitude of \

V. Barger; D. Marfatia; K. Whisnant

2003-08-12T23:59:59.000Z

398

Installation of a magnetic spectrometer on the  

E-Print Network (OSTI)

. HEDP facilities ­ The National Ignition Facility (NIF) ­ OMEGA laser 3. Known nuclear reactions used-36 cm-2 s-1) NIF OMEGA p p p d 3He p p p d 3He 4He p p 6Be ve e+ ve e+ g g Nucleosynthesis of light facilities ­ The National Ignition Facility (NIF) ­ OMEGA laser 3. Known nuclear reactions used to probe HEDP

399

Spectral and intensity variations of Galactic 26^Al emission  

E-Print Network (OSTI)

Gamma-ray line emission from the radioactive decay of 26Al reflects nucleosynthesis in massive stars and supernovae. We use INTEGRAL 26Al measurements to characterize the distribution and characteristics of 26Al source regions throughout the Galaxy. We detect the 26Al line from the inner Galaxy at 28\\sigma significance. The line appears narrow, and we constrain broadening in the source regions to 5deg.

Wang, W; Diehl, R; Halloin, H; Jean, P; Knödlseder, J; Kretschmer, K; Martin, P; Roques, P; Strong, A W; Winkler, C; Zhang, X L

2009-01-01T23:59:59.000Z

400

Direct measurement of the {sup 11}C({alpha},p){sup 14}N reaction at CRIB: A path from pp-chain to CNO  

SciTech Connect

We determined the total reaction rate of the {sup 11}C({alpha},p){sup 14}N reaction relevant to the nucleosynthesis in explosive hydrogen-burning stars. The measurement was performed by means of the thick target method in inverse kinematics with {sup 11}C RI beams. We performed the identification of the ground-state transition and excited-state transitions using time-of-flight information for the first time.

Hayakawa, S.; Kubono, S.; Kahl, D.; Yamaguchi, H.; Binh, D. N.; Hashimoto, T.; Wakabayashi, Y.; He, J. J.; Iwasa, N.; Kato, S.; Komatsubara, T.; Kwon, Y. K.; Teranishi, T.; Wanajo, S. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare (Italy); Nishina Center, RIKEN (Japan); Center for Nuclear Study, University of Tokyo (Japan)

2012-11-20T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Direct measurement of the breakout reaction {sup 11}C({alpha},p){sup 14}N in explosive hydrogen-burning process  

Science Conference Proceedings (OSTI)

We determined the {sup 11}C({alpha},p){sup 14}N reaction rate relevant to the nucleosynthesis in explosive hydrogen-burning stars. The measurement was performed by means of the thick target method in inverse kinematics with {sup 11}C RI beams. We derived the excitation functions for the ground-state transition and excited-state transitions using time-of-flight information for the first time. The present reaction rate is compared to the previous one.

Hayakawa, S.; Kubono, S.; Kahl, D.; Yamaguchi, H.; Binh, Dam N.; Hashimoto, T.; Wakabayashi, Y.; He, J. J.; Iwasa, N.; Kato, S.; Komatsubara, T.; Kwon, Y. K.; Teranishi, T.; Wanajo, S. [Center for Nuclear Study, Graduate of Science, University of Tokyo (Japan) and Institute of Physics (Japan); RCNP, Osaka University (Japan); Japan Atomic Energy Agency (Japan); Institute of Modern Physics (Japan); Department of Physics, Tohoku University (Japan); Department of Physics, Yamagata University (Japan); Department of Physics, University of Tsukuba (Japan); Department of Physics, Chung Ang University (Korea, Republic of); Department of Physics, Kyushu University (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo (Japan)

2012-11-12T23:59:59.000Z

402

Neutron beta-decay, Standard Model and cosmology  

E-Print Network (OSTI)

The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. The neutron lifetime recently obtained, 878.5 +/- 0.7stat +/- 0.3sys s, is the most accurate one to date. The new result for the neutron lifetime differs from the world average value by 6.5 standard deviations. The impact of the new result on testing of Standard Model and on data analysis for the primordial nucleosynthesis model is scrutinized.

A. P. Serebrov

2006-11-22T23:59:59.000Z

403

International Linear Collider Reference Design Report Volume 2: Physics at the ILC  

SciTech Connect

The triumph of 20th century particle physics was the development of the Standard Model and the confirmation of many of its aspects. Experiments determined the particle constituents of ordinary matter, and identified four forces that hold matter together and transform it from one form to another. Particle interactions were found to obey precise laws of relativity and quantum theory. Remarkable features of quantum physics were observed, including the real effects of 'virtual' particles on the visible world. Building on this success, particle physicists are now able to address questions that are even more fundamental, and explore some of the deepest mysteries in science. The scope of these questions is illustrated by this summary from the report Quantum Universe: (1) Are there undiscovered principles of nature; (2) How can we solve the mystery of dark energy; (3) Are there extra dimensions of space; (4) Do all the forces become one; (5) Why are there so many particles; (6) What is dark matter? How can we make it in the laboratory; (7) What are neutrinos telling us; (8) How did the universe begin; and (9) What happened to the antimatter? A worldwide program of particle physics investigations, using multiple approaches, is already underway to explore this compelling scientific landscape. As emphasized in many scientific studies, the International Linear Collider is expected to play a central role in what is likely to be an era of revolutionary advances. Discoveries from the ILC could have breakthrough impact on many of these fundamental questions. Many of the scientific opportunities for the ILC involve the Higgs particle and related new phenomena at Terascale energies. The Standard Model boldly hypothesizes a new form of Terascale energy, called the Higgs field, that permeates the entire universe. Elementary particles acquire mass by interacting with this field. The Higgs field also breaks a fundamental electroweak force into two forces, the electromagnetic and weak forces, which are observed by experiments in very different forms. So far, there is no direct experimental evidence for a Higgs field or the Higgs particle that should accompany it. Furthermore, quantum effects of the type already observed in experiments should destabilize the Higgs boson of the Standard Model, preventing its operation at Terascale energies. The proposed antidotes for this quantum instability mostly involve dramatic phenomena at the Terascale: new forces, a new principle of nature called supersymmetry, or even extra dimensions of space. Thus for particle physicists the Higgs boson is at the center of a much broader program of discovery, taking off from a long list of questions. Is there really a Higgs boson? If not, what are the mechanisms that give mass to particles and break the electroweak force? If there is a Higgs boson, does it differ from the hypothetical Higgs of the Standard Model? Is there more than one Higgs particle? What are the new phenomena that stabilize the Higgs boson at the Terascale? What properties of Higgs boson inform us about these new phenomena? Another major opportunity for the ILC is to shed light on the dark side of the universe. Astrophysical data shows that dark matter dominates over visible matter, and that almost all of this dark matter cannot be composed of known particles. This data, combined with the concordance model of Big Bang cosmology, suggests that dark matter is comprised of new particles that interact weakly with ordinary matter and have Terascale masses. It is truely remarkable that astrophysics and cosmology, completely independently of the particle physics considerations reviewed above, point to new phenomena at the Terascale. If Terascale dark matter exists, experiments at the ILC should be able to produce such particles in the laboratory and study their properties. Another list of questions will then beckon. Do these new particles really have the correct properties to be the dark matter? Do they account for all of the dark matter, or only part of it? What do their properties tell us about the evolut

Aarons, Gerald; Abe, Toshinori; Abernathy, Jason; Ablikim, Medina; Abramowicz, Halina; Adey, David; Adloff, Catherine; Adolphsen, Chris; Afanaciev, Konstantin; Agapov, Ilya; Ahn, Jung-Keun; Aihara, Hiroaki; Akemoto, Mitsuo; del Carmen Alabau, Maria; Albert, Justin; Albrecht, Hartwig; Albrecht, Michael; Alesini, David; Alexander, Gideon; Alexander, Jim; Allison, Wade; /SLAC /Tokyo U. /Victoria U. /Beijing, Inst. High Energy Phys. /Tel Aviv U. /Birmingham U. /Annecy, LAPP /Minsk, High Energy Phys. Ctr. /DESY /Royal Holloway, U. of London /CERN /Pusan Natl. U. /KEK, Tsukuba /Orsay, LAL /Notre Dame U. /Frascati /Cornell U., Phys. Dept. /Oxford U. /Hefei, CUST /Bangalore, Indian Inst. Sci. /Fermilab

2011-11-14T23:59:59.000Z

404

Baryonic Dark Matter in Galaxies  

E-Print Network (OSTI)

Cosmological nucleosynthesis calculations imply that many of the baryons in the Universe must be dark. We discuss the likelihood that some of these dark baryons may reside in the discs or halos of galaxies. If they were in the form of compact objects, they would then be natural MACHO candidates, in which case they are likely to be the remnants of a first generation of pregalactic or protogalactic Population III stars. Various candidates have been proposed for such remnants - brown dwarfs, red dwarfs, white dwarfs, neutron stars or black holes - and we review the many types of observations (including microlensing searches) which can be used to constrain or exclude them.

B. J. Carr

2000-08-01T23:59:59.000Z

405

Nuclear Masses in Astrophysics  

E-Print Network (OSTI)

Among all nuclear ground-state properties, atomic masses are highly specific for each particular combination of N and Z and the data obtained apply to a variety of physics topics. One of the most crucial questions to be addressed in mass spectrometry of unstable radionuclides is the one of understanding the processes of element formation in the Universe. To this end, accurate atomic mass values of a large number of exotic nuclei participating in nucleosynthesis are among the key input data in large-scale reaction network calculations. In this paper, a review on the latest achievements in mass spectrometry for nuclear astrophysics is given.

Christine Weber; Klaus Blaum; Hendrik Schatz

2008-12-09T23:59:59.000Z

406

Observational Tests Of Intermediate Mass Star Yields Using Planetary Nebulae  

E-Print Network (OSTI)

This paper summarizes a project designed to study abundances in a sample of planetary nebulae representing a broad range in progenitor mass and metallicity. We collect abundances of C, N, and O determined for the entire sample and compare them with theoretical predictions of planetary nebula abundances from a grid of intermediate-mass star models. We find very good agreement between observations and theory, lending strong support to our current understanding of nucleosynthesis in stars with progenitor masses below 8 solar masses. This agreement between observation and theory also supports the validity of published stellar yields of C and N in the study of the abundance evolution of these two elements.

K. B. Kwitter; R. B. C. Henry

2001-01-04T23:59:59.000Z

407

Observational Tests Of Intermediate Mass Star Yields Using Planetary Nebulae  

E-Print Network (OSTI)

This paper summarizes a project designed to study abundances in a sample of planetary nebulae representing a broad range in progenitor mass and metallicity. We collect abundances of C, N, and O determined for the entire sample and compare them with theoretical predictions of planetary nebula abundances from a grid of intermediate-mass star models. We find very good agreement between observations and theory, lending strong support to our current understanding of nucleosynthesis in stars with progenitor masses below 8 solar masses. This agreement between observation and theory also supports the validity of published stellar yields of C and N in the study of the abundance evolution of these two elements.

Kwitter, K B

2001-01-01T23:59:59.000Z

408

Physical conditions for the r-process  

Science Conference Proceedings (OSTI)

Recent works show that the r-process can proceed by competition between neutron capture and {beta}-decay in low temperature environments (process) where photo-disintegration plays no role. This is in contrast to the traditional picture of the r-process in high temperature environments ({approx} 1 Multiplication-Sign 10{sup 9} K; hot r-process) where the (n, {gamma})-({gamma}, n) equilibrium holds. In this study, we explore nucleosynthesis calculations based on a site-independent model to elucidate the physical conditions leading to cold and hot r-processes.

Wanajo, S.; Tachibana, T.; Goriely, S. [Technische Universitaet Muenchen, Excellence Cluster Universe, Boltzmannstr. 2, D-85748 Garching and Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Senior High School of Waseda University, Nerima, Tokyo 177-0044 (Japan); Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, C.P. 226, B-1050 Brussels (Belgium)

2012-11-12T23:59:59.000Z

409

THE RARE EARTH PEAK: AN OVERLOOKED r-PROCESS DIAGNOSTIC  

Science Conference Proceedings (OSTI)

The astrophysical site or sites responsible for the r-process of nucleosynthesis still remains an enigma. Since the rare earth region is formed in the latter stages of the r-process, it provides a unique probe of the astrophysical conditions during which the r-process takes place. We use features of a successful rare earth region in the context of a high-entropy r-process (S {approx}> 100k{sub B} ) and discuss the types of astrophysical conditions that produce abundance patterns that best match meteoritic and observational data. Despite uncertainties in nuclear physics input, this method effectively constrains astrophysical conditions.

Mumpower, Matthew R.; McLaughlin, G. C. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Surman, Rebecca, E-mail: mrmumpow@ncsu.edu, E-mail: gail_mclaughlin@ncsu.edu, E-mail: surmanr@union.edu [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States)

2012-06-20T23:59:59.000Z

410

Development of a detection method for {244}Pu by resonance ionization mass spectrometry.  

Science Conference Proceedings (OSTI)

The long-lived actinide {sup 244}Pu (t{sub 1/2} = 81 Myr) is expected to be present in the Interstellar Medium from fresh r-process nucleosynthesis or in direct ejecta from supernovae. Deposition onto Earth may result in traces of live {sup 244}Pu in suitable reservoirs. We are developing a method for {sup 244}Pu detection based on resonance ionization mass spectroscopy. Using Gd as a proxy, we determine an overall efficiency of 0.5% in conditions applicable to the detection of Pu, and present preliminary results on Pu detection.

Ofan, A.; Ahmad, I.; Greene, J. P.; Paul, M.; Savina, M. R. (Materials Science Division); ( PHY); (Hebrew Univ.)

2006-07-01T23:59:59.000Z

411

A Fluorescent Aerogel for Capture and Identification of Interplanetary and Interstellar Dust  

E-Print Network (OSTI)

Contemporary interstellar dust has never been analyzed in the laboratory, despite its obvious astronomical importance and its potential as a probe of stellar nucleosynthesis and galactic chemical evolution. Here we report the discovery of a novel fluorescent aerogel which is capable of capturing hypervelocity dust grains and passively recording their kinetic energies. An array of these “calorimetric” aerogel collectors in low earth orbit would lead to the capture and identification of large numbers of interstellar dust grains. Subject headings: astrochemistry — instrumentation: detectors — interplanetary medium — dust, extinction — meteors, meteoroids — techniques: image processing 1.

Gerardo Domínguez; Andrew J. Westphal; Mark L. F. Phillips; Steven M. Jones

2003-01-01T23:59:59.000Z

412

Relevant energy ranges for astrophysical reaction rates  

Science Conference Proceedings (OSTI)

Effective energy windows (Gamow windows) of astrophysical reaction rates for (p,gamma), (p,n), (p,alpha), (alpha,gamma), (alpha,n), (alpha,p), (n,gamma), (n,p), and (n,alpha) on targets with 10<=Z<=83 from proton to neutron dripline are calculated using theoretical cross sections. It is shown that widely used approximation formulas for the relevant energy ranges are not valid for a large number of reactions relevant to hydrostatic and explosive nucleosynthesis. The influence of the energy dependence of the averaged widths on the location of the Gamow windows is discussed and the results are presented in tabular form.

Rauscher, Thomas [Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel (Switzerland)

2010-04-15T23:59:59.000Z

413

Two effects relevant for the study of astrophysical reaction rates: {gamma} transitions in capture reactions and Coulomb suppression of the stellar enhancement  

Science Conference Proceedings (OSTI)

Nucleosynthesis processes involve reactions on several thousand nuclei, both close to and far off stability. The preparation of reaction rates to be used in astrophysical investigations requires experimental and theoretical input. In this context, two interesting aspects are discussed: (i) the relevant {gamma} transition energies in astrophysical capture reactions, and (ii) the newly discovered Coulomb suppression of the stellar enhancement factor. The latter makes a number of reactions with negative Q value more favorable for experimental investigation than their inverse reactions, contrary to common belief.

Rauscher, Thomas [Departement Physik, Universitaet Basel, CH-4056 Basel (Switzerland)

2009-01-28T23:59:59.000Z

414

Neutron capture measurements at a RIA-type facility  

E-Print Network (OSTI)

Neutron capture cross sections of unstable isotopes are important for neutron induced nucleosynthesis as well as for technological applications. The Rare Isotope Accelerator (RIA) or comparable facilities will be able to produce radioactive ion beams up to 10**12 particles/s and would therefore be a suitable place for (n,g) studies on radioactive isotopes with half-lives between days and months. We propose a facility for measurements of (n,g) cross sections of unstable isotopes in the keV range suited for minimal sample masses down to 10**15 atoms, corresponding to minimum half-lives of only 10 d.

R. Reifarth; R. C. Haight; M. Heil; F. Kaeppeler; D. J. Vieira

2004-01-22T23:59:59.000Z

415

Measurement of the 20 and 90 keV Resonances in the {sup 18}O(p,{alpha}){sup 15}N Reaction via the Trojan Horse Method  

SciTech Connect

The {sup 18}O(p,{alpha}){sup 15}N reaction is of primary importance in several astrophysical scenarios, including fluorine nucleosynthesis inside asymptotic giant branch stars as well as oxygen and nitrogen isotopic ratios in meteorite grains. Thus the indirect measurement of the low energy region of the {sup 18}O(p,{alpha}){sup 15}N reaction has been performed to reduce the nuclear uncertainty on theoretical predictions. In particular the strength of the 20 and 90 keV resonances has been deduced and the change in the reaction rate evaluated.

La Cognata, M.; Spitaleri, C.; Cherubini, S.; Crucilla, V.; Gulino, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tumino, A. [INFN Laboratori Nazionali del Sud and DMFCI Universita di Catania, 95123 Catania (Italy); Mukhamedzhanov, A. M.; Tribble, R. E.; Banu, A.; Goldberg, V. Z.; Tabacaru, G.; Trache, L. [Cyclotron Institute, Texas A and M University, College Station, 77843 Texas (United States); Irgaziev, B. [GIK Institute of Engineering Sciences and Technology, Topi (23640), NWFP Pakistan (Pakistan); Coc, A. [CSNSM, CNRS/IN2P3 Universite Paris Sud, F-91405 Orsay (France)] (and others)

2008-10-10T23:59:59.000Z

416

Superparticle Mass Window from Leptogenesis and Decaying Gravitino Dark Matter  

E-Print Network (OSTI)

Gravitino dark matter, together with thermal leptogenesis, implies an upper bound on the masses of superparticles. In the case of broken R-parity the constraints from primordial nucleosynthesis are naturally satisfied and decaying gravitinos lead to characteristic signatures in high energy cosmic rays. We analyse the implications for supergravity models with universal boundary conditions at the grand unification scale. Together with low-energy observables one obtains a window of superparticle masses, which will soon be probed at the LHC, and a range of allowed reheating temperatures.

Wilfried Buchmuller; Motoi Endo; Tetsuo Shindou

2008-09-26T23:59:59.000Z

417

Delayed outflows from black hole accretion tori following neutron star binary coalescence  

E-Print Network (OSTI)

Expulsion of neutron-rich matter following the merger of neutron star (NS) binaries is crucial to the radioactively-powered electromagnetic counterparts of these events and to their relevance as sources of r-process nucleosynthesis. Here we explore the long-term (viscous) evolution of remnant black hole accretion disks formed in such mergers by means of two-dimensional, time-dependent hydrodynamical simulations. The evolution of the electron fraction due to charged-current weak interactions is included, and neutrino self-irradiation is modeled as a lightbulb that accounts for the disk geometry and moderate optical depth effects. Over several viscous times (~1s), a fraction ~10% of the initial disk mass is ejected as a moderately neutron-rich wind (Y_e ~ 0.2) powered by viscous heating and nuclear recombination, with neutrino self-irradiation playing a sub-dominant role. Although the properties of the outflow vary in time and direction, their mean values in the heavy-element production region are relatively robust to variations in the initial conditions of the disk and the magnitude of its viscosity. The outflow is sufficiently neutron-rich that most of the ejecta forms heavy r-process elements with mass number A >130, thus representing a new astrophysical source of r-process nucleosynthesis, distinct from that produced in the dynamical ejecta. Due to its moderately high entropy, disk outflows contain a small residual fraction ~1% of helium, which could produce a unique spectroscopic signature.

Rodrigo Fernández; Brian D. Metzger

2013-04-24T23:59:59.000Z

418

Short-lived isotopes and 23Na production in low mass AGB Stars  

E-Print Network (OSTI)

We discuss the synthesis of some short-lived isotopes and of 23Na in thermally pulsing AGB stars with initial mass of 2 Msun and two different metallicities (Z=1.5e-2, corresponding to the metal amount in the Sun, and Z=1e-4), representative of disk and halo stars, respectively. The different nucleosynthesis channels are illustrated in some details. As previously found, the 13C formed after each third dredge up episode is usually completely consumed by alpha captures before the onset of the subsequent thermal pulse, releasing neutrons. This is the most efficient neutron source in low mass AGB stars and the resulting s-process nucleosynthesis is at the origin of the solar main component. However, in the solar metallicity model, we find that the temperature of the first formed 13C pocket remains too low during the interpulse and the 13C is not completely burnt, being partially engulfed in the convective zone generated by the following thermal pulse. Due to the rapid convective mixing in this zone, the 13C is ex...

Cristallo, S; Straniero, O; Piersanti, L; Dominguez, I

2006-01-01T23:59:59.000Z

419

Influence of new reaction rates on 18F production in novae  

E-Print Network (OSTI)

Gamma-ray emission from classical novae is dominated, during the first hours, by positron annihilation resulting from the beta decay of radioactive nuclei. The main contribution comes from the decay of 18F and hence is directly related to 18F formation during the outburst. A good knowledge of the nuclear reaction rates of production and destruction of 18F is required to study 18F synthesis in novae and the resulting gamma-ray emission. The rates relevant for the main mode of 18F destruction (i.e, through proton captures) have been the object of many recent experiments. However, subsequent analyses were focused on providing rates for X-ray burst nucleosynthesis not valid at nova temperatures (lower than 3.5 10^8 K). Accordingly, it is crucial to propose and discuss new reaction rates, incorporating all new experimental results, down to the domain of nova nucleosynthesis. We show that in this temperature regime, the 18F(p,gamma) and (p,alpha) reaction rates remain uncertain and deserve further experimental and theoretical efforts. Our hydrodynamic calculations including the new nuclear rates demonstrate that their impact on 18F synthesis in nova explosions is quite large and, consequently, the early gamma-ray emission from classical novae is also affected.

Alain Coc; Margarita Hernanz; Jordi Jose; Jean-Pierre Thibaud

2000-03-13T23:59:59.000Z

420

Stellar Evolution/Supernova Research Data Archives from the SciDAC Computational Astrophysics Consortium  

DOE Data Explorer (OSTI)

Theoretical high-energy astrophysics studies the most violent explosions in the universe - supernovae (the massive explosions of dying stars) and gamma ray bursts (mysterious blasts of intense radiation). The evolution of massive stars and their explosion as supernovae and/or gamma ray bursts describes how the "heavy" elements needed for life, such as oxygen and iron, are forged (nucleosynthesis) and ejected to later form new stars and planets. The Computational Astrophysics Consortium's project includes a Science Application Partnership on Adaptive Algorithms that develops software involved. The principal science topics are - in order of priority - 1) models for Type Ia supernovae, 2) radiation transport, spectrum formation, and nucleosynthesis in model supernovae of all types; 3) the observational implications of these results for experiments in which DOE has an interest, especially the Joint Dark Energy Mission, Supernova/Acceleration Probe (SNAP) satellite observatory, the Large Synoptic Survey Telescope (LSST), and ground based supernova searches; 4) core collapse supernovae; 5) gamma-ray bursts; 6) hypernovae from Population III stars; and 7) x-ray bursts. Models of these phenomena share a common need for nuclear reactions and radiation transport coupled to multi-dimensional fluid flow. The team has developed and used supernovae simulation codes to study Type 1A and core-collapse supernovae. (Taken from http://www.scidac.gov/physics/grb.html) The Stellar Evolution Data Archives contains more than 225 Pre-SN models that can be freely accessed.

Woosley, Stan [University of California, Santa Cruz

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

The elemental abundance pattern in a galaxy at z=2.626  

E-Print Network (OSTI)

The discovery of metal-poor stars (where metal is any element more massive than helium) has enabled astronomers to probe the chemical enrichment history of the Milky Way. More recently, element abundances in gas inside high-redshift galaxies has been probed through the absorption lines imprinted on the spectra of background quasars, but these have typically yielded measurements of only a few elements. Furthermore, interpretation of these abundances is complicated by the fact that differential incorporation of metals into dust can produce an abundance pattern similar to that expected from nucleosynthesis by massive stars. Here we report the observation of over 25 elements in a galaxy at z=2.626. With these data, we can examine nucleosynthetic processes independent of the uncertainty arising from depletion. We find that the galaxy was enriched mainly by massive stars (M > 15 solar masses) and propose that it is the progenitor of a massive, elliptical galaxy. The detailed abundance patterns suggest that boron is produced through processes that act independently of metallicity, and may require alternative mechanisms for the nucleosynthesis of germanium.

Jason X. Prochaska; J. Chris Howk; Arthur M. Wolfe

2003-04-30T23:59:59.000Z

422

Implications of a non-universal IMF from C, N, and O abundances in very metal-poor Galactic stars and damped Lyman-alpha absorbers  

E-Print Network (OSTI)

Recently revealed C, N, and O abundances in the most metal-poor damped Lyman-alpha (DLA) absorbers are compared with those of extremely metal-poor stars in the Galactic halo, as well as extragalactic H II regions, to decipher nucleosynthesis and chemical enrichment in the early Universe. These comparisons surprisingly identify a relatively high C/O ratio and a low N/O ratio in DLA systems, which is hard to explain theoretically. We propose that if these features are confirmed by future studies, this effect occurs because the initial mass function in metal-poor DLA systems has a cut-off at the upper mass end at around 20-25 Msun, thus lacks the massive stars that provide the nucleosynthesis products leading to the low C/O and high N/O ratios. This finding is a reasonable explanation of the nature of DLA systems in which a sufficient amount of cold H I gas remains intact because of the suppression of ionization by massive stars. In addition, our claim strongly supports a high production rate of N in very massiv...

Tsujimoto, T

2011-01-01T23:59:59.000Z

423

Improved $^{192,194,195,196}$Pt($n,?$) and $^{192}$Ir($n,?$) astrophysical reactions rates  

E-Print Network (OSTI)

$^{192}$Pt is produced solely by the slow neutron capture (\\textit{s}) nucleosynthesis process and hence an accurate ($n$,$\\gamma $) reaction rate for this nuclide would allow its use as an important calibration point near the termination of the \\textit{s}-process nucleosynthesis flow. For this reason, we have measured neutron capture and total cross sections for $% ^{192,194,195,196,nat}$Pt in the energy range from 10 eV to several hundred keV at the Oak Ridge Electron Linear Accelerator. Measurements on the other Pt isotopes were, in part, necessitated by the fact that only a relatively small $^{192}$Pt sample of modest enrichment was available. Astrophysical $% ^{192,194,195,196}$Pt($n,\\gamma $) reaction rates, accurate to approximately 3%--5 %, were calculated from these data. No accurate reaction rates have been published previously for any of these isotopes. At \\textit{s}-process temperatures, previously recommended rates are larger (by as much as 35%) and have significantly different shapes as functions of temperature, than our new rates. We used our new Pt results, together with $^{191,193}$Ir(n,$% \\gamma $) data, to calibrate nuclear statistical model calculations and hence obtain an improved rate for the unmeasured \\textit{s}-process branching-point isotope $^{192}$Ir.

P. E. Koehler; K. H. Guber

2013-09-03T23:59:59.000Z

424

A Quantum Approach to Dark Matter  

E-Print Network (OSTI)

This work develops and explores a quantum-based theory which enables the nature and origin of cold dark matter (CDM) to be understood without need to introduce exotic particles. The quantum approach predicts the existence of certain macroscopic quantum structures that are WIMP-like even when occupied by traditional baryonic particles. These structures function as dark matter candidates for CDM theory on large scales where it has been most successful, and retain the potential to yield observationally compliant predictions on galactic cluster and sub-cluster scales. Relatively pure, high angular momentum, eigenstate solutions obtained from Schrodinger's equation in weak gravity form the structural basis. They have no classical analogue, and properties radically different from those of traditional localised matter (whose eigenstate spectra contain negligible quantities of such states). Salient features include radiative lifetimes that can exceed the age of the universe, energies and 'sizes' consistent with galactic halos, and negligible interaction rates with radiation and macroscopic galactic objects. This facilitates the formation of sparsely populated macroscopic quantum structures that are invisible and stable. Viable structure formation scenarios are based on the seed potential wells of primordial black holes formed at the e+/e- phase transition. The structures can potentially produce suitable internal density distributions and have capacity to accommodate the required amount of halo dark matter. The formation scenarios show that it is possible to incorporate structures into universal evolutionary scenarios without significantly compromising the results of WMAP or the measurements of elemental BBN ratios.

A. D. Ernest

2004-06-06T23:59:59.000Z

425

Abstract for Hasan Yuksel  

NLE Websites -- All DOE Office Websites (Extended Search)

Yuksel Yuksel University of Wisconsin Neutrino Mass, Mixing, and Supernovae Neutrino Detection Being chargeless and weakly interacting, neutrinos also thought, for many decades, to have no mass. This simple picture is continuously challenged by many experiments and observations, and has to be reconsidered to include new physics. Today, neutrinos are rapidly becoming tools to probe early epochs of universe, stellar evolution, mechanism behind supernovae explosions, nucleosynthesis, and weak interactions. The last galactic supernova, 1987A which was observed with neutrinos preceding the light, confirmed our basic understanding of mechanism behind the SN explosion. I will briefly review neutrino mass, mixing, oscillations, discuss some of the implications of oscillations and some strategies to circumvent the

426

ORELA accelerator facility  

NLE Websites -- All DOE Office Websites (Extended Search)

The Oak Ridge Electron Linear Accelerator The Oak Ridge Electron Linear Accelerator Pulsed Neutron Source The ORELA is a powerful electron accelerator-based neutron source located in the Physics Division of Oak Ridge National Laboratory. It produces intense, nanosecond bursts of neutrons, each burst containing neutrons with energies from 10e-03 to 10e08 eV. ORELA is operated about 1200 hours per year and is an ORNL User Facility open to university, national laboratory and industrial scientists. The mission of ORELA has changed from a recent focus on applied research to nuclear astrophysics. This is an area in which ORELA has historically been very productive: most of the measurements of neutron capture cross sections necessary for understanding heavy element nucleosynthesis through the slow neutron capture process (s-process) have

427

Analytical transformed harmonic oscillator basis for three-body nuclei of astrophysical interest: Application to 6He  

E-Print Network (OSTI)

Recently, a square-integrable discrete basis, obtained performing a simple analytical local scale transformation to the harmonic oscillator basis, has been proposed and successfully applied to study the properties of two-body systems. Here, the method is generalized to study three-body systems. To test the goodness of the formalism and establish its applicability and limitations, the capture reaction rate for the nucleosynthesis of the Borromean nucleus 6He (4He + n + n) is addressed. Results are compared with previous publications and with calculations based on actual three-body continuum wave functions, which can be generated for this simple case. The obtained results encourage the application to other Borromean nuclei of astrophysical interest such as 9Be and 12C, for which actual three-body continuum calculations are very involved.

J. Casal; M. Rodríguez-Gallardo; J. M. Arias

2013-07-24T23:59:59.000Z

428

 

NLE Websites -- All DOE Office Websites (Extended Search)

the Transient Sky the Transient Sky Daniel Kasen UC Santa Cruz Abstract: In the coming years, several astronomical surveys will scan the night sky with regular cadence, revealing an enormous number of supernovae and other optical transients, many never seen before. The study of these stellar disruptions is not only a vibrant topic in itself, but also impacts fundamental questions in cosmology, nucleosynthesis, compact objects, and the sources of gravitational waves. Insight from theory and modeling is required to physically interpret this data and to explain the new phenomena discovered. Here I discuss recent advances in large scale radiation hydrodynamical simulations which are predicting the signatures of a diverse range of explosive transients. I focus first on the thermonuclear, or

429

cosmicrayrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

Cosmic Cosmic rays 1 27. COSMIC RAYS Revised October 2013 by J.J. Beatty (Ohio State Univ.), J. Matthews (Louisiana State Univ.), and S.P. Wakely (Univ. of Chicago); revised August 2009 by T.K. Gaisser and T. Stanev (Bartol Research Inst., Univ. of Delaware). 27.1. Primary spectra The cosmic radiation incident at the top of the terrestrial atmosphere includes all stable charged particles and nuclei with lifetimes of order 10 6 years or longer. Technically, "primary" cosmic rays are those particles accelerated at astrophysical sources and "secondaries" are those particles produced in interaction of the primaries with interstellar gas. Thus electrons, protons and helium, as well as carbon, oxygen, iron, and other nuclei synthesized in stars, are primaries. Nuclei such as lithium, beryllium, and boron (which are not abundant end-products of stellar nucleosynthesis)

430

Proposal for the 252Cf source upgrade to the ATLAS facility  

NLE Websites -- All DOE Office Websites (Extended Search)

the the 252 Cf source upgrade to the ATLAS facility Physics Division, Argonne National Laboratory Contact persons: Guy Savard, Richard Pardo February 22, 2005 Abstract Beams of accelerated exotic neutron-rich nuclei allow access to little known regions of the nuclear landscape that are important both structurally and for r-process nucleosynthesis. We propose to increase the radioactive beam capabilities of the ATLAS accelerator facility by the installation of a new source of ions to provide beams of short- lived neutron-rich isotopes. These isotopes will be obtained from a 1 Ci 252 Cf fission source located in a large gas catcher from which the radioactive ions will be extracted and transferred to an ECR ion source for charge breeding before acceleration in the

431

cosmicrayrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

rays rays 1 26. COSMIC RAYS Revised August 2011 by J.J. Beatty (Ohio State Univ.) and J. Matthews (Louisiana State Univ. and Southern Univ.); revised August 2009 by T.K. Gaisser and T. Stanev (Bartol Research Inst., Univ. of Delaware) 26.1. Primary spectra The cosmic radiation incident at the top of the terrestrial atmosphere includes all stable charged particles and nuclei with lifetimes of order 10 6 years or longer. Technically, "primary" cosmic rays are those particles accelerated at astrophysical sources and "secondaries" are those particles produced in interaction of the primaries with interstellar gas. Thus electrons, protons and helium, as well as carbon, oxygen, iron, and other nuclei synthesized in stars, are primaries. Nuclei such as lithium, beryllium, and boron (which are not abundant end-products of stellar nucleosynthesis) are secondaries.

432

cosmicrayrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

24. 24. COSMIC RAYS Revised August 2007 by T.K. Gaisser and T. Stanev (Bartol Research Inst., Univ. of Delaware). 24.1. Primary spectra The cosmic radiation incident at the top of the terrestrial atmosphere includes all stable charged particles and nuclei with lifetimes of order 10 6 years or longer. Technically, "primary" cosmic rays are those particles accelerated at astrophysical sources, and "secondaries" are those particles produced in interaction of the primaries with interstellar gas. Thus, electrons, protons, and helium, as well as carbon, oxygen, iron, and other nuclei synthesized in stars, are primaries. Nuclei such as lithium, beryllium, and boron (which are not abundant end-products of stellar nucleosynthesis) are secondaries. Antiprotons and positrons are also in large part secondary. Whether a small fraction of these particles may be primary

433

Electron Capture Reactions and Beta Decays in Steller Environments  

SciTech Connect

Electron capture reactions on Ni and Co isotopes are investigated by shell model calculations in steller environments. The capture rates depend sensitively on the distribution of the Gamow-Teller (GT) strength. The capture rates obtained by using GXPF1J Hamiltonian for fp-shell are found to be consistent with the rates obtained from experimental GT strength in {sup 58}Ni and {sup 60}Ni. Capture rates in Co isotopes, where there were large discrepancies among previous calculations, are also investigated. Beta decays of the N = 126 isotones are studied by shell model calculations taking into account both the GT and first-forbidden (FF) transitions. The FF transitions are found to be important to reduce the half-lives by twice to several times of those by the GT contributions only. Implications of the short half-lives of the waiting point nuclei on the r-process nucleosynthesis are discussed for various astrophysical conditions.

Suzuki, T. [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550, Japan and Center for Nuclear Study, University of Tokyo, Hirosawa, Wako-shi, Saitama, 351-0198 (Japan); Mao, H. [Graduate School of Integrated Basic Sciences, Nihon University, Sakurajosui-3-25-40, Setagaya-ku, Tokyo 156-8550, Japan and ENSPS, Pole API-Parc d'Innovation, Boulevard Sebastien Brant, BP 10413, 67412 ILLKIRCH CEDEXL (France); Honma, M. [Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, Fukushima 965-8580 (Japan); Yoshida, T. [Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kajino, T. [Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan) and National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Otsuka, T. [Department of Physics and Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan) and RIKEN, Hirosawa, Wako-shi, Saitama 351-0198 (Japan)

2011-10-28T23:59:59.000Z

434

Evaluation of electron capture reaction rates in Ni isotopes in stellar environments  

SciTech Connect

Electron capture rates in Ni isotopes are studied in stellar environments, that is, at high densities and high temperatures during the core-collapse and postbounce explosive nucleosynthesis in supernovae. Reaction rates in {sup 58}Ni and {sup 60}Ni, as well as in {sup 56}Ni, {sup 62}Ni, and {sup 64}Ni, are evaluated by shell-model calculations with the use of a new shell-model Hamiltonian in the fp shell, GXPF1J. While the previous shell-model calculations failed to reproduce the measured peaks of Gamow-Teller strength in {sup 58}Ni and {sup 60}Ni, the present new Hamiltonian is found to reproduce them very well, as well as the capture rates obtained from the observed strengths. Strengths and energies of the Gamow-Teller transitions in {sup 56}Ni, {sup 62}Ni, and {sup 64}Ni are also found to be consistent with the observations.

Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan); Center for Nuclear Study, University of Tokyo, Hirosawa, Wako-shi, Saitama 351-0198 (Japan); National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Honma, Michio [Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, Fukushima 965-8580 (Japan); Mao, Helene [ENSPS, Pole API-Parc d'Innovation, Boulevard Sebastien Brant, BP 10413, F-67412 Illkirch Cedex (France); Otsuka, Takaharu [Department of Physics and Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Kajino, Toshitaka [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Deaprtment of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2011-04-15T23:59:59.000Z

435

Making the Standard Candle: A study of how the progenitor white dwarf modulates the peak luminosity of type Ia supernovae  

SciTech Connect

The goals of the proposed research as stated in the proposal were to: • Build a suite of one-dimensional initial models of different metallicities and central densities. • Using the improved flame capturing scheme, simulate the explosion of a white dwarf with embedded Lagrangian tracer particles, and post-process the thermal histories of the tracers to reconstruct the nucleosynthesis of the explosion. • Survey the effects of a changing progenitor metallicity on the isotopic yields. Of particular interest is 1) whether the linear relation between the mass of 56Ni synthesized and the pro- genitor metallicity is moderated by the effect of electron captures in the core; and 2) how a varying central density alters the relation between metallicity and 56Ni mass. • Using these results, examine how the observed metallicity distribution would affect the brightness distribution of SNe Ia and the isotopic ratios about the Fe-peak.

Brown, Edward F [Michigan State University

2010-01-21T23:59:59.000Z

436

Making Carbon in Stars  

E-Print Network (OSTI)

The triple alpha process plays an important role in the production of 12C in stars. Its rate is known with an accuracy of about 12%. We examine the corresponding uncertainties introduced in the description of pre-supernova stars, of nucleosynthesis in a core-collapse SN explosion, and of the production of 12C during the third dredge-up in asymptotic giant branch (AGB) stars. For the AGB case we consider also the effects of uncertainties in the 14N(p,gamma)15O rate. We conclude that the present accuracy of the triplr alpha rate is inadequate and describe new experiments that will lead to a more accurate value.

Sam M. Austin

2004-11-30T23:59:59.000Z

437

Recent developments in the search for baryonic dark matter  

E-Print Network (OSTI)

Cosmological nucleosynthesis calculations imply that many of the baryons in the Universe must be dark. We discuss the likelihood that some of these dark baryons may reside in galaxies as Massive Compact Halo Objects (MACHOs), the remnants of a first generation of pregalactic or protogalactic stars. Various candidates have been proposed for such remnants and we review the many types of observations which can be used to detect or exclude them. Claims to have found positive evidence for some of the candidates have generally turned out to be spurious or questionable, so the status of the MACHO scenario remains controversial. However, it would be premature to reject MACHOs altogether and further observations are likely to resolve the issue soon.

B. J. Carr

2001-02-22T23:59:59.000Z

438

Neutron single particle structure in 131Sn and the r-process  

Science Conference Proceedings (OSTI)

Recent calculations suggest that, at late times in the r-process, the rate of neutron capture by {sup 130}Sn has a significant impact on nucleosynthesis. Direct capture into low-lying bound states is likely the dominant reaction in the r-process near the N=82 closed shell, so reaction rates are strongly impacted by the properties of neutron single particle states in this region. In order to investigate these properties, we have acquired (d,p) reaction data in the A{approx}132 region in inverse kinematics using {approx}630 MeV beams (4.85 MeV/u for {sup 130}Sn) and CD{sub 2} targets. An array of Si strip detectors, including SIDAR and an early implementation of the new Oak Ridge Rutgers University Barrel Array (ORRUBA), was used to detect reaction products. Preliminary results for the {sup 130}Sn(d,p){sup 131}Sn experiment are reported.

Kozub, R. L. [Tennessee Technological University; Bardayan, Daniel W [ORNL; Adekola, Aderemi S [ORNL; Blackmon, Jeff C [ORNL; Chae, K. Y. [University of Tennessee; Chipps, K. [Colorado School of Mines, Golden; Cizewski, J. A. [Rutgers University; Erikson, Luke [Colorado School of Mines, Golden; Hatarik, Robert [Rutgers University; Jones, K. L. [University of Tennessee; Krolas, W. [University of Warsaw; Liang, J Felix [ORNL; Ma, Zhanwen [ORNL; Matei, Catalin [Oak Ridge Associated Universities (ORAU); Moazen, Brian [University of Tennessee; Nesaraja, Caroline D [ORNL; Pain, Steven D [ORNL; Shapira, Dan [ORNL; ShrinerJr., J. F. [Tennessee Technological University; Smith, Michael Scott [ORNL; Swan, T. P. [University of Surrey, UK

2009-01-01T23:59:59.000Z

439

ASTROPHYSICAL EVIDENCE ON PHYSICS BEYOND THE STANDARD MODEL  

E-Print Network (OSTI)

Astrophysics and cosmology can be used to test the standard model of particle physics under conditions and over distance and time scales not accessible to laboratory experiments. Most of the astrophysical observations are in good agreement with the standard model. In particular, primordial nucleosynthesis, supernova explosions, stellar evolution and cosmic background radiations have been used to derive strong limits on physics beyond the standard model. However, the solution of some important astrophysical and cosmological problems may require new physics beyond the standard model. These include the origin of the initial conditions, large scale structure formation, the baryon asymmetry in the observed Universe, the dark matter problem, the solar neutrino problem and some cosmic ray puzzles. Here I review some important developments relevant to some of these problems, which took place most recently.

Arnon Dar

1995-02-20T23:59:59.000Z

440

Dark energy as an elastic strain fluid  

E-Print Network (OSTI)

The origin of the accelerated expansion of the universe is still unclear and new physics is needed on cosmological scales. We propose and test a novel interpretation of dark energy as originated by an elastic strain due to a cosmic defect in an otherwise Euclidean space-time. The strain modifies the expansion history of the universe. This new effective contribution tracks radiation at early times and mimics a cosmological constant at late times. The theory is tested against observations, from nucleosynthesis to the cosmic microwave background and formation and evolution of large scale structure to supernovae. Data are very well reproduced with Lam\\'e parameters of the order of 10^{-52} m^{-2}.

N. Radicella; M. Sereno; A. Tartaglia

2012-11-13T23:59:59.000Z

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441

A Global Model of $\\beta^-$-Decay Half-Lives Using Neural Networks  

E-Print Network (OSTI)

Statistical modeling of nuclear data using artificial neural networks (ANNs) and, more recently, support vector machines (SVMs), is providing novel approaches to systematics that are complementary to phenomenological and semi-microscopic theories. We present a global model of $\\beta^-$-decay halflives of the class of nuclei that decay 100% by $\\beta^-$ mode in their ground states. A fully-connected multilayered feed forward network has been trained using the Levenberg-Marquardt algorithm, Bayesian regularization, and cross-validation. The halflife estimates generated by the model are discussed and compared with the available experimental data, with previous results obtained with neural networks, and with estimates coming from traditional global nuclear models. Predictions of the new neural-network model are given for nuclei far from stability, with particular attention to those involved in r-process nucleosynthesis. This study demonstrates that in the framework of the $\\beta^-$-decay problem considered here, ...

Costiris, N; Gernoth, K A; Mavrommatis, E

2007-01-01T23:59:59.000Z

442