Search Menu
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information
Search Scholarly Publications

27 Search Results

Sorted by Relevance
Save Results
...

  1. Fuel Programming in Pool-Type Research Reactors of Intermediate Power Level

    Hill, Ernest E. ; Shon, Frederick J. - Nuclear Science and Engineering
    Here, a fuel cycle program is presented for an intermediate power research reactor utilizing fully enriched MTR-type fuel elements. The fuel cycle program is considered at equilibrium after many cycles have past. The program consists of shifting elements from positions of high importance outward to positions of low importance through several paths. The paths are staggered so that only the elements in one path are shifted at the conclusion of a cycle, and only one element is replaced. The method of calculating the fuel remaining in each element is shown utilizing a fractional burn-up factor for each position. Sample calculationsmore » are shown for the LPTR with 23 standard elements in the core and a desired burn-up of 15%. A method is proposed to obtain such an equilibrium condition starting with an initial loading of fuel elements having nearly equal fuel loading.« less

  2. First Search for Multijet Resonances in $$\sqrt{s} = 1.96$$ TeV $$ p\bar{p}$$ Collisions

    Aaltonen, T. - Physical Review Letters
    We present the first model independent search for three-jet hadronic resonances within multijet events in $$\sqrt{s} = 1.96$$ TeV $$ p\bar{p}$$ collisions at the Fermilab Tevatron using the CDF II detector. Pair production of supersymmetric gluinos and squarks with hadronic R-parity violating decays is employed as an example of a new physics benchmark for this signature. Selection criteria based on the kinetmatic properties of an ensemble of jet combinations within each event help to extract signal from copious QCD background. Our background estimates include all-hadronic t{anti t} decays that have a signature similar to the signal. No significant excess outsidemore » the top quark mass window is observed in data with an integrated luminosity of 3.2 fb{sup -1}. We place 95% confidence level limits on the production cross section {sigma}(p{anti p} {yields} X X') x BR ((tilde gg) {yields} 3 jet + 3 jet) where X, X' = {tilde g}, {tilde q}, or {tilde {anti q}}, with {tilde q}, {tilde {anti q}} {yields} {tilde g} + jet, as a function of gluino mass, in the range of 77 GeV/c{sup 2} to 240 GeV/c{sup 2}.« less

  3. Structural Analysis of the SHMS Cosine Theta Superconducting Dipole Force Collar

    Lassiter, Steven ; Brindza, Paul ; Fowler, Mike ; ... - IEEE Transactions on Applied Superconductivity
    Jefferson Laboratory is developing a set of innovative superconducting magnets for the 12 GeV upgrade in JLAB Hall C. Here, we will report on the finite element analysis (FEA) of the force collar for the Super High Momentum Spectrometer Cosine Theta Dipole magnet. The force collar is designed with an interference fit and intended to provide enough pressure after cool down to operating temperature to counteract Lorentz forces acting on the dipole coil during operation. By counteracting the Lorentz forces and keeping the coil pack in overall compression, movement of the coils is expected to be minimized. The dimensional geometrymore » of the cold mass is maintained in the commercial solid modeling code UG/I-DEAS while the magnetic field design is maintained in the commercial TOSCA code from Vector Fields. The three dimensional FEA was conducted in the commercial codes ANSYS and IDEAS. The method for converting the models and calculating the loads transferred to the structure is discussed. The results show the cold mass response to: force collar assembly preload, differential thermal contraction, and operational Lorentz loads. Evaluations are made for two candidate force collar materials and two candidate force collar designs.« less

  4. Neutron-deficient Mercury Isotopes1

    Fink, Richard W. ; Wiig, Edwin O. - Journal of the American Chemical Society
    In this work, high energy bombardments with protons on gold and α-particles on platinum were performed to study neutron-deficient mercury isotopes. Two new mercury isotopes have been definitely identified: Hg192, T1/2 = 5.7 ± 0.5 hours, 1.18 mev. ß+, 0.18 mev. conversion electrons, K, L X-rays and 1.39 mev. γ-ray; parent of 4.0 hour Au192. Hg193, T1/2 = 10.0 ± 0.5 hours Noß+, K, L X-rays, 0.18 mev. conversion electrons; parent of 15.3 hour Au193. Tentatively identified was Hg195 of 31 hour half-life, although this value may be in error owing to masking by the isomeric pair at Hg197. Decaymore » of Hg195 leaves gold daughter of 180-day half-life; although this genetic relation has not been established quantitatively, long-lived gold daughter has been observed. No positrons are emitted by Hg195 but K and L X-rays are detected. No activity was found which canbe allocated to Hg194. Positron-emitting 39.5-hour Au194 was not present among the gold daughters. An unidentified 2.0-hour mercury activity, present in increasing yield with increasing proton bombardment energy, must have mass number 191 or lower. Finally, the genetic relationships between Hg192-Au192 and between Hg193-Au193 have been established quantitatively.« less

  5. Gauge Invariance and Ward Identities in a Massive-Vector-Meson Model

    Lowenstein, J. H. ; Schroer, B. - Physical Review. D, Particles Fields
    Here normal-product techniques are applied to the study of gauge invariance in a massive-vector-meson model in renormalized perturbation theory. Composite fields are defined which are invariant under a one-parameter family of covariant gauge transformations. Ward identities are derived for Green's functions involving an arbitrary number of vector and axial-vector currents. The lack of lowest-order radiative corrections to the triangle anomaly of the axial-vector Ward identity is verified using Bogoliubov-Parasiuk-Hepp-Zimmermann methods.

  6. Asymptotic scale invariance in a massive Thirring model

    Gomes, M. ; Lowenstein, J. H. - Nuclear Physics. B
    The absence of Callan-Symanzik coupling-constant renormalization in a massive Thirring model is demonstrated to all orders using normal product methods. The derivation depends crucially on the mildness of the “anomaly” of the axial-vector Ward identity in this model, as well as on the special relationship between vector and axial-vector currents in two-dimensional field theory. Finally, application of power-counting arguments establishes the asymptotic scale invariance of the vertex functions when the mass m tends to zero with the normalization point μ either fixed (Gell-Mann-Low limit) or vanishing with m (Callan-Symanzik limit).

  7. Interpretation of a Large Value of the Nucleon σ Commutator

    Olshansky, R. - Physical Review. D, Particles Fields
    In this study, it is proposed that the value of the nucleon σ commutator σNN calculated from π-Ν scattering data be used to determine what part of the average baryon mass is due to the chiral-symmetry-breaking interaction. In the (3, 3*) + (3*, 3) model, the large value of σNN reported by Cheng and Dashen then implies that the baryon mass vanishes in the SU⁡ (3) × SU⁡ (3) limit. Study of a Lagrangian model shows that this possibility need not conflict with the Gell-Mann-Oakes-Renner symmetry-breaking Hamiltonian.

  8. SU3 mass differences in fifth interaction and tadpole results

    Goyal, Ashok - Nuovo Cimento, A
    Here we examine the medium strong mass splittings for pseudo-scalar mesons, vector mesons and spin-2/3 baryons in the framework of the «fifth interaction» proposed by Ne’eman. In addition to the resonance contributions from the low-lying states, we write an expression for the contribution from f8 Regge exchange in terms of contributions to electromagnetic mass differences from $$\text{A}^0_2$$ Regge exchange. Assuming that the $$\text{A}^0_2$$ Regge pole gives the correct contribution to the e.m. mass differences, we estimate the contribution of the f8-meson. In the approximation of neglecting the continuum spectrum, the ratio of tadpole contributions is given by the ratio ofmore » coupling constants of the f8-meson with hadrons. The results of the tadpole model are in agreement with the subtraction scheme of Segrè. We also find that in the presence of such anSU3-symmetry-breaking term, the renormalization of the hadronic weak-strangeness-changing vector current vertex, to second order in such a term, is quadratically divergent.« less

  9. Current-Commutator Derivation of Mass-Difference Relations

    Goyal, Ashok ; Li, Gino Fong ; Segrè, Gino - Physical Review. D, Particles Fields
    Here we investigate the consequences of the vanishing of certain double commutators to examine the consistency of SU⁡(3) × SU⁡(3)-breaking models. We also calculate the contribution to ΔI = 2 mass differences of isospin-violating terms other than the electromagnetic interactions, in the Hamiltonian.

  10. Quantum Theory of the Generalized Wave Equations. I

    Tripathy, Kishor C. - Journal of Mathematical Physics
    We have made a systematic analysis of the quantum theory of the infinite-component fields that transform under the combined representations of SL(2, C)(Majorana)ⓍDirac. A complete set of solutions of the wave equation includes solutions with timelike and spacelike momenta. We have explicitly calculated the mass spectra for the timelike and spacelike cases. Our method makes use of the decomposition of the product representation into reducible representations of the "little'" groups SU(2) and SU(1, 1). Finally, the quantization of the generalized fields is presented.
...
Search for:
All Records
Subject
MASS
Refine by:
Article Type
Availability
Journal
more less
Creator / Author
more less
Publication Date
Research Organization
more less