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Title: Constraining nuclear data via cosmological observations: Neutrino energy transport and big bang nucleosynthesis

Abstract

Here, we introduce a new computational capability that moves toward a self-consistent calculation of neutrino transport and nuclear reactions for big bang nucleosynthesis (BBN). Such a self-consistent approach is needed to be able to extract detailed information about nuclear reactions and physics beyond the standard model from precision cosmological observations of primordial nuclides and the cosmic microwave background radiation. We also calculate the evolution of the early universe through the epochs of weak decoupling, weak freeze-out and big bang nucleosynthesis (BBN) by simultaneously coupling a full strong, electromagnetic, and weak nuclear reaction network with a multi-energy group Boltzmann neutrino energy transport scheme. The modular structure of our approach allows the dissection of the relative contributions of each process responsible for evolving the dynamics of the early universe. Such an approach allows a detailed account of the evolution of the active neutrino energy distribution functions alongside and self-consistently with the nuclear reactions and entropy/heat generation and flow between the neutrino and photon/electron/positron/baryon plasma components. Our calculations reveal nonlinear feedback in the time evolution of neutrino distribution functions and plasma thermodynamic conditions. We discuss the time development of neutrino spectral distortions and concomitant entropy production and extraction from the plasma. These effectsmore » result in changes in the computed values of the BBN deuterium and helium-4 yields that are on the order of a half-percent relative to a baseline standard BBN calculation with no neutrino transport. This is an order of magnitude larger effect than in previous estimates. For particular implementations of quantum corrections in plasma thermodynamics, our calculations show a 0.4% increase in deuterium and a 0.6% decrease in 4He over our baseline. The magnitude of these changes are on the order of uncertainties in the nuclear physics for the case of deuterium and are potentially significant for the error budget of helium in upcoming cosmological observations.« less

Authors:
ORCiD logo [1];  [2];  [3];  [4];  [5]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. of California, San Diego, CA (United States). Dept. of Physics
  3. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Physics
  4. Univ. of California, San Diego, CA (United States). Dept. of Physics. Dept. of Physics and Biophysics
  5. North Carolina State Univ., Raleigh, NC (United States). Dept. of Physics
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1412854
Report Number(s):
LA-UR-16-28443
Journal ID: ISSN 2100-014X; TRN: US1800374
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
EPJ Web of Conferences
Additional Journal Information:
Journal Volume: 146; Conference: ND 2016 International Conference on Nuclear Data for Science and Technology, Bruges (Belgium), 11-16 Sep 2016; Journal ID: ISSN 2100-014X
Publisher:
EDP Sciences
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Atomic and Nuclear Physics; Astronomy and Astrophysics; nuclei, neutrinos, V&V, BBN, transport, Boltzmann equation

Citation Formats

Paris, Mark W., Fuller, George M., Grohs, Evan Bradley, Kishimoto, Chad, and Vlasenko, Alexey. Constraining nuclear data via cosmological observations: Neutrino energy transport and big bang nucleosynthesis. United States: N. p., 2017. Web. doi:10.1051/epjconf/201714601008.
Paris, Mark W., Fuller, George M., Grohs, Evan Bradley, Kishimoto, Chad, & Vlasenko, Alexey. Constraining nuclear data via cosmological observations: Neutrino energy transport and big bang nucleosynthesis. United States. doi:10.1051/epjconf/201714601008.
Paris, Mark W., Fuller, George M., Grohs, Evan Bradley, Kishimoto, Chad, and Vlasenko, Alexey. 2017. "Constraining nuclear data via cosmological observations: Neutrino energy transport and big bang nucleosynthesis". United States. doi:10.1051/epjconf/201714601008. https://www.osti.gov/servlets/purl/1412854.
@article{osti_1412854,
title = {Constraining nuclear data via cosmological observations: Neutrino energy transport and big bang nucleosynthesis},
author = {Paris, Mark W. and Fuller, George M. and Grohs, Evan Bradley and Kishimoto, Chad and Vlasenko, Alexey},
abstractNote = {Here, we introduce a new computational capability that moves toward a self-consistent calculation of neutrino transport and nuclear reactions for big bang nucleosynthesis (BBN). Such a self-consistent approach is needed to be able to extract detailed information about nuclear reactions and physics beyond the standard model from precision cosmological observations of primordial nuclides and the cosmic microwave background radiation. We also calculate the evolution of the early universe through the epochs of weak decoupling, weak freeze-out and big bang nucleosynthesis (BBN) by simultaneously coupling a full strong, electromagnetic, and weak nuclear reaction network with a multi-energy group Boltzmann neutrino energy transport scheme. The modular structure of our approach allows the dissection of the relative contributions of each process responsible for evolving the dynamics of the early universe. Such an approach allows a detailed account of the evolution of the active neutrino energy distribution functions alongside and self-consistently with the nuclear reactions and entropy/heat generation and flow between the neutrino and photon/electron/positron/baryon plasma components. Our calculations reveal nonlinear feedback in the time evolution of neutrino distribution functions and plasma thermodynamic conditions. We discuss the time development of neutrino spectral distortions and concomitant entropy production and extraction from the plasma. These effects result in changes in the computed values of the BBN deuterium and helium-4 yields that are on the order of a half-percent relative to a baseline standard BBN calculation with no neutrino transport. This is an order of magnitude larger effect than in previous estimates. For particular implementations of quantum corrections in plasma thermodynamics, our calculations show a 0.4% increase in deuterium and a 0.6% decrease in 4He over our baseline. The magnitude of these changes are on the order of uncertainties in the nuclear physics for the case of deuterium and are potentially significant for the error budget of helium in upcoming cosmological observations.},
doi = {10.1051/epjconf/201714601008},
journal = {EPJ Web of Conferences},
number = ,
volume = 146,
place = {United States},
year = 2017,
month = 9
}

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  • Cited by 8
  • In this study, we calculate the evolution of the early universe through the epochs of weak decoupling, weak freeze-out and big bang nucleosynthesis (BBN) by simultaneously coupling a full strong, electromagnetic, and weak nuclear reaction network with a multienergy group Boltzmann neutrino energy transport scheme. The modular structure of our code provides the ability to dissect the relative contributions of each process responsible for evolving the dynamics of the early universe in the absence of neutrino flavor oscillations. Such an approach allows a detailed accounting of the evolution of the νe, ν¯e, νμ, ν¯μ, ντ, ν¯τ energy distribution functions alongsidemore » and self-consistently with the nuclear reactions and entropy/heat generation and flow between the neutrino and photon/electron/positron/baryon plasma components. This calculation reveals nonlinear feedback in the time evolution of neutrino distribution functions and plasma thermodynamic conditions (e.g., electron-positron pair densities), with implications for the phasing between scale factor and plasma temperature; the neutron-to-proton ratio; light-element abundance histories; and the cosmological parameter N eff. We find that our approach of following the time development of neutrino spectral distortions and concomitant entropy production and extraction from the plasma results in changes in the computed value of the BBN deuterium yield. For example, for particular implementations of quantum corrections in plasma thermodynamics, our calculations show a 0.4% increase in deuterium. These changes are potentially significant in the context of anticipated improvements in observational and nuclear physics uncertainties.« less
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