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Title: Nucleosynthesis in the presence of primordial isocurvature baryon fluctuations

Abstract

We study big bang nucleosynthesis in the presence of large mass scale, nonlinear entropy fluctuations. Overdense regions, with masses above the local baryon Jeans mass, are expected to collapse and form condensed objects. Surviving nucleosynthesis products therefore tend to originate from underdense regions. We compute expected survival light-element ({sup 2}H, {sup 3}He, {sup 4}He, and {sup 7}Li) abundance yields for a variety of stochastic fluctuation spectra. In general, we find that spectra with significant power in fluctuations on mass scales below that of the local baryon Jeans mass ({approximately}10{sup 5} {ital M}{sub {circle_dot}}) produce nucleosynthesis yields which are in conflict with observationally inferred primordial abundances. Only when this small-scale structure is absent or suppressed, and the collapse efficiency of overdense regions is high, can there exist a range of fluctuation spectral characteristics which conceivably could meet all primordial abundance constraints. Even then, the primordial abundance of {sup 7}Li would have to be larger than {sup 7}Li/H{approx_equal}3{times}10{sup {minus}10}. In such models, abundance constraints could be met even when the precollapse baryonic fraction of the closure density is {Omega}{sub {ital b}}{approx_equal}0.2 {ital h}{sup {minus}2} ({ital h} is the Hubble parameter in units of 100 kms{sup {minus}1} Mpc{sup {minus}1}). Nucleosynthesis in these modelsmore » is characterized by high {sup 2}H/H and low {sup 4}He mass fraction relative to a homogeneous big bang at a given value of {Omega}{sub {ital b}} {ital h}{sup 2}. A potentially observable signature of these models is the production of intrinsic primordial abundance variations on baryon mass scales up to 10{sup 10}{minus}10{sup 12} {ital M}{sub {circle_dot}}. {copyright} {ital 1995 The American Astronomical Society.}« less

Authors:
 [1];  [2]
  1. Physics Research Program, Institute for Geophysics and Planetary Physics, University of California, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
  2. Department of Physics, University of California, San Diego, La Jolla, California 92093-0319 (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
281997
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 452; Journal Issue: 1; Other Information: PBD: Oct 1995
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; COSMOLOGICAL MODELS; NUCLEOSYNTHESIS; DEUTERIUM; HELIUM 3; HELIUM 4; LITHIUM 7; BARYONS; LIMITING VALUES; COSMOLOGY; ELEMENT ABUNDANCE; ENTROPY; FLUCTUATIONS; UNIVERSE; BIG BANG; EARLY UNIVERSE; LARGE-SCALE STRUCTURE

Citation Formats

Jedamzik, K, and Fuller, G M. Nucleosynthesis in the presence of primordial isocurvature baryon fluctuations. United States: N. p., 1995. Web. doi:10.1086/176278.
Jedamzik, K, & Fuller, G M. Nucleosynthesis in the presence of primordial isocurvature baryon fluctuations. United States. https://doi.org/10.1086/176278
Jedamzik, K, and Fuller, G M. 1995. "Nucleosynthesis in the presence of primordial isocurvature baryon fluctuations". United States. https://doi.org/10.1086/176278.
@article{osti_281997,
title = {Nucleosynthesis in the presence of primordial isocurvature baryon fluctuations},
author = {Jedamzik, K and Fuller, G M},
abstractNote = {We study big bang nucleosynthesis in the presence of large mass scale, nonlinear entropy fluctuations. Overdense regions, with masses above the local baryon Jeans mass, are expected to collapse and form condensed objects. Surviving nucleosynthesis products therefore tend to originate from underdense regions. We compute expected survival light-element ({sup 2}H, {sup 3}He, {sup 4}He, and {sup 7}Li) abundance yields for a variety of stochastic fluctuation spectra. In general, we find that spectra with significant power in fluctuations on mass scales below that of the local baryon Jeans mass ({approximately}10{sup 5} {ital M}{sub {circle_dot}}) produce nucleosynthesis yields which are in conflict with observationally inferred primordial abundances. Only when this small-scale structure is absent or suppressed, and the collapse efficiency of overdense regions is high, can there exist a range of fluctuation spectral characteristics which conceivably could meet all primordial abundance constraints. Even then, the primordial abundance of {sup 7}Li would have to be larger than {sup 7}Li/H{approx_equal}3{times}10{sup {minus}10}. In such models, abundance constraints could be met even when the precollapse baryonic fraction of the closure density is {Omega}{sub {ital b}}{approx_equal}0.2 {ital h}{sup {minus}2} ({ital h} is the Hubble parameter in units of 100 kms{sup {minus}1} Mpc{sup {minus}1}). Nucleosynthesis in these models is characterized by high {sup 2}H/H and low {sup 4}He mass fraction relative to a homogeneous big bang at a given value of {Omega}{sub {ital b}} {ital h}{sup 2}. A potentially observable signature of these models is the production of intrinsic primordial abundance variations on baryon mass scales up to 10{sup 10}{minus}10{sup 12} {ital M}{sub {circle_dot}}. {copyright} {ital 1995 The American Astronomical Society.}},
doi = {10.1086/176278},
url = {https://www.osti.gov/biblio/281997}, journal = {Astrophysical Journal},
number = 1,
volume = 452,
place = {United States},
year = {Sun Oct 01 00:00:00 EDT 1995},
month = {Sun Oct 01 00:00:00 EDT 1995}
}