Abstract
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 ($w\ensuremath{\equiv}1$), 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, $w\ensuremath{\approx}0.6\ifmmode\pm\else\textpm\fi{}0.2$. 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 $\ensuremath{\approx}15(1\ensuremath{-}w)$. Radical changes in astrophysical behavior seem to require changes in $w$ of more than a few percent, even for the most sensitive phenomena.
Submitted Version (
Free)
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
