1,007 research outputs found
String Theory and the Dark Glueball Problem
We study cosmological constraints on dark pure Yang-Mills sectors. Dark
glueballs are overproduced for large regions of ultraviolet parameter space.
The problem may be alleviated in two ways: via a large preferential reheating
into the visible sector, motivating certain inflation or modulus decay models,
or via decays into axions or moduli, which are strongly constrained by
nucleosynthesis and bounds. String models frequently
have multiple hidden Yang-Mills sectors, which are subject to even stronger
constraints due to the existence of multiple dark glueballs.Comment: 10 page
Dark Glueballs and their Ultralight Axions
Dark gauge sectors and axions are well-motivated in string theory. We
demonstrate that if a confining gauge sector gives rise to dark glueballs that
are a fraction of the dark matter, and the associated axion has a decay
constant near the string scale, then this axion is ultralight and naturally
realizes the fuzzy dark matter scenario with a modest tuning of a temperature
ratio. Astrophysical observations constrain the size of the glueball component
relative to the axionic component, while electric dipole moments constrain
mixing with the QCD axion.Comment: 8 pages, 2 figure
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