Abstract
We point out that the cosmological abundance of can be reduced down to observed values if during its formation, big bang nucleosynthesis is modified by the presence of light electrically neutral particles that have substantial interactions with nucleons. We find that the lithium problem can be solved without affecting the precisely measured abundances of deuterium and helium if the following conditions are satisfied: the mass (energy) and lifetimes of such particles are bounded by and , and the abundance times the absorption cross section by either deuterium or are comparable to the Hubble rate, , at the time of formation. We include -initiated reactions into the primordial nucleosynthesis framework, observe that it leads to a substantial reduction of the freeze-out abundances of , and find specific model realizations of this scenario. Concentrating on the axionlike-particle case, , we show that all these conditions can be satisfied if the coupling to quarks is in the range of , which can be probed at intensity frontier experiments.
- Received 13 November 2015
DOI:https://doi.org/10.1103/PhysRevLett.116.211303
© 2016 American Physical Society
Physics Subject Headings (PhySH)
Synopsis
Lightweight Particles Might Explain Missing Lithium
Published 25 May 2016
The apparent lack of lithium in the Universe, relative to theoretical expectations, could be explained by hypothetical lightweight and electrically neutral particles.
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