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Axions with Variable Masses

Juan Garcia-Bellido
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Abstract

Axions with variable masses, in the context of a scalar--tensor gravity theory, give a large entropy production during the matter era. The subsequent axion dilution is proportional to their present energy density. Depending on the parameters ($β_I,β_V$) of the model, this dilution relaxes or even eludes the cosmological bound on the axion mass, therefore opening the so--called ``axion window".

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Juan Garcia-Bellido. 1992-05-19. Axions with Variable Masses. https://arxiv.org/abs/hep-ph/9205224

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