Maximum Entropy Inferences on the Axion Mass in Models with Axion-Neutrino Interaction

In this work, we use the maximum entropy principle (MEP) to infer the mass of an axion which interacts to photons and neutrinos in an effective low energy theory. The Shannon entropy function to be maximized is defined in terms of the axion branching ratios. We show that MEP strongly constrains the axion mass taking into account the current experimental bounds on the neutrinos masses. Assuming that the axion is massive enough to decay into all the three neutrinos and that MEP fixes all the free parameters of the model, the inferred axion mass is in the interval 0.1 eV < m(A) < 0.2 eV, which can be tested by forthcoming experiments such as IAXO. However, even in the case where MEP fixes just the axion mass and no other parameter, we found that 0.1 eV < m(A) < 6.3 eV in the DFSZ model with right-handed neutrinos. Moreover, a light axion, allowed to decay to photons and the lightest neutrino only, is determined by MEP as a viable dark matter candidate.CNPqFAPESPUniv Fed São Paulo, Dept Fis, UNIFESP, Diadema, BrazilUniv Fed ABC, Ctr Cincias Nat & Humanas, BR-09210170 Santo Andre, SP, BrazilUniv Fed Rio Grande do Sul, Inst Fis, BR-91501970 Porto Alegre, RS, BrazilUniv Fed São Paulo, Dept Fis, UNIFESP, Diadema, BrazilCNPq: 307098/2014-1CNPq: 306636/2016-6CNPq: 458498/2014-9CNPq: 310017/2015-7FAPESP: 2013/22079-8Web of Scienc