We revisit a singlet Majoron model in which neutrino masses arise from the spontaneous violation of lepton number. If the Majoron obtains a mass of order MeV, it can play the role of dark matter. We discuss constraints on the couplings of the massive Majoron to neutrinos from supernova data and from neutrinoless double beta decay with Majoron emission. The combination of both constraints...
The impact of massive neutrinos on cosmological observables comes from a very peculiar effect: light massive neutrinos behave as radiation before their non-relativistic transition, while afterwards they gradually become a matter component. For that reason, combination of high- and low- redshift probes can provide very tight, yet model dependent, constraints on the neutrino mass sum. In this...
Motivated by recent interest in the connection between axions and flavour, we investigate a generic, generation-dependent U(1) quark flavour symmetry, with emphasis on achieving maximal reduction in the number of free Yukawa parameters. We find that there are only two inequivalent Yukawa textures, each one giving rise to six physically distinct models. The U(1) symmetries that generate these...