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de Salas, P. F., Lattanzi, M., Mangano, G., Miele, G., Pastor, S., & Pisanti, O. (2015). Bounds on very low reheating scenarios after Planck. Phys. Rev. D, 92(12), 123534–9pp.
Abstract: We consider the case of very low reheating scenarios [T-RH similar to O(MeV)] with a better calculation of the production of the relic neutrino background (with three-flavor oscillations). At 95% confidence level, a lower bound on the reheating temperature T-RH > 4.1 MeV is obtained from big bang nucleosynthesis, while T-RH > 4.7 MeV from Planck data (allowing neutrino masses to vary), the most stringent bound on the reheating temperature to date. Neutrino masses as large as 1 eV are possible for very low reheating temperatures.
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de Salas, P. F., Lineros, R. A., & Tortola, M. (2016). Neutrino propagation in the Galactic dark matter halo. Phys. Rev. D, 94(12), 123001–14pp.
Abstract: Neutrino oscillations are a widely observed and well-established phenomenon. It is also well known that deviations with respect to flavor conversion probabilities in vacuum arise due to neutrino interactions with matter. In this work, we analyze the impact of new interactions between neutrinos and the dark matter present in the Milky Way on the neutrino oscillation pattern. The dark matter-neutrino interaction is modeled by using an effective coupling proportional to the Fermi constant GF with no further restrictions on its flavor structure. For the galactic dark matter profile we consider a homogeneous distribution as well as several density profiles, estimating in all cases the size of the interaction required to get an observable effect at different neutrino energies. Our discussion is mainly focused in the PeV neutrino energy range, to be explored in observatories like IceCube and KM3NeT. The obtained results may be interpreted in terms of a light O(sub-eV-keV) or weakly interacting massive particlelike dark matter particle or as a new interaction with a mediator of O(sub-eV-keV) mass.
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Hagstotz, S., de Salas, P. F., Gariazzo, S., Pastor, S., Gerbino, M., Lattanzi, M., et al. (2021). Bounds on light sterile neutrino mass and mixing from cosmology and laboratory searches. Phys. Rev. D, 104(12), 123524–20pp.
Abstract: We present a consistent framework to set limits on properties of light sterile neutrinos coupled to all three active neutrinos using a combination of the latest cosmological data and terrestrial measurements from oscillations, beta-decay, and neutrinoless double-beta-decay (0 nu beta beta) experiments. We directly constrain the full 3 + 1 active-sterile mixing matrix elements vertical bar U-alpha 4 vertical bar(2) , with alpha is an element of (e,mu,tau), and the mass-squared splitting Delta m(41)(2) (math) m(4)(2) – m(1)(2). We find that results for a 3 + 1 case differ from previously studied 1 + 1 scenarios where the sterile is coupled to only one of the neutrinos, which is largely explained by parameter space volume effects. Limits on the mass splitting and the mixing matrix elements are currently dominated by the cosmological datasets. The exact results are slightly prior dependent, but we reliably find all matrix elements to be constrained below vertical bar U-alpha 4 vertical bar(2) less than or similar to 10(-3) . Short-baseline neutrino oscillation hints in favor of eV-scale sterile neutrinos arc in serious tension with these bounds, irrespective of prior assumptions. We also translate the bounds from the cosmological analysis into constraints on the parameters probed by laboratory searches, such as m(beta) or m(beta)(beta), the effective mass parameters probed by beta-decay and 0 nu beta beta searches, respectively. When allowing for mixing with a light sterile neutrino, cosmology leads to upper bounds of m(beta) < 0.09 eV and m(beta)(beta )< 0.07 eV at 95% CL, more stringent than the limits from current laboratory experiments.
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