Phenomenology of MaVaN’s Models in Reactor Neutrino Data

Abstract

Mass Varying Neutrinos (MaVaN’s) mechanisms were proposed to link the neutrino mass scale with the dark energy density, addressing the coincidence problem. In some scenarios, this mass can present a dependence on the baryonic density felt by neutrinos, creating an effective neutrino mass that depends both on the neutrino and baryonic densities. In this work, we study the phenomenological consequence of MaVaN’s scenarios in which the matter density dependence is induced by Yukawa interactions of a light neutral scalar particle which couples to neutrinos and matter. Under the assumption of one mass scale dominance, we perform an analysis of KamLAND neutrino data which depends on 4 parameters: the two standard oscillation parameters,Δm0,212andtan2θ12, and two new coefficients which parameterize the environment dependence of neutrino mass. We introduce an Earth’s crust model to compute precisely the density in each point along the neutrino trajectory. We show that this new description of density does not affect the analysis with the standard model case. With the MaVaN model, we observe a first order effect in lower density, which leads to an improvement on the data description.

Searching for a nondiagonal mass varying mechanism in theνμ−ντsystem

“…(4), and the phase of the oscillations, proportional to (∆m 2 ) eff , have now a matter density dependence. This was the case mostly worked in the literature [16][17][18][19][20][21][22][23]. The latter case, the Hamiltonian in the mass basis is non-diagonal and for our knowledge it was not explored in the literature for atmospheric neutrino phenomenology.…”

“…(4) Most of the previous analysis of MaVaN works for the first two generations [16][17][18][19][20][21] and then theirs constrains are related to parameters of the first generation α 1 , α 2 and α 12 similar to the parameters defined in Eq. (7).…”

“…As an example e will use in this work the MaVaN density dependence as used in Ref. [19,21], given by…”

“…For the neutrino phenomenology the consequences of MaVaN's were studied for the solar and atmospheric neutrinos [16][17][18][19][20][21][22][23]. We will use the data from Super-Kamiokande (SK for now) experiment [23].…”