Quantum decoherence and relaxation in long-baseline neutrino data
We investigate the effect of quantum decoherence and relaxation in neutrino oscillations using MINOS and T2K data. The formalism of open quantum systems is used to describe the interaction of a neutrino system with the environment, where the strength of the interaction is regulated by a decoherence parameter $Γ$. We assume an energy dependence parameterized by $Γ= γ_0 (E/\mbox{GeV})^n$, with $n=-2,0,+2$, and consider three different scenarios, allowing the investigation of the effect of relaxation and of constraining the solar and atmospheric sectors to the same decoherence parameter. The MINOS and T2K data present a complementary behavior, with regard to our theoretical model, resulting in a better sensitivity for $n = +2$ and $n = -2$, respectively. We perform a combined analyses of both experimental data, which also include a reactor constraint on $\sin^2 θ_{13}$, and observe an independence of the results to the scenarios we investigate. As highlight of our analyses we obtain the best limit on $γ_0$ for the energy dependence of $n = -2$, reporting an upper bound of $1.7 \times 10^{-23}$~GeV, at the 90\% confidence level.