Quantum decoherence and relaxation in long-baseline neutrino data

Abstract

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 = γ0(E/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 sin2θ13, and observe an independence of the results to the scenarios we investigate. Our analyses obtain limits on γ0 based on long-baseline data for scenarios allowing or not relaxation. We improve some previous bounds on γ0 and outline which data (solar, reactor, atmospheric, long-baseline) determine the more stringent constraints for different scenarios and energy dependencies.