Quantum decoherence and relaxation in long-baseline neutrino data

TL;DR

This paper explores quantum decoherence effects in neutrino oscillations using MINOS and T2K data, applying open quantum system formalism to set bounds on decoherence parameters across different energy dependencies.

Contribution

It introduces a comprehensive analysis of quantum decoherence in neutrino oscillations with a unified formalism and provides the most stringent limit on decoherence parameters for specific energy dependencies.

Findings

Best limit on decoherence parameter for n = -2: 1.7 x 10^{-23} GeV

MINOS and T2K data show complementary sensitivities for different energy dependencies

Results are consistent across different decoherence scenarios

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 $\Gamma$. We assume an energy dependence parameterized by $\Gamma = \gamma_0 (E/\mbox{GeV})^n$, 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 $\sin^2 \theta_{13}$, and observe an independence of the results to the scenarios we investigate. As highlight of our analyses we obtain the best limit on $\gamma_0$ for the energy dependence of $n = -2$, reporting an upper bound of $1.7 \times 10^{-23}$~GeV, at the 90\% confidence level.