Revealing neutrino nature and $CPT$ violation with decoherence effects

Abstract

We study decoherence effects on mixing among three generations of neutrinos. We show that in presence of a non-diagonal dissipation matrix, both Dirac and Majorana neutrinos can violate the CP T symmetry and the oscillation formulae depend on the parametrization of the mixing matrix. We reveal the CP violation in the transitions preserving the flavor, for a certain form of the dissipator. In particular, the CP violation affects all the transitions in the case of Majorana neutrinos, unlike Dirac neutrinos which still preserve the CP symmetry in one of the transitions flavor preserving. This theoretical result shows that decoherence effects, if exist for neutrinos, could allow to determine the neutrino nature and to test fundamental symmetries of physics. Next long baseline experiments could allow such an analysis. We relate our study with experiments by using the characteristic parameters and the constraints on the elements of the dissipation matrix of current experiments.

Neutrino signals of lightcone fluctuations resulting from fluctuating space-time

“…Neutrino decoherence is often represented using an open quantum system formalism [24,29,30,[36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] considering both the neutrino and its environment. The stochastic processes we consider in this work cause our knowledge of the neutrino to degrade over time, which in the language of open quantum systems constitutes the evolution from an initially pure quantum state to a mixed quantum state.…”

Particle mixing and the emergence of classicality: A spontaneous-collapse-model view

“…where, as in (49), the upper sign corresponds to the normal mass ratio while the lower sign fixes the inverted mass ratio. On Fig.…”

“…Particular attention is attracted to the analysis of the possible effects of a spontaneous collapse in the oscillations at high energies. Mixed systems propose some peculiar features, which have stimulated high interest in these systems as a rich playground for testing the very foundations of quantum mechanics [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. For example, the beauty of the neutral K-meson systems, whose relevant states measured in experiments are superpositions of states with distinct masses, is that they reveal a parallel with the spin- 1 2 particles and photons.…”

“…In particular, it can govern dissipative and decoherence effects in flavor mixing, which can be signals for new physics. For example, decoherence in neutrino oscillations can reveal the difference between Dirac and Majorana neutrinos and, moreover, break up the CPT symmetry [44,49].…”

Neutrino decoherence from quantum gravitational stochastic perturbations

“…We then demonstrate how the derived phenomena can be represented in the framework of open quantum systems, which is commonly employed in experimental neutrino decoherence searches [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. This framework is very general, making constraints on the parameters of the open quantum system difficult to physically interpret.…”