Neutrino CP Measurement in the Presence of RG Running with Mismatched Momentum Transfers

TL;DR

This paper investigates how mismatched momentum transfers at neutrino production and detection, combined with RG running effects, influence oscillation probabilities and the measurement of the CP phase, proposing a method to constrain these effects.

Contribution

It introduces a two-dimensional analysis method to account for energy and momentum transfer dependencies in neutrino oscillation experiments, enhancing CP measurement sensitivity.

Findings

Mismatched momentum transfers modify oscillation probabilities.

RG running effects can significantly impact CP phase sensitivity.

Combining long- and short-baseline experiments improves constraints.

Abstract

The neutrino mixing parameters are expected to have RG running effect in the presence of new physics. If the momentum transfers at production and detection mismatch with each other, the oscillation probabilities are generally modified and become dependent on not just the neutrino energy but also the momentum transfer. Even in the limit of vanishing baseline, the transition probability for the appearance channel is interestingly not zero. This would significantly affect the sensitivity of the genuine leptonic Dirac CP phase. We further explore the possibility of combing the long- and short-baseline neutrino experiments to constrain such RG running effect for the purpose of guaranteeing the CP measurement. To simulate the double dependence on the neutrino energy and momentum transfer, we extend the usual GLoBES simulation of fixed baseline experiments and use a two-dimensional $\chi^2$ analysis to obtain sensitivities.