Missing energy and the measurement of the CP-violating phase in neutrino oscillations

TL;DR

This paper investigates how missing energy due to undetected particles impacts the measurement of the CP-violating phase in neutrino oscillation experiments, emphasizing the need for accurate energy correction to avoid bias.

Contribution

It analyzes the effect of realistic detector capabilities on $\, ext{δ}_{CP}$ sensitivity, highlighting the importance of correcting missing energy with high accuracy.

Findings

Missing energy significantly affects $\, ext{δ}_{CP}$ measurement.

Energy correction accuracy must exceed 20% to prevent bias.

Realistic detector effects are crucial for future neutrino experiments.

Abstract

In the next generation of long-baseline neutrino oscillation experiments, aiming to determine the charge-parity violating phase $\delta_{CP}$ in the appearance channel, fine-grained time-projection chambers are expected to play an important role. In this Letter, we analyze an influence of realistic detector capabilities on the $\delta_{CP}$ sensitivity for a setup similar to that of the Deep Underground Neutrino Experiment. We find that the effect of the missing energy, carried out by undetected particles, is sizable. Although the reconstructed neutrino energy can be corrected for the missing energy, the accuracy of such procedure has to exceed 20\%, to avoid a sizable bias in the extracted $\delta_{CP}$ value.