Probing Nuclear Effects at the T2K Near Detector Using Single-Transverse Kinematic Imbalance

TL;DR

This paper demonstrates that measuring single-transverse kinematic imbalance at the T2K near detector can effectively distinguish nuclear effects like 2p-2h interactions from other model variations, aiding precision neutrino oscillation studies.

Contribution

It introduces a method to use STKI measurements at ND280 to differentiate nuclear interaction models, including 2p-2h effects, with simulated data.

Findings

STKI can distinguish 2p-2h interactions from other effects.

Fake data shows strong separation potential between nuclear models.

Method enhances understanding of nuclear effects in neutrino scattering.

Abstract

In order to make precision measurements of neutrino oscillations using few-GeV neutrino beams a detailed understanding of nuclear effects in neutrino scattering is essential. Recent studies have revealed that single-transverse kinematic imbalance (STKI), defined in the plane transverse to an incoming neutrino beam, can act as a unique probe of these nuclear effects. This work first illustrates that an exclusive measurement of STKI at the off-axis near detector of the T2K experiment (ND280) is expected distinguish the presence of interactions with two nucleons producing two holes (2p-2h) from alterations of the predominant underlying cross-section parameter ($M_A$ - the nucleon axial mass). Such a measurement is then demonstrated with fake data, showing substantial nuclear model separation potential.