Muon-neutrino-induced charged current cross section without pions: Theoretical analysis

TL;DR

This paper presents a theoretical calculation of muon-neutrino charged current cross sections without pions, using quantum-kinetic transport theory, and compares results with T2K experimental data, emphasizing the role of 2p2h processes and pion reabsorption.

Contribution

It introduces a quantum-kinetic transport theory approach to calculate neutrino cross sections and provides detailed comparisons with experimental data, highlighting the significance of 2p2h processes and pion reabsorption.

Findings

2p2h processes are relevant at backward angles.

Theoretical uncertainties are within experimental errors.

Pion reabsorption is crucial at forward angles.

Abstract

We calculate the charged current cross sections obtained at the T2K near detector for $\nu_\mu$-induced events without pions in the final state. The method used is quantum-kinetic transport theory. Results are shown first, as a benchmark, for electron inclusive cross sections on $^{12}$C and $^{16}$O to be followed with a detailed comparison with the data measured by the T2K collaboration on C$_8$H$_8$ and H$_2$O targets. The contribution of 2p2h processes is found to be relevant mostly for backwards angles; their theoretical uncertainties are within the experimental uncertainties. Particular emphasis is then put on a discussion of events in which pions are first created, but then reabsorbed. Their contribution is found to be essential at forward angles.