Neutral-current weak pion production off the nucleon in covariant chiral perturbation theory

De-Liang Yao,Luis Alvarez-Ruso,M.J Vicente Vacas

doi:10.1016/j.physletb.2019.05.036

Abstract

Neutral current single pion production induced by neutrinos and antineutrinos on nucleon targets has been investigated in manifestly relativistic baryon chiral perturbation theory with explicit Δ(1232) degrees of freedom up to O(p3). At low energies, where chiral perturbation theory is applicable, the total cross sections for the different reaction channels exhibit a sizable non-resonant contribution, which is not present in event generators of broad use in neutrino oscillation and cross section experiments such as GENIE and NuWro.

Highlights

In recent years, more precise measurements of neutrino cross sections have been achieved, and more experiments are still ongoing or planned to enrich the wealth of data for a better determination of the mechanisms of neutrino interactions with matter
A better understanding of neutrino interactions with nucleons and nuclei is of particular importance to achieve the precision goals of modern neutrino-oscillation experiments [2, 3]
Neutrino- and antineutrino-induced single pion production are among the dominant contributions to the inclusiveneutrino-nucleus cross section in the relevant energy regime of several experiments

Summary

INTRODUCTION

More precise measurements of neutrino cross sections have been achieved, and more experiments are still ongoing or planned to enrich the wealth of data for a better determination of the mechanisms of neutrino interactions with matter (see for instance Ref. [1] and references therein). Weak single pion production off the nucleon has been extensively studied at intermediate energies with various phenomenological models. A well founded low-energy model for chargedcurrent (CC) weak single pion production off the nucleon has been developed in Ref. We extend the study to the neutralcurrent reactions For this purpose, new isoscalar amplitudes, not present in the CC case and involving three distinctive low-energy constants (LECs), need to be computed. Following a general description of the electroweak amplitude for NC weak pion production on the nucleon, the external currents and the relevant terms of the chiral Lagrangian are introduced. Numerical results for integrated cross sections at low energies are presented in comparison to the output of neutrino event generators and phenomenological models

NEUTRAL-CURRENT SINGLE PION PRODUCTION

HADRONIC AMPLITUDES FROM CHPT

TOTAL CROSS SECTION AND NUMERICAL RESULTS

SUMMARY