Single pion production in electron-nucleon interactions

M Kabirnezhad

doi:10.1103/physrevd.102.053009

Abstract

This paper presents an update to the MK model, which was developed to describe single pion production in neutrino-nucleon interactions. Originally the MK model used the helicity amplitudes and the hadronic current form-factors of the Rein and Sehgal model. The update includes a new definition for the helicity amplitudes in the first and second resonance regions, and new vector-current form factors. Fits to electron-proton scattering data were used to determine these vector-current form factors, and to assign errors to the constrained free parameters of the model.

Highlights

Neutrino interactions that produce a single pion in the final state are of critical importance to accelerator-based neutrino experiments
Single pion production (SPP) channels make up the largest fraction of the inclusive neutrinonucleus cross section in the 1–3 GeV neutrino energy region covered by most accelerator-based neutrino beams
It is important to note that the MK model can only predict a single pion in the final state, while the data are the measurements of one or more pions in the final state

Summary

INTRODUCTION

Neutrino interactions that produce a single pion in the final state are of critical importance to accelerator-based neutrino experiments. Models of the SPP cross section processes are required to accurately predict the number and topology of observed finalstate particles in neutrino interactions and to help establish the relationship between neutrino energy and energy deposition in a neutrino detector. The first generation of neutrino SPP models [2,3,4] was developed with the statistical uncertainties of contemporary datasets in mind and aimed for precision at the 10% level These models neglected contributions to the cross section or simplified the processes that were thought to contribute at the few percent level. Three distinct features are extracted from the data via fits: (1) the vector form factor of the resonances used in the resonant interaction model, (2) the nucleon form factors for the nonresonant interactions, and (3) the interference phases between resonant and nonresonant helicity amplitudes

UPDATE OF MK MODEL

MW ðk2

ANALYSIS OF ELECTRON-INDUCED EXCLUSIVE DATA

RESULTS

CONCLUSION