Experimental and Theoretical Results for Weak Charge Current Backward Proton Production

TL;DR

This paper combines experimental data and theoretical calculations to analyze backward proton production from deuteron break-up by high-energy neutrinos, highlighting the role of 6-quark clusters at high momenta.

Contribution

It provides new experimental data and models the contributions of two-nucleon and six-quark components in deuteron break-up, proposing signatures to distinguish these clusters.

Findings

6q clusters explain high momentum backward proton spectrum

6q component constitutes a few percent of deuteron normalization

6q contribution dominates above 300-400 MeV/c backward proton momentum

Abstract

In this paper, we do three things in the study of deuteron break-up by high energy neutrino beams. (1) We present previously unpublished data on neutrino induced backward protons from deuteron targets; (2) we calculate the contributions from both the two-nucleon (2N) and six-quark (6q) deuteron components, which depend upon the overall normalization of the part that is 6q; and (3) we suggest other signatures for distinguishing the 2N and 6q clusters. We conclude that the 6q cluster easily explains the shape of the high momentum backward proton spectrum, and its size is nicely explained if the amount of 6q is one or a few percent by normalization of the deuteron. There is a crossover, above which the 6q contribution is important or dominant, at 300--400 MeV/c backward proton momentum.