Generalized parton distributions from neutrino experiments

TL;DR

This paper extends the analysis of deeply virtual meson production to neutrino experiments, incorporating electromagnetic corrections and expressing cross-sections in terms of proton GPDs, with implications for future experimental tests.

Contribution

It introduces a framework for analyzing neutrino-induced meson production using GPDs, including electromagnetic corrections, and assesses their significance at high Q^2.

Findings

Electromagnetic corrections decrease less rapidly with Q^2 than standard VMP contributions.

Electromagnetic effects induce angular correlations sensitive to the real and imaginary parts of the amplitude.

Corrections are a few percent at Fermilab's MINERvA kinematics and comparable to VMP at Q^2100 GeV^2.

Abstract

The analysis of deeply virtual meson production is extended to neutrino-production of the pseudo-Goldstone mesons (pions, kaons, eta-mesons) on nucleons, with the flavor content of the recoil baryon either preserved, or changed to a hyperon from the same SU(3) octet. We rely on the SU(3) relations and express all the cross-sections in terms of the proton generalized parton distributions (GPDs). The corresponding amplitudes are calculated at the leading twist level and in the leading order in \alpha_{s}, using a phenomenological parametrization of GPDs. We also included in the analysis the electromagnetic O(alpha_{em})-corrections to neutrino-induced deeply virtual meson production (\nuDVMP). We found that such electromagnetic corrections decrease with Q^2 in the Bjorken regime less than the standard \nuDVMP handbag contribution, so the electromagnetic mechanism dominates at large Q^2. The electromagnetic corrections give rise to an angular correlation between the lepton and hadron scattering planes with harmonics sensitive to the real and imaginary parts of the DVMP amplitude. These corrections constitute a few percent effect in the kinematics of the forthcoming MINERvA experiment at Fermilab and should be taken into account in precise tests of GPD parametrizations. For virtualities Q^2~100 GeV^2 these corrections become on a par with \nuDVMP handbag contributions.