Exclusive Hard Processes for Studying Hadron Structures at J-PARC

TL;DR

This paper discusses how exclusive hard processes at J-PARC can reveal detailed quark-gluon structures of hadrons, including exotic states and nucleon GPDs, using high-energy meson beams and perturbative QCD.

Contribution

It proposes new experimental approaches at J-PARC to study hadron structures through exclusive processes, combining theoretical foundations with practical measurement strategies.

Findings

Potential to access internal quark structures of exotic hadrons.

Methodology for measuring nucleon GPDs via pion-induced Drell-Yan.

Feasibility of using 10-20 GeV meson beams for these studies.

Abstract

With an appropriate hard scale, exclusive hadronic processes could provide novel information of the internal quark-gluon configurations of hadrons. The availability of 10-20 GeV secondary meson beam in the coming high-momentum beam line of Hadron Hall at J-PARC offers an unique opportunity to carry out the measurements of the exclusive hard processes. We address this interesting approach by two possibilities: (a) $\pi^- p \to K^0 \Lambda(1405)$ for the constituent quark structure of $\Lambda(1405)$, and (b) exclusive pion-induced Drell-Yan process $\pi^- p \to \gamma^* n \to l^+ l^- n$ for the generalized parton distributions (GPDs) of nucleons. Realization of such measurements at J-PARC will open up a new way of accessing the internal quark structure of exotic hadrons and also the nucleon GPDs based on a solid theoretical foundation of perturbative QCD.