Progress and Opportunities in Backward angle (u-channel) Physics

TL;DR

This paper reviews recent advances and future prospects in backward angle (u-channel) scattering, highlighting its importance for hadron spectroscopy and the need for further experimental and theoretical exploration.

Contribution

It summarizes recent progress in u-channel scattering studies, including experimental measurements and theoretical models, and outlines future research directions and challenges.

Findings

Progress in high energy baryon charge exchange measurements

Comparison of hadronic models and collinear factorization approaches

Identification of key questions and challenges for future u-channel research

Abstract

Backward angle (u-channel) scattering provides complementary information for studies of hadron spectroscopy and structure, but has been less comprehensively studied than the corresponding forward angle case. As a result, the physics of u-channel scattering poses a range of new experimental and theoretical opportunities and questions. We summarize recent progress in measuring and understanding high energy reactions with baryon charge exchange in the u-channel, as discussed in the first backward angle (u-channel) Physics Workshop. In particular, we discuss backward angle measurements and their theoretical description via both hadronic models and the collinear factorization approach, and discuss planned future measurements of u-channel physics. Finally, we propose outstanding questions and challenges for u-channel physics.