Regge signatures from forward CLAS $\Lambda(1520)$ photoproduction data

TL;DR

This paper models the $ ext{γ} p o K^+ ext{Λ}(1520)$ reaction using a Regge-effective Lagrangian approach, successfully describing data across a wide energy range and suggesting possible quark-gluon string effects at higher energies.

Contribution

It introduces a Regge trajectory exchange in the t-channel to improve the description of Λ(1520) photoproduction data across all energies and angles.

Findings

Successful description of CLAS and LEPS data at low to moderate energies.

Discrepancies at high energies and forward angles suggest additional mechanisms.

Inclusion of Regge trajectories enhances the model's accuracy.

Abstract

The $\gamma p \to K^+ \Lambda(1520)$ reaction mechanism is investigated within a Regge--effective Lagrangian hybrid approach based on our previous study of this reaction [Physical Review C89, 015203 (2014)]. Near threshold and for large $K^+$ angles, both the CLAS and LEPS data can be successfully described by considering the contributions from the contact, $t$-channel $\bar K$ exchange, $u$-channel $\Lambda(1115)$ hyperon pole, and the $s$-channel nucleon pole and $N^*(2120)$ resonance contributions. However, for higher energies and forward $K^+$ angles, systematic discrepancies with data appear, which hint the possible existence of sizable quark-gluon string mechanism effects. We show how the inclusion of a $\bar K$ Regge--trajectory exchange in the $t$-channel leads to an efficient description of the $\Lambda(1520)$ photoproduction channel over the whole energy and angular ranges accessible in the CLAS experiment.