Regge signatures from forward CLAS $Λ(1520)$ photoproduction data

Abstract

The $γp \to K^+ Λ(1520)$ 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 $Λ(1115)$ 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 $Λ(1520)$ photoproduction channel over the whole energy and angular ranges accessible in the CLAS experiment.

11 pages, 3 figures