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

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 $N^{\ast }(2120)$ 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.

Comments: 11 pages, 3 figures