Lambda(1405,1/2^-) photoproduction from the gamma p -> K^+ Lambda(1405) reaction

TL;DR

This study models the photoproduction of Lambda(1405) off protons, revealing cross section behaviors near threshold and suggesting s-channel dominance, aligning with recent experimental observations.

Contribution

It provides a theoretical analysis of Lambda(1405) photoproduction using effective Lagrangian methods, highlighting the impact of coupling strength choices on cross sections.

Findings

Cross section near threshold is 0.1 to 0.2 microbarns.

Cross section decreases beyond 1.6 GeV photon energy.

Energy dependence matches recent experimental data.

Abstract

We investigate the photoproduction of Lambda(1405,1/2^-) = Lambda* off the proton target using the effective Lagrangian in the Born approximation. We observed that, depending on the choice of the K* N Lambda* coupling strength, the total cross section becomes 0.1 <~ sigma_Lambda* <~ 0.2 mu b near the threshold and starts to decrease beyond E_gamma ~ 1.6 GeV, and the angular dependence shows a mild enhancement in the forward direction. It turns out that the energy dependence of the total cross section is similar to that shown in the recent LEPS experiment. This suggests that the production mechanism of the Lambda* is dominated by the s-channel contribution.