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

Understand

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.