Polarization of Λ(1405) in the γp → K+πΣ reaction

Abstract

In this paper, we study the polarization of the Λ(1405) in the γp→K+πΣ reaction within an effective Lagrangian approach and isobar model. In our model, the Λ(1405) is excited through the t-channel K/K⁎ exchanges and u-channel hyperon exchange. Compared to previous studies, we also include the contribution from a contact term, which is necessary for our model to interpret the polarization of the Λ(1405). In addition, we also discuss the possibility to verify the proposed two-pole structure of the Λ(1405) using the polarization data. We find that the polarization of the Λ(1405) or the polarization of the final Σ in this reaction is sensitive to the invariant mass MπΣ. Thus the measurement of the dependence of the Λ(1405) polarization on the MπΣ can offer valuable information about the pole structure of the Λ(1405).