$\bar{K} + N \to K + \Xi$ reaction and $S=-1$ hyperon resonances

Understand

The $\bar{K} + N \to K + \Xi$ reaction is studied for center-of-momentum energies ranging from threshold to 3 GeV in an effective Lagrangian approach that includes the hyperon $s$- and $u$-channel contributions as well as a phenomenological contact amplitude.

• The latter accounts for the rescattering term in the scattering equation and possible short-range dynamics not included explicitly in the model.
• Existing data are well reproduced and three above-the-threshold resonances were found to be required to describe the data, namely, the $\Lambda(1890)$, $\Sigma(2030)$, and $\Sigma(2250)$.
• For the latter resonance we have assumed the spin-parity of $J^P=5/2^-$ and a mass of 2265 MeV.