Photo-production of lowest ${\Sigma }_{1/2^{-}}^{\ast }$ state within the Regge-effective Lagrangian approach

Abstract

Since the lowest ${\Sigma }^{\ast }$ state, with quantum numbers spin-parity $J^P=1/2^{-}$, is far from established experimentally and theoretically, we have performed a theoretical study on the ${\Sigma }_{1/2^{-}}^{\ast }$ photo-production within the Regge-effective Lagrangian approach. Taking into account that the ${\Sigma }_{1/2^{-}}^{\ast }$ couples to the $\bar{K}N$ channel, we have considered the contributions from the $t$-channel $K$ exchange diagram. Moreover, these contributions from $t$-channel $K^{\ast }$ exchange, $s$-channel nucleon pole, $u$-channel $\Sigma$ exchange, and the contact term, are considered. The differential and total cross sections of the process $\gamma n\to K^{+}{\Sigma }_{1/2^{-}}^{\ast -}$ are predicted with our model parameters. The results should be helpful to search for the ${\Sigma }_{1/2^{-}}^{\ast }$ state experimentally in future.

Comments: 7 pages, 4 figures