Photoproduction of possible pentaquark states $\Lambda^0_b(5912)$ and $\Lambda^0_b(5920)$ in the $\gamma{}p\to{}\Lambda_b^{0(*)}B^+$ reactions

TL;DR

This paper presents a theoretical study predicting the production cross sections of potential pentaquark states $\\Lambda_b^0(5912)$ and $\\\Lambda_b^0(5920)$ in photon-proton reactions, suggesting future experiments could confirm their molecular pentaquark nature.

Contribution

The work introduces a chiral unitary theory-based approach to dynamically generate and analyze the production of pentaquark states in photon-proton collisions, providing specific cross section predictions.

Findings

Predicted cross sections are approximately 0.0164 nb and 0.00527 nb for the two states.

Angular distribution features can help test the molecular pentaquark hypothesis.

Future experiments like EicC and US-EIC can verify these predictions.

Abstract

In this work, we report on a theoretical study of possible pentaquark states $\Lambda^0_b(5912)$ and $\Lambda^0_b(5920)$ in the $\gamma{}p\to{}\Lambda_b^{0(*)}B^+$ reactions within an effective Lagrangian approach. In addition to the contributions from the $s$-channel nucleon pole and $t$-channel $\bar{B}^{{*}-}$ exchange, the contact term contribution are also included. Our theoretical approach is based on the chiral unitary theory where the $\Lambda^0_b(5912)$ and $\Lambda^0_b(5920)$ resonances are dynamically generated. Within the coupling constants of the $\Lambda^0_b(5912)$ and $\Lambda^0_b(5920)$ to $\bar{B}p$ and $\bar{B}^{*}p$ channels obtained from chiral unitary theory, the total and differential cross sections of the $\gamma{}p\to{}\Lambda_b^{0(*)}B^+$ are evaluated. Our calculation indicates that the cross section for $\gamma{}p\to{}\Lambda_b^{0}(5912)B^{+}$ and $\gamma{}p\to{}\Lambda_b^{0}(5920)B^{+}$ reactions are of the order of 0.0164 nb and 0.00527 nb,respectively. If measured in future experiments, such as Electron-Ion Collider in China (EicC) or US(US-EIC), the predicted total cross sections and specific features of the angular distributions can be used to test the (molecular) nature of the $\Lambda^0_b(5912)$ and $\Lambda^0_b(5920)$ that they may be pentaquark states.