# Double Polarization Observables in Pentaquark Photoproduction

## TL;DR

This paper explores polarization observables in J/psi photoproduction to understand the properties of hidden charm pentaquarks, providing predictions for upcoming experiments at Jefferson Lab.

## Contribution

It introduces the first estimates of polarization transfer and helicity correlation sensitivities to pentaquark properties in exclusive photoproduction.

## Key findings

- Sensitivity estimates for polarization transfer KLL to pentaquark couplings.
- Predictions for initial state helicity correlation ALL in polarized target experiments.
- Benchmark results for the SBS experiment at Jefferson Lab.

## Abstract

We investigate the properties of the hidden charm pentaquark-like resonances first observed by LHCb in 2015, by measuring the polarization transfer KLL between the incident photon and the outgoing proton in the exclusive photoproduction of J/psi near threshold. We present a first estimate of the sensitivity of this observable to the pentaquark photocouplings and hadronic branching ratios, and extend our predictions to the case of initial state helicity correlation ALL, using a polarized target. These results serve as a benchmark for the SBS experiment at Jefferson Lab, which proposes to measure for the first time the helicity correlations ALL and KLL in J/psi exclusive photoproduction, in order to determine the pentaquark photocouplings and branching ratios.