Speaker
Description
Hard exclusive pion production is a well established tool to study Generalized Parton Distributions (GPDs). During the last decade, extensive studies have been performed on hard exclusive $\pi^{0}$ and $\pi^{+}$ production off the proton. However, hard exclusive $\pi^{-}$ production off the proton is so far nearly unexplored. It can be described based on $N\rightarrow\Delta^{++}$ transition GPDs which can help us to gain insights into the 3D structure of the p to Δ transition. The talk will present a study of the polarized cross section ratio $\sigma_{LT’}/\sigma_0$ from hard exclusive $\pi^{-}$ electro-production off an un-polarized hydrogen target in the forward kinematic regime ($-t/Q^2$ << 1) based on beam-spin asymmetry measurements with CLAS12 at JLAB. The results will be compared to previous studies on hard exclusive $\pi^{0}$ and $\pi^{+}$ production, which show an opposite sign of the cross section ratio, and discussed in the context of a GPD and transition GPD based description.
| Submitted on behalf of a Collaboration? | Yes |
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