STRONG 2020 Workshop

 

STRONG 2020 (14-16 September - University of York) is included in the activities of the working package WP25 (Light-and heavy-quark hadron spectroscopy) of the project STRONG-2020. It has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 824093.

POSTER: SE  PWA for pion photoproduction with vfixed-t analyticity

The major topics of the workshop will cover:

1) Precision calculations in non-perturbative QCD: Effective Field Theories, analyticity, dispersion relations and Lattice QCD

2) Spectroscopy & Exotic states

3) Hadron Decays & Production

4) Form factors, LECs, fundamental parameters of QCD and light nuclei
spectroscopy

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Single-energy partial-wave analysis for pion photoproduction with fixed-t analyticity

Received 15 July 2021

Accepted 20 August 2021

DOI:https://doi.org/10.1103/PhysRevC.104.034605

©2021 American Physical Society

Abstract

Experimental data for pion photoproduction including differential cross sections and various polarization observables from four reaction channels, $\gamma p \rightarrow \pi^0 p$, $\gamma p \rightarrow \pi^+ n$, $\gamma n \rightarrow \pi^− p$, and $\gamma n \rightarrow \pi^0  n$, from threshold up to W= 2.2 GeV were used in order to perform a single-energy partial-wave analysis with minimal model dependence by imposing constraints from unitarity and fixed-t analyticity in an iterative procedure. Reaction models were only used as a starting point in the very first iteration. We demonstrate that with this procedure partial-wave amplitudes can be obtained which show only a minimal dependence on the initial model assumptions. The analysis was obtained in full isospin, and the Watson theorem is enforced for energies below W= 1.3 GeV but is even fulfilled up to W≈ 1.6 GeV in many partial waves. Electromagnetic multipoles $E_{ℓ\pm}$ and $M _{ℓ\pm}$ are presented and discussed for S, P, D, and F waves.

 

 

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