2021/08/03 by N. Rijneveen, Rijneveen, N., A. M. Gasparyan +5 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Nuclear Theory (nucl-th) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2108.01619
openalex publication_date 2021/08/03 · openalex created_date 2024/04/11 · openalex updated_date 2026/07/28
We study the reaction of pion photoproduction on the nucleon in the framework of chiral perturbation theory with explicit Δ(1232) degrees of freedom. In the covariant approach, we give results up to order ε3 in the small scale expansion scheme. Furthermore, we provide Δ-less and Δ-full results obtained in the heavy-baryon scheme to analyze the differences to the covariant approach. Low energy constants are fitted to multipole amplitudes using theoretical truncation errors estimated by a Bayesian approach. We also compare our findings to data of neutral pion production cross sections and polarization asymmetries. The description of the reaction is clearly improved by the explicit treatment of the Δ(1232) resonance.