2020/09/30 by GlueX Collaboration, S. Adhikari, C. S. Akondi +148 · 8 citations
Physics and Astronomy · #Asymmetry #High-Energy Particle Collisions Research #Meson #Nuclear physics #Nucleon #Order (exchange) #Particle physics #Particle physics theoretical and experimental studies #Physics #Pion #Pseudoscalar #Pseudoscalar meson #Quantum Chromodynamics and Particle Interactions #hep-ex #nucl-ex
paper · pdf · doi:10.1103/physrevc.103.l022201
published in Physical Review C 103(2) (American Institute of Physics) · 7 pages, 5 figures
openalex created_date 2020/09/21 · arxiv created 2021/01/08 · openalex publication_date 2021/02/22 · arxiv updated 2021/03/03 · openalex updated_date 2026/08/05
We report a measurement of the \ensuremathπ^\ensuremath- photoproduction beam asymmetry for the reaction \stackrelP\ensuremathγp\ensuremath→\ensuremathπ^\ensuremath-\mathrm\ensuremathΔ++ using data from the GlueX experiment in the photon beam energy range 8.2--8.8 GeV. The asymmetry \mathrm\ensuremathΣ is measured as a function of four-momentum transfer t to the \mathrm\ensuremathΔ++ and compared to phenomenological models. We find that \mathrm\ensuremathΣ varies as a function of t: negative at smaller values and positive at higher values of |t|. The reaction can be described theoretically by t-channel particle exchange requiring pseudoscalar, vector, and tensor intermediaries. In particular, this reaction requires charge exchange, allowing us to probe pion exchange and the significance of higher-order corrections to one-pion exchange at low momentum transfer. Constraining production mechanisms of conventional mesons may aid in the search for and study of unconventional mesons. This is the first measurement of the process at this energy.