Measurement of spin-density matrix elements in ρ(770) production with a linearly polarized photon beam at Eγ=8.2-8.8 GeV

GlueX Collaboration

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The GlueX experiment at Jefferson Lab studies photoproduction of mesons using linearly polarized 8.5GeV photons impinging on a hydrogen target which is contained within a detector with near-complete coverage for charged and neutral particles. We present measurements of spin-density matrix elements for the photoproduction of the vector meson ρ(770). The statistical precision achieved exceeds that of previous experiments for polarized photoproduction in this energy range by orders of magnitude. We confirm a high degree of s-channel helicity conservation at small squared four-momentum transfer t and are able to extract the t dependence of natural- and unnatural-parity exchange contributions to the production process in detail. We confirm the dominance of natural-parity exchange over the full t range. We also find that helicity amplitudes in which the helicity of the incident photon and the photoproduced ρ(770) differ by two units are negligible for -t<0.5GeV2/c2.

Original languageEnglish
Article number055204
Number of pages15
JournalPhysical Review C
Issue number5
Publication statusPublished - 15 Nov 2023

Bibliographical note

Funding Information:
The analysis in this article was supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DOE Grant No. DE-FG02-87ER40315. The work of A.A. was supported by the DOE, Office of Science, Office of Nuclear Physics in the Early Career Program. We would like to acknowledge the outstanding efforts of the staff of the Accelerator and the Physics Divisions at Jefferson Lab that made the experiment possible. This work was also supported in part by the U.S. Department of Energy, the U.S. National Science Foundation, NSERC Canada, the German Research Foundation, GSI Helmholtzzentrum für Schwerionenforschung GmbH, the Russian Foundation for Basic Research, the UK Science and Technology Facilities Council, the Chilean Comisión Nacional de Investigación Científica y Tecnológica, the National Natural Science Foundation of China, and the China Scholarship Council. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177.

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