Journal Article

FZJ-2021-02105

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Measurement of beam asymmetry for π − Δ + + photoproduction on the proton at E γ = 8.5 GeV

Adhikari, S. ; Akondi, C. S. ; Ali, H.FZJ* ; Amaryan, M. ; Asaturyan, A. ; Austregesilo, A. ; Baldwin, Z. ; Barbosa, F. ; Barlow, J. ; Barriga, E. ; Barsotti, R. ; Beattie, T. D. ; Berdnikov, V. V. ; Black, T. ; Boeglin, W. ; Briscoe, W. J. ; Britton, T. ; Brooks, W. K. ; Cannon, B. E. ; Chudakov, E. ; Cole, S. ; Cortes, O. ; Crede, V. ; Dalton, M. M. ; Daniels, T.FZJ* ; Deur, A. ; Dobbs, S. ; Dolgolenko, A. ; Dotel, R. ; Dugger, M. ; Dzhygadlo, R. ; Egiyan, H. ; Erbora, T. ; Ernst, A. ; Eugenio, P. ; Fanelli, C. ; Fegan, S. ; Fitches, J. ; Foda, A. M. ; Furletov, S. ; Gan, L. ; Gao, Y.FZJ* ; Gasparian, A. ; Gleason, C. ; Goetzen, K. ; Goryachev, V. S. ; Guo, L.FZJ* ; Hakobyan, H. ; Hamdi, A. ; Huber, G. M.FZJ* ; Hurley, A. ; Ireland, D. G. ; Ito, M. M. ; Jaegle, I. ; Jarvis, N. S. ; Jones, R. T.FZJ* ; Kakoyan, V. ; Kalicy, G. ; Kamel, M. ; Khachatryan, V. ; Khatchatryan, M. ; Kourkoumelis, C. ; Kuleshov, S. ; LaDuke, A. ; Larin, I. ; Lawrence, D. ; Lersch, D. I. ; Li, H.FZJ* ; Li, W.FZJ* ; Liu, B. ; Livingston, K. ; Lolos, G. J. ; Luckas, K.FZJ* ; Lyubovitskij, V. ; Mack, D.FZJ* ; Marukyan, H. ; Matveev, V. ; McCaughan, M. ; McCracken, M. ; McGinley, W. ; Meyer, C.FZJ* ; Miskimen, R. ; Mitchell, R. E. ; Mizutani, K. ; Neelamana, V. ; Nerling, F. ; Ng, L. ; Ostrovidov, A. I. ; Papandreou, Z. ; Paudel, C. ; Pauli, P. ; Pedroni, R. ; Pentchev, L. ; Peters, K. J. ; Phelps, W. ; Pooser, E. ; Reinhold, J. ; Ritchie, B. G. ; Ritman, J. (Corresponding author)FZJ* ; Rodriguez, G. ; Romanov, D. ; Romero, C. ; Salgado, C. ; Schadmand, S. ; Schertz, A. M. ; Schick, A.FZJ* ; Tichelbäcker, L.FZJ* ; Schwiening, J. ; Shen, X. ; Shepherd, M. R. ; Smith, A.FZJ* ; Smith, E. S. ; Sober, D. I. ; Somov, A. ; Somov, S. ; Soto, O. ; Stevens, J. R. ; Strakovsky, I. I. ; Sumner, B. ; Suresh, K. ; Tarasov, V. V. ; Taylor, S. ; Teymurazyan, A. ; Thiel, A.FZJ* ; Vasileiadis, G. ; Whitlatch, T. ; Wickramaarachchi, N. ; Williams, M. ; Yang, Y.FZJ* ; Zarling, J. ; Zhang, Z. ; Zhao, Z. ; Zhou, J. ; Zhou, Q.FZJ* ; Zhou, X.FZJ* ; Zihlmann, B.

2021
Inst. Woodbury, NY

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Please use a persistent id in citations: http://hdl.handle.net/2128/27769  doi:10.1103/PhysRevC.103.L022201

Abstract: We report a measurement of the $\pi^-$ photoproduction beam asymmetry for the reaction $\vec{\gamma} p \rightarrow \pi^- \Delta^{++}$ using data from the GlueX experiment in the photon beam energy range 8.2--8.8 GeV. The asymmetry $\Sigma$ is measured as a function of four-momentum transfer $t$ to the $\Delta^{++}$ and compared to phenomenological models. We find that $\Sigma$ 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.

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Contributing Institute(s):

1. Experimentelle Hadronstruktur (IKP-1)

Research Program(s):

1. 612 - Cosmic Matter in the Laboratory (POF4-612) (POF4-612)
2. 6G12 - FAIR (GSI) (POF4-6G12) (POF4-6G12)

Appears in the scientific report 2021

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Electronics and Telecommunications Collection ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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