Helicity dependent cross sections for the photoproduction of π0π± pairs from quasi-free nucleons

Ghosal, D. et al. (2023) Helicity dependent cross sections for the photoproduction of π0π± pairs from quasi-free nucleons. Physics Letters B, 847, 138273. (doi: 10.1016/j.physletb.2023.138273)

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Abstract

Photoproduction of π0π± -pairs from quasifree nucleons bound in the deuteron has been investigated to study the helicity dependence of this reaction. Measurements with a liquid deuterium target were used to extract the unpolarized cross sections for reactions on protons and neutrons. A deuterated, longitudinally polarized solid-butanol target, together with a circularly polarized photon beam, determined the double polarization observable E. From these results the spin-dependent cross sections 𝜎1∕2 and 𝜎3/2 , corresponding to the anti-parallel and parallel spin configurations of the beam photon and target nucleon, have been derived. The measurements were performed at the Mainz MAMI accelerator with tagged, circularly-polarized photon beams produced via bremsstrahlung from longitudinally polarized electron beams. The reaction products were detected with an almost 4π solid-angle covering calorimeter composed of the Crystal Ball and TAPS detectors, supplemented by plastic scintillation detectors for charged particle identification. The results are sensitive to sequential decays of nucleon resonances via intermediate states and also to the decay of nucleon resonances by emission of charged ρ mesons, and are compared to recent model results.

Item Type:Articles
Additional Information:This work was supported by Schweizerischer Nationalfonds (200020-156983, 132799, 121781, 117601), Deutsche Forschungsgemeinschaft (SFB 443, SFB 1044, SFB/TR16), the INFN-Italy, the European Community-Research Infrastructure Activity under FP7 programme (Hadron Physics, grant agreement No. 227431), the UK Science and Technology Facilities Council (ST/J000175/1, ST/G008604/1, ST/G008582/1, ST/J00006X/1, and ST/L00478X/1), the Natural Sciences and Engineering Research Council of Canada (NSERC, FRN: SAPPJ-2015-00023), Canada. The model calculation was supported by the Russian Science Foundation, Grant No. 22-42-04401. This material is based upon work also supported by the U.S. Department of Energy Office of Science, Office of Nuclear Physics Research Division, under Award Numbers DE-FG02-99-ER41110, DE-FG02-88ER40415, DE-FG02-01-ER41194, and DE-SC0014323 and by the National Science Foundation, under Grant Nos. PHY-1039130 and IIA-1358175.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Powell, Abby-Rhian and Gardner, Mr Simon and MULLEN, CHRISTOPHER and Livingston, Dr Kenneth and MacGregor, Professor Douglas and Annand, Dr John and Glazier, Dr Derek
Authors: Ghosal, D., Sokhoyan, V., Fix, A., Lutterer, S., Abt, S., Achenbach, P., Afzal, F., Ahmed, Z., Annand, J. R.M., Bashkanov, M., Beck, R., Biroth, M., Borisov, N., Braghieri, A., Briscoe, W.J., Cividini, F., Collicot, C., Costanza, S., Denig, A., Dieterle, M., Dolzhikov, A.S., Downie, E.J., Drexler, P., Fegan, S., Gardner, S., Glazier, D. I., Gorodnov, I., Gradl, W., Günther, M., Gurevich, D., Heijkenskjöld, L., Hornidge, D., Huber, G.M., Jermann, N., Käser, A., Kashevarov, V.L., Korolija, M., Krusche, B., Lazarev, A., Livingston, K., MacGregor, I.J. D., Manley, D.M., Martel, P.P., Meier, C., Miskimen, R., Mocanu, M., Mornacchi, E., Mullen, C., Neganov, A., Neiser, A., Ostrick, M., Otte, P., Paudyal, D., Pedroni, P., Powell, A., Reicherz, G., Rostomyan, T., Spieker, K., Steffen, O., Strakovsky, I.I., Thiel, A., Thiel, M., Thomas, A., Unverzagt, M., Usov, Y.A., Wagner, S., Walford, N.K., Watts, D.P., Werthmüller, D., Wettig, J., Witthauer, L., Wolfes, M., and Zachariou, N.
Subjects:Q Science > QC Physics
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physics Letters B
Publisher:Elsevier
ISSN:0370-2693
ISSN (Online):1873-2445
Published Online:27 October 2023
Copyright Holders:Copyright © 2023 The Authors
First Published:First published in Physics Letters B 847:138273
Publisher Policy:Reproduced under a Creative Commons license

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
162724Study of Strongly Interacting MatterGuenther RosnerEuropean Commission (EC)227431P&S - Physics & Astronomy
165582Nuclear Physics GroupDavid IrelandScience and Technology Facilities Council (STFC)ST/J000175/1P&S - Physics & Astronomy
162615Illuminating strongly interacting matterIan MacgregorScience and Technology Facilities Council (STFC)ST/G008604/1P&S - Physics & Astronomy