Helicity dependence of the γ 3He → πX reactions in the Δ(1232) resonance region

Costanza, S. et al. (2014) Helicity dependence of the γ 3He → πX reactions in the Δ(1232) resonance region. European Physical Journal A, 50(173), -173:. (doi: 10.1140/epja/i2014-14173-y)

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The helicity dependences of the differential cross sections for the semi-inclusive γ 3He → π0 X and γ 3He → π± X reactions have been measured for the first time in the energy region 200 < E γ 450 MeV. The experiment was performed at the tagged photon beam facility of the MAMI accelerator in Mainz using a longitudinally polarised high-pressure 3He gas target. Hadronic products were measured with the large-acceptance Crystal Ball detector complemented with additional devices for charged-particle tracking and identification. Unpolarised differential cross sections and their helicity dependence are compared with theoretical calculations using the Fix-Arenhövel model. The effect of the intermediate excitation of the Δ(1232) resonance can be clearly seen from this comparison, especially for the polarised case, where nuclear effects are relatively small. The model provides a better theoretical description of the unpolarised charged pion photoproduction data than the neutral pion channel. It does significantly better in describing the helicity-dependent data in both channels. These comparisons provide new information on the mechanisms involved in pion photoproduction on 3He and suggest that a polarised 3He target can provide valuable information on the corresponding polarised quasi-free neutron reactions.

Item Type:Articles (Other)
Glasgow Author(s) Enlighten ID:Middleton, Dr Duncan and Glazier, Dr Derek and McGeorge, Dr John and Downie, Dr Evangeline and MacGregor, Professor Douglas and Livingston, Dr Kenneth and Howdle, Mr David and Mancell, Mr Joe and Annand, Dr John and Hamilton, Dr David and Rosner, Professor Guenther
Authors: Costanza, S., Mushkarenvov, A., Rigamonti, F., Aguar Bartolome, P., Ahrens, J., Annand, J.R.M., Arends, H.J., Beck, R., Braghieri, A., Bekrenev, V., Berghauser, H., Briscoe, W.J., Cherepnya, S.N., Collicott, C., Downie, E.J., Drexler, P., Fil'kov, L.V., Fix, A., Glazier, D.I., Hamilton, D., Heid, E., Heil, W., Hornidge, D., Howdle, D., Jaegle, I., Huber, G.M., Jahn, O., Jude, T., Kashevarov, V.L., Keshelashvili, I., Kondratiev, R., Korolija, M., Krimmer, J., Krusche, B., Kruglov, S., Kulbardis, A., Lisin, V., Livingston, K., MacGregor, I.J.D., Mancell, J., Mandaglio, G., Manley, D.M., McGeorge, J.C., Middleton, D.G., Metag, V., Nefkens, B.M.K., Nikolaev, A., Oberle, M., Ostrick, M., Ortega, H., Otte, P.B., Oussena, B., Pedroni, P., Pheron, F., Polonski, A., Prakhov, S., Rosner, G., Rostomyan, T., Sarty, A.J., Schumann, S., Starostin, A., Supek, I., Thiel, M., Thomas, A., Unversagt, M., Watts, D.P., and Werthmueller, D.
Subjects:Q Science > QC Physics
College/School:College of Science and Engineering > School of Physics and Astronomy
Research Group:Nuclear Physics
Journal Name:European Physical Journal A
Publisher:Springer Berlin Heidelberg
ISSN (Online):1434-601X

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
570711Nuclear Physics GroupDavid IrelandScience & Technologies Facilities Council (STFC)ST/J000175/1P&A - PHYSICS & ASTRONOMY
577011High-Flux multi-spectral x-ray imaging with energy-sensitive CZT detectorsValentine O'SheaScience & Technologies Facilities Council (STFC)ST/I003134/1P&A - PHYSICS & ASTRONOMY
577012High-Flux multi-spectral x-ray imaging with energy-sensitive CZT detectorsValentine O'SheaInstitute of Cancer Research (EXTICR)UNSPECIFIEDP&A - PHYSICS & ASTRONOMY