Journal article
Authors list: Kaser, A.; Dieterle, M.; Witthauer, L.; Abt, S.; Achenbach, P.; Adlarson, P.; Afzal, F.; Ahmed, Z.; Ahrens, J.; Annand, J. R. M.; Arends, H. J.; Bashkanov, M.; Beck, R.; Biroth, M.; Borisov, N. S.; Braghieri, A.; Briscoe, W. J.; Cividini, F.; Collicott, C.; Costanza, S.; Denig, A.; Downie, E. J.; Drexler, P.; Fix, A.; Garni, S.; Glazier, D. I.; Gorodnov, I.; Gradl, W.; Gunther, M.; Gurevich, G. M.; Heijkenskjoeld, L.; Hornidge, D.; Huber, G. M.; Kashevarov, V. L.; Kay, S.; Keshelashvili, I.; Kondratiev, R.; Korolija, M.; Krusche, B.; Lazarev, A. B.; Lisin, V.; Livingston, K.; Lutterer, S.; MacGregor, I. J. D.; Manley, D. M.; Martel, P. P.; Metag, V.; Meyer, W.; Miskimen, R.; Mornacchi, E.; Mushkarenkov, A.; Neganov, A. B.; Neiser, A.; Oberle, M.; Ostrick, M.; Otte, P. B.; Paudyal, D.; Pedroni, P.; Polonski, A.; Prakhov, S. N.; Reicherz, G.; Ron, G.; Rostomyan, T.; Sarty, A.; Sfienti, C.; Sokhoyan, V.; Spieker, K.; Steffen, O.; Strakovsky, I. I.; Strub, Th.; Supek, I.; Thiel, A.; Thiel, M.; Thomas, A.; Unverzagt, M.; Usov, Yu. A.; Wagner, S.; Walford, N. K.; Watts, D. P.; Werthmuller, D.; Wettig, J.; Wolfes, M.; Zana, L.
Publication year: 2018
Pages: 305-312
Journal: Physics Letters B
Volume number: 786
ISSN: 0370-2693
eISSN: 1873-2445
Open access status: Gold
DOI Link: https://doi.org/10.1016/j.physletb.2018.10.006
Publisher: Elsevier
Abstract:
The helicity-dependent cross sections for the photoproduction of pi(0)eta pairs have been measured for the first time. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with the combined Crystal Ball-TAPS calorimeter. The experiment used a polarized deuterated butanol target and a circularly polarized photon beam. This arrangement allowed the sigma(1/2)(photon and target spinantiparallel) and sigma(3/2)(parallel spins) components to be measured for quasi-free production of pi(0)n pairs off protons and neutrons. The main finding is that the two helicity components contribute identically, within uncertainties, for both participant protons and neutrons. The absolute couplings for protons and neutrons are also identical. This means that nucleon resonances contributing to this reaction in the investigated energy range have almost equal electromagnetic helicity couplings, A(1/2)(n,p) and A(3/2)(n,p) Identical couplings for protons and neutrons are typical for Delta resonances and identical A(1/2) and A(3/2)components are only possible for J >= 3/2 states, which constrains possible contributions of nucleon resonances. (C) 2018 Published by Elsevier B.V.
Citation Styles
Harvard Citation style: Kaser, A., Dieterle, M., Witthauer, L., Abt, S., Achenbach, P., Adlarson, P., et al. (2018) First measurement of helicity-dependent cross sections in π0n photoproduction from quasi-free nucleons, Physics Letters B, 786, pp. 305-312. https://doi.org/10.1016/j.physletb.2018.10.006
APA Citation style: Kaser, A., Dieterle, M., Witthauer, L., Abt, S., Achenbach, P., Adlarson, P., Afzal, F., Ahmed, Z., Ahrens, J., Annand, J., Arends, H., Bashkanov, M., Beck, R., Biroth, M., Borisov, N., Braghieri, A., Briscoe, W., Cividini, F., Collicott, C., ...Zana, L. (2018). First measurement of helicity-dependent cross sections in π0n photoproduction from quasi-free nucleons. Physics Letters B. 786, 305-312. https://doi.org/10.1016/j.physletb.2018.10.006
Keywords
ETA; MAMI; MESONS; PAIRS; PHOTON; PI(0)-PAIRS; PROTON; REACTION GAMMA-P
