First Measurement Using Elliptically Polarized Photons of the Double-Polarization Observable E for γp→pπ0 and γp→nπ+
Academic Article
Publication Date:
2024
abstract:
We report the measurement of the helicity asymmetry E for the pπ0 and nπ+ final states using, for the first time, an elliptically polarized photon beam in combination with a longitudinally polarized target at the Crystal Ball experiment at MAMI. The results agree very well with data that were taken with a circularly polarized photon beam, showing that it is possible to simultaneously measure polarization observables that require linearly (e.g., G) and circularly polarized photons (e.g., E) and a longitudinally polarized target. The new data cover a photon energy range 270-1400 MeV for the pπ0 final state (230-842 MeV for the nπ+ final state) and the full range of pion polar angles, θ, providing the most precise measurement of the observable E. A moment analysis gives a clear observation of the pη cusp in the pπ0 final state.
Iris type:
1.1 Articolo in rivista
List of contributors:
Afzal, F.; Spieker, K.; Hurck, P.; Abt, S.; Achenbach, P.; Adlarson, P.; Ahmed, Z.; Akondi, C. S.; Annand, J. R. M.; Arends, H. J.; Bashkanov, M.; Beck, R.; Biroth, M.; Borisov, N.; Braghieri, A.; Briscoe, W. J.; Cividini, F.; Collicott, C.; Costanza, S.; Denig, A.; Dieterle, M.; Downie, E. J.; Drexler, P.; Fegan, S.; Gardner, S.; Ghosal, D.; Glazier, D. I.; Gorodnov, I.; Gradl, W.; Gurevich, D.; Heijkenskjöld, L.; Hornidge, D.; Huber, G. M.; Kashevarov, V. L.; Kay, S. J. D.; Korolija, M.; Krusche, B.; Lazarev, A.; Livingston, K.; Lutterer, S.; Macgregor, I. J. D.; Macrae, R. G.; Manley, D. M.; Martel, P. P.; Miskimen, R.; Mocanu, M.; Mornacchi, E.; Mullen, C.; Neganov, A.; Neiser, A.; Oberle, M.; Ostrick, M.; Otte, P. B.; Paudyal, D.; Pedroni, P.; Powell, A.; Reicherz, G.; Rostomyan, T.; Sfienti, C.; Sokhoyan, V.; Steffen, O.; Strakovsky, I. I.; Strub, T.; Supek, I.; Thiel, A.; Thiel, M.; Thomas, A.; Usov, Yu. A.; Wagner, S.; Walford, N. K.; Watts, D. P.; Werthmüller, D.; Wettig, J.; Witthauer, L.; Wolfes, M.; Zachariou, N.; Null, Null
Published in: