Details

Autor(en) / Beteiligte

• 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.

Titel

First Measurement Using Elliptically Polarized Photons of the Double-Polarization Observable E for γ p → p π 0 and γ p → n π

Ist Teil von

• Physical review letters, 2024-03, Vol.132 (12), Article 121902

Ort / Verlag

United States: American Physical Society

Erscheinungsjahr

2024

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• We report the measurement of the helicity asymmetry E for the p π 0 and n π + 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 p π 0 final state (230–842 MeV for the n π + 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 p η cusp in the p π 0 final state. Published by the American Physical Society 2024