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arXiv · 1310.5081

Beam-helicity asymmetry in associated electroproduction of real photons $ep \to eγπN$ in the $Δ$-resonance region

The HERMES Collaboration·A. Airapetian·N. Akopov·E. C. Aschenauer·W. Augustyniak·R. Avakian·A. Avetissian·E. Avetisyan·H. P. Blok·H. Böttcher·A. Borissov·J. Bowles·I. Brodski·V. Bryzgalov·J. Burns·G. P. Capitani·E. Cisbani·G. Ciullo·M. Contalbrigo·P. F. Dalpiaz·W. Deconinck·R. De Leo·E. De Sanctis·M. Diefenthaler·P. Di Nezza·M. Düren·M. Ehrenfried·G. Elbakian·F. Ellinghaus·E. Etzelmüller·R. Fabbri·S. Frullani·G. Gapienko·V. Gapienko·J. Garay García·F. Garibaldi·G. Gavrilov·V. Gharibyan·F. Giordano·S. Gliske·M. Hartig·D. Hasch·Y. Holler·I. Hristova·A. Ivanilov·H. E. Jackson·S. Joosten·R. Kaiser·G. Karyan·T. Keri·E. Kinney·A. Kisselev·V. Korotkov·V. Kozlov·P. Kravchenko·V. G. Krivokhijine·L. Lagamba·L. Lapikás·I. Lehmann·P. Lenisa·W. Lorenzon·X. -G. Lu·B. -Q. Ma·D. Mahon·N. C. R. Makins·S. I. Manaenkov·Y. Mao·B. Marianski·H. Marukyan·C. A. Miller·Y. Miyachi·A. Movsisyan·V. Muccifora·M. Murray·A. Mussgiller·Y. Naryshkin·A. Nass·M. Negodaev·W. -D. Nowak·L. L. Pappalardo·R. Perez-Benito·A. Petrosyan·P. E. Reimer·A. R. Reolon·C. Riedl·K. Rith·G. Rosner·A. Rostomyan·J. Rubin·D. Ryckbosch·Y. Salomatin·A. Schäfer·G. Schnell·B. Seitz·T. -A. Shibata·M. Stahl·M. Statera·E. Steffens·J. J. M. Steijger·J. Stewart
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Abstract

The beam-helicity asymmetry in associated electroproduction of real photons, $ep\to eγπN$, in the $Δ$(1232)-resonance region is measured using the longitudinally polarized HERA positron beam and an unpolarized hydrogen target. Azimuthal Fourier amplitudes of this asymmetry are extracted separately for two channels, $ep\to eγπ^0 p$ and $ep\to eγπ^+ n$, from a data set collected with a recoil detector. All asymmetry amplitudes are found to be consistent with zero.

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The HERMES Collaboration, A. Airapetian, N. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, H. P. Blok, H. Böttcher, A. Borissov, J. Bowles, I. Brodski, V. Bryzgalov, J. Burns, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, E. Etzelmüller, R. Fabbri, S. Frullani, G. Gapienko, V. Gapienko, J. Garay García, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Hartig, D. Hasch, Y. Holler, I. Hristova, A. Ivanilov, H. E. Jackson, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, W. Lorenzon, X. -G. Lu, B. -Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, Y. Mao, B. Marianski, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, Y. Naryshkin, A. Nass, M. Negodaev, W. -D. Nowak, L. L. Pappalardo, R. Perez-Benito, A. Petrosyan, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, A. Schäfer, G. Schnell, B. Seitz, T. -A. Shibata, M. Stahl, M. Statera, E. Steffens, J. J. M. Steijger, J. Stewart. 2014-02-11. Beam-helicity asymmetry in associated electroproduction of real photons $ep \to eγπN$ in the $Δ$-resonance region. https://doi.org/10.1007/jhep01(2014)077

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