Beam-helicity asymmetry in associated electroproduction of real photons ep -> aEuro parts per thousand e gamma pi N in the Delta-resonance region

  title={Beam-helicity asymmetry in associated electroproduction of real photons ep -> aEuro parts per thousand e gamma pi N in the Delta-resonance region},
  author={The Hermes collaboration A. Airapetian and Norayr Z. Akopov and Elke Caroline Aschenauer and Wlłodzimierz Augustyniak and Roger W. Avakian and Artur R. Avetissian and Eduard Avetisyan and Henk P. Blok and Helmut Bottcher and Aldar Borissov and Jeffrey V. Bowles and Irina Brodski and Viktor V. Bryzgalov and Jonathan G. Burns and Gabriel Capitani and Evaristo Cisbani and Giuseppe Ciullo and Marco M. Contalbrigo and P. Ferretti Dalpiaz and Willem Deconinck and Roberto De Leo and Elisabetta De Sanctis and Markus Diefenthaler and Pasquale Di Nezza and Mike Duren and Mindy L Ehrenfried and Garegin Elbakian and Frank Ellinghaus and E. Etzelmuller and Riccardo Fabbri and Salvatore Frullani and G. V. Gapienko and V. A. Gapienko and J. Garay Garc'ia and Fulvio Garibaldi and Genadi V. Gavrilov and Vahagn Gharibyan and Francesca Giordano and Stephen Gliske and Martin A. J. Hartig and Delia Hasch and Yolanda Holler and Ivana Radoslavova Hristova and Alexander Ivanilov and Howard E. Jackson and Susan Joosten and Robin Kaiser and Gevorg Ararat Karyan and Tibor Keri and Elissa Kinney and Alexei F. Kisselev and Vladimir Korotkov and Valentin M. Kozlov and Pavlo Kravchenko and V. G. Krivokhijine and Luigi Lagamba and L. Lapik'as and I. Lehmann and Paolo Lenisa and Wolfgang Lorenzon and X. Lu and B.-Q. Ma and Donald J Mc Mahon and N. C. R. Makins and Sergey Manaenkov and Yajun Mao and Bohdan Mariański and Hrachya H. Marukyan and Clark A. Miller and Yasuo Miyachi and Ashley Movsisyan and Valeria Muccifora and Michael K. Murray and Andreas Mussgiller and Yu. G. Naryshkin and Andrea Nass and Mikhail Negodaev and W.-D. Nowak and Luciano Libero Pappalardo and R. P{\'e}rez-Benito and Artem Petrosyan and Paul Reimer and Aline Reolon and Caroline Kathrin Riedl and Klaus Rith and Guenther Rosner and Armine Armand Rostomyan and Javier Rub{\'i}n and Dirk Ryckbosch and Yu. Salomatin and Andreas Schafer and Gilles Schnell and Bj{\"o}rn Ingo Seitz and T.-A. Shibata and Moritz Stahl and Marco Statera and Edith Steffens and J. J. M. Steijger and James I. Stewart and Friedrich Stinzing and S. P. Taroian and A. R. Terkulov and Rebecca M. Truty and Antoine P. Trzcinski and Jillian Margaret Twigger and Yves van Haarlem and Charlotte Van Hulse and V. V. Vikhrov and I. Vilardi and Shicheng Wang and S. V Yaschenko and Zhenyu Ye and S. C. Max Yen and Vitaly Zagrebelnyy and Benedikt Zihlmann and Pawil Zupranski},
The beam-helicity asymmetry in associated electroproduction of real photons, ep → eγπN , in the ∆(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 → eγπp and ep → eγπn, from a data set collected with a recoil detector. All asymmetry amplitudes are found to be consistent with zero. 


Publications referenced by this paper.

The Hermes recoil detector, JINST

A. Airapetian
  • 2013

The Hermes Recoil Detector: Particle Identification and Determination of Detector Efficiency of the Scintillating Fiber Tracker

X. Lu
  • Master Thesis,
  • 2009

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