The HERMES Spectrometer

Ackerstaff, K.; Airapetian, A.; Акопов, Н.; Amarian, M.; Andreev, V.; Aschenauer, E. C.; Avakian, R.; Avakian, H.; Avetissian, A.; Bains, B.; Barrow, S.; Beckhusen, W.; Beckmann, M.; Belostotski, S.; Belz, Andrea; Benisch, T.; Bernreuther, S.; Bianchi, N.; Blouw, J.; Böttcher, H.; Borissov, A.; Brack, J.; Braun, B.; Bray, B.; Brons, S.; Brückner, W.; Brüll, A.; Bulten, H.; Capitani, G. P.; Carter, P.; Chumney, P.; Cisbani, E.; Clark, Stephen K.; Colilli, S.; Coombes, H.; Court, G.R.; Delheij, P. P. J.; Devitsin, E.; Jager, C. W. de; Sanctis, E. De; Schepper, D. De; Huberts, P.K.A. de Witt; Nezza, P. Di; Doets, M.; Düren, M.; Dvoredsky, A.; Elbakian, G.; Emerson, Joseph; Fantoni, A.; Fechtchenko, A.; Ferstl, M.; Fick, D.; Fiedler, K.; Filippone, B. W.; Fischer, H.; Fortune, H. T.; Franz, J.; Frullani, S.; Funk, M.-A.; Gagunashvili, N.; Galumian, P.; Gao, Haibo; Gärber, Y.; Garibaldi, F.; Gavrilov, G.; Geiger, P.; Gharibyan, V.; Giordjian, V.; Giuliani, F.; Golendoukhin, A.; Grabowski, B.; Graw, G.; Grebeniouk, O.; Green, P.; Greeniaus, G.; Gricia, M.; Großhauser, C.; Gute, A.; Haas, J.; Hakelberg, K.; Haeberli, W.; Hansen, J. O.; Hasch, D.; Häusser, O.; Henderson, R.; Henkes, T.; Hertenberger, R.; Holler, Y.; Holt, R. J.; Ihssen, H.; Izotov, A.; Iodice, M.; Jackson, H. E.; Jgoun, A.; Jones, C. E.; Kaiser, R.; Kelsey, Jim; Kinney, E.; Kirsch, Matthias; Kisselev, A.; Kitching, P.; Kobayashi, Haruo; Kok, E.; Königsmann, K.; Kolstein, M.; Kolster, H.; Korsch, W.; Kozlov, Sergey M.; Kozlov, V.; Kowalczyk, Robert; Kramer, L.; Krause, B.; Krivchitch, A.; Krivokhijine, V. G.; Kueckes, M.; Kutt, P. H.; Kyle, G. S.; Lachnit, W.; Langstaff, R.; Lorenzon, W.; Lucentini, M.; Lung, A.; Makins, N.; Maleev, V. P.; Manaenkov, S. I.; Martens, K.; Mateos, A.; McIlhany, K.; McKeown, R. D.; Meißner, F.; Menden, F.; Mercer, D.; Metz, A.; Meyners, N.; Mikloukho, O.; Miller, C. A.; Miller, M. A.; Milner, R.; Mitsyn, V. V.; Modrak, G.; Morton, Josephine; Mozzetti, R.; Muccifora, V.; Нагайцев, А.; Naryshkin, Y.; Nathan, Alan M.; Neunreither, F.; Niczyporuk, M.; Nowak, W.-D.; Nupieri, M.; Oelwein, P.; Ogami, H.; O’Neill, T. G.; Openshaw, R.; Papavassiliou, V.; Pate, S. F.; Patrichev, S.; Pitt, M. L.; Plett, H.J.; Poolman, H. R.; Potashov, S.; Potterveld, D. H.; Povh, Bogdan; Prahl, Volker; Rakness, G.; Razmyslovich, V.; Redwine, R.; Reolon, A. R.; Ristinen, R.A.; Rith, Klaus; Roloff, H.; Röper, G.; Rossi, P.; Rudnitsky, S.; Russo, H; Ryckbosch, D.; Sakemi, Y.; Santavenere, F.; Savin, I.; Schmidt, Friedrich; Schmitt, H.; Schnell, G.; Schüler, K. P.; Schwind, A.; Shibata, T. A.; Shin, Taeho; Siebels, B.; Simon, A.; Sinram, K.; Smythe, W. R.; Sowiński, J.; Spengos, M.; Sperber, K.; Steffens, E.; Stenger, J.; Stewart, J.; Stock, F.; Stößlein, U.; Sutter, M.; Tallini, H.; Taroian, S.; Terkulov, A.; Thiessen, D.; Tipton, B.; Trofimov, V.; Trudel, A.; Tytgat, M.; Urciuoli, G. M.; Vyver, R. Van de; Brand, J. van den; Steenhoven, G. van der; Hunen, J. J. van; Westrum, Derek van; Vassiliev, A.; Vetterli, M. C.; Vincter, M. G.; Volk, E.; Wander, W.; Welch, T. P.; Williamson, S. E.; Wise, T.; Wöbke, G.; Woller, K.; Yoneyama, Satoshi; Zapfe-Düren, K.; Zeuli, T.; Zohrabian, H.

doi:10.1016/s0168-9002(98)00769-4

Cited by 304 publications

(96 citation statements)

References 12 publications

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“…The scattered positrons and coincident photons were detected by the HERMES spectrometer [14] in the polarangle range of 40 -220 mrad. A positron trigger was formed from a coincidence between three scintillator hodoscope planes and a lead-glass calorimeter.…”

mentioning

confidence: 99%

Measurement of the Beam-Spin Azimuthal Asymmetry Associated with Deeply-Virtual Compton Scattering

Airapetian¹,

Акопов²,

Akopov³

et al. 2001

Phys. Rev. Lett.

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288

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mentioning

confidence: 99%

Measurement of the Beam-Spin Azimuthal Asymmetry Associated with Deeply-Virtual Compton Scattering

Airapetian¹,

Акопов²,

Akopov³

et al. 2001

Phys. Rev. Lett.

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288

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“…The HERMES setup included a forward spectrometer [34], in which the scattered lepton and the produced hadrons were detected within an angular acceptance of ±170 mrad horizontally and ±(40-140) mrad vertically. The tracking system had a momentum resolution of about 1.5% and an angular resolution of about 1 mrad.…”

Section: Methodsmentioning

confidence: 99%

Ratios of helicity amplitudes for exclusive $$\rho ^0$$ ρ 0 electroproduction on transversely polarized protons

et al. 2017

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Exclusive ρ 0 -meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in the kinematic region 1.0 GeV 2 < Q 2 < 7.0 GeV 2 , 3.0 GeV < W < 6.3 GeV, and −t < 0.4 GeV 2 . Using an unbinned maximum-likelihood method, 25 parameters are extracted. These determine the real and imaginary parts of the ratios of several helicity amplitudes describing ρ 0 -meson production by a virtual photon. The denominator of those ratios is the dominant amplitude, the nucleon-helicity-non-flip amplitude F 0 1 2 0 1 2 , which describes the production of a longitudinal ρ 0 -meson by a longitudinal virtual photon. The ratios of nucleon-helicity-nonflip amplitudes are found to be in good agreement with those from the previous HERMES analysis. The transverse target polarization allows for the first time the extraction of ratios of a number of nucleon-helicity-flip amplitudes to F 0 1 2 0 1 2 . Results obtained in a handbag approach based on generalized parton distributions taking into account the contribution from pion exchange are found to be in good agreement with these ratios. Within the model, the data favor a positive sign for the π − ρ transition form factor. By also exploiting the longitudinal beam polarization, a total of 71 ρ 0 spin-density matrix elements is determined from the extracted 25 parameters, in contrast to only 53 elements as directly determined in earlier analyses.

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“…For this measurement, the recoil detector [14] was used in conjunction with the forward spectrometer [15]. The Hera lepton beam was transversely self-polarized by the emission of synchrotron radiation [16].…”

Section: The Hermes Experiments In 2006-2007mentioning

confidence: 99%

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

Airapetian¹,

Акопов²,

Aschenauer³

et al. 2014

J. High Energ. Phys.

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Abstract: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 → eγπ 0 p and ep → 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 Spectrometer

Cited by 304 publications

References 12 publications

Measurement of the Beam-Spin Azimuthal Asymmetry Associated with Deeply-Virtual Compton Scattering

Measurement of the Beam-Spin Azimuthal Asymmetry Associated with Deeply-Virtual Compton Scattering

Ratios of helicity amplitudes for exclusive $$\rho ^0$$ ρ 0 electroproduction on transversely polarized protons

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

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