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Measurement of angular distributions and R = σLT in diffractive electroproduction of ρ0 mesons

Publication ,  Journal Article
Ackerstaff, K; Airapetian, A; Akopov, N; Amarian, M; Aschenauer, EC; Avakian, H; Avakian, R; Avetissian, A; Bains, B; Beckmann, M; Belz, JE ...
Published in: European Physical Journal C
2000

Production and decay angular distributions were extracted from measurements of exclusive electroproduction of the ρ0(770) meson over a range in the virtual photon negative four-momentum squared 0.5 < Q2 < 4 GeV2 and the photon-nucleon invariant mass range 3.8 < W < 6.5 GeV. The experiment was performed with the HERMES spectrometer, using a longitudinally polarized positron beam and a 3He gas target internal to the HERA e± storage ring. The event sample combines ρ0 mesons produced incoherently off individual nucleons and coherently off the nucleus as a whole. The distributions in one production angle and two angles describing the ρ0 → π+π- decay yielded measurements of eight elements of the spin-density matrix, including one that had not been measured before. The results are consistent with the dominance of helicity conserving amplitudes and natural parity exchange. The improved precision achieved at 4 < W < 7 GeV, in combination with other data at W > 7 GeV, reveals evidence for an energy dependence in the ratio R of the longitudinal to transverse cross sections at constant Q2.

Duke Scholars

Published In

European Physical Journal C

ISSN

1434-6044

Publication Date

2000

Volume

18

Issue

2

Start / End Page

303 / 316

Related Subject Headings

  • Nuclear & Particles Physics
  • 0206 Quantum Physics
  • 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
 

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Ackerstaff, K., Airapetian, A., Akopov, N., Amarian, M., Aschenauer, E. C., Avakian, H., … Zohrabian, H. (2000). Measurement of angular distributions and R = σLT in diffractive electroproduction of ρ0 mesons. European Physical Journal C, 18(2), 303–316.
Ackerstaff, K., A. Airapetian, N. Akopov, M. Amarian, E. C. Aschenauer, H. Avakian, R. Avakian, et al. “Measurement of angular distributions and R = σLT in diffractive electroproduction of ρ0 mesons.” European Physical Journal C 18, no. 2 (2000): 303–16.
Ackerstaff K, Airapetian A, Akopov N, Amarian M, Aschenauer EC, Avakian H, et al. Measurement of angular distributions and R = σLT in diffractive electroproduction of ρ0 mesons. European Physical Journal C. 2000;18(2):303–16.
Ackerstaff, K., et al. “Measurement of angular distributions and R = σLT in diffractive electroproduction of ρ0 mesons.” European Physical Journal C, vol. 18, no. 2, 2000, pp. 303–16.
Ackerstaff K, Airapetian A, Akopov N, Amarian M, Aschenauer EC, Avakian H, Avakian R, Avetissian A, Bains B, Beckmann M, Belostotski S, Belz JE, Benisch T, Bernreuther S, Bianchi N, Blanchard S, Blouw J, Böttcher H, Borissov A, Brack J, Braun B, Bray B, Brückner W, Brüll A, Bruins EEW, Bulten HJ, Capitani GP, Carter P, Cisbani E, Court GR, Delheij PPJ, Sanctis ED, Schepper DD, Devitsin E, Huberts PKADW, Düren M, Dvoredsky A, Elbakian G, Emerson J, Fantoni A, Fechtchenko A, Ferstl M, Fiedler K, Filippone BW, Fischer H, Fox B, Franz J, Frullani S, Funk M-A, Gärber Y, Gagunashvili ND, Galumian P, Gao H, Garibaldi F, Gavrilov G, Geiger P, Gharibyan V, Golendukhin A, Graw G, Grebeniouk O, Green PW, Greeniaus LG, Grosshauser C, Gute A, Gyurjyan V, Haas JP, Haeberli W, Häusser O, Hansen J-O, Hasch D, Henderson R, Henkes T, Hertenberger R, Holler Y, Holt RJ, Ihssen H, Iodice M, Izotov A, Jackson HE, Jgoun A, Jones C, Kaiser R, Kinney E, Kirsch M, Kisselev A, Kitching P, Königsmann K, Kolstein M, Kolster H, Korsch W, Kozlov V, Kramer LH, Krause B, Krivokhijine VG, Kückes M, Kyle G, Lachnit W, Lorenzon W, Lung A, Makins NCR, Manaenkov SI, Martens FK, Martin JW, Mateos A, Mcllhany K, McKeown RD, Meissner F, Menden F, Mercer D, Metz A, Meyners N, Mikloukho O, Miller CA, Miller MA, Milner R, Mitsyn V, Most A, Mozzetti R, Muccifora V, Nagaitsev A, Naryshkin Y, Nathan AM, Neunreither F, Niczyporuk JM, Nowak W-D, Nupieri M, Oelwein P, Ogami H, O’Neill TG, Openshaw R, Ouyang J, Pate SF, Pitt M, Poolman HR, Potashov S, Potterveld DH, Rakness G, Redwine R, Reolon AR, Ristinen R, Rith K, Röper G, Roloff HO, Rossi P, Ruh M, Ryckbosch D, Sakemi Y, Savin I, Schüler KP, Schwind A, Shibata T-A, Shin T, Simon A, Sinram K, Smythe WR, Sowinski J, Spengos M, Steffens E, Stenger J, Stewart J, Stock F, Stösslein U, Sutter M, Tallini H, Taroian S, Terkulov A, Thiessen DM, Tipton B, Trudel A, Tytgat M, Urciuoli GM, Brand JFJVD, Steenhoven GVD, Vyver RVD, Vetterli MC, Vincter MG, Volk E, Wander W, Welch TP, Williamson SE, Wise T, Zapfe K, Zohrabian H. Measurement of angular distributions and R = σLT in diffractive electroproduction of ρ0 mesons. European Physical Journal C. 2000;18(2):303–316.
Journal cover image

Published In

European Physical Journal C

ISSN

1434-6044

Publication Date

2000

Volume

18

Issue

2

Start / End Page

303 / 316

Related Subject Headings

  • Nuclear & Particles Physics
  • 0206 Quantum Physics
  • 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics