Transverse polarization of Λ and Λ̄ hyperons in quasireal photoproduction

A. Airapetian, N. Akopov, Z. Akopov, M. Amarian, V. V. Ammosov, A. Andrus, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetissian, P. Bailey, V. Baturin, C. Baumgarten, M. Beckmann, S. Belostotski, S. Bernreuther, N. Bianchi, H. P. Blok, H. BöttcherA. Borissov, M. Bouwhuis, J. Brack, A. Brüll, I. Brunn, G. P. Capitani, H. C. Chiang, G. Ciullo, M. Contalbrigo, G. R. Court, P. F. Dalpiaz, R. De Leo, L. De Nardo, E. De Sanctis, E. Devitsin, P. Di Nezza, M. Düren, M. Ehrenfried, A. Elalaoui-Moulay, G. Elbakian, F. Ellinghaus, U. Elschenbroich, J. Ely, R. Fabbri, A. Fantoni, A. Fechtchenko, L. Felawka, B. Fox, J. Franz, S. Frullani, Y. Gärber, G. Gapienko, V. Gapienko, F. Garibaldi, E. Garutti, D. Gaskell, G. Gavrilov, V. Gharibyan, G. Graw, O. Grebeniouk, L. G. Greeniaus, W. Haeberli, K. Hafidi, M. Hartig, D. Hasch, D. Heesbeen, M. Henoch, R. Hertenberger, W. H.A. Hesselink, A. Hillenbrand, Y. Holler, B. Hommez, G. Iarygin, A. Izotov, H. E. Jackson, A. Jgoun, R. Kaiser, E. Kinney, A. Kisselev, K. Königsmann, H. Kolster, M. Kopytin, V. Korotkov, V. Kozlov, B. Krauss, V. G. Krivokhijine, L. Lagamba, L. Lapikás, A. Laziev, P. Lenisa, P. Liebing, T. Lindemann, K. Lipka, W. Lorenzon, N. C.R. Makins, H. Marukyan, F. Masoli, F. Menden, V. Mexner, N. Meyners, O. Mikloukho, C. A. Miller, Y. Miyachi, V. Muccifora, A. Nagaitsev, E. Nappi, Y. Naryshkin, A. Nass, W. D. Nowak, K. Oganessyan, H. Ohsuga, G. Orlandi, S. Potashov, D. H. Potterveld, M. Raithel, D. Reggiani, P. E. Reimer, A. Reischl, A. R. Reolon, K. Rith, G. Rosner, A. Rostomyan, D. Ryckbosch, I. Sanjiev, I. Savin, C. Scarlett, A. Schäfer, C. Schill, G. Schnell, K. P. Schüler, A. Schwind, J. Seibert, B. Seitz, R. Shanidze, T. A. Shibata, V. Shutov, M. C. Simani, K. Sinram, M. Stancari, M. Statera, E. Steffens, J. J.M. Steijger, J. Stewart, U. Stösslein, H. Tanaka, S. Taroian, B. Tchuiko, A. Terkulov, S. Tessarin, E. Thomas, A. Tkabladze, A. Trzcinski, M. Tytgat, G. M. Urciuoli, P. B. Van Der Nat, G. Van Der Steenhoven, R. Van De Vyver, D. Veretennikov, M. C. Vetterli, V. Vikhrov, M. G. Vincter, J. Visser, M. Vogt, J. Volmer, C. Weiskopf, J. Wendland, J. Wilbert, T. Wise, S. Yen, S. Yoneyama, B. Zihlmann, H. Zohrabian, P. Zupranski

Research output: Contribution to journalArticlepeer-review

Abstract

The HERMES experiment has measured the transverse polarization of Λ and Λ̄ hyperons produced inclusively in quasireal photoproduction at a positron beam energy of 27.6 GeV. The transverse polarization PnΛ of the Λ hyperon is found to be positive while the observed Λ̄ polarization is compatible with zero. The values averaged over the kinematic acceptance of HERMES are PnΛ=0.078±0.006(stat)±0.012(syst) and PnΛ̄=-0.025±0.015(stat)±0.018(syst) for Λ and Λ̄, respectively. The dependences of PnΛ and PnΛ̄ on the fraction ζ of the beam's light-cone momentum carried by the hyperon and on the hyperon's transverse momentum pT were investigated. The measured Λ polarization rises linearly with pT and exhibits a different behavior for low and high values of ζ, which approximately correspond to the backward and forward regions in the center-of-mass frame of the γ*N reaction.

Original languageEnglish (US)
Article number092008
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume76
Issue number9
DOIs
StatePublished - Nov 28 2007

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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