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Airapetian A, Akopov N, Akopov Z, Amarian M, Andrus A, Aschenauer EC, Augustyniak W, Avakian R, Avetissian A, Avetissian E, Bacchetta A, Bailey P, Balin D, Beckmann M, Belostotski S, Bianchi N, Blok HP, Böttcher H, Borissov A, Borysenko A, Bouwhuis M, Brüll A, Bryzgalov V, Capitani GP, Cappiluppi M, Chen T, Ciullo G, Contalbrigo M, Dalpiaz PF, Leo RD, Demey M, Nardo LD, Sanctis ED, Devitsin E, Nezza PD, Düren M, Ehrenfried M, Elalaoui-Moulay A, Elbakian G, Ellinghaus F, Elschenbroich U, Fabbri R, Fantoni A, Fechtchenko A, Felawka L, Frullani S, Gapienko G, Gapienko V, Garibaldi F, Garrow K, Gavrilov G, Gharibyan V, Grebeniouk O, Gregor IM, Hadjidakis C, Hafidi K, Hartig M, Hasch D, Henoch M, Hesselink WHA, Hillenbrand A, Hoek M, Holler Y, Hommez B, Hristova I, Iarygin G, Ilyichev A, Ivanilov A, Izotov A, Jackson HE, Jgoun A, Kaiser R, Kinney E, Kisselev A, Kobayashi T, Kopytin M, Korotkov V, Kozlov V, Krauss B, Krivokhijine VG, Lagamba L, Lapikás L, Laziev A, Lenisa P, Liebing P, Linden-Levy LA, Lorenzon W, Lu H, Lu J, Lu S, Ma BQ, Maiheu B, Makins NCR, Mao Y, Marianski B, Marukyan H, Masoli F, Mexner V, Meyners N, Michler T, Mikloukho O, Miller CA, Miyachi Y, Muccifora V, Nagaitsev A, Nappi E, Naryshkin Y, Nass A, Negodaev M, Nowak WD, Oganessyan K, Ohsuga H, Osborne A, Pickert N, Potterveld DH, Raithel M, Reggiani D, Reimer PE, Reischl A, Reolon AR, Riedl C, Rith K, Rosner G, Rostomyan A, Rubacek L, Rubin J, Ryckbosch D, Salomatin Y, Sanjiev I, Savin I, Schäfer A, Schill C, Schnell G, Schüler KP, Seele J, Seidl R, Seitz B, Shanidze R, Shearer C, Shibata TA, Shutov V, Sinram K, Sommer W, Stancari M, Statera M, Steffens E, Steijger JJM, Stenzel H, Stewart J, Stinzing F, Tait P, Tanaka H, Taroian S, Tchuiko B, Terkulov A, Trzcinski A, Tytgat M, Vandenbroucke A, van der Nat PB, van der Steenhoven G, van Haarlem Y, Vetterli MC, Vikhrov V, Vincter MG, Vogel C, Volmer J, Wang S, Wendland J, Wilbert J, Smit GY, Ye Y, Ye Z, Yen S, Zihlmann B, Zupranski P. Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target. Phys Rev Lett 2005; 94:012002. [PMID: 15698069 DOI: 10.1103/physrevlett.94.012002] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2004] [Indexed: 05/24/2023]
Abstract
Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion (phi) and the target spin axis (phi(S)) about the virtual-photon direction and relative to the lepton scattering plane. The extracted Fourier component sin((phi+phi(S))(pi)(UT) is a signal of the previously unmeasured quark transversity distribution, in conjunction with the Collins fragmentation function, also unknown. The component sin((phi-phi(S)(pi)(UT) arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production.
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Affiliation(s)
- A Airapetian
- Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1120, USA
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