Double spin asymmetry in exclusive ρ0 muonproduction at COMPASS

Alekseev 29, M.; Alexakhin 8, V. Y. u.; Alexandrov 18, Y. u.; Alexeev 8, G. D.; Amoroso 29, . A.; Arbuzov 8, A.; Bade lek 30, . B.; Balestra 29, F.; Ball 25, . J.; Baum 1, . G.; Barth 4, . J.; Bedfer 25, . Y.; Bernet 25, . C.; Bertini 29, . R.; Bettinelli 19, M.; Birsa 28, . R.; Bisplinghoff 3, J.; Bordalo 15, . P.; A,; Bradamante 28, . F.; Bravar 16, . A.; Bressan 28, . A.; Brona 30, . G.; Burtin 25, . E.; Bussa 29, . M. P.; Chapiro 27, A.; Chiosso 29, M.; Cicuttin 27, A.; Colantoni 29, M.; B,; Costa 29, . S.; Crespo 27, . M. L.; d’Hose 25, . N.; Dalla Torre 28, S.; Das 7, . S.; Dasgupta 6, S. S.; DeMasi 20, . R.; Dedek 19, N.; Denisov 29, O. Y. u.; C,; Dhara 7, . L.; Diaz 27, . V.; Dinkelbach 20, A. M.; Donskov 24, . S. V.; Dorofeev 24, V. A.; Doshita 21, . N.; Duic 28, . V.; ̈ unnweber 19, . W. D.; Eversheim 3, P. D.; Eyrich 9, W.; Fabro 28, . M.; Faessler 19, . M.; Falaleev 11, V.; Ferrero 29, A.; Ferrero 29, L.; Finger 22, . M.; . M. F. i. n. g. e. r. j. r. 8, .; Fischer 10, H.; Franco 15, . C.; Franz 10, . J.; Friedrich 20, J. M.; Frolov 29, . V.; C,; Garfagnini 29, R.; Gautheron 1, F.; Gavrichtchouk 8, O. P.; Gazda 30, . R.; Gerassimov 18, . S.; 20,; Geyer 19, R.; Giorgi 28, . M.; Gobbo 28, . B.; Goertz 2, . S.; 4,; Gorin 24, A. M.; Grabm ̈ uller 20, . S.; Grajek 30, . O. A.; Grasso 29, . A.; Grube 20, . B.; Gushterski 8, . R.; Guskov 8, . A.; Haas 20, F.; Hannappel 4, J.; von Harrach 16, D.; Hasegawa 17, . T.; Heckmann 2, . J.; Hedicke 10, . S.; Heinsius 10, F. H.; Hermann 16, . R.; Heß 2, C.; Hinterberger 3, . F.; vonHodenberg 10, . M.; Horikawa 21, . N.; D,; Horikawa 21, . S.; Ilgner 19, . C.; Ioukaev 8, . A. I.; Ishimoto 21, S.; Ivanov 8, . O.; Ivanshin 8, . Y. u.; Iwata 21, . T.; 32,; Jahn 3, . R.; Janata 8, A.; Jasinski 16, . P.; Joosten 3, . R.; Jouravlev 8, N. I.; Kabuß 16, E.; Kang 10, . D.; Ketzer 20, B.; Khaustov 24, G. V.; Khokhlov 24, Y. u. A.; Kisselev 1, Y. u.; 2,; Klein 4, F.; Klimaszewski 30, K.; Koblitz 16, S.; Koivuniemi 13, J. H.; Kolosov 24, V. N.; Komissarov 8, E. V.; Kondo 21, K.; ̈ onigsmann 10, K. K.; Konorov 18, I.; 20,; Konstantinov 24, V. F.; Korentchenko 8, A. S.; Korzenev 16, A.; C,; Kotzinian 8, A. M.; 29,; Koutchinski 8, N. A.; Kouznetsov 8, O.; 25,; Kravchuk 8, . N. P.; Kral 23, . A.; Kroumchtein 8, Z. V.; Kuhn 20, R.; Kunne 25, F.; Kurek 30, K.; Ladygin 24, M. E.; Lamanna 11, M.; 28,; LeGoff 25, . J. M.; Lednev 24, A. A.; Lehmann 9, . A.; Lichtenstadt 26, . J.; Liska 23, T.; Ludwig 10, I.; Maggiora 29, A.; Maggiora 29, M.; Magnon 25, A.; Mallot 11, G. K.; E,; Mann 20, . A.; Marchand 25, C.; Marroncle 25, J.; Martin 28, . A.; Marzec 31, J.; Massmann 3, F.; Matsuda 17, T.; Maximov 8, A. N.; Meyer 2, W.; Mielech 28, A.; 30,; Mikhailov 24, Y. u. V.; Moinester 26, . M. A.; Mutter 10, A.; 16,; ̈ ahle 3, . O. N.; Nagaytsev 8, A.; Nagel 20, T.; Nassalski 30, J.; Neliba 23, S.; Nerling 10, F.; Neubert 20, . S.; Neyret 25, . D. P.; Nikolaenko 24, V. I.; Nikolaev 8, K.; Olshevsky 8, A. G.; Ostrick 4, . M.; Padee 31, . A.; Pagano 28, P.; Panebianco 25, . S.; Panknin 4, . R.; Panzieri 29, . D.; B,; Paul 20, . S.; Pawlukiewicz Kaminska 30, B.; Peshekhonov 8, . D. V.; Peshekhonov 8, . V. D.; Piragino 29, G.; Platchkov 25, . S.; Pochodzalla 16, J.; Polak 14, J.; Polyakov 24, V. A.; Pretz 4, . J.; Procureur 25, S.; Quintans 15, . C.; Rajotte 19, J. F.; Rapatsky 8, V.; Ramos 15, S.; A,; Reicherz 2, G.; Richter 9, . A.; Robinet 25, . F.; Rocco 28, E.; 29,; Rondio 30, E.; Rozhdestvensky 8, A. M.; Ryabchikov 24, D. I.; Samoylenko 24, V. D.; Sandacz 30, A.; Santos 15, . H.; Sapozhnikov 8, M. G.; Sarkar 7, S.; Savin 8, I. A.; Schiavon 28, . P.; Schill 10, C.; Schmitt 20, . L.; Sch ̈ onmeier 9, . P.; Schr ̈ oder 9, . W.; Shevchenko 8, O. Y. u.; Siebert 12, H. W.; 16,; Silva 15, L.; Sinha 7, L.; Sissakian 8, A. N.; Slunecka 8, M.; Smirnov 8, . G. I.; Sosio 29, . S.; Sozzi 28, . F.; Sugonyaev 24, V. P.; Srnka 5, . A.; Stinzing 9, . F.; Stolarski 30, . M.; 10,; Sulc 14, M.; Sulej 31, R.; Takabayashi 21, N.; Tchalishev 8, V. V.; Tessaro 28, S.; Tessarotto 28, F.; Teufel 9, . A.; Tkatchev 8, . L. G.; Venugopal 3, G.; Virius 23, M.; Vlassov 8, N. V.; Vossen 10, A.; Webb 9, . R.; Weise 3, . E.; Weitzel 20, Q.; Windmolders 4, R.; Wirth 9, . S.; Wi ́ slicki 30, . W.; Zaremba 31, K.; Zavertyaev 18, . M.; Zemlyanichkina 8, E.; Zhao 16, . J.; Ziegler 3, . R.; Zvyagin 19, A.; Alekseev, M; Panzieri, Daniele

doi:10.1140/epjc/s10052-007-0376-6

The longitudinal double spin asymmetry A1 ρ for exclusive leptoproduction of ρ0 mesons, μ+N→μ+N+ρ, is studied using the COMPASS 2002 and 2003 data. The measured reaction is incoherent exclusive ρ0 production on polarised deuterons. The Q2 and x dependence of A1 ρ is presented in a wide kinematical range, 3×10-3<Q2< 7 (GeV/c)2 and 5×10-5<x<0.05. The results presented are the first measurements of A1 ρ at small Q2 (Q2< 0.1 (GeV/c)2) and small x (x<3×10-3). The asymmetry is in general compatible with zero in the whole kinematical range.