Double spin asymmetry in exclusive ρ0 muoproduction at COMPASS

Yamagata University Yamagata 992-8510 Japan
European Physical Journal C (Impact Factor: 5.44). 09/2007; 52(2):255-265. DOI: 10.1140/epjc/s10052-007-0376-6

ABSTRACT 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.

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