Diffractive ρ0 production at COMPASS experiment

The helicity structure of the diffractive leptoproduction of ρ mesons, μ+N→μ+N+ρ, is studied and preliminary results on several spin density matrix elements and R=σL/σT for incoherent exclusive ρ0 production from COMPASS 2002 data are presented. The elements r0004, r1−104, ℑmr1−13, r1−11 and R are measured at 〈W〉=10 GeV in a wide range of Q2, 0.01