Diffractive production of ρ-mesons and of ρπ-systems by neutrinos and antineutrinos on protons

Evidence is presented for diffractive production of ρ-mesons and of ρπ-systems in vp andbar ν p chargedcurrent interactions. In the (anti-)neutrino energy range 10 GeV< E _v <60 GeV the cross sections for diffractive ρ and diffractive ρπ production are found to be (0.64±0.14 (stat.)±0.08 (syst.))% and (0.28±0.08 (stat.)±0.04 (syst.))% of the charged-current cross section. The diffractive ρπ signal is consistent with being entirely due to diffractive a ₁ production. However, the data cannot distinguish between diffractive a ₁ and diffractive nonresonant ρπ production. The experimental distributions of W, Q ², x _Bj and y _Bj for diffractive ρ and ρπ events are consistent with model predictions.