Diffractive φ and ρ production in a perturbative QCD model

The elastic leptoproduction of $\ensuremath{\varphi}$ measured by the H1 Collaboration at DESY HERA is described by a perturbative QCD model, based on open $s\overline{s}$ production and parton hadron duality, proposed by Martin et al. We observe that both the total cross section and the ratio of the longitudinal and transverse cross sections are well reproduced with an effective strange-quark mass ${m}_{s}\ensuremath{\sim}370\ensuremath{-}400 \mathrm{MeV}$ for various gluon distribution functions. The possible connection of the effective mass and the momentum dependent dynamical mass associated with dynamical breaking of chiral symmetry is discussed. The $\ensuremath{\rho}$ leptoproduction data are also well reproduced with an effective quark mass $\ensuremath{\sim}315 \mathrm{MeV}.$