| Abstract |
The elastic electroproduction of rho mesons is studied at HERA with the H1 detector in the kinematic range 8 < Q^2 < 60 GeV^2, 40 < W < 180 GeV and |t| < 0.5 GeV^2. The luminosity of 42.4 pb-1 gives access to the Q^2 domain where perturbative QCD is expected to apply. The cross section has been measured as a function of Q^2, W and t. The W dependence of the gamma^* p -> rho p cross section is observed to become stronger with increasing Q^2, changing from a behaviour compatible with soft Pomeron exchange at low Q^2 to a hard dependence at large Q^2. Spin density matrix elements are measured as a function of Q^2, W and t. Significant t dependent violations of s-channel helicity conservation are observed. |
