# Diffractive photoproduction of $\rho$ mesons with large momentum transfer at HERA.

Abstract : The diffractive photoproduction of rho mesons, e p \to e rho Y, with large momentum transfer squared at the proton vertex, |t|, is studied with the H1 detector at HERA using an integrated luminosity of 20.1 pb^{-1}. The photon-proton centre of mass energy spans the range 75 < W < 95 GeV, the photon virtuality is restricted to Q^2 < 0.01 GeV^2 and the mass M_Y of the proton remnant is below 5 GeV. The t dependence of the cross section is measured for the range 1.5 < |t| < 10.0 GeV^2 and is well described by a power law, dsigma/ d|t| \propto |t|^{-n}. The spin density matrix elements, which provide information on the helicity structure of the interaction, are extracted using measurements of angular distributions of the rho decay products. The data indicate a violation of s-channel helicity conservation, with contributions from both single and double helicity-flip being observed. The results are compared to the predictions of perturbative QCD models.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00078863
Contributor : Sabine Starita <>
Submitted on : Monday, January 8, 2007 - 2:48:23 PM
Last modification on : Wednesday, September 16, 2020 - 4:24:43 PM

### Citation

A. Aktas, V. Andreev, T. Anthonis, S. Aplin, A. Asmone, et al.. Diffractive photoproduction of $\rho$ mesons with large momentum transfer at HERA.. Physics Letters B, Elsevier, 2006, 638, pp.422-431. ⟨10.1016/j.physletb.2006.05.042⟩. ⟨in2p3-00078863⟩

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