Adrien Besse*, 1, Lech Szymanowski2, Samuel Wallon3, 4
1 Irfu-SPhN, CEA, Saclay, France
2 National Centre for Nuclear Research (NCBJ), Warsaw, Poland
3 LPT, Université Paris-Sud, CNRS, 91405, Orsay, France
4 UPMC Univ. Paris 06, Faculté de physique, 4 place Jussieu, 75252 Paris Cedex 05, France
We investigate the longitudinal and transverse polarized cross-sections of the leptoproduction of the ρ meson in the high energy limit. Our model is based on the computation of the impact factor γ*(λγ)→ ρ (λρ) using the twist expansion in the forward limit which is expressed in the impact parameter space. This treatment involves in the final stage the twist 2 and twist 3 distribution amplitudes (DAs) of the ρ meson and the dipole scattering amplitude. Taking models that exist for the DAs and for the dipole cross-section. We get a phenomenological model for the helicity amplitudes. We compare our predictions with HERA data and get a fairly good description for large enough virtualities of the photon.
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* Address correspondence to this author at the Irfu-SPhN, CEA, Saclay,
France; Tel: +33 1 69 08 74 29; Fax: +33 1 69 08 75 84; E-mail: email@example.com§Presented at the Low x workshop, May 30 - June 4 2013, Rehovot and Eilat, Israel.