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arXiv · 1204.2281

The dipole representation of vector meson electroproduction beyond leading twist

A. Besse·L. Szymanowski·S. Wallon
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Abstract

We link the recent computation beyond leading twist of the impact factor of the transition gamma*T -> rhoT performed in the light-cone collinear approach, to the dipole picture by expressing the hard part of the process through its Fourier transform in coordinate space. We show that in the Wandzura-Wilczek approximation the impact factor up to twist 3 factorises in the wave function of the photon combined with the distribution amplitudes of the rho-meson and the colour dipole scattering amplitude with the t-channel gluons. We show also that beyond the Wandzura-Wilczek approximation, the hard contribution of the amplitude still exhibits the signature of the interaction of a single colour dipole with the t-channel gluons. This result allows a phenomenological approach of the helicity amplitudes of the leptoproduction of vector meson, by combining our results to a dipole/target scattering amplitude model.

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A. Besse, L. Szymanowski, S. Wallon. 2012-04-10. The dipole representation of vector meson electroproduction beyond leading twist. https://doi.org/10.1016/j.nuclphysb.2012.09.011

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