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On relative contributions of fusion and fragmentation mechanisms in J/psi photoproduction at high energy

V. A. Saleev·A. V. Shipilova
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Abstract

We study J/psi photoproduction via the fusion and fragmentation mechanisms at the HERA Collider within the frameworks of the collinear parton model and the quasi-multi-Regge kinematics approach using the factorization formalism of non-relativistic QCD at leading order in the strong-coupling constant alpha_s and the relative velocity v of the bound quarks. It is shown that the fusion production mechanism dominates over the fragmentation production mechanism at the all relevant J/psi transverse momenta. The J/psi meson p_T-spectra in the fragmentation and fusion production at the asymptotically large p_T have equal slopes in the quasi-multi-Regge kinematics approach, oppocite the collinear parton model.

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V. A. Saleev, A. V. Shipilova. 2006-12-19. On relative contributions of fusion and fragmentation mechanisms in J/psi photoproduction at high energy. https://doi.org/10.1103/physrevd.75.034012

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