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arXiv · hep-ph/9709376

Inelastic photoproduction of polarised $J/ψ$

M. Beneke·M. Krämer·M. Vänttinen
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Abstract

The comparison of $J/ψ$ photoproduction data in the inelastic region with theoretical predictions based on the NRQCD approach has remained somewhat ambiguous and controversial, in particular at large values of the inelasticity variable $z$. We study the polar and azimuthal decay angular distribution of $J/ψ$ mesons as functions of $z$ and transverse momentum $p_t$. Future measurements of decay angular distributions at the HERA $ep$ collider will provide a new test of theoretical approaches to factorisation between perturbation theory and quarkonium bound-state dynamics and shed light on the colour-octet production fraction in various regions of $z$ and $p_t$.

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M. Beneke, M. Krämer, M. Vänttinen. 1997-09-17. Inelastic photoproduction of polarised $J/ψ$. https://doi.org/10.1103/physrevd.57.4258

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