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Interplay of Interference Effects in Production of $J/Ψ$ and $Ψ'$ off Nuclei

Joerg Huefner·Boris Kopeliovich
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Abstract

Our main observations are: (i) The effective path length of the $c\bar c$ wave packet, which is produced in the nucleus, grows with the energy of the produced charmonium. The variation is controlled by the coherence length $l_c=2E_Ψ/M^2_Ψ$. (ii) A colorless $c\bar c$ wave packet produced in $pp$-interaction is a specific linear combination of the $J/Ψ$ and $Ψ'$ states, and interacts substantially weaker that any of its components. The time evolution of this wave packet is controlled by the formation length, $l_f=2E_Ψ/(M^2_{Ψ'} - M^2_Ψ)$. Exact formulas incorporating with these effects are derived. The interplay of the two phenomena results in a nontrivial energy- and $x_F$-dependence of the nuclear suppression of the charmonium production in proton-nucleus and nucleus-nucleus collisions and explains some of the experimentally observed effects.

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Joerg Huefner, Boris Kopeliovich. 1996-07-17. Interplay of Interference Effects in Production of $J/Ψ$ and $Ψ'$ off Nuclei. https://arxiv.org/abs/nucl-th/9606010

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