nucl-th digest · Feb 5, 2025

Absorption of $ψ (2 S)$ mesons in nuclei

In the present work we explore the inclusive $ψ (2 S)$ meson photoproduction from nuclei near the kinematic threshold within the collision model, based on the nuclear spectral function, for incoherent direct photon--nucleon charmonium creation processes. The model takes into account the final $ψ (2 S)$ absorption, target nucleon binding and Fermi motion. We calculate the absolute and relative excitation functions for production of $ψ (2 S)$ mesons on $^{12}$ C and $^{184}$ W target nuclei at near-threshold photon beam energies of 8.0--16.4 GeV, the absolute momentum differential cross sections for their production off these target nuclei at laboratory polar angles of 0 $^{\circ}$ --10 $^{\circ}$ , the momentum dependence of the ratio of these cross sections as well as the A-dependences of the ratios (transparency ratios) of the total cross cross sections for $ψ (2 S)$ production at photon energy of 13 GeV within the different scenarios for the $ψ (2 S) N$ absorption cross section. We also calculate the A-dependence of the ratio of $ψ (2 S)$ and $J / ψ$ photoproduction transparency ratios at photon energies around of 11.5 GeV within the adopted scenarios for this cross section. We demonstrate that both the absolute and relative observables considered reveal a definite sensitivity to these scenarios. Therefore, the measurement of such observables in future experiments at the upgraded up to 22 GeV CEBAF facility in the near-threshold energy region might shed light both on the $ψ (2 S) N$ absorption cross section and on its part associated with the nondiagonal process $ψ (2 S) + N \to J / ψ + N$ at finite momenta, which are of crucial importance in understanding of charmonium production and suppression in high-energy nucleus--nucleus collisions in a search for the quark-gluon plasma.

nucl-thhep-phnucl-exNPA(2025)·1 citation

Wednesday·February 5, 2025

Emission processes in a self-consistent field

Absorption of $ψ (2 S)$ mesons in nuclei

Affiliations

Emission processes in a self-consistent field

Absorption of ψ(2S) mesons in nuclei

Affiliations

Absorption of $ψ (2 S)$ mesons in nuclei