First measurement of the $|t|$-dependence of incoherent J/$ψ$ photonuclear production

Description
Figures from paper submitted to Physical Review Letters
Abstract:

The first measurement of the cross section for incoherent photonuclear production of J/$\psi$ vector meson as a function of the Mandelstam $|t|$ variable is presented. The measurement was carried out with the ALICE detector at midrapidity, $|y|<~0.8$, using ultra-peripheral collisions of Pb nuclei at a centre-of-mass energy per nucleon pair $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV. This rapidity interval corresponds to a Bjorken-$x$ range $(0.3$$-$$1.4)\times 10^{-3}$. Cross sections are reported in five $|t|$ intervals in the range $0.04<~|t|<~1$~GeV$^2$ and compared to the predictions of different models. Models that ignore quantum fluctuations of the gluon density in the colliding hadron predict a $|t|$-dependence of the cross section much steeper than in data. The inclusion of such fluctuations in the same models provides a better description of the data.

e-Print: arXiv:2305.06169 | PDF | inSPIRE

Paper:

Energy
5.02 TeV
System
Pb-Pb
Scope: PWG
PWG-UD (Ultraperipheral and Diffraction)
Figure image (.eps)
Energy
5.02 TeV
System
Pb-Pb
Scope: PWG
PWG-UD (Ultraperipheral and Diffraction)
Figure image (.eps)
Energy
5.02 TeV
System
Pb-Pb
Scope: PWG
PWG-UD (Ultraperipheral and Diffraction)
Figure image (.eps)