The first measurement of the cross section for coherent J/ψ photoproduction as a function of |t|, the square of the momentum transferred between the incoming and outgoing target nucleus, is presented. The data were measured with the ALICE detector in ultra-peripheral Pb–Pb collisions at a centre-of-mass energy per nucleon pair sNN=5.02TeV with the J/ψ produced in the central rapidity region |y|<0.8, which corresponds to the small Bjorken-x range (0.3−1.4)×10−3. The measured |t|-dependence is not described by computations based only on the Pb nuclear form factor, while the photonuclear cross section is better reproduced by models including shadowing according to the leading-twist approximation, or gluon-saturation effects from the impact-parameter dependent Balitsky–Kovchegov equation. These new results are therefore a valid tool to constrain the relevant model parameters and to investigate the transverse gluonic structure at very low Bjorken-x.

Acharya S., Adamova D., Adler A., Adolfsson J., Aglieri Rinella G., Agnello M., et al. (2021). First measurement of the |t|-dependence of coherent J/ψ photonuclear production. PHYSICS LETTERS. SECTION B, 817, 1-13 [10.1016/j.physletb.2021.136280].

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

Alici A.;Arcelli S.;Bellini F.;Carnesecchi F.;Cifarelli L.;Colocci M.;Ercolessi F.;Giacalone M.;Jacazio N.;Rubini N.;Scioli G.;
2021

Abstract

The first measurement of the cross section for coherent J/ψ photoproduction as a function of |t|, the square of the momentum transferred between the incoming and outgoing target nucleus, is presented. The data were measured with the ALICE detector in ultra-peripheral Pb–Pb collisions at a centre-of-mass energy per nucleon pair sNN=5.02TeV with the J/ψ produced in the central rapidity region |y|<0.8, which corresponds to the small Bjorken-x range (0.3−1.4)×10−3. The measured |t|-dependence is not described by computations based only on the Pb nuclear form factor, while the photonuclear cross section is better reproduced by models including shadowing according to the leading-twist approximation, or gluon-saturation effects from the impact-parameter dependent Balitsky–Kovchegov equation. These new results are therefore a valid tool to constrain the relevant model parameters and to investigate the transverse gluonic structure at very low Bjorken-x.
2021
Acharya S., Adamova D., Adler A., Adolfsson J., Aglieri Rinella G., Agnello M., et al. (2021). First measurement of the |t|-dependence of coherent J/ψ photonuclear production. PHYSICS LETTERS. SECTION B, 817, 1-13 [10.1016/j.physletb.2021.136280].
Acharya S.; Adamova D.; Adler A.; Adolfsson J.; Aglieri Rinella G.; Agnello M.; Agrawal N.; Ahammed Z.; Ahmad S.; Ahn S.U.; Akbar Z.; Akindinov A.; Al...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/847344
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