Speaker
Description
Photonuclear interactions in ultraperipheral heavy-ion collisions can be used to improve our understanding of gluonic nuclear structure In particular, coherent photoproduction of vector mesons are processes sensitive to the gluon distribution of the target nucleus, especially at small values of the parton momentum fraction x, where the onset of gluon saturation effects is expected. A systematic study of exclusive vector meson production allows us to probe cold nuclear matter with different color dipole sizes, thus with different sensitivities to gluon saturation effects. In the case of heavy quarkonia production, the heavy quark masses set a sufficiently large scale that allows for an interpretation in terms of perturbative quantum chromodynamics calculations. In this talk, the first measurement and observation of exclusive coherent Y(1S) photoproduction in PbPb collisions by the CMS experiment will be presented. The measurement is compared to calculations based on small-x linear or nonlinear evolution.
| Category | Experiment |
|---|---|
| Collaboration | CMS |
