Conveners
Parallel session 15: Physics of ultraperipheral collisions I
- Andre Govinda Stahl (CERN)
In an ultra-peripheral collision, where the impact parameter is larger than the sum of the nuclear radii, the nuclei mainly interact electromagnetically. These reactions are mediated by virtual photons. A photon can interact with a gluon in the target nucleus and produce a pair of charm quarks. These charm quarks then fragment and are observed as open charm hadrons ($\rm D^{0}$, $\rm D^{∗}...
According to quantum chromodynamics, at high energy, hadrons exhibit a dynamic equilibrium between gluon splitting and recombination, known as saturation. Diffractive photonuclear production of J/ψ vector mesons provides unique insights into the gluon distribution of hadrons. The Mandelstam-t variable, representing the momentum transfer, probes hadron structure within the impact-parameter...
The fully stripped ions used in heavy ion collisions at the LHC are an excellent source of high-energy quasi-real photons. These can interact with photons emitted by the oncoming nucleus, or with the nucleus itself, either directly in inelastic processes or diffractively via pomeron exchange. Diffractive photonuclear processes can produce exclusive vector mesons that are uniquely sensitive...
In ultra-relativistic heavy ion collisions, the charged ions produce an intense flux of equivalent photons. Photon-induced processes are the dominant interaction mechanism when the colliding nuclei have an impact parameter larger than the nuclear diameter. In these ultra-peripheral collisions (UPCs), the photon provides a clean, energetic probe of the partonic structure of the nucleus,...
The ultraperipheral collisions are a source of various interesting phenomena based on photon-induced reactions. We calculate cross sections for single and any number of n, p, $\alpha$, $\gamma$ in ultraperipheral heavy-ion collision for LHC energies emitted in forward/backward directions. We analyze the production of a given number of neutrons relevant for a recent ALICE experiment [1] using...
