Related papers: STAR UPC Results
The lepton pair production in ultra-peripheral collisions (UPC) is studied in the classical field approximation. We derive a general form of the cross section in terms of photon distributions which depend on the transverse momentum and…
Due to coherence, there are strong electromagnetic fields of short duration in very peripheral collisions. They give rise to photon-photon and photon-nucleus collisions with high flux up to an invariant mass region hitherto unexplored…
Ultra-peripheral heavy ion collisions involve long range electromagnetic interactions at impact parameters larger than twice the nuclear radius, where no hadronic nucleon-nucleon collisions occur. The first observation of coherent rho…
We calculate the total cross sections and probabilities of electromagnetic productions of electron, muon and tauon pair productions simultaneously. At the Large Hadron Collider (LHC), the available electromagnetic energy is sufficient to…
Ultra-relativistic heavy-ions carry strong electromagnetic and nuclear fields. Interactions between these fields in peripheral nucleus-nucleus collisions can probe many interesting physics topics. This presentation will focus on coherent…
At the initial stage of nuclear-nuclear collisions, heavy quarks are generated in hard partonic scatterings. This allows them to participate in the entire evolution of the heavy-ion collisions. During hadronization, different type of…
Peripheral collisions of relativistic heavy ions uniquely probe many aspects of QED. Examples include $e^+e^-$ pair production and nuclear excitation in strong fields. After discussing these reactions, I will draw parallels between…
The strong electromagnetic fields carried by relativistic highly charged ions make heavy-ion colliders attractive places to study photonuclear interactions and two-photon interactions. At RHIC, three experiments have studied coherent…
Vector meson photoproduction at high energies has attracted increased interest in recent years due to the unique kinematical ranges offered by the LHC experiments. The ALICE and LHCb collaborations have provided measurements of vector meson…
In recent years, a large number of papers have appeared that dealt with $\EPEM$ pair production in heavy ion collisions at high energies. To a large extent these studies were motivated by the existence of relativistic heavy ion accelerators…
High energy photons originating from the electromagnetic field of ultrarelativistic lead nuclei can interact with the other lead ion. These reactions are studied in the ultra-peripheral heavy ion collisions to probe the physics of strong…
Vector meson photoproduction is an important probe of nuclear structure. Light vector mesons are most sensitive to low$-x$ structure, as long as they are not too light for perturbative QCD calculations. The $\rho'$ is of interest as an…
Photons emitted from the electromagnetic fields of relativistic heavy ions can fluctuate into quark anti-quark pairs and scatter from a target nucleus, emerging as vector mesons. These coherent interactions are identifiable by final states…
Exclusive vector meson photoproduction, $pp\to ppV$ and $\bar pp\to\bar ppV$ occurs with significant rates at hadron colliders. The reaction can be used to study the gluon distribution of protons. Vector mesons may be produced with either…
A simple schematic model anchored on the notion of hadronic freedom inferred from hidden local symmetry in the vector manifestation, the infinite tower of vector mesons in holographic QCD and "stickiness" of $\pi\pi$ interactions inferred…
We present an updated theoretical treatment of ultraperipheral collisions (UPCs) of heavy ions, within the SuperChic Monte Carlo generator. This in particular accounts for mutual ion excitation through additional photon exchanges between…
Recently, significant enhancements of $e^{+} e^{-}$ pair production at very low transverse momentum ($p_{T} < 0.15$ GeV/c) were observed by the STAR collaboration in peripheral hadronic A+A collisions. This excesses can not be described by…
We present a unified description of the vector meson and dilepton production in elementary and in heavy ion reactions. The production of vector mesons is described via the excitation of nucleon resonances. Medium effects in heavy ion…
This article gives an overview of recent highlights from experimental measurements of heavy-ion collisions at ultra-relativistic energies: Measurements of electroweak probes constrain both the initial collision geometry and the nuclear…
An introductory overview of electromagnetic probes in ultra-relativistic heavy-ion collisions is provided. Experimental evidence supporting the production of thermal photons and dileptons in heavy-ion collisions at the Relativistic Heavy…