The anomalous magnetic moment of the tau lepton ($a_{\tau}$) is a sensitive probe for the search for deviations from the Standard Model predictions and thus for new physics. This study investigates the feasibility of measuring $a_{\tau}$ using ultra-peripheral collisions (UPCs) at the LHC, where photon-photon interactions ($\gamma\gamma\to \tau^+\tau^-$) produce tau lepton pairs. We focus on...
In ultra-relativistic heavy-ion collisions, high rates of $\gamma\gamma$ processes occur through the interaction of the large electromagnetic fields of the heavy nuclei. For large impact parameters between the nuclei, i.e. interaction distances larger than the nuclei's radii, the di-photon interaction can be the only one taking place, leading to very clean signatures in the detector. One of...
To be included
I will discuss the recent NLO calculations for gamma-gamma physics.
The current state of art estimations lead to cross sections
for $AA \to \gamma \gamma AA$ which are somewhat
smaller than the measured ones by the ATLAS and CMS Collaborations.
We calculate inelastic contribution to $\gamma \gamma \to \gamma \gamma$
scattering process in $A A \to \gamma \gamma X Y$ where $X, Y = A, A'$.
We include processes of coupling of photons to individual...
In ultra-relativistic heavy-ion collisions, the Lorentz-contracted electromagnetic fields of the ions generate intense quasi-real photon fluxes. These lead to photon-induced interactions that have been observed in ultra-peripheral collisions (UPCs), such as vector meson and lepton-pair production. The high photon flux also enables the occurrence of multiple photon-induced processes in a single...
Kaon pairs can be produced via photoproduction ($\gamma$-Pomeron) or photon-photon fusion ($\gamma\gamma$). A significant contribution to kaon pair production comes from the decay of scalar, tensor, and vector mesons. The study will provide a comprehensive description of dikaon production at both the elementary ($\gamma\gamma \to m \to K^+ K^-$) and nuclear ($Pb Pb \to Pb Pb K^+ K^-$) levels....
One of the most pressing questions in both hot and cold QCD communities is what the physics mechanism responsible for modified parton densities in heavy nuclei is. One promising channel to address this question is the photoproduction of vector mesons, which is considered a clean probe to the nuclear parton structures.
We present a measurement of $\pi^+\pi^-\pi^+\pi^-$ and $\pi^+\pi^-$...
Relativistic heavy-ion collisions generate extremely strong electromagnetic (EM) fields, providing an ideal environment to study the EM excitation of the vacuum. The Breit-Wheeler process, which involves the electron-position pair production via photon-photon interactions, represents the lowest-order decay mode of the QED vacuum excitation. This process was first observed by the STAR...
In recent years, the description of lepton-pair production in ultra-peripheral collisions (UPCs) of heavy nuclei has attracted significant attention, particularly with the release of new RHIC data. The description of this process can be achieved by introducing the so-called Wigner distribution of the photons. They are related via Fourier transform to the generalised transverse momentum...
Photon-induced processes in ultra-peripheral collisions have attracted considerable attention in recent years due to their potential to probe various aspects of nuclear and particle physics. A key feature of these processes is the azimuthal modulation of particle production, which provides critical insights into the underlying dynamics of interactions involving quasi-real photons. In this talk...
In ultraperipheral collisions, the invariant mass spectrum of $\pi^+ \pi^-$ pairs is very complex due to the numerous production channels and intermediate states. The quantum ambiguity between production channels, referred to as the Entanglement Enabled Spin Interference (EESI) effect, leads to angular anisotropy in the final state. The most dominant contribution to the invariant mass spectrum...
In ultraperipheral Pb+Pb collisions, intense electromagnetic fields enable the generation of magnetic monopole pairs via the Schwinger mechanism. Due to their high ionization and unique trajectories in a solenoidal magnetic field, monopoles are expected to leave a large number of clusters in the innermost ATLAS pixel detector without associated reconstructed charged-particle tracks or...
