CERN Accelerating science

ATLAS Slides
Report number	ATL-PHYS-SLIDE-2023-658
Title	Measurement of dilepton production from photon fusion processes in UPC in Pb+Pb collisions with the ATLAS detector
Author(s)	Grabowska-Bold, Iwona (AGH University of Krakow (PL))
Corporate author(s)	The ATLAS collaboration
Collaboration	ATLAS Collaboration
Submitted by	iwona.grabowska@cern.ch on 09 Jan 2024
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Free keywords	UPC ; dilepton ; exclusive processes ; non-UPC dimuons ; HEAVYIONS
Abstract	Relativistic heavy-ion beams at the LHC are accompanied by a large flux of equivalent photons, leading to multiple photon-induced processes. This talk presents a series of measurements of dilepton production from photon fusion performed by the ATLAS Collaboration. Recent measurements of exclusive dielectron production in ultra-peripheral collisions (UPC) are presented. These processes provide strong constraints on the nuclear photon flux and its dependence on the impact parameter and photon energy. Comparisons of the measured cross-sections to QED predictions from the Starlight and SuperChic models are also presented. Tau-pair production measurements can constrain the tau lepton's anomalous magnetic dipole moment (g-2), and a recent ATLAS measurement using muonic decays of tau leptons in association with electrons and tracks provides one of the most stringent limits available to date.