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Exclusive dielectron production in ultraperipheral Pb+Pb collisions at psNN = 5.02 TeV with ATLAS

Publikace na Matematicko-fyzikální fakulta |
2023

Tento text není v aktuálním jazyce dostupný. Zobrazuje se verze "en".Abstrakt

Exclusive production of dielectron pairs,

! e+e-, is studied using Lint = 1.72 nb-1 of data from ultraperipheral collisions of lead nuclei at p sNN = 5.02TeV recorded by the ATLAS detector at the LHC. The process of interest proceeds via photon-photon interactions in the strong electromagnetic fields of relativistic lead nuclei. Dielectron production is measured in the fiducial region defined by following requirements: electron transverse momentum pe

T > 2.5 GeV, absolute electron pseudorapidity |e| < 2.5, dielectron invariant mass mee > 5 GeV, and dielectron transverse momentum pee

T < 2 GeV. Differential cross-sections are measured as a function of mee, average pe

T, absolute dielectron rapidity

|yee|, and scattering angle in the dielectron rest frame, | cos |, in the inclusive sample, and also with a requirement of no activity in the forward direction. The total integrated fiducial cross-section is measured to be 215 +- 1(stat.) +23

-20(syst.) +- 4(lumi.) μb. Within experimental uncertainties the measured integrated cross-section is in good agreement with the QED predictions from the Monte Carlo programs Starlight and SuperChic, confirming the broad features of the initial photon fluxes. The differential cross-sections show systematic differences from these predictions which are more pronounced at high |yee| and

| cos | values.