Articulo
Observation of Light-by-Light Scattering in Ultraperipheral Pb + Pb Collisions with the ATLAS Detector
Registro en:
issn:1079-7114
issn:0031-9007
Autor
Alconada Verzini, María Josefina
Alonso, Francisco
Arduh, Francisco Anuar
Dova, María Teresa
Hoya, Joaquín
Monticelli, Fernando Gabriel
Orellana, Gonzalo Enrique
Wahlberg, Hernán Pablo
The ATLAS Collaboration
Institución
Resumen
This Letter describes the observation of the light-by-light scattering process, γγ→γγ, in Pb+Pb collisions at √s<sub>NN</sub> = 5.02 TeV. The analysis is conducted using a data sample corresponding to an integrated luminosity of 1.73 nb⁻¹, collected in November 2018 by the ATLAS experiment at the LHC. Light-by-light scattering candidates are selected in events with two photons produced exclusively, each with transverse energy Eᵞ<sub>T</sub> > 3 GeV and pseudorapidity |ηᵧ|<2.4, diphoton invariant mass above 6 GeV, and small diphoton transverse momentum and acoplanarity. After applying all selection criteria, 59 candidate events are observed for a background expectation of 12±3 events. The observed excess of events over the expected background has a significance of 8.2 standard deviations. The measured fiducial cross section is 78±13(stat)±7(syst)±3(lumi) nb. La lista completa de autores que integran el documento puede consultarse en el archivo. Instituto de Física La Plata