ÚTEFČVUT Ústav technické a experimentální fyziky ČVUT v PrazeInstitute of Experimental and Applied Physics, CTU in Prague

Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC

NázevTitle
Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHCEvidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC
Druh výsledkuResult type
Článek v časopiseJournal article
AutořiAuthors
M. Aaboud, G. Aad, B. Abbott, J. Abdallah, B. Ali, K. Augsten, D. Caforio, P. Gallus, M. Havránek, Z. Hubáček, M. Myška, S. Pospíšil, V. Šimák, T. Slavíček, K. Smolek, M. Solar, A. Sopczak, M. Suk, V. Vacek, M. Šuta, P. Vokáč, V. Vrba, M. Zeman
Klíčová slovaKeywords
delbruck scattering, peripheral collisions, Pair production, gamma-gamma, collider, positron, Energy, physics
ExperimentCollaboration
ATLAS
DOIDOI
10.1038/NPHYS4208
Časopis / citaceJournal / citation
Nature Physics 13(9), 852-858 (2017) · ISSN 1745-2473
RokYear
2017
JazykLanguage
eng
ZáznamyRecords
ProjektProject
Získávání nových poznatků o mikrosvětě v infrastruktuře CERNAcquiring new pieces of knowledge about micro-world in CERN research infrastructure
CitovánoCited by
512 (INSPIRE-HEP)
2017: 302018: 472019: 562020: 502021: 562022: 562023: 532024: 682025: 522026: 43
Plný text (open access)Full text (open access)
https://www.nature.com/nphys/journal/v13/n9/pdf/nphys4208.pdf
Citace ke staženíDownload citation
TXT · BibTeX

AbstraktAbstract

Light-by-light scattering (gamma gamma -> gamma gamma) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 mu b(-1) of lead-lead collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13 candidate events were observed with an expected background of 2.6 +/- 0.7 events. After background subtraction and analysis corrections, the fiducial cross-section of the process Pb + Pb (gamma gamma) -> Pb-(center dot) + Pb-(center dot) gamma gamma, for photon transverse energy E-T > 3 GeV, photon absolute pseudorapidity vertical bar eta vertical bar < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 +/- 24 (stat.) +/- 17 (syst.) nb, which is in agreement with the standard model predictions.

Light-by-light scattering (gamma gamma -> gamma gamma) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 mu b(-1) of lead-lead collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13 candidate events were observed with an expected background of 2.6 +/- 0.7 events. After background subtraction and analysis corrections, the fiducial cross-section of the process Pb + Pb (gamma gamma) -> Pb-(center dot) + Pb-(center dot) gamma gamma, for photon transverse energy E-T > 3 GeV, photon absolute pseudorapidity vertical bar eta vertical bar < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 +/- 24 (stat.) +/- 17 (syst.) nb, which is in agreement with the standard model predictions.

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