Light-by-light scattering (γγ → γγ) 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 μ1of 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 (γγ) → Pb(∗)+ Pb(∗)γγ,for photon transverse energy ET> 3GeV, photon absolute pseudorapidity |η| <2.4, diphoton invariant mass greater than 6GeV, diphoton transverse momentum lower than 2GeV 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.

M. Aaboud, G.A. (2017). Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC. NATURE PHYSICS, 13(9), 852-858 [10.1038/nphys4208].

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

G. L. Alberghi;L. Bellagamba;S. Biondi;D. Boscherini;A. Bruni;G. Bruni;G. D’amen;S. De Castro;F. Fabbri;L. Fabbri;M. Franchini;A. Gabrielli;B. Giacobbe;F. Lasagni Manghi;L. Massa;A. Mengarelli;A. Polini;L. Rinaldi;M. Romano;C. Sbarra;N. Semprini-Cesari;M. Sioli;R. Spighi;G. Ucchielli;S. Valentinetti;M. Villa;C. Vittori;I. Vivarelli;A. Zoccoli;
2017

Abstract

Light-by-light scattering (γγ → γγ) 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 μ1of 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 (γγ) → Pb(∗)+ Pb(∗)γγ,for photon transverse energy ET> 3GeV, photon absolute pseudorapidity |η| <2.4, diphoton invariant mass greater than 6GeV, diphoton transverse momentum lower than 2GeV 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.
2017
M. Aaboud, G.A. (2017). Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC. NATURE PHYSICS, 13(9), 852-858 [10.1038/nphys4208].
M. Aaboud, G. Aad, B. Abbott, J. Abdallah, O. Abdinov, B. Abeloos, S. H. Abidi, O. S. AbouZeid, N. L. Abraham, H. Abramowicz, H. Abreu, R. Abreu, Y. A...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/621559
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