Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC
- P. Jackson
- L. Lee
- A. Petridis
- M. J. White
- J. Bouffard
- A Fischer
- S. Guindon
- V Jain
- S. P. Swift
- J. Dassoulas
- N. Dehghanian
- D. M. Gingrich
- S. Jabbar
- R. W. Moore
- J. L. Pinfold
- X. Sun
- Hao Wang
- O. Cakir
- A. K. ÇİFTÇİ
- H. Duran Yildiz
- S. Kuday
- I. Turk Cakir
- S Sultansoy
- N. Berger
- A. M. Burger
- M. Delmastro
- L. Di Ciaccio
- S. Elles
- K. Grevtsov
- T. Guillemin
- T Hryn'ova
- S. Jezequel
- O. Kivernyk
- I. Koletsou
- R. Lafaye
- J. Levêque
- N. Lorenzo Martinez
- P. Mastrandrea
- E. Sauvan
- B. H. Smart
- S Todorova-Nova
- A. Vallier
- I. Wingerter-Seez
- E. Yatsenko
- R. E. Blair
- S. Chekanov
- T. LeCompte
- J. Love
- D. Malon
- J. Metcalfe
- A. Paramonov
- L Price
- J. Proudfoot
- Ryu S
- R. W. Stanek
- P. van Gemmeren
- R Wang
- J. S. Webster
- J H Zhang
- E. Cheu
- K. A. Johns
- S. Jones
- W. Lampl
- 雷 〓
- R. Leone
- P. Loch
- R. Nayyar
- J. P. Rutherfoord
- M. A. Shupe
- E. W. Varnes
- V Veeraraghavan
- J. Abdallah
- A. Brandt
- D. Bullock
- S. Darmora
- K. De
- A. Farbin
- L. Feremenga
- J. Griffiths
- H Hadavand
- L. Heelan
- H. Y. Kim
- N. Ozturk
- A. R. Stradling
- Usai G
- A. Vartapetian
- a J. T. White
- J. Yu
- S. Angelidakis
- S. Chouridou
- D. Fassouliotis
- N. Giokaris
- I. Gkialas
- Ioannou P
- C. Kourkoumelis
- K. Papageorgiou
- N. Tsirintanis
- T. Alexopoulos
- N. Benekos
- M. Dris
- HLHui Li
- HLHui Li
- HLHui Li
- HLHui Li
- HLHui Li
- HLHui Li
- HLHui Li
- HLHui Li
- HLHui Li
- HLHui Li
- HLHui Li
- HLHui Li
- GTG. Tsipolitis
Nature Physics · 2017 · Nature Portfolio
5 views · 0 downloads
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 μb−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 (γγ) → Pb(∗) + Pb(∗)γγ, for photon transverse energy ET > 3 GeV, photon absolute pseudorapidity |η| < 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. Quantum electrodynamics predicts a rare process in which light is scattered by light. The ATLAS Collaboration reports signs of this elusive effect in the collisions of ultra-relativistic lead ions.