Measurement of exclusive gamma gamma -> l(+)l(-) production in proton-proton collisions at root s=7 TeV with the ATLAS detector
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Atlas detectorProton-proton collisionsAstronomyAstrophysicsParticlesPhysics
Aad., G.; et al. Measurement of exclusive gamma gamma -> l(+)l(-) production in proton-proton collisions at root s=7 TeV with the ATLAS detector. Physics Letter B, 749: 242-261 (2015). [http://hdl.handle.net/10481/39169]
PatrocinadorOpen Access funded by SCOAP³ - Sponsoring Consortium for Open Access Publishing in Particle Physics; We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; EPLANET, ERC and NSRF, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG and AvH Foundation, Germany; GSRT and NSRF, Greece; RGC, Hong Kong SAR, China; ISF, MINERVA, GIF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Norway; MNiSW and NCN, Poland; GRICES and FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MSTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SER, SNSF and Cantons of Bern and Geneva, Switzerland; NSC, Taiwan; TAEK, Turkey; STFC, the Royal Society and Leverhulme Trust, United Kingdom; DOE and NSF, United States of America. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN and the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK) and BNL (USA) and in the Tier-2 facilities worldwide.
This Letter reports a measurement of the exclusive γγ→ℓ+ℓ−γγ→ℓ+ℓ− (ℓ=e, μℓ=e, μ) cross-section in proton–proton collisions at a centre-of-mass energy of 7 TeV7 TeV by the ATLAS experiment at the LHC, based on an integrated luminosity of 4.6 fb−14.6 fb−1. For the electron or muon pairs satisfying exclusive selection criteria, a fit to the dilepton acoplanarity distribution is used to extract the fiducial cross-sections. The cross-section in the electron channel is determined to be View the MathML sourceσγγ→e+e−excl.=0.428 ± 0.035 (stat.) ± 0.018 (syst.) pb for a phase–space region with invariant mass of the electron pairs greater than 24 GeV24 GeV, in which both electrons have transverse momentum pT>12 GeVpT>12 GeV and pseudorapidity |η|<2.4|η|<2.4. For muon pairs with invariant mass greater than 20 GeV20 GeV, muon transverse momentum pT>10 GeVpT>10 GeV and pseudorapidity |η|<2.4|η|<2.4, the cross-section is determined to be View the MathML sourceσγγ→μ+μ−excl.=0.628 ± 0.032 (stat.) ± 0.021 (syst.) pb. When proton absorptive effects due to the finite size of the proton are taken into account in the theory calculation, the measured cross-sections are found to be consistent with the theory prediction.