Simultaneous measurements of the tt¯, W+W-, and Z/γ∗→ττ production cross-sections using an integrated luminosity of 4.6fb-1 of pp collisions at s=7TeV collected by the ATLAS detector at the LHC are presented. Events are selected with two high transverse momentum leptons consisting of an oppositely charged electron and muon pair. The three processes are separated using the distributions of the missing transverse momentum of events with zero and greater than zero jet multiplicities. Measurements of the fiducial cross-section are presented along with results that quantify for the first time the underlying correlations in the predicted and measured cross-sections due to proton parton distribution functions. These results indicate that the correlated next-to-leading-order predictions for tt¯ and Z/γ∗→ττ underestimate the data, while those at next-to-next-to-leading-order generally describe the data well. The full cross-sections are measured to be σ(tt¯)=181.2$\pm$2.8-9.5+9.7$\pm$3.3$\pm$3.3pb, σ(W+W-)=53.3$\pm$2.7-8.0+7.3$\pm$1.0$\pm$0.5pb, and σ(Z/γ∗→ττ)=1174$\pm$24-87+72$\pm$21$\pm$9pb, where the cited uncertainties are due to statistics, systematic effects, luminosity and the LHC beam energy measurement, respectively. The W+W- measurement includes the small contribution from Higgs boson decays, H→W+W-. \copyright 2015 CERN, for the ATLAS Collaboration.
Simultaneous measurements of the t t ¯, W+W-, and Z/γ∗ →ττ production cross-sections in pp collisions at s =7TeV with the ATLAS detector / Aad, G; Aloisio, Alberto; Alviggi, Mariagrazia; Canale, Vincenzo; Chiefari, Giovanni; DELLA PIETRA, Massimo; DELLA VOLPE, Domenico; Giordano, Raffaele; Merola, Leonardo; Patricelli, Sergio; Conventi, Francesco; Rossi, Elvira; SANCHEZ PINEDA, ARTURO RODOLFO; Carlino, Gianpaolo; DE ASMUNDIS, Riccardo; DI DONATO, Camilla; Doria, Alessandra; Iengo, Paolo; Izzo, Vincenzo; Sekhniaidze, Givi; Et, A. l.. - In: PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY. - ISSN 1550-7998. - 91:5(2015). [10.1103/PhysRevD.91.052005]
Simultaneous measurements of the t t ¯, W+W-, and Z/γ∗ →ττ production cross-sections in pp collisions at s =7TeV with the ATLAS detector
ALOISIO, ALBERTO;ALVIGGI, MARIAGRAZIA;CANALE, VINCENZO;CHIEFARI, GIOVANNI;DELLA PIETRA, MASSIMO;DELLA VOLPE, DOMENICO;GIORDANO, RAFFAELE;MEROLA, LEONARDO;PATRICELLI, SERGIO;CONVENTI, FRANCESCO;ROSSI, ELVIRA;SANCHEZ PINEDA, ARTURO RODOLFO;CARLINO, GIANPAOLO;DE ASMUNDIS, Riccardo;DI DONATO, CAMILLA;IENGO, PAOLO;IZZO, VINCENZO;
2015
Abstract
Simultaneous measurements of the tt¯, W+W-, and Z/γ∗→ττ production cross-sections using an integrated luminosity of 4.6fb-1 of pp collisions at s=7TeV collected by the ATLAS detector at the LHC are presented. Events are selected with two high transverse momentum leptons consisting of an oppositely charged electron and muon pair. The three processes are separated using the distributions of the missing transverse momentum of events with zero and greater than zero jet multiplicities. Measurements of the fiducial cross-section are presented along with results that quantify for the first time the underlying correlations in the predicted and measured cross-sections due to proton parton distribution functions. These results indicate that the correlated next-to-leading-order predictions for tt¯ and Z/γ∗→ττ underestimate the data, while those at next-to-next-to-leading-order generally describe the data well. The full cross-sections are measured to be σ(tt¯)=181.2$\pm$2.8-9.5+9.7$\pm$3.3$\pm$3.3pb, σ(W+W-)=53.3$\pm$2.7-8.0+7.3$\pm$1.0$\pm$0.5pb, and σ(Z/γ∗→ττ)=1174$\pm$24-87+72$\pm$21$\pm$9pb, where the cited uncertainties are due to statistics, systematic effects, luminosity and the LHC beam energy measurement, respectively. The W+W- measurement includes the small contribution from Higgs boson decays, H→W+W-. \copyright 2015 CERN, for the ATLAS Collaboration.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.