Measurement of the integrated and differential $t \bar t$ production cross sections for high-$p_t$ top quarks in $pp$ collisions at $\sqrt s =$ 8 TeV

• Main Author: CMS collaboration (2294 authors)
• Publication Date: 2016
• Other Authors: Calpas, Betty, Nayak, Aruna, Bargassa, Pedrame, Beirão Da Cruz E Silva, Cristóvão, Di Francesco, Agostino, Faccioli, Pietro, Ferreira Parracho, Pedro Guilherme, Gallinaro, Michele, Hollar, Jonathan, Leonardo, Nuno, Lloret Iglesias, Lara, Nguyen, Federico, Rodrigues Antunes, Joao, Seixas, Joao, Toldaiev, Oleksii, Vadruccio, Daniele, Varela, Joao, Vischia, Pietro, David Tinoco Mendes, Andre, Silva, Pedro, Musella, Pasquale, Pela, Joao
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://dx.doi.org/10.1103/PhysRevD.94.072002; http://hdl.handle.net/10400.26/27080

The cross section for pair production of top quarks (tt¯) with high transverse momenta is measured in pp collisions, collected with the CMS detector at the LHC with s=8  TeV in data corresponding to an integrated luminosity of 19.7  fb-1. The measurement is performed using lepton+jets events, where one top quark decays semileptonically, while the second top quark decays to a hadronic final state. The hadronic decay is reconstructed as a single, large-radius jet, and identified as a top quark candidate using jet substructure techniques. The integrated cross section and the differential cross sections as a function of top quark pT and rapidity are measured at particle level within a fiducial region related to the detector-level requirements and at parton level. The particle-level integrated cross section is found to be σtt¯=0.499±0.035(stat+syst)±0.095(theo)±0.013(lumi)  pb for top quark pT>400  GeV. The parton-level measurement is σtt¯=1.44±0.10(stat+syst)±0.29(theo)±0.04(lumi)  pb. The integrated and differential cross section results are compared to predictions from several event generators.