Measurement of the top-quark mass in $t\bar{t}$ events with lepton+jets final states in $pp$ collisions at $\sqrt{s}=7$ TeV

• Main Author: CMS collaboration (2199 authors)
• Publication Date: 2012
• Other Authors: Hollar, Jonathan, Nayak, Aruna, Almeida, Nuno, Bargassa, Pedrame, David Tinoco Mendes, Andre, Faccioli, Pietro, Ferreira Parracho, Pedro Guilherme, Gallinaro, Michele, Seixas, Joao, Varela, Joao, Vischia, Pietro, Lloret Iglesias, Lara, Musella, Pasquale, Rodrigues Antunes, Joao, Silva, Pedro, Pela, Joao, Leonardo, Nuno
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://dx.doi.org/10.1007/JHEP12(2012)105; http://hdl.handle.net/10400.26/26265

The mass of the top quark is measured using a sample of t t-bar candidate events with one electron or muon and at least four jets in the final state, collected by CMS in pp collisions at sqrt(s) = 7 TeV at the LHC. A total of 5174 candidate events is selected from data corresponding to an integrated luminosity of 5.0 inverse femtobarns. For each event the mass is reconstructed from a kinematic fit of the decay products to a t t-bar hypothesis. The top-quark mass is determined simultaneously with the jet energy scale (JES), constrained by the known mass of the W boson in q anti-q decays, to be 173.49 +/- 0.43 (stat.+JES) +/- 0.98 (syst.) GeV.