2011/11/16 by C. Bertella, Claudia Bertella, Bertella, Claudia
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High-Energy Particle Collisions Research #Particle Detector Development and Performance #Particle physics theoretical and experimental studies #hep-ex
paper · pdf · doi:10.48550/arxiv.1111.3745
3 pages, PDFLATEX, 4 pdf figures, conference proceedings for PIC2011
arxiv created 2011/11/16 · openalex publication_date 2011/11/16 · arxiv updated 2015/03/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The top quark pair production cross section in the fully hadronic final state is characterized by a six jet topology, two of which could be identified as originating from a b-quark using ATLAS b-tagging algorithms. Compared to other decay channels, this final state presents an advantageous larger branching ratio; on the other hand it suffers from a very large QCD multi-jet background, generally difficult to estimate from Monte Carlo simulation and therefore evaluated using data-driven techniques. The analysis is performed using 36pb-1 of pp collisions produced at the LHC with a center-of-mass energy of 7 TeV. The observed upper limit is set at 261 pb at 95% confidence level, where the expected Standard Model cross-section for the ttbar process is 165+11-16 pb. In the future, when the LHC luminosity increases, it is essential, to efficiently trigger on these fully hadronic ttbar events, to use dedicated triggers. An overview of the analysis for ttbar production cross section measurement in the fully hadronic final state and the state-of-the-art of the b-jet trigger performance estimation are presented in this contribution.