The top quark mass is measured in the tt̄ → dileptonchannel (lepton=e, µ) using ATLAS data recorded in the year 2012 at the LHC. The data were taken at a proton-proton centre-of-mass energy of √s=8 TeV and correspond to an integrated luminosity of about 20.2fb-1. Exploiting the template method, and using the distribution of invariant masses of lepton-b-jetpairs, the top quark mass is measured to be mtop=172.99 ±0.41 (stat) ±0.74 (syst) GeV, with a total uncertainty of 0.84 GeV. Finally, acombination with previous ATLAS mtop measurements from √s=7TeVdata in the tt̄ → dilepton and tt̄→lepton+jetschannels results in mtop=172.84 ±0.34 (stat) ±0.61 (syst) GeV, with a total uncertainty of 0.70 GeV.

Measurement of the top quark mass in the tt̄ → Dileptonchannel from √s=8 TeV ATLAS data

CAVASINNI, VINCENZO;DELL'ORSO, MAURO;DONATI, SIMONE;RODA, CHIARA MARIA ANGELA;