Measurement of the Mass Difference between Top and Anti-top Quarksin Top Pair Events from \boldmath{$pp$} Collisions at \boldmath{$\sqrt{s}$} = 7~TeV

• Authors:
• Vikash Chavda

Abstract

A measurement of the mass difference between top and anti-top quarks produced in $pp$ collisions at $\sqrt{s}=7$ TeV with the ATLAS detector at the LHC is presented. The analysis uses the full 2011 data sample, corresponding to an integrated luminosity of 4.7 fb$^{-1}$. An event-by-event mass difference is calculated for every event consistentwith $\ttbar$ production and decay in the semi-leptonic channel.A likelihood fit to the full double $b$-tagged data set yields a measured valueof $\Delta(m) = m_{t}-m_{\bar{t}} = 0.67 \pm{0.61}~(\mathrm{stat.}) \pm{0.19}~(\mathrm{syst.})~\mathrm{GeV}$, consistent with the Standard Model, and more generally, the CPT Theorem, prediction of no mass difference.

Details

Original language English The University of Manchester Un-Ki Yang (Supervisor) 31 Dec 2013