Measurement of the top quark mass using the B-hadron lifetime technique

A measurement of the top quark mass using the transverse decay length ($L_{\rm xy}$) of B-hadrons reconstructed in $t\bar{t}$ candidate events with exactly one charged lepton or one electron and one muon in the final state is presented. The analysis makes use of the proton-proton collision data recorded by the CMS experiment at a center of mass energy of $\sqrt{s}=8\;\mathrm{TeV}$ during the year 2012. Using the median of the $L_{\rm xy}$ distribution reconstructed in data we measure: $m_{\rm t}=173.5\pm 1.5_{\rm stat} \pm1.3_{\rm syst}\pm 2.6_{p_{T}({\rm t})}\mathrm{GeV}$ where the last uncertainty is related to the modeling of the transverse momentum spectrum of the top quark. The result is found to be in good agreement with previous measurements of the top quark mass.