Measurement of the Top Quark Mass Using Dilepton Events

The D0 Collaboration has performed a measurement of the top quark mass mₜ based on six candidate events for the process tt̄→bW⁺b̄W^-, where the W bosons decay to eν or μν. This sample was collected during an exposure of the D0 detector to an integrated luminosity of 125pb^-1 of √s0ex0ex=0ex0ex1.80ex0exTeVpp̄ collisions. We obtain ${m}ₜ{{0ex}{0ex}}={{0ex}{0ex}}168.4±{}12.3(stat)±{}3.6(syst){{0ex}{0ex}}GeV{/c}²$, consistent with the measurement obtained using single-lepton events. Combination of the single-lepton and dilepton results yields ${m}ₜ{{0ex}{0ex}}={{0ex}{0ex}}172.0±{}7.5GeV{/c}²$.