Abstract
We present a measurement of the top-quark mass in events containing two leptons (electrons or muons) with a large transverse momentum, two or more energetic jets, and a transverse-momentum imbalance. We use the full proton-antiproton collision data set collected by the CDF experiment during the Fermilab Tevatron Run~II at center-of-mass energy $\sqrt{s} = 1.96$ TeV, corresponding to an integrated luminosity of 9.1 fb$^{-1}$. A special observable is exploited for an optimal reduction of the dominant systematic uncertainty, associated with the knowledge of the absolute energy of the hadronic jets. The distribution of this observable in the selected events is compared to simulated distributions of ${t\bar{t}}$ dilepton signal and background.We measure a value for the top-quark mass of $171.5\pm 1.9~{\rm (stat)}\pm 2.5~{\rm (syst)}$ GeV/$c^2$.
Highlights
The sample is further selected using the criteria developed for the ttcross section measurement in the dilepton channel [15]
To detect jets we look for clusters of energy in the calorimeter using a cone algorithm with radius R = (∆η)2 + (∆φ)2 = 0.4 [18], where φ denotes the azimuthal angle
We find that approximately half of these events feature a small distance in the η-φ space between the fake lepton and the axis of one of the jets (j), ∆Rlj = (∆ηlj )2 + (∆φlj
Summary
At the Tevatron, the most accurate Mtop measurements in the dilepton channel [6, 7] use methods of full or partial reconstruction of the top-quark events. In these analyses, the systematic uncertainty dominates over the statistical one with a large contribution of the jet-energy scale (JES) uncertainty. The sample is further selected using the criteria developed for the ttcross section measurement in the dilepton channel [15] In this analysis we introduce additional requirements to improve event modeling and to reduce the total background.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
