Combination of CDF and D0 Results on the Mass of the Top Quark
Tevatron Electroweak Working Group
TL;DR
This paper presents a combined analysis of top-quark mass measurements from CDF and DØ at the Tevatron, integrating Run I and Run II results with careful treatment of correlated uncertainties. Using a BLUE-like χ^2 minimization, the authors combine eleven measurements across decay channels and JES categories, including a novel in-situ JES calibration and an independent lxy-based method. The resulting world-average mass is M_t = 171.4 ± 2.1 GeV/c^2, with about 1.2% precision dominated by jet-energy-scale uncertainties. The work demonstrates how cross-experiment, cross-channel correlations can be managed to yield a consistent, precise top-quark mass estimate and discusses paths to further improvement with larger Run II data.
Abstract
We summarize the top-quark mass measurements from the CDF and DO experiments at Fermilab. We combine published Run-I (1992-1996) measurements with the most recent preliminary Run-II (2001-present) measurements using up to 1 fb-1 of data. Taking correlated uncertainties properly into account the resulting preliminary world average mass of the top quark is Mtop = 171.4 +/- 1.2 (stat) +/- 1.8 (syst) GeV/c2, which corresponds to a total uncertainty of 2.1 GeV/c2. The top-quark mass is now known with a precision of 1.2%.