Precise measurement of the top quark mass from lepton+jets events at D0

TL;DR

A likelihood technique is used that reduces theJet energy scale uncertainty by combining an in situ jet energy calibration with the independent constraint on the jet energy scale (JES) from the calibration derived using photon+jets and dijet samples.

Abstract

We measure the mass of the top quark using top quark pair candidate events in the lepton+jets channel from data corresponding to 1 fb-1 of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron collider. We use a likelihood technique that reduces the jet energy scale uncertainty by combining an in-situ jet energy calibration with the independent constraint on the jet energy scale (JES) from the calibration derived using photon+jets and dijet samples. We find the mass of the top quark to be 171.5+-1.8(stat.+JES)+-1.1(syst.) GeV.

Figures (3)

• Figure 1: Comparison between data and MC 2-jet ($m_{\textrm{2j}}$) and 3-jet ($m_{\textrm{3j}}$) invariant mass distributions.
• Figure 2: Mean values of $m_{t}$ and $k_{\textrm{jes}}$ from ensemble tests versus true values parameterized by straight lines. Dashed lines represent identical fitted and true values.
• Figure 3: (a) Projection of data likelihood onto the $m_{t}$ axis with best estimate shown. (b) Expected uncertainty distribution for $m_{t}$ with measured uncertainty indicated by the arrow.