Precise measurement of the top quark mass in the lepton+jets topology at CDF II

TL;DR

This paper reports a highly precise measurement of the top quark mass using proton-antiproton collision data from the CDF experiment, employing a probability-based method that constrains jet energy scale in situ.

Contribution

The study introduces a direct probability density method for top quark mass measurement that improves precision by simultaneously constraining jet energy scale.

Findings

Top quark mass measured as 170.8 GeV/c^2 with total uncertainty of 2.6 GeV/c^2.

Utilized 167 events from 955 pb^-1 of data.

Achieved the most precise single measurement of the top quark mass to date.

Abstract

We present a measurement of the mass of the top quark from proton-antiproton collisions recorded at the CDF experiment in Run II of the Fermilab Tevatron. We analyze events from the single lepton plus jets final state ($t\bar t\to W^+bW^-\bar b\to l\nu b q \bar q'\bar b$). The top quark mass is extracted using a direct calculation of the probability density that each event corresponds to the $t\bar t$ final state. The probability is a function of both the mass of the top quark and the energy scale of the calorimeter jets, which is constrained {\it in situ} by the hadronic $W$ boson mass. Using 167 events observed in 955 pb$^{{-}1}$ of integrated luminosity, we achieve the single most precise measurement of the top quark mass, 170.8 $\pm$ 2.2 (stat.) $\pm$ 1.4 (syst.) GeV/$c^2$.