Measurement of the top quark mass with dilepton events selected using neuroevolution at CDF

TL;DR

This paper presents a precise measurement of the top quark mass using dilepton events selected by a neural network optimized through neuroevolution, analyzing 344 events from proton-antiproton collisions.

Contribution

It introduces a novel neural network selection method optimized for statistical precision via neuroevolution in top quark mass measurement.

Findings

Measured top quark mass: 171.2 GeV/c^2

Statistical uncertainty: 2.7 GeV/c^2

Systematic uncertainty: 2.9 GeV/c^2

Abstract

We report a measurement of the top quark mass $M_t$ in the dilepton decay channel $t\bar{t}\to b\ell'^{+}\nu'_\ell\bar{b}\ell^{-}\bar{\nu}_{\ell}$. Events are selected with a neural network which has been directly optimized for statistical precision in top quark mass using neuroevolution, a technique modeled on biological evolution. The top quark mass is extracted from per-event probability densities that are formed by the convolution of leading order matrix elements and detector resolution functions. The joint probability is the product of the probability densities from 344 candidate events in 2.0 fb$^{-1}$ of $p\bar{p}$ collisions collected with the CDF II detector, yielding a measurement of $M_t= 171.2\pm 2.7(\textrm{stat.})\pm 2.9(\textrm{syst.})\mathrm{GeV}/c^2$.