# Measurement of the Top-Quark Mass with Dilepton Events Selected Using Neuroevolution at CDF

﻿

http://hdl.handle.net/10138/24482

#### Citation

Aaltonen , T , Mehtälä , P , Orava , R , Mäki , T , Saarikko , H , Österberg , K & CDF Collaboration 2009 , ' Measurement of the Top-Quark Mass with Dilepton Events Selected Using Neuroevolution at CDF ' , Physical Review Letters , vol. 102 , no. 15 , pp. 152001 . https://doi.org/10.1103/PhysRevLett.102.152001

 Title: Measurement of the Top-Quark Mass with Dilepton Events Selected Using Neuroevolution at CDF Alternative title: Measurement of the top quark mass with dilepton events selected using neuroevolution at CDF Author: Aaltonen, T.; Mehtälä, Petteri; Orava, Risto; Mäki, Tuula; Saarikko, Heimo; Österberg, Kenneth; CDF Collaboration Contributor organization: Helsinki Institute of PhysicsDepartment of PhysicsParticle Physics and Astrophysics Date: 2009 Language: eng Number of pages: 8 Belongs to series: Physical Review Letters ISSN: 0031-9007 DOI: https://doi.org/10.1103/PhysRevLett.102.152001 URI: http://hdl.handle.net/10138/24482 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 $M_t= 171.2\pm 2.7(\textrm{stat.})\pm 2.9(\textrm{syst.})\mathrm{GeV}/c^2$.We report a measurement of the top-quark mass Mt in the dilepton decay channel tt̅ →bl′+νl′b̅ l-ν̅ l. 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 pp̅ collisions collected with the CDF II detector, yielding a measurement of Mt=171.2±2.7(stat)±2.9(syst)  GeV/c2. Description: Revised version as published in Phys. Rev. Lett Subject: 114 Physical sciences hep-ex Peer reviewed: Yes Usage restriction: restrictedAccess Self-archived version: submittedVersion
﻿