Carleton ATLAS graduate student wins first prize

Wednesday, February 26, 2014


Tom McCarthy wins first prize at Banff Winter Nuclear & Particle Physics conference


Congratulations to Tom McCarthy who won first prize in the student talk competition at the recent  Banff Winter Nuclear & Particle Physics Conference.   Tom, a PhD student in our particle physics program, presented his analysis Feb 16 of Measurement of the top quark mass in the all-hadronic t-tbar channel with sqrt(s)=8 TeV proton-proton collision data from the ATLAS experiment.

 

Abstract Below:

This talk outlines a current measurement of the top quark mass being made with sqrt(s) = 8 TeV ATLAS data, specifically using events in which pairs of top quarks are created, and which subsequently decay to an all-hadronic final state.  The top quark, discovered in 1995 at Fermilab, is by far the heaviest of the known fundamental particles making up the Standard Model of Particle Physics.  One of the primary challenges of this all-hadronic (or all-jets) decay channel is the presence of other QCD-initiated background events which mimic signal events and which have a production cross-section several orders of magnitude larger than signal events.  Techniques which take advantage of the kinematic properties of t-tbar events, together with a data-driven estimation of the QCD background, must be employed in order to separate the signal from this overwhelming background.  An additional complication arises from the combinatorics of assigning the correct jets to each of the top quark decay products when reconstructing top quark candidates.  Means to address both of these challenges will be discussed in order to make such a top quark mass measurement competitive with other decay topologies.