Measurement of the Mass Difference between t and [overline t] Quarks

We present a direct measurement of the mass difference between t and t̄ quarks using tt̄ candidate events in the lepton+jets channel, collected with the CDFII detector at Fermilab's 1.96 TeV Tevatron pp̄ Collider. We make an event by event estimate of the mass difference to construct templates...

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Bibliographic Details
Main Authors: CDF Collaboration, Bauer, Gerry P, Gomez-Ceballos, Guillelmo, Goncharov, Maxim, Makhoul, Khaldoun, Paus, Christoph M. E.
Other Authors: Massachusetts Institute of Technology. Laboratory for Nuclear Science
Format: Article
Published: American Physical Society (APS) 2018
Online Access:http://hdl.handle.net/1721.1/116674
https://orcid.org/0000-0002-6047-4211
Description
Summary:We present a direct measurement of the mass difference between t and t̄ quarks using tt̄ candidate events in the lepton+jets channel, collected with the CDFII detector at Fermilab's 1.96 TeV Tevatron pp̄ Collider. We make an event by event estimate of the mass difference to construct templates for top quark pair signal events and background events. The resulting mass difference distribution of data is compared to templates of signals and background using a maximum likelihood fit. From a sample corresponding to an integrated luminosity of 5.6fb ⁻¹, we measure a mass difference, ΔM top =M t -M t̄ =-3.3±1.4(stat) ±1.0(syst)GeV/c², approximately 2standard deviations away from the CPT hypothesis of zero mass difference.