Measurement of spin correlation in top quark pair production at ATLAS

McLaughlan, Thomas (2014). Measurement of spin correlation in top quark pair production at ATLAS. University of Birmingham. Ph.D.

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Abstract

This thesis presents a study of spin correlation in ttˉ production in the ATLAS detector, in proton-proton collisions, corresponding to an integrated luminosity of 4:7fb\(^1\), with a centre of mass energy of \(\surd\)s = 7 TeV. Both the dilepton and single lepton channels are considered, the latter providing a greater challenge due to the necessity to reconstruct the down-type quark resulting from the W boson decay. A simple technique is employed to reconstruct single lepton ttˉ events, with the transverse angle between the charged lepton and down-type quark used as a probe of the spin correlation. In the dilepton channel, the transverse angle between both charged leptons is used. The extracted value of spin correlation in each channel is consistent with Standard Model predictions, with the result in the e\(\mu\) channel alone sufficient to exclude a model without spin correlation at 7:8\(\sigma\). Also described is the author's contribution to the maintenance and development of the Atlantis Event Display.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):