Top Quark Charge Measurement at CDF
Dr. Boisvert main analysis while on CDF involved measuring the top quark electric charge. While it has been established that the top quark decays predominantly to a W boson and a bottom quark, the correlation of the charge of the W and the accompanying bottom quark has not been investigated. The alternative to the Standard Model top quark would then be a charge -4/3 quark which would be an exotic quark, part of an hypothetical 4th generation of quarks. Such a model has been studied and is consistent with all electroweak measurements.
The analysis consists of first pairing the b jets and the lepton(s) coming from the W bosons and then to get the charge of the b jet, obtained using the jet charge algorithm. The result using 1.5fb-1 of CDF data is to reject the exotic quark hypothesis at 87% confidence level. The analysis is currently being updated with 2fb-1 and will be published soon after in PRL.