Title : "Test of Lepton Flavor Universality with the B_c meson at LHCb"
Notes: This is also a thesis defense for Jack, who is Hassan Jawahery's student, but is open to everyone.
Abstract : The LHCb experiment at the Large Hadron collider is a unique laboratory for studying the properties of heavy quarks. The physics program of the experiment includes studies of CP violation, measurements of CKM matrix parameters, searches for rare decays, quarkonia studies, and other flavor physics, forward physics, and new physics topics.
This talk presents a measurement of the ratio of the branching fractions Br(B_c-->J/psi tau nu)/Br(B_c-->J/psi mu nu), which provides a test of the universality of the couplings of leptons (e, mu and tau) in electroweak interactions. Similar measurements in the light B mesons (B0 and B+) at BaBar, Belle, and LHCb are in excess of precise Standard Model predictions.