Scalar diquark in top-antitop production and constraints on Yukawa sector of grand unified theories
J. Stefan Institute, Jamova 39, P. O. Box 3000, 1001 Ljubljana, SloveniaDepartment of Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, SloveniaE-mail: jernej.kamenik@ijs.siA colored weak singlet scalar state with hypercharge 4/3 is one of the possible candidates for theexplanation of the unexpectedly large forward-backward asymmetry in tt¯production as measuredby the CDF and D0 experiments. We investigate the role of this state in a plethora of flavor chang-ing neutral current processes and precision observables of down-quarks and charged leptons. Ouranalysis includes tree- and loop-level mediated observables in the K and B systems, the chargedlepton sector, as well as the Z !bb¯ width. We perform a fit of the relevant scalar couplings. Thisapproach can explain the (g 2)