Speaker
Dr
Edmond Berger
(ANL)
Description
The forward-backward asymmetry for top quarks measured in proton-antiproton collisions at the Tevatron shows a large deviation from
standard model expectations. Among possible interpretations, the exchange of a non-universal $Z^\prime$ is of some interest as it naturally predicts a top quark in the forward region of large rapidity. To reproduce the size of the Tevatron asymmetry, the couplings of the $Z^\prime$ to standard model quarks must be large, inevitably leading to copious production of same-sign top quark pairs
at the Tevatron and at the Large Hadron Collider (LHC). We discuss the
constraints on this model from (a) the Tevatron top-antitop cross section, (b) the Tevatron top-antitop invariant mass distribution, and the same sign top pair cross section limits at the Tevatron. We explore the discovery potential for $tt$ and $ttj$ production in early LHC experiments at 7 TeV and conclude that if {\it no} $tt$ signal is observed with 1~fb$^{-1}$ of integrated luminosity, then a non-universal $Z^\prime$ alone cannot explain the Tevatron forward-backward asymmetry.
Author
Dr
Edmond Berger
(ANL)
