Gustavo Marques Tavares - Explaining the t-tbar Asymmetry with a Light Axigluon

When: September 12, 2011 (Mon), 12:00PM to 01:00PM (add to my calendar)
Location: PRB 595

This event is part of the Preliminary Oral Exam.

Title:  Explaining the t-tbar Asymmetry with a Light Axigluon

Examining Committee:  Martin Schmaltz, John Butler, Claudio Chamon and Andrew Cohen

Abstract:
In this talk I propose a light axigluon with flavor universal couplings to quarks to explain the Tevatron t-tbar forward-backward asymmetry. In this model the asymmetry arises from interference between s-channel gluon and axigluon diagrams and requires a relatively weakly coupled axigluon (g{axi} = g{qcd}/3). Axigluon-gluon interference does not contribute to the t-tbar cross section. New contributions to the cross section arise only at fourth order in the axigluon coupling and are very small for a sufficiently broad axigluon. I will also present possible UV completions of the phenomenological axigluon which explain the required small couplings and large width. Such UV completions necessarily contain new colored fermions or scalars below the axigluon mass and predict multi-jet events with large cross sections at the Tevatron and LHC.