物理系学术报告：New Results in Top Quark Polarization and Spin Correlation



The Speaker:	Dr. Matthew Baumgart (PITT PACC/CMS & Carnegie Mellon Univ.)
Titel:	New Results in Top Quark Polarization and Spin Correlation
Time:	04/29 Monday 2:00pm
Location:	the 3rd floor of Science Building
Abstract:	Since tops decay before hadronizing or depolarizing, information about their spin is passed on to their daughter particles. Interest in this polarization and correlation of top quark spins predates their discovery. Inspired by the forward-backward anomaly at the Tevatron and the status of the LHC as a top factory, we have studied the spin polarization and correlation induced in ttbar production from a general perspective. This has yielded powerful new observables to test the Standard Model and probe beyond it. We emphasize the key role played by the sums and differences of azimuthal decay angles about the ttbar production axis in regions of SM phase space and for models of new physics such as heavy, narrow bosons, broad axigluons, and chromo-electromagnetic dipole moments. Additionally, we discuss how the transverse polarization of individual tops allows us to observe models designed to explain the AFB anomaly at the Tevatron, but avoid current LHC constraints.