# HEP/Astro Seminar - Tuesday, 10 June 2003

## Abstract

A new technique for testing the physics of top decay is examined using CDF Run I data. The angular distribution of the leptons from t $\to W +$ b $\to lepton + \nu ~+$ b reveals the structure of the electroweak theory. The angular distribution is mainly symmetric from the longitudinally polarized component resulting from the heavy top mass. However, parity violation from the electroweak theory introduces an asymmetry in the angular distribution which can be used to differentiate between a V-A theory and a V+A theory. Since the angle is often not well measured due to lack of information about the neutrino, the invariant mass of the lepton and b provides a reference frame independent tool to search for a V+A asymmetry. By comparing the $M^{2}_{lepton+b}$ distributions of the data to those expected for a V-A theory and that of a V+A theory, one can fit for the most likely V+A fraction in the t-W-b coupling.

## 14:00, Smith Lab 1094

Last updated June 2003, Matthew Wingate