TU-A6-4 11:15

First Measurement Of The Ratio Of Ttbar Production Cross Section Through Gluon-Gluon Fusion Over Quark-Antiquark Annihilation In Ppbar Collisions At Sqrt(s) = 1.96 TeV*, Shabnaz Pashapour , P.K. Sinervo , University of Toronto — Following the discovery of the top quark, various studies have been dedicated to understanding the properties of this heavy particle. According to the Standard Model, in collisions at 1.96 TeV, one expects about 15% of the top quark pairs to be produced through gluon-gluon fusion and the remaining 85% through quark-antiquark annihilation. We will present the first measurement of the relative rate of production through these two processes, , in 0.7 fb^-1 data collected by the Collider Detector at Fermilab (CDF). This measurement provides a test of the QCD predictions for pair-production mechanism, and a technique to test for unexpected sources of top quark production. The average number of gluons in the candidate events is measured using the low p_T charged particle multiplicity, which is then used to determine . The correlation between the charged track multiplicity and the average number of gluons is determined using W+n jet(s) and dijet data calibration samples and verified using the Standard Model Monte Carlo calculations.

* This work is being supported by NSERC

* This work is being supported by NSERC