Top Dilepton Cross Section in 1.2 fb^-1 using  the DIL Selection

Authors:

Monica Tecchio, David Mietlicki, Dan Amidei, Alexei Varganov
University of Michigan

Tuula Maki
University of Helsinki and HIP

Victoria Giakoumopoulou
University of Athens

Yuji Takeuchi, Naoki Kimura
University of Tsukuba

Chang-Seong Moon
Seoul National University

Abstract:

A measurement of the ttbar production cross section in pp collisions at sqrt{s} = 1.96 TeV using dilepton events is reported. The data were collected by the CDF II Detector. Signal and background estimates have been optimized for this sample. The preliminary result in a dataset corresponding to an integrated luminosity of 1.2 fb^-1 is:

6.16±1.05_stat±0.72_syst±0.37_lumi pb

where the first uncertainty is statistical, the second is the convolution of acceptance and background systematics and the third is due to the 6% uncertainty in  the luminosity measurement.

Selection:

Information on the DIL event selection is available from CDF Public Conference Note

Results:

The following table contains a summary of the background estimates for each jet bin before the H_T and Opposite Sign requirements are applied and in the 2 jet bin after applying only the H_T cut. The last column contains the candidate events with all cuts applied. This table also shows the total background expectation, the ttbar expectation for the cross section of the 6.7 pb , their sum (labeled as "Total SM expectation") and the number of candidate events in 1.2fb^-1 of data.

The following table shows the total number of background, SM expectation and 1.2 fb^-1 data candidate events, divided by lepton flavor contribution.

The following plot eps presents the background and signal composition of the Inclusive 1.2 fb^-1 DIL events vs jet multiplicity after the Z-veto, MET and L-cut have been applied.