First Measurement of the Ratio sigma_(t-tbar) / sigma_(Z/\gamma*->ll) and Precise Extraction of the t-tbar Cross Section

TL;DR

This paper presents the first measurement of the ratio of top-antitop to Z/gamma* cross sections at 1.96 TeV, leading to a precise determination of the top-antitop production cross section with reduced luminosity uncertainty.

Contribution

It introduces a novel ratio-based method to measure the top-antitop cross section, minimizing luminosity uncertainties and combining two complementary measurement techniques.

Findings

Measured sigma_(top-antitop) = 7.70 +/- 0.52 pb.

Used ratio method to reduce luminosity uncertainty.

Combined two measurement approaches for improved accuracy.

Abstract

We report a measurement of the ratio of the top-antitop to Z/gamma* production cross sections in sqrt(s) = 1.96 TeV proton-antiproton collisions using data corresponding to an integrated luminosity of up to 4.6 fb-1, collected by the CDF II detector. The top-antitop cross section ratio is measured using two complementary methods, a b-jet tagging measurement and a topological approach. By multiplying the ratios by the well-known theoretical Z/gamma*->ll cross section, the extracted top-antitop cross sections are effectively insensitive to the uncertainty on luminosity. A best linear unbiased estimate is used to combine both measurements with the result sigma_(top-antitop) = 7.70 +/- 0.52 pb, for a top-quark mass of 172.5 GeV/c^2.