Combination of CDF and D0 Measurements of the Single Top Production Cross Section

TL;DR

The paper presents a Bayesian combination of CDF and D0 measurements of the inclusive single-top production cross section in the Tevatron's ppbar collisions, producing a precise result that agrees with the Standard Model. By incorporating all channels and correlations, the analysis achieves improved precision and derives constraints on the CKM element |Vtb| under multiple theory cross-section normalizations. The work demonstrates the power of cross-experiment data sharing and Bayesian inference in extracting weak signals from challenging backgrounds. It highlights how such combinations refine tests of the Standard Model and CKM structure in the top sector.

Abstract

We report a combination of the CDF and D0 measurements of the inclusive single top quark production cross section in the s- and t-channels in ppbar collisions at a center of mass energy of 1.96TeV. The total integrated luminosity included in CDF's analysis is 3.2 fb^-1 and D0's analysis has 2.3 fb^-1. A Bayesian analysis is used to extract the cross section from the distributions of multivariate discriminants provided by the collaborations. For a top quark mass m_t=170 GeV/c^2, we measure a cross section of 2.76 +0.58 -0.47 pb. We extract the CKM matrix element |Vtb|=0.88+-0.07 with a 95% C.L. lower limit of |Vtb|>0.77.

Figures (3)

• Figure 1: The posterior probability distribution of the combined CDF and D0 analyses.
• Figure 2: The posterior probability distribution of the combined CDF and D0 analyses for $|V_{tb}|$. The right plot shows only the posterior, $V_{tb}$ measurement and limit using a theory cross section of 3.46 pb.
• Figure 3: Tevatron single top cross section measurements and their combination.