Top quark pair production at small transverse momentum in hadronic collisions

TL;DR

This paper develops a theoretical framework using effective field theories to accurately resum small transverse momentum effects in top quark pair production at hadron colliders, and compares predictions with experimental data.

Contribution

It derives a factorization formula for small transverse momentum in top pair production and computes the soft functions at next-to-leading order, advancing precision in theoretical predictions.

Findings

Numerical results agree with experimental data within uncertainties.

Resummation formulas match fixed-order calculations when expanded.

Discusses implications for transverse-momentum-dependent asymmetries at Tevatron.

Abstract

We investigate the transverse momentum resummation for top quark pair production at hadron colliders using the soft-collinear effective theory and the heavy-quark effective theory. We derive the factorization formula for $t\bar{t}$ production at small pair transverse momentum, and show in detail the procedure for calculating the key ingredient of the factorization formula: the next-to-leading order soft functions. We compare our numerical results with experimental data and find that they are consistent within theoretical and experimental uncertainties. To verify the correctness of our resummation formula, we expand it to the next-to-leading order and the next-to-next-to-leading order, and compare those expressions with the exact fixed-order results numerically. Finally, using the results of transverse momentum resummation, we discuss the transverse-momentum-dependent forward-backward asymmetry at the Tevatron.