O(alpha_s^2) Corrections to e+e- to ttbar Total and Differential Cross Sections Near Threshold

Abstract

Recently full O(alpha_s^2, alpha_s*beta, beta^2) corrections to the threshold total cross section for e+e- to ttbar have been calculated, and the reported corrections turned out to be unexpectedly large. We study how to reduce theoretical uncertainties of the cross section. We adopt a new mass definition proposed by Beneke, which incorporates a renormalon-pole cancellation in the total energy of a static quark-antiquark pair. This improves the convergence of the 1S resonance mass, while the normalization of the cross section scarcely changes. We argue that resummations of logarithms are indispensable, since two largely separated scales dictate the shape of the cross section. As a first step, we resum logarithms in the Coulombic part of the t-tbar potential and observe a considerable improvement in the convergence of corresponding corrections. There still remain, however, large corrections, which arise from a 1/r^2 term in the ttbar potential. We also calculate full O(alpha_s^2, alpha_s*beta, beta^2) corrections to the momentum distributions of top quarks in the threshold region. Corrections to the distribution shape are small on the 1S resonance. At higher energies, corrections become larger.

23 pages, LaTeX2e, 16 PostScript figures, uses graphicx.sty; Descriptions on the momentum distribution are enlarged; A derivation of the momentum distribution formula is added as an appendix; Other minor changes; In ver.4, comparison with O(alfs) final-state interaction corrections to momentum distribution added; two figures added

References in corpus (14)

• The static potential in QCD to two loops
• A quark mass definition adequate for threshold problems
• Two-loop QCD corrections to the heavy quark pair production cross section in e+e- annihilation near the threshold
• Top quark production near threshold and the top quark mass
• Quarkonia and the Pole Mass
• Top Quark Pair Production at Threshold: Complete Next-to-next-to-leading Order Relativistic Corrections
• Top quark production at threshold with O(alpha_s^2) accuracy
• One-loop QCD interconnection effects in pair production of top quarks
• Top quark production near threshold: NNLO QCD correction
• On the relation between QCD potentials in momentum and position space
• The Perturbative QCD Potential and the ttbar Threshold
• Axial Contributions at the Top Threshold
• Final-State Interactions in e^+e^- -> t\bar{t} -> b l^+ ν\bar{b} W^- Near Top Quark Threshold
• Top quark production near threshold: on resummation of O( (β_0α_s)^n) QCD corrections

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