Related papers: A Renormalization Group Improved Calculation of To…
The total cross section for top quark pair production close to threshold in e+e- annihilation is investigated. Details are given about the calculation at next-to-next-to-leading logarithmic order. The summation of logarithms leads to a…
We consider top-anti-top production near threshold in $e^+ e^-$ collisions, resumming Coulomb-enhanced corrections at next-to-next-to-leading order (NNLO). We also sum potentially large logarithms of the small top quark velocity at the…
To achieve reliable predictions of the top-antitop threshold cross section at a future e+e- Linear Collider logarithms of the top velocity need to be resummed. I review the issues that make this problem complicated and show how the task can…
Predictions for the total cross section for e+e- -> t tbar near threshold are reviewed. The renormalization group improved results at NNLL order have improved convergence and reduced scale dependence relative to fixed order results at NNLO.…
We calculate the cross section of the process e^+e^- \to t\bar t near threshold by resumming Coulomb-like terms with next-to-next-to-leading (NNLO) accuracy. The nonrelativistic Green function formalism and the method of ``direct matching''…
Top quark pair production close to threshold at a next linear collider is discussed, with special focus on the influence of rescattering corrections. Numerical results are shown for the differential cross-section, i.e. the momentum…
We review the theoretical ideas and tools required to arrive at a next-to-next-to-leading order (NNLO) description of the heavy quark-antiquark production cross section in $e^+e^-$ annihilation for the case that the center of mass kinetic…
The next-to-next-to-leading order (NNLO) QCD corrections to top quark threshold pair production in gamma-gamma collisions are computed. The NNLO effects turn out to be significant. Threshold cross sections in gamma-gamma and e+e- collisions…
We compute the O(alpha_s^3) inclusive cross section for the process pp -> t-tbar-h in the Standard Model, at sqrt(s)=14 TeV. The next-to-leading order corrections drastically reduce the renormalization and factorization scale dependence of…
In this talk we discuss the process e+e- -> t t-bar near threshold. In particular we discuss a quark mass definition which is a generalization of the static PS mass. The new definition allows us to calculate recoil corrections to the static…
We study the effect of the resummation of logarithms for t\bar{t} production near threshold and inclusive electromagnetic decays of heavy quarkonium. This analysis is complete at next-to-next-to-leading order and includes the full…
We present an analytical description of top-antitop pair production near the threshold in $e^+e^-$ annihilation and $\g\g$ collisions. A set of basic observables considered includes the total cross sections, forward-backward asymmetry and…
We report on a complete calculation of electroweak production of top quark pairs in $e^+e^-$ annihilation at next-to-next-to-leading order in Quantum Chromodynamics. Our setup is fully differential and can be used to calculate any…
Top quark polarization in $e^+e^-$ annihilation into $t\bar t$ is calculated for linearly polarized beams. The Green function formalism is applied to this reaction near threshold. The Lippmann--Schwinger equations for the $S$-wave and…
The total cross section of the top quark-antiquark pair production near threshold in $\gamma\gamma$ collision is computed analytically up to the next-to-leading order in perturbative and nonrelativistic expansion for general photon…
We study the effects of QCD corrections to the process $e^+e^-\rightarrow t\bar t+X\rightarrow b\ell^+\nu \bar b\ell^-\bar \nu+X$ above threshold. We show how to treat consistently to ${\cal O}(\alpha_s)$ the gluon radiation in both the…
We review the physics involved in the production and decay of top quarks in e^+e^- -> ttbar near threshold, with special emphasis on the recent theoretical study on the decay process of top quarks in the threshold region. The energy-angular…
We calculate the next-to-next-to-leading order correction to the cross section for top quark pair production in e+e- annihilation in the threshold region, resumming all O [ (alpha_s/beta)^n (alpha_s^2, beta^2, alpha_s beta) ] terms of…
We discuss the resummation of the potentially large O((\beta_0\alpha_s)^n) QCD corrections to the total cross section of the process e^+e^- \to t \bar t near the threshold. In this approximation, the cross section factorization into the…
In this paper, we present an improved analysis of the top-quark pair production via the process $e^{+}e^{-}\to \gamma^{*}\to t\bar{t}$ near the threshold region up to next-to-next-to-next-to-leading order (N$^3$LO) QCD corrections. Near the…