Related papers: Rigorous QCD-Potential for the $t\bar{t}$-System a…
We develop a procedure to analytically calculate higher-order contributions to the high-temperature real-time static potential in QCD. It is based on the introduction of a semi-hard external scale, which lies between the hard scale (the…
Nonrelativistic bound states are studied using an effective field theory. Large logarithms in the effective theory can be summed using the velocity renormalization group. For QED, one can determine the structure of the leading and…
The possibility of formation for a bound state of a $t$ quark and a lighter one is investigated using potential model predictions and heavy quark effective theory approach. Resulting estimates for the 1S--2S splitting of the energy levels…
Future e^+ e^- linear colliders will enable us to determine the top quark mass with high accuracy from the measurement of the 1S peak position of (remnant of) toponium. The estimated statistical error in this measurement is about 50 MeV…
In this talk we discuss the process e^+e^-\to t\bar t near threshold, calculated with NNLO accuracy as well as top quark mass definitions adequate for the threshold. As new definition we suggest the PS-bar mass which allows to calculate…
We suggest an infrared-insensitive quark mass, defined by subtracting the soft part of the quark self energy from the pole mass. We demonstrate the deep relation of this definition with the static quark-antiquark potential. At leading order…
QCD corrections to inclusive Higgs boson production at the LHC are evaluated at next-to-next-to leading order. By performing asymptotic expansion of the cross section near the limit of infinitely heavy top quark we obtained a few first top…
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…
We present an evaluation of the t\bar{t} cross section near threshold at next-to-next-to-leading logarithmic accuracy, using a two-step matching procedure. QED corrections are taken into account as well and are shown to be numerically…
We determine the next-to-leading logarithmic (NLL) QCD corrections to the cross section sigma(e+e- to t bar t H) for center-of-mass energies up to 500 GeV. The dynamics is dominated by nonrelativistic effects, and the summation of terms…
Recent striking lattice results on strong interaction and bound states above T_c can be explained by the nonperturbative Q\bar Q potential, predicted more than a decade ago in the framework of the field correlator method. Explicit…
It is shown how nonrelativistic QCD (NRQCD) can be used to determine next-to-next-to-leading order relativistic and short-distance contributions to the total $t\bar t$ production cross section in the threshold regime at lepton colliders. A…
We discuss the QCD corrections to the large-$m_t$ electroweak contributions to $\Delta r$ and to the process $Z\to b \bar b$ as two of the most representative examples. This needs the construction of an effetive field theory below the top…
We present an indirect determination of the top-quark pole mass $m_t$ within a global analysis of parton distribution functions (PDFs), based on the public NNPDF framework. We consider a wide range of measurements, including both single-…
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…
ATLAS and CMS have recently reported enhancements in the top-antitop production rate near threshold, a region where non-perturbative QCD dynamics associated with toponium formation become relevant. We investigate how this behaviour is…
Employing the heavy quark pole mass and static potential that were obtained from resummation of the renormalon-caused large order behavior to all orders, and matching the resummed static potential to the long distance Cornell potential we…
Combining recent perturbative analyses on the static QCD potential and the quark pole mass, we find that, for the heavy quarkonium states $c\bar{c}$, $b\bar{b}$ and $t\bar{t}$, (1) ultra-soft (US) corrections in the binding energies are…
Using non-relativistic effective theories, new next-to-next-to-leading order (NNLO) QCD corrections to the total $t\bar t$ production cross section at the Linear Collider have been calculated recently. In this article the NNLO calculations…
In the framework based on the quasipotential method and relativistic quark model a new covariant expression for the heavy quark fragmentation amplitude to fragment into the pseudoscalar and vector S-wave heavy mesons is obtained. It…