Jan Piclum

Next-to-Next-to-Next-to-Leading Order QCD Prediction for the Top Antitop S-Wave Pair Production Cross Section Near Threshold in e + e − Annihilation

We present the third-order QCD prediction for the production of top antitop quark pairs in electron-positron collisions close to the threshold in the dominant S-wave state. We observe a significant reduction of the theoretical uncertainty and discuss the sensitivity to the top quark mass and width.

Inclusive top-pair production phenomenology with TOPIXS

A bstractWe discuss various aspects of inclusive top-quark pair production based on Topixs, a new, flexible program that computes the production cross section at the Tevatron and LHC at next-to-next-to-leading logarithmic accuracy in soft and Coulomb resummation, including bound-state effects and the complete next-to-next-to-leading order result in the

The bottom-quark mass from non-relativistic sum rules at NNNLO

q\overline q

Leptonic decay of the

channel, which has recently become available. We present the calculation of the top-pair cross section in pp collisions at 8 TeV centre-of-mass energy, as well as the cross sections for hypothetical heavy quarks in extensions of the standard model. The dependence on the parton distribution input is studied. Further we investigate the impact of LHC top cross section measurements at

\Upsilon

\sqrt {s} = {7}

(1

TeV on global fits of the gluon distribution using the NNPDF re-weighting method.

S

Abstract We determine the mass of the bottom quark from high moments of the b b ¯ production cross section in e + e − annihilation, which are dominated by the threshold region. On the theory side next-to-next-to-next-to-leading order (NNNLO) calculations both for the resonances and the continuum cross section are used for the first time. We find m b PS ( 2 GeV ) = 4.532 − 0.039 + 0.013 GeV for the potential-subtracted mass and m b MS ¯ ( m b MS ¯ ) = 4.193 − 0.035 + 0.022 GeV for the MS ¯ bottom-quark mass.

) meson at third order in QCD

We present the complete next-to-next-to-next-to-leading order short-distance and bound-state QCD correction to the leptonic decay rate Γ(ϒ(1S)→ℓ+ℓ-) of the lowest-lying spin-1 bottomonium state. The perturbative QCD prediction is compared to the measurement Γ(ϒ(1S)→e+e-)=1.340(18)  keV.

Threshold production of unstable top

A bstractWe develop a systematic approach to describe the finite lifetime effects in the threshold production of top quark-antiquark pairs. It is based on the nonrelativis-tic effective field theory with an additional scale ρ1/2mt characterizing the dynamics of the top-quark decay, which involves a new expansion parameter ρ = 1 − mW /mt. Our method naturally resolves the problem of spurious divergences in the analysis of the unsta-ble top production. Within this framework we compute the next-to-leading nonresonant contribution to the total cross section of the top quark-antiquark threshold production in electron-positron annihilation through high-order expansion in ρ and confirm the recently obtained result. We extend the analysis to the next-to-next-to-leading O(αs) nonreso- nant contribution which is derived in the leading order in ρ. The dominant nonresonant contribution to the top-antitop threshold production in hadronic collisions is also obtained.

Three-loop matching of the vector current

We evaluate the three-loop corrections to the matching coefficient of the vector current between Quantum Chromodynamics (QCD) and non-relativistic QCD. The result is presented in the MSbar scheme where large perturbative corrections are observed. The implications on the threshold production of top quark pairs are briefly discussed.