Related papers: Multiloop Calculations: towards R at Order alpha_s…
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…
Within the framework of higher-twist collinear factorization, transverse momentum broadening for the final hadrons in semi-inclusive deeply inelastic $e+A$ collisions is studied at the next-to-leading order (NLO) in perturbative QCD.…
We discuss cross sections for hadron + hadron to 2 jets + anything in which three jet variables are measured. Such cross sections are useful especially for determining parton distributions. We define a new cross section d sigma/dX_A dX_B d…
We consider the thrust ($T$) distribution in electron-positron ($e^+e^-$) annihilation into hadrons and we perform the all-order resummation of the large logarithms of $1-T$ up to next-to-next-to-next-to-next-to-leading logarithmic…
Using the CLEO III detector, we measure absolute cross sections for e+e- --> hadrons at seven center-of-mass energies between 6.964 and 10.538 GeV. The values of R, the ratio of hadronic and muon pair production cross sections, are…
We calculate next to leading order QCD corrections to semi-inclusive polarized deep inelastic scattering and $e^+e^-$ annihilation cross sections for processes where the polarization of the identified final-state hadron can also be…
We compute the full one-loop EW contributions of O(\alpha_S alpha_EM^3) entering the electron-positron into two b-quarks and one gluon cross section at the Z peak and LC energies. We include both factorisable and non-factorisable virtual…
We sketch how the R*-operation can be used to compute the pole terms of Feynman diagrams. We identify computational difficulties when performing five-loop calculations, and provide four solutions that drastically reduce the number of terms…
We performed the calculation of the full O(alpha) corrections to e+e- -> mu- nu-bar u d-bar with the help of the GRACE/1-LOOP system. We discuss how a finite decay width introduces a serious gauge invariance breaking, particularly for…
We present the full ${{\cal O}}(\alpha)$ electroweak radiative corrections to associated Higgs top pair production in $e^+e^-$ collisions. We combine these results with a new calculation of the full one-loop QCD corrections. The computation…
The strong corrections to the R-ratio of electron-positron annihilation into hadrons are studied at the higher-loop levels. Specifically, the essentials of continuation of the spacelike perturbative results into the timelike domain are…
We discuss the problems that arise when one wishes to extend the existing general methods of computing radiative corrections to QCD jet cross sections to beyond next-to-leading order. Then we present a subtraction scheme that can be defined…
The forward-backward asymmetry in e+ e- annihilation into a quark-antiquark pair is considered in the double-logarithmic approximation at energies much higher than the masses of the weak bosons. It is shown that after accounting to all…
We compute power corrections to hadronic event shapes in $e^+e^-$ annihilation, assuming an infrared regular behaviour of the effective coupling $\alpha_s$. With the integral of $\alpha_s$ over the infrared region as the only…
In this work we provide all the missing ingredients for calculating parity-violating 3-jet observables in e^+e^- collisions at next-to-leading order (NLO) including the full quark mass dependence. In particular we give explicit results for…
We review algorithmic methods for two-loop calculations in HQET, and the analogous methods for on-shell QCD, needed for matching HQET to QCD.
In view of the forthcoming experiments at high energy $e^+ e^-$ colliders, LEP2 and beyond, the process $e^+ e^- \to W^+ W^- \to 4f$ has been investigated for {\it off-shell} $W$'s. After deriving the matrix element for the process within…
The results of evaluation of mixed QED X QCD corrections to R(s) in e^+e^- annihilation and R_{\tau} in hadronic decay of the \tau lepton to O(\alpha^n\alpha_s^m), m+n \leq 3, are presented. The net effect on \alpha_s(M_Z) from the Z decay…
The calculation of the quartic mass terms at order \alpha_s^3 to the hadronic R ratio is described. It is based on the operator product expansion for the quark current correlator, combined with an application of the renormalization group…
Recent results and methods of three-loop calculations in HQET are reviewed.