Related papers: Quartic Mass Corrections to $R_{had}$
Recent analytical and numerical results for the three-loop polarization function allow to present a phenomenological analysis of the cross section for massive quark production in electron positron annihilation to order $\alpha_s^2$.…
The radiative meson decays $V\to P\gamma$ and $P\to \gamma\gamma$ are analyzed using the quark triangle diagram. Experimental data yield well determined estimates of the universal quark-antiquark-meson couplings $g_{Vq\bar{q}'}$ and…
In this paper we investigate supersymmetric effects to the threshold production cross section of top quark pairs in electron positron annihilation. In particular, we consider the complete one-loop corrections from the strong and weak sector…
We examine the corrections to the lowest order gravitational interactions of massive particles arising from gravitational radiative corrections. We show how the masslessness of the graviton and the gravitational self interactions imply the…
O(\alpha) QED radiative corrections to neutral current deep inelastic production of heavy quarks are calculated in the leading log approximation and compared with the corresponding corrections assuming a massless charm parton. Besides the…
We present complete O(alpha_s^2) corrections to the decay b-->c+l+nu at the point where the invariant mass of the leptons sqrt{q^2} equals the c quark mass. We use this result, together with previously obtained corrections at the ends of…
We assume that all quark and lepton $3 \times 3$ mass matrices which appear in the standard model lagrangian (after spontaneous symmetry breaking) with neutrinos treated as Dirac patricles have the triangular form. Such matrices have not…
With the QGP opacity computed perturbatively and with the global entropy constraints imposed by the observed $dN_{ch}/dy\approx1000$, radiative energy loss alone cannot account for the observed suppression of single non-photonic electrons.…
Details of a recent calculation of O(alpha_s^2) corrections to the decay b -> c,l,nu_l, taking into account the c-quark mass, are described. Construction of the expansion in the mass ratio m_c/m_b as well as the evaluation of new four-loop…
The size of non-perturbative corrections to event shape observables is predicted to fall like powers of the inverse centre of mass energy. These power corrections are investigated for different observables from $e^+e^-$-annihilation…
The bottom quark pole mass $M_b$ is determined using a sum rule which relates the masses and the electronic decay widths of the $\Upsilon$ mesons to large $n$ moments of the vacuum polarization function calculated from nonrelativistic…
Two different two-loop relations between the pole- and the MS-mass of the top quark have been derived in the literature which were based on different treatments of the tadpole diagrams. In addition, the limit M_W^2/m_t^2 \to 0 was employed…
The coupling constants of the order $p^2$ low-energy weak effective lagrangian can be determined from the $K\to\pi$ and $K\to 0$ weak matrix elements, choosing degenerate quark masses for the first of these. However, for typical values of…
We evaluate the collisional energy loss of a energetic fermion with mass $M$ propagating through a hot QED plasma with temperature $T$, including mass corrections, that is, keeping the mass $m$ of the fermion constituents of the plasma,…
We calculate four-loop QCD corrections to the electroweak $\rho$ parameter with a non-vanishing $b$ quark mass. At three loops, it was observed that elliptic integrals contribute to this observable. This prompts the question of which…
At the LHC a precise measurement of the Higgs boson mass (if discovered), at the level of 0.1-1%, will be possible through the channel g g --> H --> 4l for a wide range of Higgs mass values. To match such an accuracy, the systematic effects…
The intermediate quarkonium state $\chi_2(^3P_2)$ in electron-positron annihilation to proton and antiproton as well as in antiproton-proton annihilation to electron and positron can produce backward-forward asymmetry, when populated…
In this talk we discuss the calculation of the QCD corrections to parity-violating 3-jet observables in e^+e^- collisions, keeping the full quark mass dependence.
Positronium annihilation amplitudes that are computed by assuming a factorization approximation with on-shell intermediate leptons, do not exhibit good analytical behavior. We propose an ansatz which allows to include binding energy…
We calculate the ${\cal O}(\alpha_{{\rm ew}})$ electroweak radiative corrections to $e^+ e^- \to t \bar{t} h$ at a electron-positron linear collider (LC) in the standard model. We analyze the dependence of the ${\cal O}(\alpha_{{\rm ew}})$…