Related papers: Two-loop corrections to the Isgur-Wise function in…
We calculate the two-loop corrections to heavy-quark pair production in the gluon fusion channel which arise from diagrams involving a closed light-quark loop. The calculation is carried out by keeping the exact dependence on the…
We perform a calculation of the isospin and hypercharge axialvector current propagators to two loops in SU(3)xSU(3) chiral perturbation theory. A large number of order p^6 divergent counterterms are fixed, and complete two-loop renormalized…
We present a complete analysis of the Heavy Quark Effective Theory Lagrangian at order $1/m^2$ in the leading logarithmic approximation, including effects induced by spectator quarks. At this order new correction terms appear in the…
We report on progress in the calculation of 3-loop corrections to the deep-inelastic structure functions from massive quarks in the asymptotic region of large momentum transfer $Q^2$. Recently completed results allow us to obtain the…
We report a calculation of all two-loop QED corrections with closed fermion loops for the n=1 and n=2 states of H-like ions and for a wide range of the nuclear charge numbers Z=1-100. The calculation is performed to all orders in the…
Within a systematic approach based on the dimensionally regularized nonrelativistic quantum electrodynamics, we derive the complete result for the two-loop correction to order $(\alpha/\pi)^2 (Z \alpha)^4$ for the $g$ factor of an electron…
We compute two-loop corrections to the associated production of a Higgs boson with a $Z$ boson and to off-shell $Z$ boson pair production in the gluon fusion channel, mediated by a heavy quark. We perform deep expansions in the high-energy…
We present the O(alpha_s^4) virtual QCD corrections to gluon-gluon scattering due to the interference of tree and two-loop amplitudes. We work in conventional dimensional regularisation and give analytic expressions renormalised in the…
We calculate the perturbative corrections to order \alpha_s^2\beta_0 to the sum rule derived from the second moment of the time-ordered product of b \to c currents near zero recoil. This sum rule yields a bound on \lambda_1, the expectation…
We calculate the one-loop QCD corrections for the decay of an off-shell vector boson with vector couplings into two pairs of quarks of equal or unequal flavours keeping all orders in the number of colours. These matrix elements are relevant…
Recently two-loop electroweak corrections to the neutral current four-fermion processes at high energies have been presented. The basic ingredient of this calculation is the evaluation of the two-loop corrections to the Abelian vector form…
A summary of recent results obtained for higher-order corrections to precision observables in the Standard Model and the Minimal Supersymmetric Standard Model is given. In the Standard Model electroweak two-loop results valid for arbitrary…
I present a very simple model, based on the model of Isgur, Scora, Grinstein and Wise \cite{ISGW}, which can be used to calculate the effects which appear at subleading order in heavy quark effective theory. I include both general formalism…
We apply analytic perturbation theory to the Gross--Llewellyn Smith sum rule. We study the $Q^2$ evolution and the renormalization scheme dependence of the analytic three-loop QCD correction to this sum rule, and demonstrate that the…
We calculate next-to-leading QCD corrections to the decay $H^+ \to u\bar d$ for generic up and down quarks in the final state. A recently developed algorithm for evaluation of massive two-loop Feynman diagrams is employed to calculate…
We calculate the two-loop QCD correction to the form factors of on-shell b-quark decay to an energetic massless quark, which constitutes the last missing piece required for an O(alpha_s^2) determination of |V_ub| from inclusive…
We study two-to-two parton scattering amplitudes in the high-energy limit of perturbative QCD by iteratively solving the BFKL equation. This allows us to predict the imaginary part of the amplitude to leading-logarithmic order for arbitrary…
In this paper, we compute the constrained QCD effective potential up to two-loop order with finite quark mass and chemical potential. We present the explicit calculations by using the double line notation and analytical expressions for…
We discuss the two-loop evolution of the flavor-nonsinglet meson distribution amplitude in perturbative QCD. After reviewing previous two-loop computations, we outline the incompatibility of these solutions with the group property of the…
We present complete two-loop radiative corrections to the graviton-quark-antiquark form factor G^* \rightarrow q \overline q and graviton-gluon-gluon form factor G^* \rightarrow g g in SU(N) gauge theory with n_f light flavours using…