Related papers: Two-Loop Heavy-Flavor Contribution to Bhabha Scatt…
The method of Mellin-Barnes representation is used to calculate dimensionally regularized massive on-shell double box Feynman diagrams contributing to Bhabha scattering at two loops.
We have calculated first and second order corrections to several sum rules measured in deep inelastic lepton-hadron scattering. These corrections, which are due to heavy flavors only, are compared with the existing perturbation series which…
We compute the two-loop heavy quark jet-function in the heavy quark limit. This is one of the key ingredients in next-to-next-to-leading order (NNLO) and next-to-next-to-leading-log order (NNLL) computations of the invariant mass…
We report on recent progress in the calculation of the 3-loop massive Wilson coefficients in deep-inelastic scattering at general values of $N$ for neutral and charged current reactions in the asymptotic region $Q^2 \gg m^2$. Four new out…
We compute the two-loop QCD corrections to the heavy quark form factors in case of the vector, axial-vector, scalar and pseudo-scalar currents up to second order in the dimensional parameter $\epsilon = (4-D)/2$. These terms are required in…
We find that scattering amplitudes in massive scalar QCD can manifest the duality between color and kinematics at loop-level. Specifically we construct the one-loop integrands for four-point scattering between two distinct massive scalars,…
Multi-loop scattering amplitudes constitute a serious bottleneck in current high-energy physics computations. Obtaining new integrand level representations with smooth behaviour is crucial for solving this issue, and surpassing the…
A physically defined effective charge can incorporate quark masses analytically at the flavor thresholds. Therefore, no matching conditions are required for the evolution of the strong coupling constant through these thresholds. In this…
Three--loop contributions to massive QED vacuum polarization are evaluated by a combination of analytical and numerical techniques. The first three Taylor coefficients, at small $q^2$, are obtained analytically, using $d$\/--dimensional…
In this talk we discuss a number of ChPT calculations relevant for lattice QCD. These include the finite volume corrections at two-loop order for masses and decay constants. The second part is about hadronic vacuum polarization where we…
We present an exploratory study of the electromagnetic corrections to meson masses and the hadronic vacuum polarization using $N_f=2+1$ Domain Wall fermions. These corrections are estimated with two different approaches, a stochastic…
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…
The infrared exponentiation properties of dimensionally-regularized multi-loop scattering amplitudes are typically hidden at the level of the integrand, materializing only after integral evaluation. We address this long-standing problem by…
The most recent recalculation of the two-loop correction to the static quark-antiquark potential gave the numerical value different from the previously known one. We comment on the effect this change produces on the numerical estimates of…
Spectral functions at finite temperature and two-loop order are investigated, for a medium consisting of massless particles. We consider them in the timelike and spacelike domains, allowing the propagating particles to be any valid…
We study the vacuum polarization tensor of QED (quantum electrodynamics) at high temperatures up to the two loop levels and its effect on the electromagnetic properties of a medium. One loop corrections to QED coupling vanish at low…
Using the integrability conditions that we recently obtained in QCD$_2$ with massless fermions, we arrive at a sufficient number of conservation laws to be able to fix the scattering amplitudes involving a local version of the Wilson loop…
The accurate knowledge of luminosity at e^+ e^- flavour factories requires the precision calculation of the Bhabha cross section at large scattering angles. In order to achieve a theoretical accuracy at the 0.1% level, the relevant effect…
The contribution from hadronic vacuum polarisation effects is responsible for a large fraction of the theoretical uncertainty in the running of the QED coupling. The current level of uncertainty has become a limitation for electroweak…
We present O(alpha_s^2) corrections to the decay t-->bW in the limit of a very large top quark mass, m_t >> m_W. We find that the O(alpha_s^2) effects decrease the top quark decay width Gamma_t by about 2%: Gamma_t =…