Related papers: Heavy quark medium polarization at next-to-leading…
As a stringent test of the nonrelativistic QCD factorization approach for inclusive heavy-quarkonium production in high-energy hadron collision, the polarized heavy-quarkonium production at the Tevatron is discussed. The polarization of…
We calculate the fragmentation function for a light quark to decay into a lepton pair to leading order in the QCD coupling constant. In the formal definition of the fragmentation function, a QED phase must be included in the eikonal factor…
Fully analytical results for the first two moments of the heavy-quark vacuum polarisation function at four loops in quantum chromo-dynamics are presented.
Recent developments in the evaluation of vector-meson spectral functions in hot and dense matter are discussed with emphasis on connections to the chiral phase transition in QCD. Model independent approaches including chiral low-density…
Top quark polarization in $e^+e^-$ annihilation into $t\bar t$ is calculated for linearly polarized beams. The Green function formalism is applied to this reaction near threshold. The Lippmann--Schwinger equations for the $S$-wave and…
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…
The real and imaginary part of the vacuum polarisation function $\Pi(q^2)$ induced by a massive quark is calculated in perturbative QCD up to order $\alpha_s^2$. The method is described and the results are presented. This extends the…
Motivated by applications in thermal QCD and cosmology, we elaborate on a general method for computing next-to-leading order spectral functions for composite operators at vanishing spatial momentum, accounting for real, virtual as well as…
We present a calculation of the perturbative quark-to-quark transverse parton distribution function at next-to-next-to-leading order based on a gauge invariant operator definition. We demonstrate for the first time that such a definition…
The energy dependence of the total hadroproduction cross section of pseudo-scalar quarkonia is computed via matching Next-to-Leading Order (NLO) Collinear-Factorisation (CF) results with resummed higher-order corrections, proportional to…
We present all relevant details of our calculation of the complete next-to-leading order (O(alpha_s^2 alpha)) QCD corrections to heavy flavor photoproduction with longitudinally polarized point-like photons and hadrons. In particular we…
The next-to-leading order analysis for the cross section for hadroproduction of top quark pairs close to threshold is presented. Within the framework of non-relativistic QCD a significant enhancement compared to fixed order perturbation…
Heavy quarkonium production at high transverse momentum ($p_T$) in hadronic collisions is explored in the QCD factorization approach. We find that the leading power in the $1/p_T$ expansion is responsible for high $p_T$ regime, while the…
We analyse inclusive photoproduction of polarized $^3P_1$ quarkonium in the framework of QCD. To separate nonperturbative and perturbative parts in the density matrix of the produced quarkonium we use a method , which is equivalent to the…
We present calculations of heavy quark and quarkonium production at CERN LEP2 in the k_T-factorization QCD approach. Both direct and resolved photon contribution are taken into account. The conservative error analisys is performed. The…
In this talk I briefly review the recent progress in calculation of the high order corrections to the parameters of the nonrelativistic heavy quark-antiquark system in the effective theory approach.
The heavy quark production in ultraperipheral heavy ion collisions is investigated, in particular we focus on the results from the coherent interactions given by the two-photon process. One addresses the heavy quark total cross sections at…
We present new results on the reconstruction of mesonic spectral functions for three temperatures $1.1T_c$, $1.2T_c$ and $1.4T_c$ in quenched QCD. Making use of non-perturbatively improved clover Wilson valence quarks allows for a clean…
In the investigation of in-medium modifications of quarkonia and for determining heavy quark diffusion coefficients, correlation functions play a crucial role. For the first time we perform a continuum extrapolation of charmonium and…
We investigate one-particle semi-inclusive processes in lepton-hadron scattering. In unpolarized scattering order $Q^{-1}$ corrections appear only when transverse momenta are detected. We consider the twist two and three matrix elements and…