Related papers: Third order Coulomb correction to ttbar threshold …
The experimental results of the future electron -- ion ($e A$) collider are expected to constrain the dynamics of the strong interactions at small values of the Bjorken -- $x$ variable and large nuclei. Recently it has been suggested that…
We study higher-order QCD corrections for the production of a top-antitop quark pair ($t{\bar t}$ production) at the Large Hadron Collider in the Standard Model Effective Field Theory. We consider effects of new physics parametrized by the…
Future hadron collider experiments will allow for a detailed investigation of $t\bar{t}$ spin correlation effects. In this talk, recent progress in the theoretical description of these effects is reported. In particular, next-to-leading…
A higher order QED calculation of the ultraperipheral heavy ion cross section for mu+ mu- pair production at RHIC and LHC is carried out. The so-called "Coulomb corrections" lead to an even greater percentage decrease of mu+ mu- production…
We discuss calculations of the inclusive total cross section for heavy quark production at hadron collider energies within the context of perturbative quantum chromodynamics, including resummation of the effects of initial-state soft gluon…
The role of the top quark in completing the Standard Model quark sector is reviewed, along with a discussion of production, decay, and theoretical restrictions on the top quark properties. Particular attention is paid to the top quark as a…
Two-loop contributions to the electromagnetic form factors are calculated in the kinematic regime close to the fermion-antifermion threshold. The results are presented in an expansion in the velocity $\beta$ of the fermions in the c.m.…
The 3-dimensional wave function for a sharply cut-off Coulomb potential is analytically derived. The asymptotic form of the related scattering amplitude reveals a failure of the standard renormalization factor which is believed to be…
We consider the currents formed by a heavy and a light quark within Quantum Chromodynamics and compute the matching to Heavy Quark Effective Theory to three-loop accuracy. As an application we obtain the third-order perturbative corrections…
The energy dependence of the cross sections of $p\bar p$, $n\bar n$, and meson production in $e^+e^-$ annihilation in the vicinity of the $p\bar p$ and $n\bar n$ thresholds is studied. The proton-neutron mass difference and the $p\bar p$…
Recent calculations of heavy quark cross sections near threshold at next-to-next-to-leading order have found second-order corrections as large as first-order ones. We analyse long-distance contributions to the heavy quark potential in…
Cross sections of the heavy quarkonium production process $e^+e^-\to H + \gamma$ at the c.m. energy of $Z^0$-boson resonance are calculated at leading order in $\alpha_s$ with relativistic corrections resummed within the framework of…
We review in brief the threshold expansion, a method to perform the expansion of Feynman integrals near the heavy quark-antiquark threshold, and its relation to the construction of two effective theories, non-relativistic QCD (NRQCD) and…
We resum threshold double logarithms that appear in inclusive production of heavy quarkonium. This resolves the catastrophic failure of fixed-order perturbation theory where quarkonium cross sections at large transverse momentum can turn…
Coulomb corrections to perturbation theory for producing electron-positron pairs in ultrarelativistic heavy ion collisions are considered in a part-analytical, part-numerical approach. Production probabilities are reduced from perturbation…
Three-loop QCD corrections to the vector current correlator are considered. The large momentum procedure is applied in order to evaluate mass corrections up to order $(m^2/q^2)^6$. The inclusion of the first seven terms to the ratio…
The differential cross section of double bremsstrahlung from high-energy electron in the electric field of heavy atoms is derived. The results are obtained with the exact account of the atomic field by means of the quasiclassical…
Formulating a quasiclassical approach we determine the cross section for the complete four-body break-up of the lithium ground state following single photon absorption from threshold up to 220 eV excess energy. In addition, we develop a new…
We present the most precise value for the Higgs boson cross-section in the gluon-fusion production mode at the LHC. Our result is based on a perturbative expansion through N$^3$LO in QCD, in an effective theory where the top-quark is…
In the framework of nonrelativistic QCD, we compute the leading double-logarithmic corrections of order alpha_s^3 ln^2(1/alpha_s) to the heavy-quark-antiquark bound-state wave function at the origin, which determines the production and…