Related papers: Radiation Zeros in High-Energy $e^+e^-$ Annihilati…
The exchange of gluons between heavy quarks produced in $e^+e^-$ interactions results in an enhancement of their production near threshold. We study QCD threshold effects in $\gamma\gamma$ collisions. The results are relevant to heavy quark…
A class of meson decay modes sensitive to only one quark topology at leading G_F order (annihilation of valence quarks through a W) is described. No experimental observations, nor even upper limits, have been reported for these decays. This…
The analysis of $1/m_Q^2$ corrections of the previous paper is extended to the semileptonic decays of heavy baryons. We focus on the simplest case, the ground state $\Lambda_Q$ baryons, in which the light degrees of freedom are in a state…
We analyze the $Wt\bar b$ production processes and especially the rate of longitudinal $W$ polarization sensitive to a possible top quark mass scale dependence and to the presence of strong final state $Wt$ interactions for example…
In this contribution we discuss recent progress in associated top-quark pair production with one or two isolated photons, $pp\to t\bar{t}\gamma(\gamma)$. The focus is the simultaneous inclusion of higher-order effects and photon radiation…
We review the present theoretical and experimental status of heavy quark production in high-energy collisions. In particular, we cover hadro- and photoproduction at fixed target experiments, at HERA and at the hadron colliders, as well as…
We use a hadron resonance gas model to calculate the quark-antiquark condensates for light (up and down) and strange quark flavors at finite temperatures and chemical potentials. At zero chemical potentials, we find that at the temperature…
The thermal multihadron production observed in different high energy collisions poses many basic problems: why do even elementary, $e^+e^-$ and hadron-hadron, collisions show thermal behaviour? Why is there in such interactions a…
We present factorization theorems for two exclusive heavy-quarkonium production processes: production of two quarkonia in e^+e^- annihilation and production of a quarkonium and a light meson in B-meson decays. We describe the general proofs…
We derive radiation reaction from QED in a strong background field. We identify, in general, the diagrams and processes contributing to recoil effects in the average momentum of a scattered electron, using perturbation theory in the Furry…
The advent of back-scattered laser beams for electron-positron colliders will allow detailed studies of a large array of high energy photon-photon and photon-electron collision processes with polarized beams. These include tests of…
We derive the atomic radiative corrections predicted by QED using an alternative approach that offers the advantage of physical clarity and transparency. The element that gives rise to these corrections is the fluctuating zero-point…
The longitudinal polarization of hyperons in $e^+e^-$ annihilation at high energies depends on the longitudinal polarization of the quark produced at the $e^+e^-$ annihilation vertex whereas the spin alignment of vector mesons is…
Recently it has been shown that the vacuum state in QED is infinitely degenerate. Moreover a transition among the degenerate vacua is induced in any nontrivial scattering process and determined from the associated soft factor. Conventional…
We calculate the complete $O(\alpha^2)$ initial state radiation corrections to $e^+ e^-$ annihilation into a neutral vector boson in a direct analytic computation without any approximation. The corrections are represented in terms of…
In the framework of a newly developed factorization formalism which is based on NRQCD, explicit cancellations are shown for the infrared divergences that appeared in the previously calculated hadronic annihilation decay rates of P-wave and…
The collisions of high energy photons produced at an electron-positron collider provide a comprehensive laboratory for testing QCD, electroweak interactions, and extensions of the Standard Model. The luminosity and energy of the colliding…
The time-scales of rehadronization are considered for a baryon-free QGP at RHIC and LHC energies. The non-equilibrium nucleation scenario leads to mechanical instability of the supercooled QGP phase which then may be suddenly converted in a…
We analyze the zero point energy of composite particles (or resonances) which are dynamically created from relativistic fermions. We compare the zero point energies in medium to the vacuum one, taking into account the medium modification of…
It is well known that in the presence of strong external electromagnetic fields many processes forbidden in standard QED become possible. One example is the one-photon annihilation process considered recently by the present authors in the…