Related papers: Hard gluon emission from colored scalar pairs\brea…
We consider the electron-positron annihilation process into hadrons $R_{e^+e^-}$ up to $\mathcal{O}(\alpha_{s}^{3})$ and we adopt the smearing method suggest by Poggio, Quinn and Weinberg to confront the experimental data with theory. As a…
Event-shape distributions in $e^+e^-$ annihilation offer a unique lab oratory for understanding perturbative and non-perturbative aspects of QCD. Dressed Gluon Exponentiation is a resummation method designed to evaluate differ ential cross…
Collider experiments have recently measured the production cross section of hard jets separated by a rapidity gap as a function of transverse momentum and gap size. We show that these measurements reveal the relative frequencies for the…
We consider the virtual effects of a general type of Anomalous (triple) Gauge Couplings on various experimental observables in the process of electron-positron annihilation into a final fermion-antifermion state. We show that the use of a…
We present first calculations of QCD matrix-elements in perturbation theory at finite Nc beyond 2 loops in the eikonal approximation for e+ e- annihilation processes. For the emission of n soft energy-ordered gluons we solve both the colour…
We study heavy quarkonium production associated with gluons in $\rm e^+e^-$ annihilation as an illustration of the perturbative QCD (pQCD) factorization approach, which incorporates the first nonleading power in the energy of the produced…
A complete numerical solution of the evolution equation for parton multiplicities in quark and gluon jets with initial conditions at threshold is presented. Data on both hadron and jet multiplicities in e+e- annihilation are well described…
The emission of energetic gluons in $\tt$ production in $\ee$ annihilation can have important experimental consequences, in particular on top quark mass measurements. We present compact, analytical expressions for the gluon energy…
We explore the correspondence between the final state in e^+e^- annihilation and the small-x hadronic wavefunction in the transverse plane both in weakly coupled QCD and strongly coupled N=4 SYM. At strong coupling, the virtual and static…
We present the convolution integral for fermion pair production in the electroweak standard theory to order O(alpha) including also soft photon exponentiation. The result is complete in the sense that it includes initial and final state…
We investigate the quantum chromodynamics (QCD) corrections to hadronic final states in electron-positron collisions at $\mathcal{O}(\alpha_s^3)$ in the strong coupling constant $\alpha_s$. Namely, we analytically compute the total cross…
We consider the process of annihilation of e^+ e^- to three pion final state for the case of moderately high energies. The final state emission of virtual and real photon is considered explicitly. The calculations are performed in frames of…
The processes of muons (tau) and charged pions pairs production at electron-positron annihilation with first order radiative corrections are considered. The calculation results are presented assuming the energies of final particles (cms…
We describe ZFITTER, a Fortran program based on a semi-analytical approach to fermion pair production in e+e- annihilation at a wide range of centre-of-mass energies, including the PETRA, TRISTAN, LEP1/SLC, and LEP2 energies. A flexible…
The production of top quark pairs accompanied by a hard gluon in $e^+e^-$ annihilation is studied including next-to-leading order corrections in the strong coupling. At leading order, the fraction r of $t\bar{t}g$ events with respect to all…
A detailed investigation of the theoretical ambiguities present in the QCD description of photon production in $e^+e^-$ annihilation is given. It is pointed out that in a well-defined perturbative analysis it is necessary to subtract the…
We study the color randomization of two-gluon states produced after splitting of a primary fast gluon in the quark-gluon plasma. We find that for the LHC conditions the color randomization of the $gg$ pairs is rather slow. At jet energies…
The semi-inclusive decay processes of a top quark into a charged pseudo-scalar meson and a jet are studied within the framework of QCD factorization. The leading power of the decay matrix elements can be factorized into heavy-to-light quark…
We determine the O(\alpha_s) radiative corrections to polarized top quark pair production in e+ e- -annihilations with a specified gluon energy cut. We write down fully analytical results for the unpolarized and polarized O(\alpha_s) cross…
We propose a qualitatively new mechanism for quarkonium production, motivated by the global features of the experimental data and by the successes/failures of existing models. In QCD, heavy quarks are created in conjunction with a…