Related papers: QCD connection between hadron and jet multipliciti…
Recent developments and results on the comparison of gluon to quark jets are discussed. A most important topic is the introduction of explicit energy scales of the jets. The scaling violation of the fragmentation function and the increase…
The theory of strong interactions, quantum chromodynamics (QCD), is quite successful in the prediction and description of main features of multiparticle production processes at high energies. The general perturbative QCD approach to these…
In jet quenching, a hard QCD parton, before fragmenting into a jet of hadrons, deposits a fraction of its energy in the medium, leading to suppressed production of high-$p_T$ hadrons. Assuming that the deposited energy quickly thermalizes,…
The phenomenological energy dissipation in QCD jets evolution with colour coherence is considered and the corresponding modified parton multiplicity and distribution function are computed.
We begin with short review of the analytic approach (AA) to QCD recently developed and applied to the process of $e^+e^-$ annihilation into hadrons at low energies. Besides summary of the theoretical description of smeared experimental data…
Various QCD studies based on jet observables in hadronic final states in deep-inelastic scattering and hadron-hadron collisions are presented. Measured quantities are event shape variables, jet rates and jet cross sections. QCD analyses…
The extension of the factorization theorems of perturbative QCD to power corrections associated with re-scattering in nuclear collisions is reviewed. The importance of hadron-nucleus collisions is discussed.
We study QCD correction to the pair production of colored scalar particles in electron-positron annihilation with an emphasis on gluon emission in the final state. We discuss the usefulness of working in a ``quasi-two-body'' frame and…
We demonstrate that perturbative QCD leads to positive 3D parton--parton correlations inside nucleon explaining a factor two enhancement of the cross section of multi-parton interactions observed at Tevatron at $x_i\ge 0.01$ as compared to…
Low-energy particle production perpendicular to the event plane in three-jet events produced in Z decays in e+e- annihilation is measured and compared to that perpendicular to the event axis in two-jet events. The topology dependence of the…
In this paper we provide a physical picture for the QCD phase transition in terms of qualitative changes in the spectral functions. Our approach takes into account the crossover nature of this transition and counts for the observed strong…
Calculations of radiative corrections to the top quark width are reviewed. QCD effects are discussed for $t-\bar t$ systems produced in $e^+e^-$ annihilation near the energy threshold.}
This is an introduction to the use of QCD perturbation theory, emphasizing generic features of the theory that enable one to separate short-time and long-time effects. I also cover some important classes of applications: electron-positron…
Motivated by various excesses observed by the Fermi-LAT and AMS collaborations, we perform a detailed analysis of QCD uncertainties on particle spectra from dark-matter annihilation (or decay) into jets. When annihilated to SM particles,…
Peripheral collisions of relativistic heavy ions uniquely probe many aspects of QED. Examples include $e^+e^-$ pair production and nuclear excitation in strong fields. After discussing these reactions, I will draw parallels between…
At low temperatures we expect that all QCD observables are defined in terms of hadrons. This includes the partition function as well as the Polyakov loop in all representations. We analyze the physics underlying a microscopic derivation of…
High-energy heavy-ion collisions at the Relativistic Heavy-Ion Collider and the Large Hadron Collider have evolved from qualitative understanding into precise extraction of the properties of the Quantum Chromodynamics medium at extremely…
The total cross section for scattering virtual photons at high energy is sensitive to pomeron physics. If the photons are sufficiently virtual, QCD perturbation theory applies, so that the reaction probes the short distance pomeron. We…
We argue that high energy proton-nucleus (p+A) collisions provide an excellent laboratory for studying nuclear size enhanced parton multiple scattering where power corrections to the leading twist perturbative QCD factorization approach can…
Measurements of heavy quark production in electron-positron collisions are used to analyse the strong interactions between quarks and anti-quarks. A scaling behaviour is observed in distributions of the rapidity change of D*, B*, and B…