Related papers: Perturbative Universality in Soft Particle Product…
We discuss the behaviour of the energy spectrum of particles in jets near the limit of small momenta of a few hundred MeV. In QCD parton cascades the soft gluons are coherently emitted from all faster partons in the jet and their production…
The perturbative QCD approach, based on Modified Leading Log Approximation and Local Parton Hadron Duality, is shown to describe inclusive features of multiparticle production in the soft region. Further predictions of this approach are…
The analytical perturbative approach, if taken to the limit of its applicability, allows one to predict an energy independent limit for the one-particle invariant density in QCD jets E dn/d^3p at very small momenta p. This is a direct…
We present some basic elements of the treatment of particle multiplicities in jets from high energy collisions within perturbative QCD. Then we discuss the universal features of the inclusive particle spectrum for the limiting case of…
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…
A scaling law for the one-particle invariant density E dn/d^3p at small momenta is observed in experimental data. We show that these results are consistent with the predictions of the analytical QCD approach, based on Modified Leading Log…
In e+e- collisions the particle spectra at low momenta reflect the properties of the underlying "soft" QCD gluon bremsstrahlung: the particle density, in the limit p\to 0, becomes independent of the incoming energy \sqrt{s} and directly…
The momentum spectra of particles in different high energy processes, such as e^+e^- annihilation, pp and nuclear collisions in the limit p,p_T -> 0 exhibit similar properties because of the dominant role of coherent soft gluon…
We discuss observables in multiparticle production for three kinds of limits of decreasing kinematical scales: 1. the transition jet \to hadron (limit y_{cut}\to 0 of the resolution parameter y_{cut}); 2. single particle inclusive…
The production of gluons in a jet is considered in limited phase space, either with a cut in transverse momentum with respect to the jet axis $k_\perp<k_\perp^{cut}$ or with a cut in absolute momentum $|\vec{k} | <k^{cut}$. It is shown in…
The quenching of jets (and high-pT particle spectra) observed in heavy-ion collisions is interpreted as due to the energy lost by hard partons crossing the Quark Gluon Plasma. Here we review recent efforts to include in its modeling…
A large variety of jet properties can be described perturbatively by evolving the parton cascade down to small scales of order of a few 100 MeV. We discuss two recent applications of this approach: 1. the soft limit of the particle spectrum…
Soft photons produced in heavy ion collisions are an important tool for probing the properties of the quark-gluon plasma. It is therefore crucial to understand the background - soft photons produced in elementary collisions. Low theorem…
Productions of soft photon with low transverse momenta in high-energy hadron-hadron collisions and $e^+$-$e^-$ annihilations indicate that they are consistently produced in excess of what are predicted by electromagnetic bremsstrahlung when…
QCD predicts soft radiation patterns that are particularly simple for $W+ {jet}$ production. We demonstrate how these patterns can be used to distinguish between the parton-level subprocesses probabilistically on an event-by-event basis. As…
It is proposed that soft particle production in hadronic collisions is dominated by multiple gluon exchanges between partons from the colliding hadrons, followed by radiation of hadronic clusters from the coloured partons distributed…
I survey some recent advances in the applications of the analytical perturbative approach to the description of particle distributions in multi-jet processes. New tests of the perturbatively based picture in the (semi) soft region are…
Soft QCD is beyond perturbative control, and therefore phenomenological models have to be developed. These are implemented and combined within event generators. Typical aspects considered are multiparton interactions, colour reconnection,…
The Modified Leading Log Approximation of QCD and the local parton hadron duality picture are shown to give a fully satisfactory description of data on charged particle energy spectra in $e^+e^-$ annihilation. The analysis of data in terms…
An essential part of high-energy hadronic collisions is the soft hadronic activity that underlies the primary hard interaction. It includes soft radiation from the primary hard partons, secondary multiple parton interactions (MPI), and…