Related papers: QCD connection between hadron and jet multipliciti…
We calculate the probability for rapidity gaps in the parton cascade for different approximations within the perturbative QCD and compare the results with recent measurements. The aim is to find out whether the dual connection between the…
In this paper we present an analysis of the multiple hadron production induced by primary heavy quarks in e+e- annihilation with the account of most complete and corrected experimental data. In the framework of perturbative QCD, new…
We describe recent applications of the MLLA evolution equations to the calculation of mean multiplicities in quark and gluon jets and the higher moments of hadron and sub-jet multiplicity distributions in $e^+e^-$-annihilation as function…
I discuss the calculation of QCD jet rates in e+e- annihilation as a testing ground for parton shower simulations and jet finding algorithms.
It has recently been established that hadronisation corrections to QCD jets vary as $1/R$, at small $R$, for jets of radius $R$. Here we demonstrate, using jets in the $k_t$ algorithm, that the magnitude of these $1/R$ corrections are…
The production of identified hadrons inside jets in $e^+ e^-$ annihilation allows for detailed studies of parton-to-hadron fragmentation functions in a clean environment. We compute hadron-in-jets production cross sections for $e^+e^- \to…
Charged particle energy spectra in e+e- annihilation are compared with the analytical predictions from the QCD evolution equation in the Modified Leading Log Approximation. With the nonperturbative initial condition shifted down to…
The reaction $e^+e^-$ annihilation into three jets was recently computed for massive quarks at next-to-leading order in perturbative QCD. We discuss some results of our calculation for b jets produced at the Z resonance.
We study electron-positron annihilations into six jets at the parton level in perturbative Quantum Chromo-Dynamics. We use helicity amplitude methods. Results are presented for the case of the Durham and Cambridge jet clustering algorithms…
Superposition of jets of different flavors as well as superposition of jets of different topologies describe well observed structures (shoulder, H_q oscillations) in e+e- annihilation. The analysis of similar effects seen in experimental…
We present the QCD analysis of D-parameter distribution in near-to-planar 3-jet e+e- annihilation events. We derive the all-order resummed perturbative prediction and the leading power suppressed non-perturbative corrections both to the…
It was shown that at typical energies and luminosities of an $e^+e^-$ linear collider one can observe a significant suppression of fluctuations of the number of gluons in small angular regions. This property of jets is expected in $e^+e^-$…
This is a written version of two lectures given at the First School on Field Theory and Gravitation in Vitoria (Brasil) April 15-19, 1997. We discuss the foundation of QCD as the theory of strong interactions and the perturbative analysis…
The duality between partonic and hadronic descriptions of physical phenomena is one of the most remarkable features of strong interaction physics. A classic example of this is in electron-nucleon scattering, in which low-energy cross…
Jet emission at hadron colliders follows simple scaling patterns. Based on perturbative QCD we derive Poisson and staircase scaling for final state as well as initial state radiation. Parton density effects enhance staircase scaling at low…
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…
We present an enumeration of all possible amplitudes that contribute to an n-jet process in QCD. We estimate the number of amplitudes for large number of jets and determine the actual number of amplitudes to be calculated, which is smaller…
We point out that the fragmentation of a strange quark into nucleons versus antinucleons is not necessarily identical $D_{p/s}(z,Q^2) \neq D_{\bar p/s}(z,Q^2)$, even though the perturbative contributions from gluon splitting and evolution…
We employ data taken by the JADE and OPAL experiments for an integrated QCD study in hadronic e+e- annihilations at c.m.s. energies ranging from 35 GeV through 189 GeV. The study is based on jet-multiplicity related observables. The…
We discuss some important issues concerning multiplicities in quark and gluon jets in e+e- annihilation. In QCD the properties of a jet in general depend on two scales, the energy and virtuality of the jet. Frequently theoretical…