相关论文: Recent QCD results from OPAL

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…

Perturbative QCD analysis is presented of the cumulative out-of-plane momentum distribution in the near-to-planar e+e- annihilation events, K_out << Q. In this kinematical region multiple gluon radiation effects become essential. They are…

The predicted effects of final state interactions such as colour reconnection are investigated by measuring properties of hadronic decays of W bosons, recorded at a centre-of-mass energy of sqrt(s)=182.7 GeV in the OPAL detector at LEP.…

We present first results of resumming soft gluon effects in a simulation of high energy collisions beyond the leading-colour approximation. We work to all orders in QCD perturbation theory using a new parton branching algorithm. This…

We review recent developments related to jet clustering algorithms and jet finding. These include fast implementations of sequential recombination algorithms, new IRC safe algorithms, quantitative determination of jet areas and quality…

The charged particle multiplicities of two- and three-jet events from the reaction e+e- -> Z0 -> hadrons are measured for Z0 decays to light quark (uds) flavors. Using recent theoretical expressions to account for biases from event…

Using data from e+e- annihilation into hadrons, taken with the OPAL detector at LEP at the Z pole between 1991 and 1995, we performed a simultaneous measurement of the colour factors of the underlying gauge group of the strong interaction,…

Several preliminary QCD results from e+e- interactions at LEP are reported. These include studies of event shape variables, which are used to determine alpha_s and for studies of the validity of power corrections. Further, a study of color…

Selected, recent results, primarily from collider experiments but including some fixed target experiments, are presented as a survey of Quantum Chromodynamics (QCD). The concepts of leading order and next-to-leading order QCD are…

The observation of quark and gluon jets has played a crucial role in establishing Quantum Chromodynamics [QCD] as the theory of the strong interactions within the Standard Model of particle physics. The jets, narrowly collimated bundles of…

We present a short survey of the theoretical expectations on glueballs and hybrids as well as of the present phenomenological status. The possibility to obtain new information on gluonic mesons from the study of gluon jets in comparison to…

The constituent nature of candidate gluonic mesons can be studied by comparing their production in quark and gluon jets. The production rate for such mesons depends on the colour confinement processes at the end of the perturbative…

A summary is given of some recent QCD results from LEP. For LEP-2, the topics include event shape measurements, determinations of the strong coupling constant, and measurements of the charged particle multiplicity distribution at the…

We develop a new formalism for computing and including both the perturbative and nonperturbative QCD contributions to the scale evolution of average gluon and quark jet multiplicities. The new method is motivated by recent progress in…

Jet quenching has become a fundamental tool to study the hot QCD matter produced in heavy ion collisions. While important theoretical and experimental advances have been made in the last two decades, the extraction of the medium properties…

Three-particle correlations in quark and gluon jets are computed for the first time in perturbative QCD. We give results in the double logarithmic approximation and the modified leading logarithmic approximation. In both resummation…

We present a new observable zest and demonstrate its potential to differentiate between jets originated by gluons, top quark and vector bosons. Zest has salient properties such as boost invariance, stability against global color flow of…

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…

Jets and their substructure in pp collisions offer a unique opportunity to probe various aspects of quantum chromodynamics (QCD), ranging from perturbative QCD (pQCD) tests to studies of non-perturbative phenomena such as hadronization.…

The study of the differences of the fragmentation of quarks and gluons to jets of hadrons gives insight into the fundamental structure of QCD. Results from different approaches to properties of quarks and gluons are shown. The colour factor…