Political sociologists have distinguished between Weberian states in which elite promotions are based on meritocratic criteria and states in which personalistic networks dominate government careers, linking these different career types to state structures and capacity. While researchers also recognize that elite networks are important even in highly bureaucratized states, there is little system...

In Phys. Rev. D 58, 014014 (1998) and 71, 094013 (2005), we determined non-perturbative D, D, D, D s , and Λ + c fragmentation functions, both at leading and next-to-leading order in the MS factorization scheme, by fitting ee data taken by the OPAL Collaboration at CERN LEP1. The starting points for the evolution in the factorization scale μ were taken to be μ0 = 2mQ, where Q = c, b. For the re...

ISSN 0418{9833 MZ-TH/00{09 hep{ph/0003148 Mar h 2000 Gluon Fragmentation to Gluonium H. Spiesberger1 and P. M. Zerwas2 1 Institut f ur Physik, Johannes-Gutenberg-Universitat, Staudinger Weg 7, D-55099 Mainz, Germany 2 Deuts hes Elektronen-Syn hrotron DESY, D-22603 Hamburg, Germany Abstra t The fragmentation of gluons to gluonium states is analyzed qualitatively in the nonperturbative region. ...

We study the fragmentation of the b quark in top decay in NLO QCD, within the framework of perturbative fragmentation, which allows one to resum large logarithms ∼ log(m 2 t /m 2 b). We show the b-energy distribution, which we compare with the exact O(α S) result for a massive b quark. We use data from e + e − machines in order to describe the b-quark hadronization and make predictions for the ...

Abstract Light charged hadron production data in the current fragmentation region at HERA are calculated using next-to-leading order perturbative calculations and fragmentation functions obtained from similar data from e+e− reactions. General good agreement is found at large photon virtuality Q2 and intermediate momentum fraction xp, consistent with fragmentation function universality. The desc...

We study soft-gluon radiation in top quark decay within the framework of perturbative fragmentation functions. We present results for the b-quark energy distribution, accounting for soft-gluon resummation to next-to-leading logarithmic accuracy in both the MS coefficient function and in the initial condition of the perturbative fragmentation function. The results show a remarkable improvement a...

The perturbative QCD approach to quarkonium decay into a photon and hadrons is reconsidered. It is shown that a consistent treatment within perturbative QCD calls for the introduction of a fragmentation contribution which has been neglected so far. The ensuing phenomenological implications are discussed, and, in particular, the possibility of measuring the gluon fragmentation function of the ph...

Hadronic jets are amongst the most striking phenomena in high-energy physics, and their importance is sure to persist as searching for new physics at hadron colliders becomes the main activity in our field. Signatures involving jets almost always have the largest cross sections but are the most difficult to interpret and to distinguish from background. Insight into the properties of jets is the...

Single spin asymmetries in p ↑ (¯ p ↑) p → π X have been measured to be large. They can be understood within perturbative QCD by introducing new k ⊥ and spin dependences in fragmentation and/or distribution functions. We discuss first how these effects in distribution functions alone can account for existing data and predict single spin asymmetries in other processes; then we see how similar ef...

The fragmentation function of a scalar leptoquark into possible S-wave bound states with a heavy anti-quark is calculated to the leading order in perturbative QCD for the high energy processes at large transverse momenta. The one-loop equations for the q 2-evolution of moments of the fragmentation function due to the hard gluon emission by the leptoquark are derived. The integral probabilities ...