Next-to-Leading-Order Corrections to the Production of Heavy-Flavour Jets in e+e- Collisions

In this paper we describe the calculation of the process e+e- -> Z/gamma -> QQbar + X, where Q is a heavy quark, at order alpha_s^2.Comment: 49 pages, Latex, epsfig, 6 figures. Tables 2 and 3 labels and captions have been fixe

The design and performance of a high efficiency power conversion system for use with the WJ-274 traveling-wave tube Final report, phase I

Design and performance of high efficiency power conversion system for use with WJ-274 traveling wave tube compatible with extraterrestrial environments - spaceborne communication

On the Fragmentation Function for Heavy Quarks in e+e- collisions

We use a recent O(alpha_s^2) calculation of the differential cross section for the production of heavy quarks in e+e- annihilation to compute a few moments of the heavy quark single-inclusive production cross section. We verify that, contrary to some recent claims, the leading and next-to-leading logarithmic terms in this cross section are correctly given by the standard NLO fragmentation function formalism for heavy quark production.Comment: 14 pages, Latex, epsfig, 4 figure

NATIONAL HEALTH SERVICE REFORM AND REGIONAL DEVOLUTION IN ITALY: ARE THEY CONSISTENT WITH THE PUBLIC FINANCE STRATEGY? A CRITICAL ANALYSIS OF THE PRESENT SITUATION IN THE FRIULI VENEZIA GIULIA REGION

The demographic and epidemiological transition and the increased share of public health spending in total spending over the last 35 years has forced the central government in Italy to reform the National Health Service

Wbbj production at NLO with POWHEG+MiNLO

We present a next-to-leading order plus parton-shower event generator for the production of a W boson plus two bottom quarks and a jet at hadron colliders, implemented in the POWHEG BOX framework. Bottom-mass effects and spin correlations of the decay products of the W boson are fully taken into account. The code has been automatically generated using the two available interfaces to MadGraph4 and GoSam, the last one updated to a new version. We have applied the MiNLO prescription to our Wbbj calculation, obtaining a finite differential cross section also in the limit of vanishing jet transverse momentum. Furthermore, we have compared several key distributions for Wbbj production with those generated with a next-to-leading order plus parton-shower event generator for Wbb production, and studied their factorization- and renormalization-scale dependence. Finally, we have compared our results with recent experimental data from the ATLAS and CMS Collaborations.Comment: Version as accepted for publication. Added references, one table and one figure. All the rest is the same as version

Power-suppressed effects in heavy quark fragmentation functions

This talk summarizes the results of a phenomenological analysis of heavy quark fragmentation data published by the CLEO and BELLE collaborations at \sqrt{s} = 10.6 GeV and by the LEP collaborations at \sqrt{s} = 91.2 GeV. Several theoretical ingredients are employed: next-to-leading order initial conditions, evolution and coefficient functions; soft-gluon resummation to next-to-leading-log accuracy; a next-to-leading order matching condition for the crossing of the bottom threshold in the evolution. Important initial-state electromagnetic radiation effects in the CLEO and BELLE data are also accounted for. We find that with reasonably simple choices of a non-perturbative correction to the fixed-order initial condition for the evolution, the data from CLEO and BELLE can be fitted with remarkable accuracy. The fitted fragmentation function, when evolved to LEP energies, does not however represent fairly the D* fragmentation spectrum measured by ALEPH. Large non-perturbative corrections to the coefficient functions of the meson spectrum are needed in order to reconcile CLEO/BELLE and ALEPH results.Comment: Latex, 9 pages, talk given by M. Cacciari at FRIF workshop on first principles non-perturbative QCD of hadron jets, LPTHE, Paris, France, 12-14 Jan 200

Crossing Heavy-Flavour Thresholds in Fragmentation Functions

In analogy with parton distribution functions, also parton fragmentation functions obey matching conditions when crossing heavy-flavour thresholds. We compute these matching conditions at next-to-leading order in the strong coupling constant alpha_s in the MSbar scheme. Our results can be used for the dynamical generation of the heavy-flavour component in next-to-leading order fits to light-hadrons fragmentation functions. Furthermore, when computing perturbatively the charm fragmentation function from first principles and evolving it to higher scales, our matching conditions should be used for consistency when crossing the bottom threshold.Comment: 9 pages, 2 figure