Paolo Nason

The total cross section for the production of heavy quarks in hadronic collisions

We present the result.8 of a full calculation of the QCD O(a

Matching NLO QCD and parton showers in heavy flavour production

) radiative corrections to the total cross aection for the production of a heavy quark pair. We find large contributions for parton s&energies near threshold and well above threshold. The implications for the production of top and bottom quarks at collider energies are discussed.

The One Particle Inclusive Differential Cross-Section for Heavy Quark Production in Hadronic Collisions

We apply the MC@NLO approach to the process of heavy flavour hadroproduction. MC@NLO is a method for matching next-to-leading order (NLO) QCD calculations and parton shower Monte Carlo (MC) simulations, with the following features: fully exclusive events are generated, with hadronisation according to the MC model; total rates are accurate to NLO; NLO results for distributions are recovered upon expansion in αS; hard emissions are treated as in NLO computations while soft/collinear emissions are handled by the MC simulation, with the same logarithmic accuracy as the MC; matching between the hard and soft regions is smooth, and no intermediate integration steps are necessary. The method was applied previously to the hadroproduction of gauge boson pairs, which at NLO involves only initial-state QCD radiation and a unique colour structure. In heavy flavour production, it is necessary to include contributions from final-state QCD radiation and different colour flows. We present illustrative results on top and bottom production at the Tevatron and LHC.

QCD analysis of first

Abstract We present formulae and results on the one-particle inclusive differential cross section for heavy quark production in hadronic collisions, including the O(αS3) radiative corrections. We discuss the general range of applicability of the results and present transverse momentum and rapidity distributions. We consider the production of top, bottom and charm quarks at energies of interest for current experiments.

b

The first data on bottom quark production in p collisions at 1.96 TeV have recently been obtained by the CDF collaboration. These data probe the region of pT ~ 0, providing a new invaluable input on the issue of the compatibility between next-to-leading-order (NLO) QCD and data. We reconsider the evaluation of the b cross section, in view of recent theoretical developments, and of the latest inputs on structure function fits. We show that the new CDF measurements are in good agreement with NLO QCD. If CDF preliminary data are confirmed, a long-standing discrepancy between NLO QCD predictions and hadron-collider data can be settled.

cross-section data at 1.96-TeV

We discuss the excess in the hadroproduction of B mesons at the Tevatron. We show that an accurate use of up-to-date information on the B fragmentation function reduces the observed excess to an acceptable level. Possible implications for experimental results reporting bottom quark cross sections, also showing an excess with respect to next-to-leading order theoretical predictions, are discussed.

Is there a significant excess in bottom hadroproduction at the tevatron

We review the present theoretical and experimental status of heavy quark production in high-energy collisions. In particular, we cover hadro- and photoproduction at fixed target experiments, at HERA and at the hadron colliders, as well as aspects of heavy quark production in e+e- collisions at the Z0 peak.

Heavy quark production

We present a calculation of the D*+, D+ and D0 meson single inclusive production cross section for the Tevatron Run II. We use the FONLL approach in perturbative QCD, which, besides including the known next-to-leading order corrections, also provides for the resummation at the next-to-leading logarithmic level of terms enhanced at large pT by powers of log (pT/m), where m is the charm mass and pT is its transverse momentum. Non-perturbative effects in charm hadronization are extracted, in moment space, from recent ALEPH data for D* fragmentation in e+e? collisions.

Charm cross sections for the Tevatron Run II

Heavy quark production in hadronic collisions is a subject of considerable experi- mental and theoretical interest. There is of course great interest in the searches for the top quark at hadronic colliders, and one needs a theoretical prediction of the hadronic cross section in order to put a bound on the top quark mass[1]. Further- more, heavy quarks produced in hadronic collisions are a copious source of leptons at high p ⊥, and therefore constitute a significant leptonic background, which should be fully understood in order to search for new physics. Finally, there are a large number of charm production experiments, and various theoretical attempt have been made to explain their results.