Second-generation theoretical technologies – heavy quark expansions, QCD sum rules and QCD simulations on the lattice – are arriving on the scene, allowing a treatment of charm decays that is genuinely based on QCD. The availability of those theoretical tools strengthens the case for the need for comprehensive precision measurements of charm decays. It is pointed out that the decays of charm me...

We present a strategy designed to separate several possible origins of the well-known enhancement of the ∆I = 1/2 amplitude in non-leptonic kaon decays. In particular, we seek to disentangle the contribution of physics at the typical QCD scale (soft-gluon exchange) from the effects at the scale of the charm quark mass. This is achieved by considering QCD with an unphysically light charm quark, ...

The scattering cross sections of charm mesons with hadrons such as the pion, rho meson, and nucleon are studied in an effective Lagrangian. In heavy ion collisions, rescattering of produced charm mesons by hadrons affects the invariant mass spectra of both charm meson pairs and dileptons resulting from their decays. These effects are estimated for heavy ion collisions at Super Proton Synchrotro...

The measured D, D, D, D s and Λ c photoproduction cross sections have been used to determine charm fragmentation ratios and fractions of c quarks hadronising as a particular charm hadron, f(c → D,Λc). Events with a D meson produced in association with an energetic jet have been used to measure the charm fragmentation function. The results are compared with different models and with previous mea...

The effect of gluon shadowing on charm quark production in large impact parameter ultrarelativistic heavy ion collisions is investigated. Charm production cross sections are calculated for a range of non-central impact parameters which can be accurately inferred from the global transverse energy distribution. We show that charm production is a good probe of the local parton density which determ...

We assess the theoretical uncertainties on the total charm cross section. We discuss the importance of the quark mass, the scale choice and the parton densities on the estimate of the uncertainty. We conclude that due to the small charm quark mass, which amplifies the effect of varying the other parameters in the calculation, the uncertainty on the total charm cross section is difficult to

We prove that Conjecture H of Caporaso et al. [CHarM], §6 together with Lang’s conjecture implies the uniformity of rational points on varieties of general type, as predicted in [CHarM]; a few applications in arithmetic and geometry are stated. As in [א], one uses the fact that rational points on X B are n-tuples of points when trying to bound n, as well as the fact that the Noetherian inductio...

The study of heavy-flavoured jets allows a detailed investigation of pQCD and the potential to understand the heavy quark production mechanism. In this paper only charm is considered. Measurements relating to the universality of charm fragmentation fraction are made. Measurements of both inclusive jets and dijets with a charm meson have been performed to probe the dynamics and the contents of t...

In charged current deep inelastic scattering charm is dominantly produced in scattering events on strange quarks, thereby allowing for an experimental determination of the nucleon’s strange sea density. A measurement of the energy spectrum of final state charm fragments (D-mesons) determines the charm fragmentation function at spacelike scales considerably below typical ee c.m.s. energies. NLO ...

Recent results on the production of open charm in electron proton scattering at HERA are reviewed. Results on the fragmentation of charm are presented and compared to the measurements at e + e − colliders. Recent results on the charm contribution to the proton structure function F2 are shown. Furthermore, measurements of inclusive D * meson, D * + jet and D * + muon production are presented. Th...