In this research we described the effective Hamiltonian theory and applied this theory to the calculation of current-current (Q1,2) and QCD penguin (Q3,…,6) c quark decay rates. We calculated the decay rates of semileptonic and hadronic of charm quark in the effective Hamiltonian theory. We investigated the decay rates of D meson decays according to Spectator Quark Model (SQM) for the calculati...

The systematic investigations of the role of the virtual charm axial currents in the decay of B-mesons to η ′ K and the spin structure of the nucleon are performed. We reduce the divergence of the virtual charm axial current to a specific gluon operator. Since this operator receives the main contribution from topologically nontrivial components of the QCD vacuum, we rederive the Diakonov-Petrov...

We outline the existing descriptions of the charm component of the deep inelastic proton structure function F2. We discuss recent approaches to include charm mass effects in the parton evolution equations and the coefficient functions. Contribution to the Proceedings of the Madrid low x Workshop, June 18-21 1997, Miraflores, Spain Both H1 and ZEUS have used c → D to measure charm production in ...

I will describe recent results from the HPQCD collaboration using a new very accurate method for charm quarks in lattice QCD, that we have used in calculations including the full effect of u, d and s sea quarks. Multiple values of the lattice spacing and of the u, d and s sea quark masses allow us to extrapolate reliably, with a full error budget, to the real world. This opens up the field of c...

We report on the charm physics potential at BES-III at BEPC-II which will make significant contribution to quark flavor physics this decade. The charm physics program will include studies of leptonic, semileptonic and hadronic charm decays, and tests for physics beyond the Standard Model. Event samples of the order of 30 million DD pairs, 2 million D S D− S pairs at threshold and 10 × 10 J/ψ de...

We have applied the Meson Cloud Model (MCM) to calculate the charm and strange antiquark distribution in the nucleon. The resulting distribution, in the case of charm, is very similar to the intrinsic charm momentum distribution in the nucleon. This seems to corroborate the hypothesis that the intrinsic charm is in the cloud and, at the same time, explains why other calculations with the MCM in...

The RHIC experiments have measured the nuclear modification factor RAA of non-photonic electrons in Au+Au collisions at √ sNN = 200 GeV. This RAA exhibits a large suppression for pt > 2 GeV/c which is commonly attributed to heavy-quark energy loss. It is expected that the heavy-quark radiative energy loss is smaller than the light quark one because of the so-called deadcone effect. An enhanceme...

Production of open and hidden charm hadrons in heavy ion collisions is considered within the statistical coalescence model. The charmed quark-antiquark pairs are assumed to be created at the initial stage of the reaction in hard parton collisions. The number of these pairs is conserved during the evolution of the system. At the hadronization stage, the charmed (anti)quarks are distributed among...

We study the centrality dependence to be expected if only charmonium production in the corona survives in high energy nuclear collisions, with full suppression in the hot, deconfined core. To eliminate cold nuclear matter effects as far as possible, we consider the ratio of charmonium to open charm production. The centrality dependence of this ratio is found to follow a universal geometric form...

The world average values for the probabilities that a charm quark fragments into D and D s have been calculated to be f(c → D) = 0.235± 0.007 (±0.007) and f(c → D s ) = 0.101± 0.009 (±0.025), respectively. The average values for D, D and Λ c have been also calculated. [email protected] On leave from Moscow State University, supported by GIF, contract I-0444-176.07/95 Introduction The probab...