Charm quark mass dependence in a global QCD analysis

The European Physical Journal C - We propose a dispersive representation of the charged pion vector form factor that is consistent with chiral symmetry and fulfills the constraints imposed by...     

Electrical studies of surface reconstruction resulting from chalcogen evaporation at the Ag2±δX/Vacuum interface (X=S, Se)X/Vacuum interface (X=S, Se)

We have investigated the dissociation rates of nonstoichiometric semiconductors Ag_2±δX (X=S, Se) to the vacuum by means of solid-state electrochemical technique. The values of chalcogen fluxes from the sample’s surface were measured versus compound’s composition and temperature. There has been obtained experimental evidence of the surface reconstruction of silver chalcogenides when the exact phase composition δ_cr.(T) is reached. This critical value δ_cr. correlates with the order-disorder transition in the silver sublattice for the Ag_2±δX/vacuum interface.     

Measurement of the gluon polarization in lepton pair production

The process of the lepton pair production in the collisions of unpolarized and longitudinally-polarized protons is considered in the framework of the perturbative QCD. The possibility of using such process for the measurement of the gluon polarization inside the proton is studied     

Transport properties of the interface metal chalcogenide/vacuum

The process of spontaneous thermal dissociation of the semiconducting nonstoichiometric compounds Cu_2-δX (X=S, Se) in vacuum has been investigated. Thermogravimetric, X-ray and electrochemical techniques reveal that the dissociation rates sharply decrease at δ≤δ_cr. (δ_cr.=f(T)) and the chalcogen fluxes from the compounds into the vacuum become immeasurably small. The results of the experiments are discussed in terms of the formation of a phase at the surface with properties of a compound of constant composition. Possible reasons are the excess surface energy together with the high mobility of copper ions which results probably in the reconstruction of the subsurface layers.     

Neutrino dimuon production and the strangeness asymmetry of the nucleon

We have performed the first global QCD analysis to include the CCFR and NuTeV dimuon data, which provide direct constraints on the strange and antistrange parton distributions, s(x) and . To explore the strangeness sector, we adopt a general parametrization of the non-perturbative functions satisfying basic QCD requirements. We find that the strangeness asymmetry, as represented by the momentum integral , is sensitive to the dimuon data provided the theoretical QCD constraints are enforced. We use the Lagrange multiplier method to probe the quality of the global fit as a function of [S ^-] and find -0.001 < [S ^-] < 0.004. Representative parton distribution sets spanning this range are given. Comparisons with previous work are made.Received: 15 January 2004, Revised: 23 November 2004, Published online: 15 February 2005PACS: 11.30.Hv, 12.15.-y, 13.15. + g, 12.38.-t, 13.60.Hb     

Preasymptotic nature of hadron scattering vs small-x HERA data

We emphasize that recently observed regularities in hadron interactions and deep-inelastic scattering are of a preasymptotic nature and it is impossible to draw conclusions on the true asymptotic behavior of observables without unitarization procedures. Unitarization is important and changes the scattering picture drastically.