相关论文: Diffractive open charm production at HERA
The first observation of open b production in ep collisions is reported. An event sample containing muons and jets has been selected which is enriched in semileptonic b quark decays. The visible cross section \sigma(ep -> b \bar{b}X -> \mu…
We calculate the cross section of charm photoproduction at HERA collider in the framework of the kt-factorization QCD approach. Our analysis cover the inclusive charm production as well as charm and associated jet production processes. Both…
The measured D*+/-, D0, D+/-, D_s+/- and /\_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, /\_c). Events with a D*+/-…
The long standing mystery of smallness of diffractive dissociation of hadrons to large effective masses (the Pomeron-proton cross section is only 2 mb) witnesses that the gluonic clouds of valence quarks are so small (r_0=0.3fm) that soft…
Differential cross sections, $d\sigma/d x_\gamma^{\rm OBS}$, for dijet photoproduction events with a tagged $D^*$ meson are presented, where $x_\gamma^{\rm OBS}$ is the fraction of the photon energy contributing to the two highest…
We consider single-diffractive (SD) Higgs production in association with heavy flavour in proton-proton collisions at the LHC. The main focus of our study is a reliable estimate of SD/inclusive ratio, not a precision computation of the…
We use an anti-de Sitter/Quantum Chromodynamics (AdS/QCD) holographic light-front wavefunction for the $\rho$ and $\phi$ mesons, in conjunction with the Color Glass Condensate (CGC) dipole cross-section whose parameters are fitted to the…
We study in perturbative QCD the helicity ampltiudes of the process $\gamma^{*} p \to \rho p $ at large virtualities $Q$ of the photon $\gamma^{*}$. We estimate all spin flip amplitudes taking into account an important effect of the scale…
The production and semi-leptonic decay of heavy quarks have been studied in the photoproduction process $e^+p -> e^+ + {dijet} + e^- + X with the ZEUS detector at HERA using an integrated luminosity of 38.5 ${\rm pb^{-1}}$. Events with…
We calculate the contribution to inclusive high tranverse momentum ($p_T$) charm production at HERA from the excitation of charm in the photon. At large values of \pt\ the results of such a calculation, in the structure function language,…
The coefficient functions for heavy-flavour production in deeply inelastic electron-hadron scattering have been calculated previously. Analytic expressions are impossible to publish due to their length. Therefore we have tabulated them as…
Inclusive production cross sections are measured in deep inelastic scattering at HERA for meson states composed of a charm quark and a light antiquark or the charge conjugate. The measurements cover the kinematic region of photon virtuality…
We investigate open charm meson production in fixed-target LHCb experiment at $\sqrt{s}=86.6$ GeV in $p+^4\!\mathrm{He}$ collisions. Theoretical calculations of charm cross section are done in the framework of the $k_{T}$-factorization…
Recent experimental results on diffractive high $E_T$ jet production and diffractive open charm production, obtained by the H1 and ZEUS experiments at HERA, are presented. Various theoretical models for diffractive hard scattering are…
In this paper we consider the process of diffraction dissociation in deep inelastic scattering producing a small mass. This process is analyzed by the calculation of $\bar q\, q$ and $\bar q\, q\, G$ production. We show that the small…
Results on open charm and beauty production and on the search for top production in high-energy electron-proton collisions at HERA are reviewed. This includes a discussion of relevant theoretical aspects, a summary of the available…
The process of charm quark fragmentation is studied using $D^{*\pm}$ meson production in deep-inelastic scattering as measured by the H1 detector at HERA. Two different regions of phase space are investigated defined by the presence or…
The inclusive jet, dijet and trijet production cross-sections in deep-inelastic scattering (DIS) at $\sqrt{s}$=320GeV have been measured at the electron-proton collider HERA by the H1 and ZEUS collaborations using data taken in 1998-2000.…
Processes of heavy quark photoproduction at HERA energies and beyond are investigated using the semihard ($k_{\bot}$ factorization) approach. Virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as the…
At high-energies the gluon-gluon fusion is the dominant mechanism of $c \bar c$ production. This process was calculated in the NLO collinear as well as in the k$_t$-factorization approaches in the past. We show that the present knowledge of…