相关论文: Subthreshold photoproduction of charm
We discuss the calculation of $F_2^{\gamma}({\rm charm})$ to next-to-leading order (NLO) in QCD, including contributions from both hadronlike and pointlike photons. We show that the former dominates strongly below $x\simeq 0.01$, and the…
Production measurements of charm hadrons, particularly the yield ratios of different hadron species as a function of the transverse momentum, are important to study the charm hadronisation mechanism. In this contribution, measurements of…
We report on a study of the reaction, $\gamma p \to p \pi^+\pi^+\pi^-\pi^-\pi^0$, at an incident photon energy of 19.3 GeV. The most significant feature of this reaction is $\Delta^{++}$ production which occurs with a cross section of…
We calculate the cross section and the beam asymmetry for exclusive photoproduction of charmed particles near threshold ($\gamma+p\to \Lambda_c^+ +\bar{D^0}$), in the framework of an effective Lagrangian model. We discuss the sensitivity of…
The study of $J/\psi$ photoproduction at low energies has consequences for the understanding of multiple aspects of nonperturbative QCD, ranging from mechanical properties of the proton, to the binding inside nuclei, and the existence of…
We investigate near-threshold $J/\psi$ photoproduction off the nucleon, focusing on hadronic rescattering effects induced by open-charm meson-baryon intermediate states. Beyond the conventional Pomeron-exchange mechanism, the $\bar…
RHIC-PHENIX has observed a large suppression pattern and azimuthal anisotropy of non-photonic electron at mid-rapidity ($\mid\eta\mid<0.35$) in Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV. To understand these results and the interaction…
Consequences resulting from the D Dbar excess derived indirectly by the NA50 experiment in S+U and Pb+Pb collisions at sqrt(s)=19, 17 GeV, relevant for the identification of the QCD phase transition in these collisions, are discussed. The…
Some recent results from the Fermilab fixed-target experiment E789 on production of charm, charmonium, and beauty are summarized and compared to model predictions. The data indicate that heavy-quark and quarkonium production are not yet…
This review is devoted to the study of charm production in ep and pp collisions. The total set of measurements obtained by the two collaborations H1 and ZEUS from HERA and their combination is outlined, as well as complementary data…
We present recent results on heavy flavour production at Tevatron Run II for typically ~1/fb of analysed proton-antiproton data at a c.m. energy of 1.96 TeV. This includes results on single and correlated open charm and bottom cross…
We propose to measure the photo-production cross section of $J/{\psi}$ near threshold, in search of the recently observed LHCb hidden-charm resonances $P_c$(4380) and $P_c$(4450) consistent with 'pentaquarks'. The observation of these…
The next-to-leading open charm production in $\gamma p$ collisions is calculated within the Perturbative Fragmentation Functions formalism, to allow resummation of $\as\log(\pt^2/m^2)$ terms. In the large $\pt$ region $(\pt > m)$ the result…
We present calculations of NNLO threshold corrections for beauty and charm production in pi- p and pp interactions at fixed-target experiments.
The results of the SERP-E-184 experiment at the U-70 accelerator (IHEP, Protvino) are presented. Interactions of the 70 GeV proton beam with carbon, silicon and lead targets were studied to detect decays of charmed $D^0$, $\bar D^0$, $D^+$,…
There are different approaches for diffractive photoproduction of charmonia. Recently, a new approach is proposed, in which charm quarks are taken as heavy quarks and the nonperturbative effect related to charmonia can be handled with…
We consider the photo-excitation of charm and bottom pentaquarks with the holographic assignments $[\frac 12\frac 12^-]_{S=0,1}$ and $[\frac 12\frac 32^-]_{S=1}$, in the photo-production of heavy vector mesons such as charmonia and…
A model of $\pi N$ pair photoproduction on nuclei at high momentum transfer is presented. The $A(\gamma,\pi N)B$ reaction amplitude is obtained by means of an extended impulse approximation, according to which the nuclear wavefunction…
We report measurements of the charm-anticharm production asymmetries for $\Lambda_c^+$, $\Sigma_c^{++}$, $\Sigma_c^0$, $\Sigma_c^{++*}$, $\Sigma_c^{0*}$, and $\Lambda_c^+(2625)$ baryons from the Fermilab photoproduction experiment FOCUS…
The production of D^0, D^*+, D^+, D_s+ and Lambda_c^+ charm hadrons and their antiparticles in ep scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 pb^-1. The fractions of charm quarks…