相关论文: Hard exclusive photoproduction of $\Phi$ mesons
We consider the reaction $\gamma p \to M p$, with M being either a $\Phi$ or a $J/\Psi$ meson, within perturbative QCD treating the proton as a quark-diquark system. The phenomenological couplings of gauge bosons to (spatially extended)…
We present predictions for differential cross sections for the reaction $\gamma p \to \Phi p$ and give an outlook to which extent our calculations may be generalized to the photoproduction of $J/\Psi$ mesons. Our results are obtained within…
We investigate the reaction gamma+p -> V+p, with V denoting a Phi or a J/Psi meson, within the scope of perturbative QCD, treating the proton as a quark-diquark system. Our predictions extrapolate the existing forward differential…
We report on an attempt to describe hard exclusive photoproduction of $J/\Psi$ mesons, i.e. the reaction $\gamma p \to J/\Psi p$, by means of a modified version of the hard-scattering approach, in which the proton is treated as a…
The cross section for $\phi$ meson photoproduction on the proton has been measured for the first time up to a four-momentum transfer -t = 4 GeV^2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. At low…
The reactions gamma p -> K+ Lambda and gamma p -> K* Lambda are analyzed within perturbative QCD, allowing for diquarks as quasi-elementary constituents of baryons. The diquark-model parameters and the quark-diquark distribution amplitudes…
The amplitude for $\gamma p \to \phi p$ is calculated in a pQCD $k_{T}$ - factorization approach. The total cross section for this process is compared with HERA data. Total cross section, as a function of photon-proton energy and photon…
Differential cross sections at $t=t_{\text{min}}$ and decay asymmetries for the $\gamma p\rightarrow\phi p$ reaction have been measured using linearly polarized photons in the range 1.5 to 2.9 GeV. These cross sections were used to…
The amplitude for $\gamma p \to V p$, where $V$ is a $J/\psi$ or $\Upsilon$ ground state or excited vector meson, is calculated in a pQCD $k_{T}$-factorization approach. We use this amplitude to predict the cross section for exclusive…
We present predictions for the exclusive photoproduction of $\Phi$-meson on Proton at large tranfer, where we use a quark-diquark structure model for the proton. Extrapolation from our results to lower tranfers is comparable in magnitude…
We study the photoproduction of the vector mesons $\Phi$ and $J/\Psi$ off a proton in the kinematical regime of large energies and scattering angles within the framework of perturbative QCD. Our investigations are based on the hard…
We discuss diffractive dissociation of gluons into heavy quark pairs. The particular mechanism is similar to the diffractive dissociation of virtual photons into quarks, which drives diffractive deep inelastic production of charm in the…
The amplitude for $\gamma p \to J/\psi p$ ($\gamma p \to \psi' p$) is calculated in a pQCD $k_{T}$-factorization approach. The total cross section for this process is calculated for different unintegrated gluon distributions and compared…
We consider the reactions gamma p --> M B, with M B being either K+ Lambda, K+ Sigma0, or Pi n, within a diquark model which is based on perturbative QCD. The model parameters and the quark-diquark distribution amplitudes of the baryons are…
We analyze the reactions gamma+p => M+B, with M B being either K+ Lambda, K+ Sigma0, or pi+ n, within perturbative QCD, allowing for diquarks as quasi-elementary constituents of baryons. The diquark-model parameters and the quark-diquark…
The diffractive electro- or photo-production of two mesons separated by a large rapidity gap gives access to generalized parton distributions (GPDs) in a very specific way. First, these reactions allow to easily access the chiral-odd…
The Common Muon Proton Apparatus for Structure and Spectroscopy (COMPASS) at CERN with its use of beams of naturally polarized muons scattered of a polarized deuteron target, provides an environment of hard scattering between quasi-real…
Exclusive photoproduction of $\rho^0(770)$ mesons is studied using the H1 detector at the $ep$ collider HERA. A sample of about 900000 events is used to measure single- and double-differential cross sections for the reaction $\gamma p \to…
Elastic and proton-dissociative photoproduction of $\rho^0$, $\phi$ and $J/\psi$ vector mesons ($\gamma p\to Vp$, $\gamma p\to VN$, respectively) have been measured in e^+p interactions at HERA up to -t=3 GeV$^2$, where t is the…
The cross section is estimated for the $\pi^+\pi^-\pi^0$ invariant mass distribution in the $\gamma p$ reaction in the GeV region. This reaction is assumed to proceed through the formation of the $\omega$ meson in the intermediate state,…