相关论文: Coherent electroproduction of vector mesons on spi…
We estimate the leading order amplitudes for exclusive photon and meson electroproduction reactions at large Q^2 in the valence region in terms of skewed quark distributions. As experimental investigations can currently only be envisaged at…
We systematically study exclusive diffractive (photo) production of vector mesons ($J/\psi$, $\psi(2s)$, $\phi$ and $\rho$) off protons in high-energy collisions and investigate whether the production is a sensitive probe of gluon…
The exclusive photoproduction of lepton pairs on nucleon and nucleus target is investigated within the high energy color dipole approach, where the main physical quantity is the dipole-target elastic scattering amplitude that captures the…
The existence of a large primordial neutrino asymmetry is an intriguing possibility, both observationally and theoretically. Such an asymmetry can lead to the resonant production of $\mathrm{keV}$-scale sterile neutrinos, which are a…
We consider the production of excited electrons with spin-1/2 at the future SPPC-based electron-proton colliders with center-of-mass energies of $8.4$, $11.6$, $26.6$ and $36.8$ TeV. These exotic particles are predicted in the composite…
Single-spin asymmetries have been measured for semi-inclusive electroproduction of $\pi^+$, $\pi^-$, $\pi^0$ and $K^+$ mesons in deep-inelastic scattering off a longitudinally polarised deuterium target. The asymmetries appear in the…
Hard exclusive leptoproduction of real photons from an unpolarized proton target is studied in an effort to elucidate generalized parton distributions. The data accumulated during the years 1996--2005 with the HERMES spectrometer are…
Under the framework of the vector meson dominance model (VMD), the absolute scattering lengths of light vector mesons ($\phi$, $\omega$, and $\rho$) with the deuteron are calculated from the cross sections of vector meson photoproduction…
The inclusion of the unstable features of a spin-1 particle, without breaking the electromagnetic gauge invariance, can be properly accomplished by including higher order contributions as done in the so-called fermion loop scheme (for the W…
We consider the leptonic asymmetry generation in the nuMSM via hadronic decays of sterile neutrinos at T<<T_{EW}, when the masses of two heavier sterile neutrinos are between pion mass and 2 GeV. The choice of upper mass bound is motivated…
A systematic multiple scattering formalism for vector meson electroproduction from nuclei is developed, with emphasis on the formation, propagation and hadronization scales for quark-gluon fluctuations of the virtual high-energy photon. The…
We study the coherent photoproduction of pseudoscalar mesons---particularly of neutral pions---placing special emphasis on the various sources that put into question earlier nonrelativistic-impulse-approximation calculations. These include:…
We apply the tensor-pomeron model to small-$x$ deep-inelastic lepton-proton scattering and photoproduction. Our model includes a soft and a hard tensor pomeron as well as a reggeon contribution. Data with c.m. energies $6 < \sqrt{s} < 318$…
The complete experiment problem for photoproduction of single pseudoscalar mesons is reviewed briefly. If this problem is investigated in the context of a truncated partial wave analysis, the chance emerges to obtain a unique multipole…
The purely on-shell approach to effective field theories requires the construction of independent contact terms. Employing the little-group-covariant massive-spinor formalism, we present the first systematic derivation of independent…
The pseudoscalar and vector heavy meson masses are calculated in the \epsilon-regime of Heavy Meson Chiral Perturbation Theory to order \epsilon^4. The results of this calculation will allow the determination of low-energy coefficients…
A model for soft high-energy scattering is developed. The model is formulated in terms of effective propagators and vertices for the exchange objects: the pomeron, the odderon, and the reggeons. The vertices are required to respect standard…
Including destructively interfering off-diagonal transitions of diffraction-dissociation type, we arrive at a formulation of GVD for exclusive vector-meson production in terms of a continuous spectral representation of dipole form. The…
The coherent production of vector mesons in photon - hadron interactions is considered one of the most promising observables to probe the QCD dynamics at high energies and the transverse spatial distribution of the gluons in the hadron wave…
The GlueX experiment at Jefferson Lab studies photoproduction of mesons using linearly polarized $8.5\,\text{GeV}$ photons impinging on a hydrogen target which is contained within a detector with near-complete coverage for charged and…