We explain the early onset of shadowing in nuclear photoabsorption within a multiple scattering approach and discuss its relation to in-medium modifications of the ρ 0. The nuclear photoabsorption cross section is known to be shadowed at large energies, i.e. σ γA < Aσ γN. This was at first interpreted as a confirmation of the vector meson dominance (VMD) model, which assumes that the photon mig...

We show how to obtain information about the states of an effective field theory in terms of the underlying fundamental theory. In particular we analyze the spectroscopic nature of meson resonances from the meson-meson scattering amplitudes of the QCD low energy effective theory, combined with the expansion in the large number of colors. The vectors follow a q̄q behavior, whereas the σ, κ and f0(...

We present a dynamical study of e + e − production in C + C and Ca + Ca collisions at BEVALAC/SIS energies on the basis of the covariant transport approach HSD employing momentum-dependent ρ-meson spectral functions that include the pion modifications in the nuclear medium as well as the polarization of the ρ-meson due to resonant ρ−N scattering. We find that the experimental data from the DLS ...

Spin effects in B c → X c¯ c π(ρ) decays. Abstract The two-particle hadronic decays of B c meson into S-wave and P-wave charmonium states X c¯ c are considered in the framework of hard gluon exchange model. It is shown that decay width of B c meson into P-wave charmonium states exceeds one for S-wave states. In compare with the previous estimations we predict the enhancement by factor ∼ 2 the b...

We show how to obtain information about the states of an effective field theory in terms of the underlying fundamental theory. In particular, we analyze the spectroscopic nature of meson resonances from the meson-meson scattering amplitudes of the QCD low energy effective theory, combined with the expansion in the large number of colors. The vectors follow a qq behavior, whereas the sigma, kapp...

We discuss a formula for the sum of tree diagrams of n-bosons scattering from a heavy fermion. This formula can be considered as a generalization of the eikonal formula to include non-abelian vertices. It will be used to demonstrate the consistency of multi-meson-fermion scattering in the large-N c limit.

The scattering cross sections of charm mesons with hadrons such as the pion, rho meson, and nucleon are studied in an effective Lagrangian. In heavy ion collisions, rescattering of produced charm mesons by hadrons affects the invariant mass spectra of both charm meson pairs and dileptons resulting from their decays. These effects are estimated for heavy ion collisions at Super Proton Synchrotro...

The hadronic decays η, η ′ → 3π and η ′ → ηππ are investigated within the framework of U(3) chiral effective field theory in combination with a relativistic coupled-channels approach. Final state interactions are included by deriving sand p-wave interaction kernels for meson-meson scattering from the chiral effective Lagrangian and iterating them in a Bethe-Salpeter equation. Very good overall ...

We examine the potential of the COMPASS experiment at CERN to study color transparency via exclusive vector meson production in hard muon-nucleus scattering. It is demonstrated that COMPASS has high sensitivity to test this important prediction of perturbative QCD. Expanded version of the talk presented at the Workshop on ”Nucleon Structure and Meson Spectroscopy” physics to be studied at the C...

Using the quark-meson coupling model, we study the longitudinal response function for quasielastic electron scattering from nuclear matter within relativistic RPA. In QMC the coupling constant between the scalar meson and the nucleon is expected to decrease with increasing nuclear density. Furthermore, since the electromagnetic form factors of the in-medium nucleon are modified at the same time...