相关论文: The width of the omega meson in the nuclear medium
We calculate the spectral function of the omega meson in nuclear matter at zero temperature by means of the low-density theorem. The omega N forward scattering amplitude is calculated within a unitary coupled-channel effective Lagrangian…
The $\Delta$ decay in the nuclear medium is calculated in the relativistic meson-nucleon model. The delta spreading width is calculated and compared with the Pauli-blocked $\pi$N decay width. The influence of relativistic mean fields is…
We explore how the $\eta$-$\pi^0$ mixing angle and the $\eta$ meson decay into $\pi^{+}\pi^{-}\pi^0$ and 3$\pi^{0}$ are modified in the nuclear medium on the basis of the in-medium chiral effective theory with the isospin asymmetry $\alpha$…
We calculate the mass and width of the sigma meson in nuclear medium by considering that it couples to two virtual pions and to a pair of nucleon-antinucleon states and to particle-hole states. The mass is calculated by using the spectral…
The mass and decay width of the $\phi$ meson in cold nuclear matter are computed in an effective Lagrangian approach, with the medium dependence of these properties obtained by evaluating kaon-antikaon loop contributions to the $\phi$…
We investigate the modification induced on the nucleon-nucleon cross section by screening of the interaction inside nuclear matter. The interaction is described by the relativistic one boson exchange of $\sigma$, $\omega$ and $\pi$ mesons.…
Medium modifications of the $\pi \omega \rho$ vertex are analyzed in context of the $\omega \to \pi^0 \gamma^\ast$ and $\rho \to \pi \gamma^\ast$ decays in nuclear matter. A relativistic hadronic model with mesons, nucleons, and…
The $\omega$-, $\rho$- and $\phi$-resonance production and their dileptonic decay in $\pi^- A$ reactions at 1.1 - 1.7 GeV/c are calculated within the intranuclear cascade (INC) approach. The invariant mass distribution of the dilepton pair…
We have measured the energy spectra of pions and protons emitted in the weak decay of 12_Lambda_C, 28_Lambda_Si, and Lambda_Fe hypernuclei produced via the (pi+, K+) reaction. The decay widths of the pi- mesonic decay (Lambda -> p + pi-)…
We calculate the effective mass of the $\omega$ meson in nuclear matter in a relativistic random-phase approximation to the Walecka model. The dressing of the meson propagator is driven by its coupling to particle-hole pairs and…
We discuss recent experimental results on the modification of hadron properties in a nuclear medium. Particular emphasis is placed on an $\omega$ production experiment performed by the CBELSA/TAPS collaboration at the ELSA accelerator. The…
It is known that the decay process \eta\rightarrow\pi^0\pi^+\pi^- in free space is possible due to the isospin-symmetry breaking in Quantum Chromodynamics (QCD), i.e., the small mass difference between u and d quarks: The small width is…
The decay width of the $\omega$ meson at finite temperature is calculated using the Gell-Mann Sharp Wagner model of $\rho$ pole dominance. Effective masses of the $\rho$ and $\omega$ are determined within the framework of real-time…
The properties of vector mesons in nuclear matter are discussed. I examine the constraints imposed by elementary processes on the widths of $\rho$ and $\omega$ mesons in nuclear matter. Furthermore, results for the $\rho$- and…
Invariant mass spectra of e+e- pairs have been measured in 12 GeV p+A reactions to detect possible in-medium modification of vector mesons. Copper and carbon targets are used to study the nuclear-size dependence of e+e- invariant mass…
Masses of hadrons (baryons as well as mesons) are modified in the nuclear medium because of their interactions. In this paper we investigate the effect of in-medium meson masses on the properties of the nuclear matter. The calculations are…
The bosonic excitations induced by the omega meson propagation in dense nuclear matter is studied within the framework of random phase approximation. The collective modes are then analyzed by finding the zeros of the relevant dielectric…
The invariant mass spectra of $\phi \to K^{+}K^{-}$ are measured in 12 GeV $p+A$ reactions in order to search for the in-medium modification of $\phi$ mesons. The observed $K^{+}K^{-}$ spectra are well reproduced by the relativistic…
The photo production of $\omega$ mesons on the nuclei C, Ca, Nb and Pb has been measured using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the $\omega$ meson cross section on the nuclear…
The work presented at this workshop is divided into two parts. In the first part, the mass and decay width of the $\phi$-meson in cold nuclear matter are computed in an effective Lagrangian approach. The medium dependence of these…