Related papers: omega -> pi pi decay in nuclear medium
The decay channel J/\psi->gamma omega omega, omega -> pi+ pi- pi0 is analyzed using a sample of 5.8x10^7 J/psi events collected with the BESII detector. The omega omega invariant mass distribution peaks at 1.76 GeV/c^2, just above the omega…
We study the decay Omega^- -> Xi^- pi^+ pi^- in heavy-baryon chiral perturbation theory. At leading order, the decay is completely dominated by the Xi^{*0}(1530) intermediate state, and the predicted rate and Xi^-pi^+ mass distribution are…
An $\omega$-meson in motion with respect to a nuclear medium can couple to a $\sigma$-meson through a particle-hole excitation. This coupling is large. We investigate its consequences for the width of $\omega$-mesons in matter and for the…
A nonstandard method for calculating the nuclear $2\nu\beta\beta$ - decay amplitude is proposed. The method is based on the explicit use of those approximate symmetries of a nuclear hamiltonian, which correspond to the operators of allowed…
The decay widths of four-body double-pion decays $\ds\to pn \pi^0\pi^0$, $\ds\to pn \pi^+\pi^-$, and iso-scalar parts of $\ds\to pp \pi^0\pi^-$ and $\ds\to nn \pi^+\pi^0$ are explicitly calculated with the help of the $d^*$ wave function…
The decay width of a phi meson is reduced from its vacuum value as its mass decreases in hot hadronic matter as a result of the partial restoration of chiral symmetry. This reduction is, however, cancelled by collisional broadening through…
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 shift, width broadening, and spectral density for the $\rho$ and $\omega$ mesons in a heat bath of nucleons and pions are calculated using a general formula which relates the self-energy to the real and imaginary parts of the…
We propose formulas of the nuclear beta-decay rate that are useful in a practical calculation. The decay rate is determined by the product of the lepton and hadron current densities. A widely used formula relies upon the fact that the…
We complement studies of the neutral pion transition form factor pi^0 --> gamma^(*) gamma^(*) with calculations for the electromagnetic decay widths of the processes pi^0 --> e^+ e^-, pi^0 --> e^+ e^- gamma and pi^0 --> e^+ e^- e^+ e^-.…
We investigate the bulk properties of symmetric nuclear matter within the framework of an in-medium modified chiral solitonic model with $\pi$, $\rho$ and $\omega$ mesons. We consider the modification of meson degrees of freedom in nuclear…
In-medium chiral perturbation theory is used to calculate the density dependence of the quark condensate $<\bar qq>$. The corrections beyond the linear density approximation are obtained by differentiating the interaction contributions to…
The Lambda decay rates in nuclei has been calculated in ref. 1 using the Propagator Method in Local Density Approximation. We have studied the dependence of the widths (including the one for the two-body induced process Lambda NN -> NNN) on…
We reexamine the $\omega \to \pi^{0} \pi^{0} \gamma $ decay, adding the effect of $\omega-\rho$ mixing to the amplitude calculated with the aid of chiral perturbation theory and vector meson dominance. We predict the neutral decay to occur…
In nuclear matter, the pion weak decay constant is separated into the two components $f_t, f_s$ corresponding to the time and space components of the axial-vector current. Using QCD sum rules, we compute the two decay constants from the…
We calculate the S-wave decay widths and energy shifts for pi pi and pi K atoms in the framework of QCD+QED. The evaluation - valid at next-to-leading order in isospin symmetry breaking - is performed within a non-relativistic effective…
The \tau \to \omega,\phi \pi^- \nu_\tau decays of the \tau lepton are studied using the method of phenomenological SU(3) * SU(3) chiral Lagrangians. It is shown that the obtained value for the \tau \to \phi \pi \nu_\tau decay probability is…
Sigma decay and its relation with chiral phase transition are discussed at finite temperature and density in the framework of the Nambu-Jona-Lasinio model. The decay rate for the process sigma -> 2 pions to first order in a 1/N_c expansion…
Fits of pion-nucleus potentials to large sets of pionic atom data reveal departures of parameter values from the corresponding free $\pi N$ parameters. These medium effects can be quantitatively reproduced by a chiral-motivated model where…
We present a study of the $\pi\pi$ scattering amplitude in the $\sigma$ and $\rho$ channels at finite temperature and nuclear density within a chiral unitary framework. Meson resonances are dynamically generated in our approach, which…