Abstract: We present a study of the many-body interaction between a D* and multi-rho. We use an extrapolation to SU(4) of the hidden gauge formalism, which produced dynamically the resonances f(2)(1270) in the rho rho interaction and D-2* (2460) in the rho D* interaction. We then let a third particle, rho, D*, or a resonance, collide with them, evaluating the scattering amplitudes in terms of the fixed center approximation of the Faddeev equations. We find several clear resonant structures above 2800 MeV in the multibody scattering amplitudes. They would correspond to new charmed resonances, D-3*, D-4*, D-5*, and D-6*, which are not yet listed in the Particle Data Group, which would be analogous to the rho(3)(1690), f(4)(2050), rho(5)(2350), f(6)(2510) and K-3*(1780), K-4*(2045), K-5*(2380) described before as multi-rho and K*-multi-rho states, respectively.

Abstract: We make a theoretical study of the eta(1405) -> pi(0)f(0)(980) and eta(1405) -> pi(0)a(0)(980) reactions with an aim to determine the isospin violation and the mixing of the f(0)(980) and a(0)(980) resonances. We make use of the chiral unitary approach where these two resonances appear as composite states of two mesons, dynamically generated by the meson-meson interaction provided by chiral Lagrangians. We obtain a very narrow shape for the f(0)(980) production in agreement with a BES experiment. As to the amount of isospin violation, or f(0)(980) and a(0)(980) mixing, assuming constant vertices for the primary eta(1405) -> pi K-0 (K) over bar and eta(1405) -> pi(0)pi(0)eta production, we find results which are much smaller than found in the recent experimental BES paper, but consistent with results found in two other related BES experiments. We have tried to understand this anomaly by assuming an I = 1 mixture in the eta(1405) wave function, but this leads to a much bigger width of the f(0)(980) mass distribution than observed experimentally. The problem is solved by using the primary production driven by eta' -> K*(K) over bar followed by K* -> K pi, which induces an extra singularity in the loop functions needed to produce the f(0)(980) and a(0)(980) resonances. Improving upon earlier work along the same lines, and using the chiral unitary approach, we can now predict absolute values for the ratio Gamma(pi(0), pi(+)pi(-))/Gamma(pi(0), pi(0)eta) which are in fair agreement with experiment. We also show that the same results hold if we had the eta(1475) resonance or a mixture of these two states, as seems to be the case in the BES experiment.

Abstract: The aim of this paper is to investigate an efficient strategy that allows one to obtain pi pi phase shifts and rho meson properties from QCD lattice data with high precision. For this purpose we evaluate the levels of the pi pi system in the rho channel in finite volume using chiral unitary theory. We investigate the dependence on the pi mass and compare this with other approaches which use QCD lattice calculations and effective theories. We also illustrate the errors induced by using the conventional Luscher approach instead of a more accurate one that was recently developed that takes into account exactly the relativistic two-meson propagators. Finally, we make use of this latter approach to solve the inverse problem, getting pi pi phase shifts from “synthetic” lattice data, providing an optimal strategy and showing which accuracy is needed in these data to obtain the rho properties with a desired accuracy.