arXiv subjects

G. Ríos

Publications and source records attributed to G. Ríos.

4 recordsLinked to original sources

arXiv2014

Bound states on the lattice with partially twisted boundary conditions

We propose a method to study the nature of exotic hadrons by determining the wave function renormalization constant $Z$ from lattice simulations. It is shown that, instead of studying the volume-dependence of the spectrum, one may investigate the dependence of the spectrum on the twisting angle, imposing twisted boundary conditions on the fermion fields on the lattice. In certain cases, e.g., the case of the $DK$ bound state which is addressed in detail, it is demonstrated that the partial twisting is equivalent to the full twisting up to exponentially small corrections.

hep-lat↗

arXiv2013

Properties and composition of the $f_0(500)$ resonance

In this talk we review our recent developments on the understanding of the nature of the f_0(500) resonance---or sigma meson---coming from the N_c expansion, dispersion relations with Chiral Perturbation Theory, as well as finite energy sum rules and semi-local duality.

hep-ph↗

arXiv2008

Chiral extrapolation of the sigma and rho mesons from dispersion relations and Chiral Perturbation Theory

We review our recent study of the pion mass dependence of the rho and sigma resonances, generated from one-loop SU(2) Chiral Perturbation Theory (ChPT) with the Inverse Amplitude Method (IAM). In order to properly account for the Adler zero region, we also review the recently obtained modified version of the IAM; which is based on analyticity, elastic unitarity and ChPT at low energies, thus yielding the correct pion mass dependence of the resonance pole positions up to next-to-leading order in ChPT. As main results we find that the rho-pi-pi coupling constant is almost pion mass independent and that the rho mass shows a smooth pion mass dependence while that of the sigma shows a strong non-analyticity. These findings are important for studies of the meson spectrum on the lattice.

hep-ph↗

arXiv2007

Scalar mesons from Unitarized Chiral Perturbation Theory: N_c and quark mass dependences

We review recent studies of light scalar meson properties by means of unitarization techniques, obtained from dispersion theory, and applied to the Chiral Perturbation Theory expansion. In particular, light scalars do not follow the N_c dependence of $\bar q q$ states although a subdominant quark-antiquark component may be observed to arise for the f_0(600) around 1 GeV, where another quark-antiquark multiplet is believed to exist. Finally, we present our preliminary results on the quark mass dependence of the f_0(600) and rho(770) resonances.

hep-ph↗