arXiv subjects

Jenifer Nebreda

Publications and source records attributed to Jenifer Nebreda.

2 recordsLinked to original sources

arXiv2013

Determination of Chiral Perturbarion Theory low energy constants from a precise description of pi-pi scattering threshold parameters

We report on our determination of the values of the one and two loop low energy constants appearing in the Chiral Perturbation Theory calculation of the pi-pi scattering amplitude. For this we use a precise sum rule determination of scattering lengths and slopes that appear in the effective range expansion. In addition we provide new sum rules and the values for these coefficients up to third order in the expansion. Our results when using only the scattering lengths and slopes of the S, P, D and F waves are consistent with previous determinations, but seem to require higher order contributions if they are to accommodate the third order coefficients of the effective range expansion.

hep-ph↗

arXiv2012

Enhanced non-quark-antiquark and non-gluebal N_c behavior of light scalar mesons

We report our results on the nature of the lightest scalar resonances, where we show that a quark-antiquark or glueball interpretation of the scalars f_0(600) and K^*_0(800) requires a very unnatural fine tuning to satisfy 1/N_c-expansion predictions for quark-antiquark or glueball states, which is not needed in the case of the lightest vector mesons ρ(770) and K^*(892). For this we consider scattering observables whose value is fixed to 1 for quark-antiquark and glueball states up to corrections suppressed by more than one power of 1/N_c, thus enhancing contributions of other nature. This allows us to evaluate these observables and check the 1/N_c predictions at N_c=3 without the need to extrapolate to unphysical N_c values. This is done using recent and very precise dispersive ππand πK scattering data analyses.

hep-ph↗