On the determination of $σ$ from experimental data on the $ππ$ isoscalar $S$-wave at low energies
Abstract
Description
We investigate the determination of the pole associated to $σ$ from $ππ$ scattering data below the $K\bar{K}$ threshold, including the new precise data from $K_{e4}$ decay reported recently by the NA48/2 Collaboration. Using a large class of analytic parametrizations based on expansions in powers of conformal variables, we obtain for the mass and width of $σ$ values which are consistent with those calculated recently using ChPT and Roy equations, but have larger theoretical uncertainties.
6 pages, talk at SCADRON 70 (Workshop on Scalar Mesons and Related Topics, Lisbon, 11-16 February 2008)
6 pages, talk at SCADRON 70 (Workshop on Scalar Mesons and Related Topics, Lisbon, 11-16 February 2008)