Another look at $\pi \pi$ scattering in the scalar channel

Abstract

We set up a general framework to describe $\pi \pi$ scattering below 1 GeV based on chiral low-energy expansion with possible spin-0 and 1 resonances. Partial wave amplitudes are obtained with the $N/D$ method, which satisfy unitarity, analyticity and approximate crossing symmetry. Comparison with the phase shift data in the J=0 channel favors a scalar resonance near the $\rho$ mass.

Comments: 17 pages, 5 figures, REVTeX