Polarized pK- scattering in Unitary Baryon Chiral Perturbation Theory

Abstract

We study pK − scattering in the energy range from threshold through the Λ(1520) peak in UBChPT, taking into account O(q) vertices from meson-baryon contact interactions and s-and u-channel groundstate baryon exchange, s-and u-channel decuplet-and nonet-baryon exchange and t-channel vectormeson exchange, as well as O(q 2 ) flavor-breaking vertices. Detailed fits to data are presented, including a substantial body of differential cross-section data with meson momentum q lab > 300 MeV not considered in previous treatments. * E-mail: abouzas@mda.cinvestav.mx 1 O(q n ) denotes a generic quantity of chiral order n, with q a nominally small quantity such as a meson momentum or mass.

The nature of the Λ(1405) resonance in chiral dynamics

“…In this way, we briefly demonstrate that the simple model [137] can reproduce the essential feature of the meson-baryon scattering amplitude. It should be nevertheless pointed out that the systematic studies including higher order terms are necessary to obtain more quantitative description of the amplitude [112,113,114,115,141].…”

“…The KN scattering length is given exactly at the threshold with definite absolute value, so the precise determination is very important to constrain theoretical models. In response to the accurate data, the model for the S = −1 meson-baryon scattering was updated by performing systematic χ 2 analyses with the NLO interaction terms [112,113,114,115,141]. The NLO calculation with the separable form factor was also performed in Ref.…”

Addition theorems for spin spherical harmonics: II. Results

“…Our main motivation for the present paper is the application of its results to the partial-wave analysis of scattering processes. In that context, partial waves satisfying two-body unitarity play an essential role in the theoretical approach (see [4] for a realistic application to hadronic reactions and an extensive reference list). Two-body intermediate states with different spins must be included in the analysis in order to satisfy unitarity, both as genuine asymptotic states or, in the case of resonances, as an approximation to higher n-body intermediate states.…”