6 research outputs found
Global analysis of the negative parity non-strange baryons in the 1/Nc expansion
A global study of the negative parity non-strange baryon observables is
performed in the frame- work of the 1/Nc expansion. Masses, partial decay
widths and photo-couplings are simultaneously analyzed. A main objective is to
determine the composition of the spin 1/2 and 3/2 nucleon states, which come in
pairs and involve two mixing angles which can be determined and tested for
consistency by the mentioned observables. The issue of the assignment of those
nucleon states to the broken SU(4) x O(3) mixed-symmetry multiplet is studied
in detail, with the conclusion that the assignment made in the old studies
based on the non-relativistic quark model is the preferred one. In addition,
the analysis involves an update of the input data with respect to previous
works.Comment: 30 pages, 3 figure
Weyl geometry, anti-De Sitter space, and -theory
We study the Gaussian approximation to the quantum fluctuations of the metric
of the four dimensional anti-De Sitter spacetime. The associated massless
scalar field has a quartic self interaction, for which we construct the
generating functional of the -point correlation functions. The concomitant
infrared divergence is cured by a mass renormalization provided by the
cosmological constant, which is also responsible for the renormalization of the
coupling constant of the field theory.Comment: 9 pages, 1 figur