Scalar-isoscalar states, gravitational form factors, and dimension-2 condensates in a large-Nc Regge approach

Abstract

Scalar-isoscalar states are analyzed within the large-Nc Regge approach. We find that the lightest f0(600) scalar-isoscalar state fits very well into the pattern of the radial Regge trajectory. We confirm the obtained mass values from an analysis of the pion and nucleon spin-0 gravitational form factors, recently measured on the lattice. We find that a simple two-state model suggests a meson nature of f0(600), and a glueball nature of f0(980), which naturally explains the ratios of various coupling constants. Finally, matching to the OPE requires a fine-tuned mass condition of the vanishing dimension-2 condensate in the Regge approach with infinitely many scalar-isoscalar states.

Talk given at the 9th Conference On Quark Confinement and the Hadron Spectrum (Confinement IX), 30 Aug. - 3 Sept. 2010, Madrid, Spain