0++ states in a large-Nc Regge approach

TL;DR

This paper uses a large-Nc Regge approach to analyze scalar-isoscalar states, fitting the lightest state into a Regge trajectory and supporting an alternating meson-glueball pattern with implications for QCD condensates.

Contribution

It introduces a Regge-based framework for scalar-isoscalar states, confirming mass values from lattice data and proposing an alternating meson-glueball pattern.

Findings

The $f_0(600)$ fits well into a radial Regge trajectory.

Mass values are consistent with lattice QCD results.

An alternating meson-glueball pattern is supported by the spectrum.

Abstract

Scalar-isoscalar states ($J^{PC}=0^{++}$) are discussed within the large-$N_c$ Regge approach. We find that the lightest $f_0(600)$ scalar-isoscalar state fits very well into the pattern of the radial Regge trajectory where the resonance nature of the states is advantageously used. 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 provide arguments suggesting an alternating meson-glueball pattern of the 0++ states, which is supported by the pseudoscalar-isovector 0+- excited spectrum and asymptotic chiral symmetry. 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.