English

Meson coupling constants at high mass and large N_c

High Energy Physics - Theory 2008-11-26 v2 High Energy Physics - Phenomenology Nuclear Theory

Abstract

Quark-hadron duality implies that a process described in terms of quark loops should be the hadronic amplitude when averaged over a sufficient number of states. Ambiguities associated with the notion of quark hadron duality can be made arbitrarily small for highly excited mesons at large NcN_c. QCD is expected to form a string like description at large NcN_c yielding an exponentially increasing Hagedorn spectrum for high mass. It is shown that in order to reconcile quantum-hadron duality with a Hagedorn spectrum, the magnitude of individual coupling constants between high-lying mesons in a typical decay process must be characteristically larger than the average of the coupling constants to mesons with nearby masses. The ratio of the square of the average coupling to the average of the coupling squared (where the average is over mesons with nearby masses) drops {\it exponentially} with the mass of the meson. Scenarios are discussed by which such a high precision cancellation can occur.

Keywords

Cite

@article{arxiv.hep-th/0612209,
  title  = {Meson coupling constants at high mass and large N_c},
  author = {Thomas D. Cohen and Elizabeth S. Werbos},
  journal= {arXiv preprint arXiv:hep-th/0612209},
  year   = {2008}
}

Comments

6 pages, reorganized (moved calculations to appendix)

R2 v1 2026-07-22T15:40:00.484Z