$1/N_c$ approximation and universality of vector mesons

Abstract

In this work, we argue that the observed differences in the value of the vector coupling constant extracted from the decays $\rho \to \pi \pi$ ($g_{\rho }=6.0$), $\rho \to l^{+}{l}^{-}$ ($g_{\rho }=5.0$) and $\omega \to l^{+}{l}^{-}$ ($g_{\rho }=5.7$), where $l=e,\mu$, are an indication of the important role played by the $1/N_c$ corrections in the description of these processes. We show that an emission of a photon by charged meson loops in the ${\rho }^0,\omega ,\varphi \to \gamma$ transitions is a key process that allows to describe above vector meson decays into two leptons with a single value $g_{\rho }=6.0$. Our result supports the idea of universality of neutral vector mesons and clarifies the role of accounting of $1/N_c$ corrections to its fulfilment.

arXiv comment9 pages, 2 figuras, the version accepted for publication in Physical Review D

References in corpus (9)

• Measurement of the ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to {\pi }^{+}{\pi }^{-}$ Cross Section between 600 and 900 MeV Using Initial State Radiation
• Precise Measurement of the e+ e- --> pi+ pi- (gamma) Cross Section with the Initial-State Radiation Method at BABAR
• Direct determination of the strange and light quark condensates from full lattice QCD
• Effective chiral Lagrangians for spin-1 mesons
• Pion Observables in the Extended NJL Model with Vector and Axial-Vector Mesons
• The Momentum--Space Bosonization of the Nambu--Jona-Lasinio Model with Vector and Axial-Vector Mesons
• Effective Chiral Meson Lagrangian For The Extended Nambu-Jona-Lasinio Model
• Electromagnetic form factor of pion in the field theory inspired approach
• A general framework to diagonalize vector--scalar and axial-vector--pseudoscalar transitions in the effective meson Lagrangian

Cited by in corpus (1)

• The decay ${\eta }^{\prime }\to \pi \rho$ in the chiral NJL model