On the relation between low-energy constants and resonance saturation

Abstract

Although there are phenomenological indications that the low-energy constants in the chiral lagrangian may be understood in terms of a finite number of hadronic resonances, it remains unclear how this follows from QCD. One of the arguments usually given is that low-energy constants are associated with chiral symmetry breaking, while QCD perturbation theory suggests that at high energy chiral symmetry is unbroken, so that only low-lying resonances contribute to the low-energy constants. We revisit this argument in the limit of large Nc, discussing its validity in particular for the low-energy constant L8, and conclude that QCD may be more subtle that what this argument suggests. We illustrate our considerations in a simple Regge-like model which also applies at finite Nc.

15 pages, one figure

References in corpus (4)

• Parity Doubling Among the Baryons
• Qualitative solution of QCD sum rules
• Large-Nc QCD and Pade Approximant Theory
• The operator product expansion does not imply parity doubling of hadrons

Cited by in corpus (7)

• A Rational Approach to Resonance Saturation in large-Nc QCD
• Unraveling duality violations in hadronic tau decays
• Resonance saturation of the chiral couplings at NLO in 1/Nc
• Parity doubling from Weinberg sum rules
• 1/N_c and 1/n preasymptotic corrections to Current-Current correlators
• On the structure of two-point Green-functions at next-to-leading order in 1/Nc
• Resonance Form-Factors: L8 Determination at Next-to-Leading Order in 1/NC