Origin of ΔI=1/2 Rule for Kaon Decays: QCD Infrared Fixed Point

2012/03/06 by Crewther, R. J., Tunstall, Lewis C.
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th)

paper · doi:10.48550/arxiv.1203.1321

Abstract

We replace ordinary chiral SU(3)_L * SU(3)_R perturbation theory CHPT₃ by a new theory CHPT_sigma based on a low-energy expansion about an infrared fixed point alpha_IR for 3-flavor QCD. At alpha_IR, the quark condensate _vac =\= 0 induces nine Nambu-Goldstone bosons: pi, K, eta and a 0++ QCD dilaton sigma. Physically, sigma appears as the f₀(500) resonance, a pole at a complex mass with real part < m_K. The ΔI = 1/2 rule for nonleptonic K-decays is then a consequence of CHPT_sigma, with a K_S-sigma coupling fixed by data for K_S⁰ --> gamma gamma and gamma gamma --> pi pi. We estimate R_IR ~ 5 for the nonperturbative Drell-Yan ratio R = sigma(e+e- --> hadrons)/sigma(e+e- --> mu+mu-) at alpha_IR.

Related

• Status of Chiral-Scale Perturbation Theory
• The Delta I=1/2 Rule in Kaon Decays: A New Look
• ΔI=1/2 Rule and B_K : 2014
• I : Chiral Perturbation for Kaons II: The ΔI=1/2-rule in the Chiral Limit
• The Delta I=1/2 rule and epsilon'/epsilon