Short- and long-distance contributions to the rare decay KL -> mu+ mu-

DANIEL GOMEZ DUMM; ANTONIO PICH

Montpellier

Conferencia; International Euroconference on Quantum Chromodynamics (QCD 98); 1998

The interplay between short- and long-distance contributions to the KL -> mu+ mu- decay amplitude is analyzed. The long-distance piece is estimated using chiral perturbation theory techniques and large-NC considerations, leading to a consistent description of the pi0 -> e+ e-, eta -> mu+ mu- and KL -> mu+ mu- branching ratios.