Rare decay pi0 —>e+ e-: Theory confronts KTeV dataстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Within the dispersive approach to the amplitude of the rare decay pi0 --> ee the nontrivial dynamics is contained only in the subtraction constant. We express this constant, in the leading order in (me/Lambda)^2 perturbative series, in terms of the inverse moment of the pion transition form factor given in symmetric kinematics. By using the CELLO and CLEO data on the pion transition form factor given in asymmetric kinematics, the lower bound of the decay branching ratio is found. The restrictions following from QCD allow us to make a quantitative prediction for the branching B0(pi0 --> ee)= (6.2 \pm 0.1) 10^-8 which is
3sigma below the recent KTeV measurement. We confirm our prediction by using the quark models and phenomenological approaches based on the vector meson dominance. The decays eta --> ll are also discussed.