1207.0567 (B. Ananthanarayan et al.)

The 27-plet contributions to the CP-conserving $K\rightarrow πl^+l^-$
decays    [PDF]

B. Ananthanarayan, I. Sentitemsu Imsong

We revisit the the rare kaon decays $K\to \pi l^+l^-$ which are of interest specially due to the recent measurements of the charged kaon decay spectra. We compute the contribution of the 27-plet to the decay amplitudes in one loop SU(3) Chiral Perturbation Theory. We estimate the resulting impact to be $\sim 10%$ to the branching ratios of the charged kaon decays, and also noticeably influence the shape of the spectra. With current values of the constants $G_8$ associated with the octet and $G_{27}$ associated with the 27-plet, the contribution of the latter pushes the spectrum in the correct direction for the charged lepton spectra. We also discuss the impact for the neutral decay rates and spectra.

View original: http://arxiv.org/abs/1207.0567