First observation of KL -> pi+- e-+ nu e+ e-
High Energy Physics - Experiment
2012-08-27 v1
Abstract
This letter is the first report of the KL -> pi+- e-+ nu e+ e- decay. Based on 19208+-144 events, we determine the branching fraction, B(KL -> pi+- e-+ nu e+ e-; Mee > 5 MeV/c^2, E*ee > 30 MeV) = (1.285+-0.041)x10^-5, and Gamma(Ke3ee; Mee >5 MeV/c^2) / Gamma(Ke3) = [4.57+-0.04(stat)+-0.14(syst)]x10^-5. This ratio agrees with a theoretical prediction based on chiral perturbation theory (ChPT) calculated to O(p^4). The measured kinematical distributions agree with those predicted by just ChPT O(p^4), but show significant disagreement with ones predicted by leading order ChPT.
Keywords
Cite
@article{arxiv.0705.3108,
title = {First observation of KL -> pi+- e-+ nu e+ e-},
author = {KTeV Collaboration},
journal= {arXiv preprint arXiv:0705.3108},
year = {2012}
}