The KTeV E799 experiment has conducted a search for the rare decays, K L→π0π0μ+μ- and K L→π0π0X0→π0π0μ+μ-, where the X0 is a possible new neutral boson that was reported by the HyperCP experiment with a mass of (214.3±0.5)MeV/c2. We find no evidence for either decay. We obtain upper limits of Br(KL→π0π0X0→ π0π0μ+μ-)<1.0×10-10 and Br(KL→π0π0μ+μ-)<9. 2×10-11 at the 90% confidence level. This result rules out the pseudoscalar X0 as an explanation of the HyperCP result under the scenario that the d̄sX0 coupling is completely real.
ASJC Scopus subject areas
- Physics and Astronomy(all)