A. Lai
Published 2000-06-30, updated 2000-07-05Version 2
The decay rate of the neutral long-lived K meson into the e+ e- e+ e- final state has been measured with the NA48 detector at the CERN SPS. Using data collected in 1999, a total of 132 events has been observed with negligible background. The total number of kaons was determined to be 5.1 x 10^10. This observation corresponds to a preliminary branching ratio of Gamma(K_L -> e+ e- e+ e-)/Gamma(K_L -> all) = (3.67 +- 0.32(stat) +- 0.23(sys) +- 0.08(norm)) x 10^-8, where the first error is statistical, the second systematic, and the third error is due to the uncertainty in the normalization.
Comments: LaTeX, 10 pages, 4 Figures. Fig. 2 corrected (wrong cut shape before). Contributed paper # 229 to ICHEP 2000, Osaka
Journal: Phys.Lett. B615 (2005) 31-38
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