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Precise measurement of the decay ${K_{L}\toπ^0γγ}$

A. Lai
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Abstract

The decay rate of $\klpgg$ has been measured with the NA48 detector at the CERN SPS. A total of 2558 $\klpgg$ candidates have been observed with a residual background of 3.2%. The branching ratio is determined to be $(1.36 \pm0.03_{(stat)} \pm0.03_{(syst)}\pm 0.03_{(norm)})\times10^{-6}$ and the vector coupling constant $a_v = -0.46 \pm0.03_{(stat)} \pm0.04_{(syst)}$. This result suggests that the CP-violation effects are dominating in the $\klpee$ decay. An upper limit for the $\klpgg$ decay rate in the two photon mass region $m_{γγ}<m_{π^0}$ is also given.

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A. Lai. 2002-05-06. Precise measurement of the decay ${K_{L}\toπ^0γγ}$. https://doi.org/10.1016/s0370-2693(02)01863-4

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