The decay rate of KL → π0γγ has been measured with the NA48 detector at the CERN SPS. A total of 2558 KL → π0γγ candidates have been observed with a residual background of 3.2%. The branching ratio is determined to be (1.36±0.03(stat)±0.03(syst)±0.03(norm))×10^(−6) and the vector coupling constant av =−0.46±0.03(stat)±0.04(syst). This result suggests that the CP-violation effects are dominating in the KL→π0e+e− decay. An upper limit for the KL →π0γγ decay rate in the two photon mass region mγγ <mπ0 is also given.
Precise measurement of the decay K(L) --> pi0 gamma gamma.
ANZIVINO, Giuseppina;IMBERGAMO, ERMANNO;NAPPI, Aniello;PICCINI, Mauro
2002
Abstract
The decay rate of KL → π0γγ has been measured with the NA48 detector at the CERN SPS. A total of 2558 KL → π0γγ candidates have been observed with a residual background of 3.2%. The branching ratio is determined to be (1.36±0.03(stat)±0.03(syst)±0.03(norm))×10^(−6) and the vector coupling constant av =−0.46±0.03(stat)±0.04(syst). This result suggests that the CP-violation effects are dominating in the KL→π0e+e− decay. An upper limit for the KL →π0γγ decay rate in the two photon mass region mγγFile in questo prodotto:
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