The decay rate of KL-->pi0 gamma gamma has been measured with the NA48 detector at the CERN SPS. A total of 2558 KL-->pi0 gamma gamma 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 a_v=−0.46±0.03(stat)±0.04(syst). This result suggests that the CP-violation effects are dominating in the KL --> pi0 e+ e- decay. An upper limit for the KL-->pi0 gamma gamma decay rate in the two photon mass region m_{gamma gamma} < m_{pi0} is also given.
Precise measurement of the decay K_L --> pi0 gamma gamma
CONTALBRIGO, Marco;DALPIAZ, Pietro;GIANOLI, Alberto;MARTINI, Mara;PETRUCCI, Ferruccio Carlo;SAVRIE', Mauro;
2002
Abstract
The decay rate of KL-->pi0 gamma gamma has been measured with the NA48 detector at the CERN SPS. A total of 2558 KL-->pi0 gamma gamma 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 a_v=−0.46±0.03(stat)±0.04(syst). This result suggests that the CP-violation effects are dominating in the KL --> pi0 e+ e- decay. An upper limit for the KL-->pi0 gamma gamma decay rate in the two photon mass region m_{gamma gamma} < m_{pi0} is also given.File in questo prodotto:
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