We report the observation of the rare charm decay D0→K-π+e+e-, based on 468 fb-1 of e+e- annihilation data collected at or close to the center-of-mass energy of the (4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. We find the branching fraction in the invariant mass range 0.675<0.875 GeV/c2 of the electron-positron pair to be B(D0→K-π+e+e-)=(4.0±0.5±0.2±0.1)×10-6, where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty in the branching fraction of the decay D0→K-π+π+π- used as a normalization mode. The significance of the observation corresponds to 9.7 standard deviations including systematic uncertainties. This result is consistent with the recently reported D0→K-π+μ+μ- branching fraction, measured in the same invariant mass range, and with the value expected in the standard model. In a set of regions of m(e+e-), where long-distance effects are potentially small, we determine a 90% confidence level upper limit on the branching fraction B(D0→K-π+e+e-)<3.1×10-6.

Observation of the Decay D0 →K-π+e+e- / Lees, J.P., Poireau, V., Tisserand, V., Grauges, E., Palano, A., Eigen, G., Brown, D.N., Kolomensky, Yu.G., Fritsch, M., Koch, H., Schroeder, T., Hearty, C., Mattison, T.S., Mckenna, J.A., So, R.Y., Blinov, V.E., Buzykaev, A.R., Druzhinin, V.P., Golubev, V.B., Kozyrev, E.A., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 122:8(2019), p. 081802. [10.1103/PhysRevLett.122.081802]

Observation of the Decay D0 →K-π+e+e-

Faccini, R.;Ferroni, F.;Pilloni, A.;
2019

Abstract

We report the observation of the rare charm decay D0→K-π+e+e-, based on 468 fb-1 of e+e- annihilation data collected at or close to the center-of-mass energy of the (4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. We find the branching fraction in the invariant mass range 0.675<0.875 GeV/c2 of the electron-positron pair to be B(D0→K-π+e+e-)=(4.0±0.5±0.2±0.1)×10-6, where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty in the branching fraction of the decay D0→K-π+π+π- used as a normalization mode. The significance of the observation corresponds to 9.7 standard deviations including systematic uncertainties. This result is consistent with the recently reported D0→K-π+μ+μ- branching fraction, measured in the same invariant mass range, and with the value expected in the standard model. In a set of regions of m(e+e-), where long-distance effects are potentially small, we determine a 90% confidence level upper limit on the branching fraction B(D0→K-π+e+e-)<3.1×10-6.
2019
Physics and Astronomy (all)
01 Pubblicazione su rivista::01a Articolo in rivista
Observation of the Decay D0 →K-π+e+e- / Lees, J.P., Poireau, V., Tisserand, V., Grauges, E., Palano, A., Eigen, G., Brown, D.N., Kolomensky, Yu.G., Fritsch, M., Koch, H., Schroeder, T., Hearty, C., Mattison, T.S., Mckenna, J.A., So, R.Y., Blinov, V.E., Buzykaev, A.R., Druzhinin, V.P., Golubev, V.B., Kozyrev, E.A., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 122:8(2019), p. 081802. [10.1103/PhysRevLett.122.081802]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1266410
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