Observation of the Decay D⁰ → K⁻ π ⁺ e ⁺ e ⁻

Author(s)

J.P. Lees
P. Poireau
V. Tisserand
E. Grauges
A. Palano
G. Eigen
D. N. Brown
Yu. G. Kolomensky
M. Fritsch
H. Koch
T. Schroeder
C. Hearty
T. S. Mattison
J. A. McKenna
R. Y. So
V. E. Blinov
A. R. Buzykaev
V. P. Druzhinin
V. B. Golubev
Milind Purohit, University of South CarolinaFollow
ET. Al.

Document Type

Article

Abstract

We report the observation of the rare charm decay D⁰ → K−πþeþe−, based on 468 fb−1 of eþe− annihilation data collected at or close to the center-of-mass energy of the ϒð4SÞ resonance with the BABAR detector at the SLAC National Accelerator Laboratory. We find the branching fraction in the invariant mass range 0.675 < m(e⁺e⁻) < 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.

Digital Object Identifier (DOI)

https://doi.org/10.1103/PhysRevLett.122.081802

Publication Info

Published in Physcial Review Letters, Volume 122, Issue 8, 2019.

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Rights

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

APA Citation

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., … Wu, S. L. (2019a). Observation of the decay . Physical Review Letters, 122(8). https://doi.org/10.1103/physrevlett.122.081802