1. A Measurement of the Branching Ratio of $��^0$ Dalitz Decay using $K_L \rightarrow ��^0��^0��^0$ Decays
- Author
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Abouzaid, E., Arenton, M., Barker, A. R., Bellantoni, L., Blucher, E., Bock, G. J., Cheu, E., Coleman, R., Corcoran, M. D., Cox, B., Erwin, A. R., Escobar, C. O., Glazov, A., Golossanov, A., Gomes, R. A., Gouffon, P., Hsiung, Y. B., Jensen, D. A., Kessler, R., Kotera, K., Ledovskoy, A., McBride, P. L., Monnier, E., Nguyen, H., Niclasen, R., Phillips, D. G., Ramberg, E. J., Ray, R. E., Ronquest, M., Santos, E., Slater, W., Smith, D., Solomey, N., Swallow, E. C., Toale, P. A., Tschirhart, R., Wah, Y. W., Wang, J., White, H. B., Whitmore, J., Wilking, M. J., Winstein, B., Winston, R., Worcester, E. T., Yamanaka, T., Zimmerman, E. D., and Zukanovich, R. F.
- Subjects
High Energy Physics - Experiment (hep-ex) ,High Energy Physics::Phenomenology ,FOS: Physical sciences ,High Energy Physics::Experiment - Abstract
We present a measurement of $B(��^0 \rightarrow e^+e^- ��)/B(��^0 \rightarrow ����)$, the Dalitz branching ratio, using data taken in 1999 by the E832 KTeV experiment at Fermi National Accelerator Laboratory. We use neutral pions from fully reconstructed $K_L$ decays in flight; the measurement is based on about 60 thousand $K_L \rightarrow ��^0��^0��^0 \rightarrow ����~����~e^+e^-��$ decays. We normalize to $K_L \rightarrow ��^0��^0��^0 \rightarrow 6��$ decays. We find $B(��^0 \rightarrow e^+e^- ��)/B(��^0 \rightarrow ����)$ $(m_{e^+e^-}$ > 15 MeV/$c^2)$ = $[3.920 \pm 0.016(stat) \pm 0.036 (syst)] \times 10^{-3}$. Using the Mikaelian and Smith prediction for the $e^+e^-$ mass spectrum, we correct the result to the full $e^+e^-$ mass range. The corrected result is $B(��^0 \rightarrow e^+e^- ��)/B(��^0 \rightarrow ����) = [1.1559 \pm 0.0047(stat) \pm 0.0106 (syst)]$%. This result is consistent with previous measurements and the uncertainty is a factor of three smaller than any previous measurement., 11 pages, 7 figures; v2 accepted version
- Published
- 2019
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