A Measurement of the Branching Ratio of $\pi^0$ Dalitz Decay using $K_L \rightarrow \pi^0\pi^0\pi^0$ Decays
| Autor: | 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 II, 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., Zukanovich, R. F. |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Phys. Rev. D 100, 032003 (2019) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevD.100.032003 |
| Popis: | We present a measurement of $B(\pi^0 \rightarrow e^+e^- \gamma)/B(\pi^0 \rightarrow \gamma\gamma)$, 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 $K_L \rightarrow \pi^0\pi^0\pi^0 \rightarrow \gamma\gamma~\gamma\gamma~e^+e^-\gamma$ decays. We normalize to $K_L \rightarrow \pi^0\pi^0\pi^0 \rightarrow 6\gamma$ decays. We find $B(\pi^0 \rightarrow e^+e^- \gamma)/B(\pi^0 \rightarrow \gamma\gamma)$ $(m_{e^+e^-}$ > 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 $B(\pi^0 \rightarrow e^+e^- \gamma)/B(\pi^0 \rightarrow \gamma\gamma) = [1.1559 \pm 0.0047(stat) \pm 0.0106 (syst)]$%. This result is consistent with previous measurements and the uncertainty is a factor of three smaller than any previous measurement. Comment: 11 pages, 7 figures; v2 accepted version |
| Databáze: | arXiv |
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