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arXiv 1902.01375hep-ex
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用$K_L \rightarrow π^0π^0π^0$衰变测量$π^0$ Dalitz衰变的分支比

A Measurement of the Branching Ratio of $π^0$ Dalitz Decay using $K_L \rightarrow π^0π^0π^0$ Decays

E. Abouzaid, M. Arenton, A. R. Barker, L. Bellantoni, E. Blucher, G. J. Bock, E. Cheu, R. Coleman, M. D. Corcoran, B. Cox, A. R. Erwin, C. O. Escobar, A. Glazov… 展开作者

E. Abouzaid, M. Arenton, A. R. Barker, L. Bellantoni, E. Blucher, G. J. Bock, E. Cheu, R. Coleman, M. D. Corcoran, B. Cox, A. R. Erwin, C. O. Escobar, A. Glazov, A. Golossanov, R. A. Gomes, P. Gouffon, Y. B. Hsiung, D. A. Jensen, R. Kessler, K. Kotera, A. Ledovskoy, P. L. McBride, E. Monnier, H. Nguyen, R. Niclasen, D. G. Phillips, E. J. Ramberg, R. E. Ray, M. Ronquest, E. Santos, W. Slater, D. Smith, N. Solomey, E. C. Swallow, P. A. Toale, R. Tschirhart, Y. W. Wah, J. Wang, H. B. White, J. Whitmore, M. J. Wilking, B. Winstein, R. Winston, E. T. Worcester, T. Yamanaka, E. D. Zimmerman, R. F. Zukanovich

摘要:

我们提出了一个测量的$B(π^0 \rightarrow e^+e^- γ)/B(π^0 \rightarrow γγ)$,Dalitz分支比,使用的数据在1999年由E832千万亿电子伏的实验在费米国家加速器实验室。我们使用的中性π介子来自飞行中完全重建的$K_L$衰变;测量是基于大约6万个$K_L \rightarrow π^0π^0π^0 \rightarrow γγ~γγ~e^+e^-γ$衰变。我们对$K_L \rightarrow π^0π^0π^0 \rightarrow 6γ$衰变进行归一化。我们发现$B(π^0 \rightarrow e^+e^- γ)/B(π^0 \rightarrow γγ)$ $(m_{e^+e^-}$ > 15 MeV/ $c^2)$ = $[3.920 \pm 0.016(stat) \pm 0.036 (syst)] \times 10^{-3}$ .使用$e^+e^-$质谱的Mikaelian和Smith预测,我们将结果校正为完整的$e^+e^-$质量范围。校正结果为$B(π^0 \rightarrow e^+e^- γ)/B(π^0 \rightarrow γγ) = [1.1559 \pm 0.0047(stat) \pm 0.0106 (syst)]$ %。这一结果与以前的测量结果一致,不确定性是以前任何测量结果的三分之一。

英文摘要:

We present a measurement of $B(π^0 \rightarrow e^+e^- γ)/B(π^0 \rightarrow γγ)$, 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 $K_L \rightarrow π^0π^0π^0 \rightarrow γγ~γγ~e^+e^-γ$ decays. We normalize to $K_L \rightarrow π^0π^0π^0 \rightarrow 6γ$ decays. We find $B(π^0 \rightarrow e^+e^- γ)/B(π^0 \rightarrow γγ)$ $(m_{e^+e^-}$ > 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 $B(π^0 \rightarrow e^+e^- γ)/B(π^0 \rightarrow γγ) = [1.1559 \pm 0.0047(stat) \pm 0.0106 (syst)]$%. This result is consistent with previous measurements and the uncertainty is a factor of three smaller than any previous measurement.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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