Laboratoire d'Annecy-le-Vieux de Physique des Particules, Université de Savoie, CNRS/IN2P3, F-74941 Annecy-Le-Vieux, France.
Phys Rev Lett. 2010 Aug 20;105(8):081803. doi: 10.1103/PhysRevLett.105.081803. Epub 2010 Aug 19.
We report a direct measurement of D0-D0 mixing parameters through a time-dependent amplitude analysis of the Dalitz plots of D(0) → K(S)(0) π+ π- and, for the first time, D0 → K(S)(0)K+ K- decays. The low-momentum pion π(s)(+) in the decay D*+ → D0 π(s)(+) identifies the flavor of the neutral D meson at its production. Using 468.5 fb(-1) of e+ e- colliding-beam data recorded near square root(s)=10.6 GeV by the BABAR detector at the PEP-II asymmetric-energy collider at SLAC, we measure the mixing parameters x = [1.6 ± 2.3(stat) ± 1.2(syst) ± 0.8(model)] × 10(-3), and y = [5.7 ± 2.0(stat) ± 1.3(syst) ± 0.7(model)] × 10(-3). These results provide the best measurement to date of x and y. The knowledge of the value of x, in particular, is crucial for understanding the origin of mixing.
我们通过对 D(0)→K(S)(0)π+π-和 D0→K(S)(0)K+K-衰变的道格拉斯图的时间相关幅度分析，直接测量了 D0-D0 混合参数。这是首次对 D0→K(S)(0)K+K-衰变进行时间相关幅度分析。在 D*+→D0π(s)(+)衰变中，低动量π介子π(s)(+)可以确定中性 D 介子在产生时的味道。利用 SLAC 的 PEP-II 非对称能对撞机上 BABAR 探测器在 √s=10.6 GeV 附近收集的 468.5 fb-1 e+e-对撞数据，我们测量到混合参数 x = [1.6 ± 2.3(stat) ± 1.2(syst) ± 0.8(model)]×10-3，和 y = [5.7 ± 2.0(stat) ± 1.3(syst) ± 0.7(model)]×10-3。这些结果提供了目前对 x 和 y 的最佳测量。特别是 x 值的知识对于理解混合的起源至关重要。
