CP VIOLATION IN NEUTRAL B DECAYS ON THE ϒ (4S) WITH SYMMETRIC ENERGIES
CP VIOLATION IN NEUTRAL B DECAYS ON THE ϒ (4S) WITH SYMMETRIC ENERGIES
复制标题
具有对称能量的 ϒ (4S) 中性 B 衰变中的 CP 破坏
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
K. Berkelman
中科院分区：
文献类型：
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作者：
K. Berkelman
B介子衰变CP破坏的有利检验给出了sin 2α和sin 2β，其中α和β是Kobayashi-Maskawa矩阵元的幺正三角形中的夹角。在经典的B工厂实验中，sin 2α或sin 2β是通过观察一个依赖于时间的CP来获得的，该CP破坏了由混合介导的标记B 0，对衰变中的不对称性。同样的测量可以在一个对称能量对撞机上进行，该对撞机工作在π（4S）共振，给出足够的亮度和顶点分辨率。也就是说，假设在相互作用点处的束的垂直扩展很小，对于两个事件子类，在两个衰减顶点的高度之间的观测中点的测量中的质心分离是CP破坏参数sin 2α或sin 2β的良好统计估计。对于一个典型的探测器，所需的事件数大约是非对称B Factory在相同精度下所需的事件数的三倍。
The favored tests of CP violation in B meson decays give sin 2α and sin 2β, where α and β are angles in the unitarity triangle relating the Kobayashi–Maskawa matrix elements. In the classic B Factory experiment sin 2α or sin 2β is obtained by observing a time dependent CP violating asymmetry in the decay of tagged B0, pairs, mediated by mixing. The same measurement can be performed at a symmetric energy collider operating at the ϒ (4S) resonance, given sufficient luminosity and vertex resolution. That is, provided the vertical spread of the beam at the interaction point is small, for two-event subclasses the centroid separation in measurements of the observed midpoint between the heights of the two decay vertices is a good statistical estimator for the CP violation parameter sin 2α or sin 2β. With a typical detector the number of events needed is about three times what an asymmetric B Factory would require for the same accuracy.