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arXiv 0809.4956hep-ex
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最近CP破坏和来自NA48实验的|Vus|测量

Recent CP violation and |Vus| measurements from the NA48 experiment

Cristina Biino

摘要:

从最近的分析结果在欧洲核子研究中心的NA 48实验与其他实验进行比较,并面临的理论预测,以提供对CKM矩阵和CP破坏的约束。可观测的eta+-与间接和直接CPV的参数有关(eta+- = ε + ε ′)。|eta+-|通过测量衰变率的比率:γ(K_L至π + π-)/γ(K_L至π ε ν),使用具有专用的纯高强度K_L光束的NA 48运行来确定。NA 48/2的主要目的是通过高精度测量K ~+~ 3 π衰变Dalitz图中线性斜率参数g的不对称性A_g =(g+ - g-)/(g+ + g-)来寻找直接的CP破坏。所有数据样本的最终结果进行了总结和讨论。在NA 48/2实验中,用低偏压触发的特殊数据样本测量了带电K衰变的衰变率R(Ke ~ 3/K ~ 2 pi)、R(Kmu ~ 3/K ~ 2 pi)和R(Kmu ~ 3/Ke ~ 3)。使用(K+-至pi+-pi 0)归一化通道的最新PDG平均值,然后使用Ke 3和Kmu 3分支分数作为输入来推导CKM矩阵元素Vus。

英文摘要:

Results from recent analyses of the NA48 experiment at CERN are compared with other experiments and confronted with theoretical predictions to provide constraints on the CKM matrix and on CP Violation. The observable eta+- is related to the parameters of indirect and direct CPV (eta+- = epsilon + epsilon'). |eta+-| has been determined by measuring the ratio of decay rates: Gamma(K_L to pi+pi-)/Gamma(K_L to pi e nu), using an NA48 run with a dedicated pure high-intensity K_L beam. The main objective of NA48/2 has been to search for direct CP violation by high precision measurement of the asymmetry A_g = (g+ - g-)/(g+ + g-) of the linear slope parameter g in the Dalitz plot of K+- to 3pi decays. The final results from all data samples are summarised and discussed. The decay rates R(Ke3/K2pi), R(Kmu3/K2pi) and R(Kmu3/Ke3) have been measured with charged K decays from special data samples with a low bias trigger in the NA48/2 experiment. Using the latest PDG average for the (K+- to pi+- pi0) normalisation channel, the Ke3 and Kmu3 branching fractions are then used as input to deduce the CKM matrix element Vus.

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