arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1906.08013hep-ex
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首先使用早期Belle II数据查看时间相关CP破坏

First look at time-dependent CP violation using early Belle II data

Stefano Lacaprara

摘要:

含时CP破坏现象是精确测量标准模型基本参数和寻找新物理的有力工具。在SuperKEKB能量不对称$e^+e^-$对撞机上进行的Belle II实验是对日本KEK实验室B工厂设施的重大升级。这台机器的设计光度是$8\times{10}^{35}~cm^{-2}s^{-1}$,Belle II实验的目标是记录$50~ab^{-1}$的数据,比其前身多50倍。从2018年2月到7月,机器已经完成了一次调试运行,达到了$5.5\times10^{33}~cm^{-2}s^{-1}$的峰值光度,Belle II已经记录了大约$0.5~fb^{-1}$的数据样本。SuperKEKB已于二零一九年三月开始正式营运。该早期数据集用于建立检测器在感兴趣的最终状态的重建效率方面的性能,用于测量时间相关的CP破坏,例如$J/ψK_0$、$η' K_0$和$ϕK_0$。第一次评估的B味标记能力的实验,连同估计的Belle II的CKM角$ϕ_1/β$和$ϕ_2/α$的敏感性和潜在的新物理学的贡献,在企鹅幅度为主的衰变和$b\to sγ$过渡。在本文中,我们将提出估计的敏感性$ϕ_1$在黄金通道$b\to c\bar{c} s$和企鹅占主导地位的模式$B_0\to η' K_0,\quadϕK_0,\quad K_0π_0(γ)$。一项研究的时间依赖性分析的$B_0\toπ_0π_0$,相关的$ϕ_2$的测量,和可行的,只有在干净的环境中的$e^+e^-$对撞机,也将给出。

英文摘要:

Time dependent CP-violation phenomena are a powerful tool to precisely measure fundamental parameters of the Standard Model and search for New Physics. The Belle II experiment at the SuperKEKB energy-asymmetric $e^+e^-$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times{10}^{35}~cm^{-2}s^{-1}$ and the Belle II experiment aims to record $50~ab^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run, achieved a peak luminosity of $5.5\times10^{33}~cm^{-2}s^{-1}$ , and Belle II has recorded a data sample of about $0.5~fb^{-1}$ . Main operation of SuperKEKB has started in March 2019. This early data set is used to establish the performance of the detector in terms of reconstruction efficiency of final states of interest for the measurement of time dependent CP violation, such as $J/ψK_0$ , $η' K_0$, and $ϕK_0$. A first assessment of the B flavor tagging capabilities of the experiment will be given, along with estimates of the Belle II sensitivity to the CKM angles $ϕ_1/β$ and $ϕ_2/α$ and to potential New Physics contributions in penguin amplitudes dominated decays and in $b\to sγ$ transitions. In this paper we will present estimates of the sensitivity to $ϕ_1$ in the golden channels $b\to c\bar{c} s$ and in the penguin-dominated modes $B_0\to η' K_0,\quadϕK_0,\quad K_0π_0(γ)$. A study for the time-dependent analysis of $B_0\toπ_0π_0$, relevant for the measurement of $ϕ_2$, and feasible only in the clean environment of an $e^+e^-$ collider, will also be given.

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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