Flavor physics at the CEPC: a general perspective*
Xiaocong 小聪 Ai 艾, Wolfgang Altmannshofer, Peter Athron, Xiaozhi 晓智 Bai 白, Lorenzo Calibbi, Lu 璐 Cao 曹, Yuzhi 逾之 Che 车, Chunhui 春晖 Chen 陈, Ji-Yuan 纪元 Chen 陈, Long 龙 Chen 陈, Mingshui 明水 Chen 陈, Shanzhen 缮真 Chen 陈, Xuan 暄 Chen 陈, Shan 山 Cheng 程, Cheng-Wei 正偉 Chiang 蔣, Andreas Crivellin, Hanhua Cui, O. Deschamps, Sébastien Descotes–Genon, Xiaokang 小康 Du 都, Shuangshi 双世 Fang 房, Yu 宇 Gao 高, Yuanning 原宁 Gao 高, Li‐Sheng Geng, P. Goldenzweig, Jiayin 嘉荫 Gu 顾, Feng-Kun 奉坤 Guo 郭, Yuchen 禹辰 Guo 郭, Zhi-Hui 志辉 Guo 郭, Tao 涛 Han 韩, Hong-Jian 红建 He 何, Jibo 吉波 He 何, Miao 苗 He 何, Xiaogang 小刚 He 何, Yanping 燕萍 Huang 黄, Gino Isidori, Quan 全 Ji 纪, Jianfeng 建锋 Jiang 江, Xu-Hui 旭辉 Jiang 蒋, Jernej F. Kamenik, Tsz Hong 子康 Kwok 郭, Gang Li, Geng 更 Li 李, Haibo 海波 Li 李, Haitao 海涛 Li 李, Hengne 衡讷 Li 李, Honglei 洪蕾 Li 李, Liang 亮 Li 李, Lingfeng 凌风 Li 李, Qiang 强 Li 李, Qiang 强 Li 李, Shu 数 Li 李, Xiaomei 笑梅 Li 李, Xin-Qiang 新强 Li 李, Yiming 一鸣 Li 李, Yubo 郁博 Li 李, Yuji 玉己 Li 李, Zhao 钊 Li 李, Hao 浩 Liang 梁, Zhijun 志均 Liang 梁, Libo 立波 Liao 廖, Zoltan Ligeti, Jia 佳 Liu 刘, Jianbei 建北 Liu 刘, Tao 滔 Liu 刘, Yi 义 Liu 刘, Yong 勇 Liu 刘, Zhen 真 Liu 刘, Xinchou 辛丑 Lou 娄, Peng-Cheng 鹏程 Lu 路, A. Lusiani, Hong-Hao 鸿浩 Ma 马, Kai 凯 Ma 马, F. Mahmoudi, Yajun 亚军 Mao 冒, Yaxian 亚显 Mao 毛, David Marzocca, Juan-Juan Niu, S. Prell, Huirong 辉荣 Qi 祁, Sen 森 Qian 钱, Zhuoni 卓妮 Qian 钱, Qin 溱 Qin 秦, Ariel Rock, Jonathan L. Rosner, Manqi 曼奇 Ruan 阮, Dingyu 鼎煜 Shao 邵, Chengping 成平 Shen 沈, Xiaoyan 肖雁 Shen 沈, Haoyu 澔玙 Shi 石, Liaoshan 辽珊 Shi 石, Zong-Guo 宗国 Si 司, Cristian Sierra, Huayang 华洋 Song 宋, Shufang 淑芳 Su 苏, Wei 伟 Su 苏, Zhijia 志嘉 Sun 孙, Michele Tammaro, Dayong 大勇 Wang 王, En 恩 Wang 王
Abstract
Abstract We discuss the landscape of flavor physics at the Circular Electron-Positron Collider (CEPC), based on the nominal luminosity outlined in its Technical Design Report. The CEPC is designed to operate in multiple modes to address a variety of tasks. At the Z pole, the expected production of 4 Tera Z bosons will provide unique and highly precise measurements of Z boson couplings, while the substantial number of boosted heavy-flavored quarks and leptons produced in clean Z decays will facilitate investigations into their flavor physics with unprecedented precision. We investigate the prospects of measuring various physics benchmarks and discuss their implications for particle theories and phenomenological models. Our studies indicate that, with its highlighted advantages and anticipated excellent detector performance, the CEPC can explore beauty and τ physics in ways that are superior to or complementary with the Belle II and Large-Hadron-Collider-beauty experiments, potentially enabling the detection of new physics at energy scales of 10 TeV and above. This potential also extends to the observation of yet-to-be-discovered rare and exotic processes, as well as testing fundamental principles such as lepton flavor universality, lepton and baryon number conservation, etc., making the CEPC a vibrant platform for flavor physics research. The WW threshold scan, Higgs-factory operation and top-pair productions of the CEPC further enhance its merits in this regard, especially for measuring the Cabibbo-Kobayashi-Maskawa matrix elements, and Flavor-Changing-Neutral-Current physics of Higgs boson and top quarks. We outline the requirements for detector performance and considerations for future development to achieve the anticipated scientific goals. The role of machine learning for innovative detector design and advanced reconstruction algorithms is also stressed. The CEPC flavor physics program not only develops new capabilities for exploring flavor physics beyond existing projects but also enriches the physics opportunities of this machine. It should be remarked that, given the richness of the CEPC flavor physics, this manuscript is not meant to be a comprehensive survey, but rather an investigation of representative cases. Uncovering the full potential of flavor physics at the CEPC will require further dedicated explorations in the future.