Tomographic beta-gamma spectroscopy of nuclear beta decay
Abstract
Nuclear decay, a sensitive probe of nuclear structure and weak interactions, has become a precision test bed for physics beyond the Standard Model, driven by recent advances in spectrometric techniques. Here we introduce tomographic - spectroscopy (TBGS) of nuclear decay, a method that detects the energies of , , and internal conversion electrons while simultaneously reconstructing the energy deposition vertices. Using the PandaX-4T detector operated as a TBGS, we obtain a precise and unbiased decay scheme of Pb, a key background isotope in searches for dark matter and Majorana neutrinos. For the first time, transitions of Pb to both the ground and excited states of Bi are measured concurrently, revealing discrepancies in branching ratios of up to 4.7 relative to previous evaluations. Combined with state-of-the-art theoretical spectral-shape calculations, these results establish a new benchmark for background modelling in rare-event searches and highlight the potential of TBGS as a versatile tool for fundamental physics and nuclear applications.
Cite
@article{arxiv.2510.24612,
title = {Tomographic beta-gamma spectroscopy of nuclear beta decay},
author = {PandaX Collaboration and Zhe Yuan and Zihao Bo and Wei Chen and Xun Chen and Yunhua Chen and Chen Cheng and Xiangyi Cui and Manna Deng and Yingjie Fan and Deqing Fang and Xuanye Fu and Zhixing Gao and Yujie Ge and Lisheng Geng and Karl Giboni and Xunan Guo and Xuyuan Guo and Zichao Guo and Chencheng Han and Ke Han and Changda He and Jinrong He and Houqi Huang and Junting Huang and Yule Huang and Ruquan Hou and Xiangdong Ji and Yonglin Ju and Xiaorun Lan and Chenxiang Li and Jiafu Li and Mingchuan Li and Peiyuan Li and Shuaijie Li and Tao Li and Yangdong Li and Zhiyuan Li and Qing Lin and Jianglai Liu and Yuanchun Liu and Congcong Lu and Xiaoying Lu and Lingyin Luo and Yunyang Luo and Yugang Ma and Yajun Mao and Yue Meng and Binyu Pang and Ningchun Qi and Zhicheng Qian and Xiangxiang Ren and Dong Shan and Xiaofeng Shang and Xiyuan Shao and Guofang Shen and Manbin Shen and Wenliang Sun and Xuyan Sun and Yi Tao and Yueqiang Tian and Yuxin Tian and Anqing Wang and Guanbo Wang and Hao Wang and Haoyu Wang and Jiamin Wang and Lei Wang and Meng Wang and Qiuhong Wang and Shaobo Wang and Shibo Wang and Siguang Wang and Wei Wang and Xu Wang and Zhou Wang and Yuehuan Wei and Weihao Wu and Yuan Wu and Mengjiao Xiao and Xiang Xiao and Kaizhi Xiong and Jianqin Xu and Yifan Xu and Shunyu Yao and Binbin Yan and Xiyu Yan and Yong Yang and Peihua Ye and Chunxu Yu and Ying Yuan and Youhui Yun and Xinning Zeng and Minzhen Zhang and Peng Zhang and Shibo Zhang and Siyuan Zhang and Shu Zhang and Tao Zhang and Wei Zhang and Yang Zhang and Yingxin Zhang and Yuanyuan Zhang and Li Zhao and Kangkang Zhao and Jifang Zhou and Jiaxu Zhou and Jiayi Zhou and Ning Zhou and Xiaopeng Zhou and Zhizhen Zhou and Chenhui Zhu and Marlom Ramalho and Jouni Suhonen},
journal= {arXiv preprint arXiv:2510.24612},
year = {2025}
}