Measurement of Hyperfine Structure and the Zemach Radius in ^{6}Li^{+} Using Optical Ramsey Technique

Wei Sun; Pei-Pei Zhang; Peng-Peng Zhou; Shao-Long Chen; Zhi-Qiang Zhou; Yao Huang; Xiao-Qiu Qi; Zong-Chao Yan; Ting-Yun Shi; G W F Drake; Zhen-Xiang Zhong; Hua Guan; Ke-Lin Gao

doi:10.1103/PhysRevLett.131.103002

Measurement of Hyperfine Structure and the Zemach Radius in ^{6}Li^{+} Using Optical Ramsey Technique

Phys Rev Lett. 2023 Sep 8;131(10):103002. doi: 10.1103/PhysRevLett.131.103002.

Authors

Wei Sun^{1

2}, Pei-Pei Zhang¹, Peng-Peng Zhou^{1

2

3}, Shao-Long Chen^{1

2}, Zhi-Qiang Zhou^{1

2

3}, Yao Huang^{1

2}, Xiao-Qiu Qi⁴, Zong-Chao Yan^{1

5}, Ting-Yun Shi¹, G W F Drake⁶, Zhen-Xiang Zhong^{1

7}, Hua Guan^{1

2}, Ke-Lin Gao^{1

2}

Affiliations

¹ State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
² Key Laboratory of Atomic Frequency Standards, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
³ University of Chinese Academy of Sciences, Beijing 100049, China.
⁴ Key Laboratory of Optical Field Manipulation of Zhejiang Province and Physics Department of Zhejiang Sci-Tech University, Hangzhou 310018, China.
⁵ Department of Physics, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3.
⁶ Canterbury College and Department of Physics, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
⁷ Center for Theoretical Physics, College of Science, Hainan University, Haikou 570228, China.

PMID: 37739370
DOI: 10.1103/PhysRevLett.131.103002

Abstract

We investigate the 2^{3}S_{1}-2^{3}P_{J} (J=0, 1, 2) transitions in ^{6}Li^{+} using the optical Ramsey technique and achieve the most precise values of the hyperfine splittings of the 2^{3}S_{1} and 2^{3}P_{J} states, with smallest uncertainty of about 10 kHz. The present results reduce the uncertainties of previous experiments by a factor of 5 for the 2^{3}S_{1} state and a factor of 50 for the 2^{3}P_{J} states, and are in better agreement with theoretical values. Combining our measured hyperfine intervals of the 2^{3}S_{1} state with the latest quantum electrodynamic (QED) calculations, the improved Zemach radius of the ^{6}Li nucleus is determined to be 2.44(2) fm, with the uncertainty entirely due to the uncalculated QED effects of order mα^{7}. The result is in sharp disagreement with the value 3.71(16) fm determined from simple models of the nuclear charge and magnetization distribution. We call for a more definitive nuclear physics value of the ^{6}Li Zemach radius.