title: Laser Spectroscopy of the Fine-Structure Splitting in the 2^{3}P_{J} Levels of ^{4}He.
abstract: The fine-structure splitting in the 2^{3}P_{J} (J=0, 1, 2) levels of ^{4}He is of great interest for tests of quantum electrodynamics and for the determination of the fine-structure constant α. The 2^{3}P_{0}-2^{3}P_{2} and 2^{3}P_{1}-2^{3}P_{2} intervals are measured by laser spectroscopy of the ^{3}P_{J}-2^{3}S_{1} transitions at 1083 nm in an atomic beam, and are determined to be 31 908 130.98±0.13  kHz and 2 291 177.56±0.19  kHz, respectively. Compared with calculations, which include terms up to α^{5}Ry, the deviation for the α-sensitive interval 2^{3}P_{0}-2^{3}P_{2} is only 0.22 kHz. It opens the window for further improvement of theoretical predictions and an independent determination of the fine-structure constant α with a precision of 2×10^{-9}.
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, iChem Center, University of Science and Technology of China, Hefei 230026, China.
authors.forename: X
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, iChem Center, University of Science and Technology of China, Hefei 230026, China.|Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Y R
authors.initials: YR
authors.lastname: Sun
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, iChem Center, University of Science and Technology of China, Hefei 230026, China.
authors.forename: J-J
authors.initials: JJ
authors.lastname: Chen
authors.affiliation: School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, China.
authors.forename: W
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Pachucki
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, iChem Center, University of Science and Technology of China, Hefei 230026, China.
authors.forename: S-M
authors.initials: SM
authors.lastname: Hu