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Determination of G with Angular-Acceleration-Feedback Method
Chao Xue,1, 2 Jun-Fei Wu,3 Shan-Qing Yang,3 Cheng-Gang Shao,3 Liang-Cheng Tu,3 and Jun Luo1, 2, 3
1 TianQin Research Center for Gravitational Physics,
Sun Yat-sen University (Zhuhai Campus), Zhuhai 519082, P. R. China.
2 School of Physics and Astronomy, Sun Yat-sen University (Zhuhai Campus), Zhuhai 519082, P. R. China.
3 MOE Key Laboratory of Fundamental Physical Quantities Measurement,
Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
The Newtonian gravitational constant G, which plays an significant role in many fields, is the first fundamental physics constant introduced by human beings, but the accuracy of G is the worst among all of the constant. In 2016, the Committee on Data for Science and Technology recommended an updated value of G(CODATA-2014) with a relative uncertainty of 47 ppm, which is still many orders of magnitude larger than that of other fundamental constants. Therefore, two independent determinations using torsion pendulum with the time-of-swing(ToS) method and the
angular-acceleration-feedback(AAF) method were performed in the cave laboratory at Huazhong University of Science and Technology. This report will mainly focus on the latter. Compared with the previous precise torsion balance experiments, this method is extremely insensitive to the anelasticity of the fibre. Since 2008, the proof-of-principle experiments with AAF method have been carried out. Based on the preliminary results, a series of improvements were adopted to reduce sources of uncertainty in the present work. Meanwhile, we measured the G values at three different conditions, named as AAF-I, AAF-II and AAF-III. Finally, we obtained the weighted mean value of G for the AAF method is 6.674484(78)×10−11 m3 kg−1 s−2 with a combined relative uncertainty of 11.61 ppm.
