1. Short-range test of the universality of gravitational constant $G$ at the millimeter scale using a digital image sensor
- Author
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Ninomiya, K., Akiyama, T., Hata, M., Hatori, M., Iguri, T., Ikeda, Y., Inaba, S., Kawamura, H., Kishi, R., Murakami, H., Nakaya, Y., Nishio, H., Ogawa, N., Onishi, J., Saiba, S., Sakuta, T., Tanaka, S., Tanuma, R., Totsuka, Y., Tsutsui, R., Watanabe, K., and Murata, J.
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General Relativity and Quantum Cosmology - Abstract
The composition dependence of gravitational constant $G$ is measured at the millimeter scale to test the weak equivalence principle, which may be violated at short range through new Yukawa interactions such as the dilaton exchange force. A torsion balance on a turning table with two identical tungsten targets surrounded by two different attractor materials (copper and aluminum) is used to measure gravitational torque by means of digital measurements of a position sensor. Values of the ratios $\tilde{G}_{Al-W}/\tilde{G}_{Cu-W} -1$ and $\tilde{G}_{Cu-W}/G_{N} -1$ were $(0.9 \pm 1.1_{\mathrm{sta}} \pm 4.8_{\mathrm{sys}}) \times 10^{-2}$ and $ (0.2 \pm 0.9_{\mathrm{sta}} \pm 2.1_{\mathrm{sys}}) \times 10^{-2}$ , respectively; these were obtained at a center to center separation of 1.7 cm and surface to surface separation of 4.5 mm between target and attractor, which is consistent with the universality of $G$. A weak equivalence principle (WEP) violation parameter of $\eta_{Al-Cu}(r\sim 1\: \mathrm{cm})=(0.9 \pm 1.1_{\mathrm{sta}} \pm 4.9_{\mathrm{sys}}) \times 10^{-2} $ at the shortest range of around 1 cm was also obtained., Comment: submitted to Class. Quantum Grav
- Published
- 2017
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