title: Test of cosmic spatial isotropy for polarized electrons using a rotatable torsion balance.
abstract: To test the cosmic spatial isotropy, we use a rotatable torsion balance carrying a transversely spin-polarized ferrimagnetic Dy6Fe23 mass. With a rotation period of 1 h, the period of anisotropy signal is reduced from one sidereal day by about 24 times, and hence the 1/f noise is reduced. Our present experimental results constrain the cosmic anisotropy Hamiltonian H=C(1)sigma(1)+C2sigma(2)+C3sigma(3) (sigma(3) is in the axis of earth rotation) to (C(2)(1)+C(2)(2))(1/2)=(1.1+/-2.0)x10(-20) eV and /C(3)/=(1.1+/-6.0)x10(-19) eV. This improves the previous limits on (C(2)(1)+C(2)(2))(1/2) by 27 times.
authors.affiliation: Center for Gravitation and Cosmology, Department of Physics, Tsing Hua University, Hsinchu, Taiwan 30055, Republic of China.
authors.forename: Li-Shing
authors.initials: LS
authors.lastname: Hou
authors.forename: Wei-Tou
authors.initials: WT
authors.lastname: Ni
authors.forename: Yu-Chu M
authors.initials: YC
authors.lastname: Li