Rotatable-torsion-balance equivalence principle experiment for the spin-polarized HoFe3

We use a rotatable torsion balance to perform an equivalence principle test on a magnetically shielded spin-polarized body of HoFe3. With a rotation p eriod of one hour, the period of possible signal is reduced from one solar day by 24 times, and hence the 1/f noise is greatly reduced. Our present ex perimental results give a limit of (-0.68 +/- 0.90) x 10(-9) on the Eotvos parameter eta (S)(0) and a limit of (1.8 +/- 5.3) x 10(-9) on the Eotvos pa rameter eta (S)(p) of equivalence of the polarized body compared with unpol arized aluminum-brass cylinders in the solar gravitational field, and a lim it (-0.24 +/- 0.55) x 10(-9) on the Eotvos parameter eta (E)(0) in the eart h gravitational field. This improves the previous limit on the Eotvos param eter eta (S)(p) for polarized electrons in the solar gravitational held by one order of magnitude.