Wednesday, November 14, 2012

1211.2644 (Ping-Han Chu et al.)

Laboratory Search for Spin-dependent Short-range Force from
Axion-Like-Particles using Optically Polarized 3He gas
   [PDF]

Ping-Han Chu, Alec Dennis, ChangBo Fu, Haiyan Gao, Rakshya Khatiwada, Georgios Laskaris, Ke Li, Erick Smith, William Michael Snow, Haiyang Yan, Wangzhi Zheng
The possible existence of short-range forces between unpolarized and polarized spin-1/2 particles has attracted the attention of physicists for decades. These forces are predicted in various theories and provide a possible new source for parity (P) and time reversal (T) symmetry violation. We use an ensemble of polarized 3He gas in a cell with a 250 um thickness glass window to search for a force from scalar boson exchange over a sub-millimeter ranges. This interaction would produce a NMR frequency shift as an unpolarized mass is moved near and far from the polarized ensemble. We report a new upper bound on the product g_{s}g_{p}^{n} of the scalar couplings to the fermions in the unpolarized mass, and the pseudoscalar coupling of the polarized neutron in the 3He nucleus for force ranges from 1e-4 to 1e-2 m, which corresponds to a mass range of 2e-3 to 2e-5 eV for the scalar boson.
View original: http://arxiv.org/abs/1211.2644

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