Search for an exotic parity-odd spin- and velocity-dependent interaction using a magnetic force microscope

Abstract

Exotic spin-dependent interactions may be generated by exchanging hypothetical bosons that have been proposed to solve some mysteries in physics by theories beyond the standard model of particle physics. The search for such interactions can be conducted by tabletop scale experiments using high precision measurement techniques. Here we report an experiment to explore the parity-odd interaction between moving polarized electrons and unpolarized nucleons using a magnetic force microscope. The polarized electrons are provided by the magnetic tip at the end of a silicon cantilever, and their polarizations are approximately magnetized in the plane of the magnetic coating on the tip. A periodic structure with alternative gold and silicon dioxide stripes provides unpolarized nucleons with periodic number density modulation. The exotic forces are expected to change the oscillation amplitude of the cantilever which is measured by a fiber laser interferometer. Data has been taken by scanning the tip over the nucleon source structure at constant separation, and no exotic signal related to the density modulation has been observed. Thus, the experiment sets a limit on the electron-nucleon coupling constant, $g_A^e{g}_V^N\le 9\times 10^{-15}$ for 15 $\mu$m $\le \lambda \le$ 180 $\mu$m, using a direct force measurement method.

9 pages, 7 figures

References in corpus (8)

• Dark Energy and the Accelerating Universe
• Spin-Dependent Macroscopic Forces from New Particle Exchange
• Preferred-Frame and CP-Violation Tests with Polarized Electrons
• Limits on a CP-violating scalar axion-nucleon interaction
• New CP-violation and preferred-frame tests with polarized electrons
• Limits on the Axial Coupling Constant of New Light Bosons
• Probing low-mass vector bosons with parity nonconservation and nuclear anapole moment measurements in atoms and molecules
• Experimental limit on an exotic parity-odd spin- and velocity-dependent interaction using an optically polarized vapor