Improved Limits on the Spin- and Velocity-Dependent Exotic Interaction in the Micrometer Range

Area of Science:

• * Particle physics
• * Beyond Standard Model physics
• * Experimental physics

Background:

• * The Standard Model of particle physics has limitations in explaining certain phenomena.
• * Exotic interactions beyond the Standard Model are hypothesized to solve these puzzles.
• * Experimental searches for such interactions are crucial for advancing fundamental physics.

Purpose of the Study:

• * To experimentally search for a spin- and velocity-dependent exotic interaction.
• * To investigate interactions between nucleons in a gold sphere and electrons in a spin source.
• * To probe exotic forces in the micrometer range.

Main Methods:

• * Utilized a microfabricated spin source with periodically varying electron spin density.
• * Employed a gold sphere-coated cantilever to measure forces.
• * Drove the spin source to oscillate and extracted the 10th harmonic signal to isolate exotic interactions.

Main Results:

• * No signal indicative of the hypothesized exotic interaction was observed.
• * New upper limits were placed on the coupling constant of the exotic interaction.
• * Limits were set for interaction ranges below 10 micrometers, with f⊥ ≤ 2.2×10⁻⁹ at 2.1 μm.

Conclusions:

• * The experiment did not detect the spin- and velocity-dependent exotic interaction.
• * The findings provide stringent constraints on new physics beyond the Standard Model.
• * This research contributes to the ongoing quest for new fundamental forces and particles.