Limits on Axions and Axionlike Particles within the Axion Window Using a Spin-Based Amplifier

Area of Science:

• Particle Physics
• Cosmology
• Quantum Sensing

Background:

• Axion and axionlike particles are hypothetical candidates for dark matter and dark energy.
• Existing searches for these particles often focus on specific mass ranges and interaction types.
• Novel experimental techniques are needed to probe the 'axion window' and beyond.

Purpose of the Study:

• To constrain hypothetical axionlike particles within the 10 μeV–1 meV mass range.
• To search for exotic dipole-dipole interactions between polarized electron and neutron spins.
• To demonstrate the utility of a spin-based amplifier for fundamental physics searches.

Main Methods:

• Utilized a spin-based amplifier employing hyperpolarized long-lived $^{129}$Xe nuclear spins.
• Employed $^{129}$Xe nuclear spins as a sensitive sensor for pseudomagnetic fields.
• Searched for an exotic dipole-dipole interaction mediated by axionlike particles.

Main Results:

• Obtained a direct upper bound on the product of coupling constants $g_{p}^{e}g_{p}^{n}$.
• Constrained axionlike particle models within the "axion window" using a novel spin-sensing technique.
• Demonstrated the effectiveness of the spin-based amplifier for detecting exotic interactions.

Conclusions:

• The spin-based amplifier technique provides a powerful new tool for searching for beyond-Standard-Model particles.
• This method offers a direct way to probe the "axion window" and constrain fundamental coupling constants.
• The technique is extendable to searches for a wide range of hypothetical particles and interactions.