Production and detection of very light spin-zero bosons at optical frequencies

TL;DR

This paper evaluates a laboratory optical-frequency approach to test PVLAS's claim of a very light neutral spin-zero boson by using generation-regeneration in magnetic fields. It introduces Phase Measurement and Signal Enhancement (PSE) with interferometric readout to boost sensitivity and enable mass determination, and it extends the concept with periodic-field magnets to access a broad LNB mass range. The authors propose realistic instrumentations including high-power optical sources and imaging detectors, and outline potential 'LNB factory' configurations for large-scale production and detection. If realized, the approach would provide a direct laboratory test of beyond-Standard-Model photon couplings and could clarify the nature of the PVLAS signal and the LNB parameter space.

Abstract

The PVLAS collaboration has observed rotation of the plane of polarization of light passing through a magnetic field in vacuum and has proposed that the effect is due to interaction of photons with very light spin-zero bosons. This would represent new physics beyond the Standard Model, and hence it is of high interest to test this hypothesis. We describe a proposed test of the PVLAS result, and ways of producing, detecting, and studying such bosons with light in the optical frequency range. Novel features include methods for measurements of boson mass, interaction strengths, and decay- or oscillation-lengths with techniques not available in the x-ray region.

Figures (5)

• Figure 1: Schematic layout of apparatus showing input laser beam, LNB generation magnet 1, photon regeneration magnet 2, and detector. The magnetic fields are transverse to the beam direction. The main beam elements are a polarization rotator B1, a possible optical cavity (B2,B3), a turning mirror B4 that also transmits a fraction of the beam for alignment purposes, and a "wall" W that prevents primary laser light from reaching the regeneration magnet. Optical elements E1-E2-E3 and E1-D1-D3-E3 form an interferometer.
• Figure 2: Coupling scale performance of proposed apparatus, versus LNB mass, compared with the PVLAS upper and lower 3-$\sigma$ limits. The 'Simple' curve gives the 5-$\sigma$ confirmation level for a 200-h run, while the 'Enhanced' curve is for a 4-h run using the signal enhancement technique described here.
• Figure 3: Sample simulation of use of PSE method. Points are simulated data, curve is least-squares fit.
• Figure 4: Example of magnets to produce periodic fields: (a) alternating magnetic fields produced by rotatable magnet segments, (b) similar magnets used to form a helical field.
• Figure 5: Regenerated photon rates from adjustable-period alternating-field magnet systems, for a coupling scale of $M_b = 5 \times 10^5$ GeV. The magnets are length 10 m and field amplitude 1.5 T, with a 900-nm beam at 10 kW. The peaks, from left to right, are for masses of 0.9, 1.1, 1.3, 1.5, and 1.7 meV. The points are for a segment length of 0.2 m, the lines for 0.01 m.