Synopsis

Producing Axions from Photon Collisions  

Physics 13, s59
The collision of two intense light beams may produce detectable signatures of dark matter particles called axions.

Axions—hypothetical particles that are much lighter than electrons—could hold the key to important physics puzzles, from the matter–antimatter asymmetry to the nature of dark matter. So far, the strongest constraints on their properties, such as their mass and how they couple to photons, come from astrophysical measurements that look for axions produced by photons interacting with magnetic fields inside the Sun. Now, Konstantin Beyer at the University of Oxford, UK, and colleagues propose a lab-scale experiment based on colliding intense laser beams. The researchers say that, for an important range of axion masses, their approach would be as sensitive as astrophysical searches but much less dependent on hard-to-test models of astrophysical axion-generation processes.

The team’s scheme is a variation of the “light-shining-through-a-wall” (LSW) method of axion detection. In LSW, axions created by a laser beam propagating in a magnetic field would be detected after passing through a wall that shields the detector from the laser photons. The team’s new scheme uses two laser beams, whose collision may produce axions through a light–light scattering process. After passing through the wall, the axions would be converted into detectable photons by a magnetic field.

Using laser beams with parameters expected for a planned European facility called Extreme Light Infrastructure, the researchers’ calculations show that their method would be at least as sensitive as solar searches for axions with masses of around an electron-volt. They say that the scheme could be further improved in two ways. First, even more powerful lasers would boost the detection sensitivity, since axion production rates scale nonlinearly with the photon number. Second, tunable x-ray free-electron lasers would test a broader range of possible axion masses.

This research is published in Physical Review D.

–Matteo Rini

Matteo Rini is the Deputy Editor of Physics.


Subject Areas

Particles and FieldsOptics

Related Articles

Sterile Neutrino Down but Not Completely Out
Particles and Fields

Sterile Neutrino Down but Not Completely Out

Neutrino experiments place the most stringent limits to date on a hypothetical fourth neutrino, but the possibility that such a particle exists remains open. Read More »

Powdering Up for Neutrinos
Particles and Fields

Powdering Up for Neutrinos

The search for neutrinos from past supernovae is getting an upgrade as Japan’s Super-Kamiokande experiment begins adding gadolinium powder to its giant water-based detector. Read More »

Electron Accelerator Recycles Energy for a Brighter Beam
Particles and Fields

Electron Accelerator Recycles Energy for a Brighter Beam

A test electron accelerator reuses the energy of the particles in order to achieve a brighter beam without drawing more power from the grid. Read More »

More Articles