Probing the Quantum Vacuum with High Power Laser and 4th Generation Light Sources in the Search for New Physics
Lead Research Organisation:
University of Oxford
Department Name: Oxford Physics
Abstract
A common perception is that laboratory tests of fundamental physics necessarily require large particle colliders. However, thanks to the development of ultra high-intensity optical lasers and 4th generation light sources, new approaches are now possible that exploit the simultaneous interactions of multiple photons with matter and vacua via quantum field fluctuations. In this proposal, we will employ these high-field non-perturbative quantum optics processes to search for new fundamental particles. Since accelerator-based searches have not yet found new physics at high energies, ultra high-intensity optical lasers and 4th generation light sources offer a novel complementary approach for searches at optical and X-ray energies.
This proposal addresses an important question in fundamental physics by developing a laboratory search for new particles beyond the Standard Model called axions. Our work will be able to probe axion masses bigger than a few eV up to a keV - a region that is currently inaccessible to laboratory searches. In the eV-keV mass range. the searches proposed here are the only model-independent ones, meaning that the experiments have full control over both the production and reconversion of axions within the same apparatus - without the need to assume that axions are produced by astrophysical objects (such as the Sun) or constitute a large fraction of the dark matter.
This proposal addresses an important question in fundamental physics by developing a laboratory search for new particles beyond the Standard Model called axions. Our work will be able to probe axion masses bigger than a few eV up to a keV - a region that is currently inaccessible to laboratory searches. In the eV-keV mass range. the searches proposed here are the only model-independent ones, meaning that the experiments have full control over both the production and reconversion of axions within the same apparatus - without the need to assume that axions are produced by astrophysical objects (such as the Sun) or constitute a large fraction of the dark matter.
Publications
Vacalis G
(2024)
Classical Larmor formula through the Unruh effect for uniformly accelerated electrons
in Physical Review D
Vacalis G
(2023)
Detection of high-frequency gravitational waves using high-energy pulsed lasers
in Classical and Quantum Gravity
Halliday JWD
(2025)
Bounds on Heavy Axions with an X-Ray Free Electron Laser.
in Physical review letters
Halliday J
(2024)
New bounds on heavy axions with an X-ray free electron laser
Halliday J
(2025)
Bounds on Heavy Axions with an X-Ray Free Electron Laser
in Physical Review Letters
Gregori G
(2023)
Measuring Unruh radiation from accelerated electrons
Gregori G
(2024)
Measuring Unruh radiation from accelerated electrons
in The European Physical Journal C
Beyer K
(2023)
Parametric co-linear axion photon instability
in Physics Letters B
| Description | We have performed a new experiment at EuXFEL to look for axions in the meV-few keV mass range. We were able to improve on previous results at several discrete axion masses. For axion masses m_a ? 200 eV, we are able to achieve a sensitivity within a factor 10 of the most competitive previous searches. Although our search is presently not as sensitive as these experiments, our result constitutes an important validation, especially as the limits in previous work were extracted assuming different production and detection mechanisms for axions, namely, spontaneous axion decay and/or flavor-changing meson decay, rather than the Primakoff process as in our case. In parallel to the above, we have also performed new calculations looking at the interaction of high intensity laser beams with electrons. These calculations clarify the role of the Unruh radiation in explaining the radiation from accelerated charged particles. Using these calculations, we are now working on developing a new axion search using high power laser beams. Finally, we are working to add a new axion solver to the OSIRIS particle-in-cell code. Once completed, this will allow us to perform advanced calculations of axion generation in a variety of astrophysical and laboratory systems, going beyond the simple models employed so far in the community. |
| Exploitation Route | We emphasize that this is not the best sensitivity achievable with our current experiment. Issues with x-ray heating forced us to attenuate the x-ray flux by a factor of 1,000. Moreover, the x-ray bunch structure was set with the number of pulses per train limited to one, out of a possible 300. Issues with retaining alignment also limited data acquisition time to 60-90 min at each detuning angle; with a more stable setup that would include active cooling of the first conversion crystal, these times could be increased by a factor of 30. Furthermore, we could also fully exploit the Borrmann effect and use Ge crystals up to 1.5 mm in thickness. Taken together, these improvements would increase the sensitivity by a factor ~150, bringing the estimated bounds close to the expectation for QCD axions to be dark matter. Thus our work paves the way for a new type of lab-based axion searches that are able to explore a region of axion masses that has not been looked at in details so far. |
| Sectors | Education |
| URL | https://cerncourier.com/a/xfels-join-hunt-for-axion-like-particles/ |