Bulletin of the American Physical Society
APS April Meeting 2019
Volume 64, Number 3
Saturday–Tuesday, April 13–16, 2019; Denver, Colorado
Session Y04: Searching for Axions
1:30 PM–3:18 PM,
Tuesday, April 16, 2019
Sheraton Room: Plaza F
Sponsoring Unit: DAP
Chair: Guido Mueller, University of Florida
Abstract: Y04.00003 : ALPSII: Using Long Baseline Cavities to Probe the Hidden Sector*
2:42 PM–3:18 PM
View Presentation Abstract
Aaron D Spector
Aaron D Spector
ALPS II is what is known as a light-shining-through-a-wall (LSW) experiment. LSW experiments try to measure the coupling constant (gaγ) between photons and axion-like particles by shining a high power laser through a magnetic field at an optical barrier. This generates a beam of axion-like particles that pass through the barrier while the light is blocked. On the other side of the barrier, a second string of magnets convert some of the axion-like particles back to photons.
To boost the probability of axion-like particles reconverting to photons, ALPS II will be the first LSW experiment to employ optical cavities both before and after the wall. The use of two ~100 m cavities requires a sophisticated optical system to maintain their resonance condition and colinearity with respect to each other. 5.3 T superconducting dipole magnets repurposed from the HERA accelerator will provide the magnetic fields. The experiment will also have two independent detection methods, a transition edge sensor as well as a heterodyne detection scheme, to confirm the results. With this, ALPS II will achieve a sensitivity in the coupling between photons and axion-like particles of gaγ > 2×10-11 GeV-1 for m < 0.1 meV, roughly a factor of 1000 better than previous LSW experiments. I will give an overview of the experiment and discuss progress as well as challenges related to the optical system, magnets, detectors, and site preparation.
*This work is supported by the Helmholtz Foundation, the DFG, the Heising-Simons Foundation, and the NSF.
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