High Energy Physics Seminars

In this talk, I will briefly review the global effort in searching for axions, a hypothetical particle that can potentially address the strong CP problem, explain the nature of dark matter, and has deep connections with string theories. I will focus on a new resonance in the axion-photon system, axion magnetic resonance (AMR), that can greatly enhance the conversion rate between axions and photons. A series of axion search experiments rely on converting axions into photons inside a constant magnetic field background. A common bottleneck of such experiments is the conversion amplitude being suppressed by the axion mass when ma≳10−4 eV. I will show that a spatial or temporal variation in the magnetic field can cancel the difference between the photon dispersion relation and that of the axion, hence greatly enhancing the conversion probability. I will demonstrate that the enhancement can be achieved by both a helical magnetic field profile and a harmonic oscillation of the magnitude. Our approach can extend the projected ALPS II reach in the axion-photon coupling (gaγ) by two orders of magnitude at ma=10−3eV with moderate assumptions.