Particle Physics

It has been recently pointed out that variable weak gravitational lensing effects on the motion of background stars can be used to probe nonluminous structures inside the Milky Way halo. I will describe one possible detection strategy targeting collapsed dark matter structures in the mass range from million to billion solar masses. The data analysis technique will be discussed in detail with an application to the second data release of Gaia.

We propose a novel design of a laboratory search for axions based on photon regeneration with superconducting RF cavities. Our particular setup uses a toroid as a region of confined static magnetic field, while production and detection cavities are positioned in regions of vanishing external field. This permits cavity operation at quality factors of Q ~ 10¹⁰ - 10¹². The limitations due to fundamental issues such as signal screening and back-reaction are discussed, and the optimal sensitivity is calculated. This experimental design can potentially probe axion-photon couplings beyond astrophysical limits, comparable and complementary to next generation optical experiments.

The stability of dark matter and its interactions with the Standard Model remain some of the biggest mysteries of our time. Instead of inventing ad hoc stabilization symmetries I propose to economically use the existing baryon and lepton number symmetries of the SM. This can lead to interesting signatures in terrestrial experiments, shower us in anti-helium, and keep neutron stars warm.