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New Probes of Axions and Ultra-Heavy Dark Matter

  • Author(s): Riggins, Paul
  • Advisor(s): Rajendran, Surjeet
  • et al.
Abstract

The Standard Model of particle physics is known to be incomplete, and many extensions and modifications have been proposed to resolve outstanding issues. In order to discriminate which of these many ideas may be correct, we seek novel approaches to acquire new data and apply old data. The research in this dissertation advances these efforts, probing physics beyond the Standard Model in three distinct ways. First, we propose a novel design of a laboratory search for axions based on photon regeneration with superconducting radiofrequency resonant cavities. We use a confined static magnetic field to avoid degrading the large resonant quality factors. After analysis of fundamental issues and limitations, we conclude this design can potentially probe axion-photon couplings beyond astrophysical limits, comparable and complementary to next generation optical experiments. Second, we demonstrate that rotational superradiance can be efficient in millisecond pulsars. We use measurements from the two fastest known pulsars to place bounds on bosons with masses below 10^−11 eV and Yukawa couplings to neutrons, exceeding fifth force constraints by 3 orders of magnitude for masses near the pulsar rotation rates. For certain neutron star equations of state, these measurements also constrain the QCD axion. Third, we consider dark matter (DM) candidates that heat white dwarfs through the production of high-energy Standard Model (SM) particles, and show that such particles will efficiently thermalize the stellar medium and ignite type Ia supernovae. Based on the existence of long-lived white dwarfs and the observed supernovae rate, we derive new constraints on DM with masses greater than 10^16 GeV which produce SM particles through DM-DM annihilations, DM decays, and DM-SM scattering interactions in the stellar medium.

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