ABSTRACT: I will show how properties such as spin, mass, and couplings of ultra-light (fuzzy) dark matter can be tested with binary pulsars by searching for secular variations in the orbital parameters. In particular, if fuzzy dark matter is a carrier of a vector fifth force, for example B-L, the constraints obtained with this method are the most stringent on … Read More

ABSTRACT: Dark matter is the dominant source of matter in our Universe. However, while dark matter dictates the evolution of large-scale astrophysical systems through its gravitational effects, the particle nature of dark matter is unknown. This is despite the significant effort that has gone into the search for particle dark matter over the past decades. In this talk I will … Read More

Abstract: A large theoretical and experimental program has been directed at the search for WIMPs. But the absence of indisputable evidence for non-gravitational WIMP interactions with ordinary matter has led workers in the field to broaden their approach. Particular interest has recently been shown in sub-GeV dark matter, because these scenarios have interesting theoretical motivation, evade current experimental bounds, but … Read More

ABSTRACT: Neutrinos and new light particles, which arise in many extensions of the Standard Model of particle physics, are an important probe of the (thermal) history of the universe. However, they are hard to detect in terrestrial experiments due to their weak couplings to ordinary matter. On the other hand, the high temperatures in the early universe allow an efficient … Read More

ABSTRACT: Generally we do not think about QCD when we try to explain the matter–antimatter asymmetry of the universe. I will describe a model where we raise the QCD confinement scale. This can generate a first-order phase transition and triggers electroweak breaking. This provides a baryogenesis scenario with many other cosmological consequences.generated in a very simple fashion. I will also … Read More

ABSTRACT: If dark matter stems from the background of a very light gauge boson, this gauge boson could exert forces on test masses in gravitational wave detectors, resulting in displacements with a characteristic frequency set by the gauge boson mass. We outline a novel search strategy for such dark matter, assuming the dark photon is the gauge boson of U(1)_B … Read More

ABSTRACT: The QCD axion is a very well-motivated extension of the standard model that explains the strong-CP puzzle and is an excellent dark matter candidate. The simplest models of the QCD axion are very predictive and set up a narrow target space for experiments. I will describe interesting cosmological and field theory mechanisms which broaden this parameter space significantly. This … Read More

Abstract: Our Universe should be filled with a stochastic gravitational-wave background due to several traditional astrophysical sources and possibly some early-Universe sources. I will review some of these sources and then discuss work on an array of techniques to seek/constrain the gravitational-wave background, including measurement of small- and large-scale CMB temperature/polarization fluctuations, weak lensing, pulsar-timing measurements, stellar astrometry, and circular … Read More

Abstract: Neutrinos and dark matter both provide evidence that the standard model is incomplete. Could they be connected in some way? Both dark matter and neutrinos weakly interact with the matter that we are familiar with but there is reason to believe that they couple to one another more strongly. I’ll review these motivations along with some recent developments in … Read More