Search Talks

In this talk, I will discuss constraints on dark matter (DM) from collider physics, neutron stars and DM halo shapes. Monojet plus missing energy searches at hardron colliders limit DM interactions with quarks and gluons, which provide a complementary probes of DM to direct detection. Stars can capture ambient DM particles. The captured scalar DM particles may form a Bose-Einstein condensate, leading to a black hole at the center of the host neutron star that eventually causes its destruction. The observation of old neutron stars exclude a wide range of the DM-neutron scattering cross-section for the scalar asymmetric DM. In various well-motivated models, DM has self-interactions which may leave imprints on galactic dynamics. I will discuss an upper bound on DM self-interaction cross section derived from elliptical DM halo shapes which is about two orders of magnitude stronger than the result from the Bullet Cluster.

Sound waves with long-distance propagation are both a consequence of hydrodynamics, and a danger to hydrodynamics' very existence, as they violate the assumption of local equilibration. In the talk, I will discuss what the thermally excited sound and shear waves do to viscosity. In 2+1 dimensions, the shear viscosity and the diffusion constant cease being independent transport coefficients. In 3+1 dimensions, the fluctuations render the second-order hydrodynamics invalid.