Abstract
Dark matter makes up >80% of nonrelativistic matter in our cosmos, yet its particle identity (mass, spin etc) is unknown. What can we learn about the mass and intrinsic spin of dark matter particles from astrophysical observations? I will discuss how spin can determine the lightest mass dark matter particles can have. When dark matter is a sufficiently light boson, it becomes wavelike — I will show that in this case its intrinsic spin angular momentum can impact the (i) variation of dark matter density inside halos, (ii) lead to formation of solitons with macroscopic intrinsic spin, and (iii) leave clues in initial conditions for formation of structure in the early universe. Time permitting, I might briefly discuss direct detection prospects for such dark matter, and novel connections to “spinor” Bose-Einstein Condensates in the laboratory.