Shedding light on the dark side of the Universe

Consistent explanation for astrophysical Dark Matter (DM) remains one
of the major unsolved problems of contemporary fundamental physics.
First, I will give a brief historical overview of this problem and the
current state of the art. Then, I will focus on a novel class of Dark
Matter (DM) candidates in the form of a heavy composite Axion-Like
Particle (ALP) with highly suppressed electromagnetic interactions
populating vast yet unexplored domains in the ALP parameter space. I
will demonstrate how the simplest confining gauge theory in the dark
sector yields a composite ALP state in the form of glueballs. Such a
glueball ALP (GALP) features very specific properties such as unique
electromagnetic coupling-mass relation found in terms of two distinct
fundamental scales -- the large dark fermion mass scale and the
dynamical scale of dark confinement. Finally, I will overview novel
phenomenological probes for composite DM, in particular, for direct
detection experiments such as PandaX.