Gravitational wave imprints of physics beyond the Standard Model

The origin of dark matter(DM) and the baryon asymmetry of our Universe have been two of the most long-standing puzzles of particle physics and cosmology, hinting towards some new physics beyond the Standard Model. While the quest for the conventional WIMP DM at several direct search and collider experiments has not led to any positive results so far, the high scale of asymmetry generation through leptogenesis is out of direct reach of any current experiments. In this regard, cosmological gravitational waves may provide a novel alternate window into such early Universe physics. This talk will discuss DM scenarios beyond the conventional WIMP paradigm, with their imprints on the cosmological gravitational wave(GW) background from inflation, topological defects and primordial black holes. The shape of such GW spectrum is dictated by the DM phenomenology and/or the scale of leptogenesis. Possible explanation of the stochastic GW background signal at nano-Hz frequencies, reported recently by several pulsar timing array experiments will also be discussed, along with their impact on some particle physics scenarios.