Primordial Gravitational Wave Signatures of Theories Beyond the Standard Model

The Standard Model of elementary particles describes remarkably well phenomena at the fundamental level, nevertheless, it exhibits several shortcomings. For instance, it does not account for dark matter, does not explain the origin of the matter-antimatter asymmetry of the Universe, and leaves the neutrinos massless. In this talk, I will discuss how gravitational waves originating from processes happening within one-trillionth of a second after the Big Bang can shed light on those and other mysteries. Such primordial gravitational waves can be generated by first order phase transitions, cosmic strings, and domain walls, and the shape of the resulting signal depends on the extension of the Standard Model realized in Nature. I will also demonstrate how those signatures can be searched for in current and upcoming experiments: gravitational wave interferometers, pulsar timing arrays, and via astrometric observations.