Audible gravitational waves echoes from invisible sectors
PT-CERN Call 2022/2
Universidade de Aveiro
CIDMA - Centro de Investigação em Matemática e Aplicações da Universidade de Aveiro
The recent Nobel prize awarded detection of gravitational waves (GWs)  has opened up a new era of GW astronomy and, more generally, fundamental physics explorations. A potential observation of the stochastic background of primordial GWs may indicate possible New Physics (NP) beyond the SM (BSM) . Indeed, such an observation may unravel NP that appears inaccessible to traditional collider and astroparticle physics measurements. This project aims to explore the potential of future GW interferometers such as LISA, BBO, DECIGO, Einstein Telescope (ET), and Cosmic Explorer (CE) in probing NP scenarios that include both electroweak (EW) scale as well as higher-energy phase transitions. The goal is to develop a (so far lacking) general-purpose and modular computational suite to automatize the calculation of the primordial GW (pGW) spectrum for generic BSM theories. While such tools will be valuable to the community, we will make use of those to study concrete physics cases, in particular, this will be applied in three classes of models: 1) minimal extensions of the SM in terms of the number of new particles, symmetries, etc. (e.g. classical scale invariance [25,26]); 2) extensions of the SM scalar sector with higher dimensional operators encoding unknown NP effects [11,30]; 3) GUT-inspired scenarios. While not exclusive, one will consider as guiding principle scenarios inspired by a recently proposed framework [3,4], based on a Unification paradigm where the family replication observed in nature emerges from a fundamental gauge interaction. With new symmetries present in an energy range from the TeV scale up to 10 PeV, this project will focus on the production of pGW covering the mHz-kHz frequency range, which is precisely the region where the aforementioned experiments operate.