Gravitational Wave Gastronomy

Abstract

The symmetry breaking of grand unified gauge groups in the early Universe often leaves behind relic topological defects such as cosmic strings, domain walls, or monopoles. For some symmetry breaking chains, hybrid defects can form where cosmic strings attach to domain walls or monopoles attach to strings. In general, such hybrid defects are unstable, with one defect 'eating' the other via the conversion of its rest mass into the other's kinetic energy and subsequently decaying via gravitational waves. In this work, we determine the gravitational wave spectrum from 1) the destruction of a cosmic string network by the nucleation of monopoles which cut up and 'eat' the strings, 2) the collapse and decay of a monopole-string network by strings that 'eat' the monopoles, 3) the destruction of a domain wall network by the nucleation of string-bounded holes on the wall that expand and 'eat' the wall, and 4) the collapse and decay of a string-bounded wall network by walls that 'eat' the strings. We call the gravitational wave signals produced from the 'eating' of one topological defect by another gravitational wave gastronomy. We find that the four gravitational wave gastronomy signals considered yield unique spectra that can be used to narrow down the SO(10) symmetry breaking chain to the Standard Model and the scales of symmetry breaking associated with the consumed topological defects. Moreover, the systems we consider are unlikely to have a residual monopole or domain wall problem.

Tracking Down the Route to the SM with Inflation and Gravitational Waves

“…Nevertheless, it is worth to establish possible breaking routes where hybrid topological defects can leave a distinct GW imprint. Recently, these observations have been also revived in [37] with a similar motivation to ours.…”

Domain walls seeding the electroweak phase transition

“…and depends on the 4d couplings through the dimensionless combination κ/η. Similar interaction terms where h 0 and s 0 are replaced by continuum states will also appear in Ṽ alongside the ones shown in (26).…”

“…At the order O(1/m 4 KK ) interactions are generated up to the eighth power together with momentum-dependent operators 2 . All these new terms should then be added to the ones shown in (26).…”

“…where we have replaced the sum over the states in the box of size 2L with an integral over q k . The coefficient c 4κ (q) is the analogue of c 4κ in (26) for the operator h 2 0 s 2 k , in which s 0 has now been replaced with states of the continuum tower. The integral (28) is dominated by the lightest KK states due to the 1/q 2 suppression, so that we can write…”

“…ii) Include a (large enough) number of scattering states and integrate them out at tree level in favour of an effective potential for h 0 and s 0 only, according to the discussion in Sec. IV A. iii) Neglect the scattering states altogether and minimize the quartic potential for s 0 and h 0 in (26). This corresponds to the lowest level of accuracy.…”