Detectable Gravitational Wave Signals from Affleck-Dine Baryogenesis

Abstract

In Affleck-Dine baryogenesis, the observed baryon asymmetry of the Universe is generated through the evolution of the vacuum expectation value (VEV) of a scalar condensate. This scalar condensate generically fragments into non-topological solitons (Q-balls). If they are sufficiently long-lived, they lead to an early matter domination epoch, which enhances the primordial gravitational wave signal for modes that enter the horizon during this epoch. The sudden decay of the Q-balls into fermions results in a rapid transition from matter to radiation domination, producing a sharp peak in the gravitational wave power spectrum. Avoiding the problem of gravitino over-abundance favours scenarios where the peak frequency of the resonance is within the range of the Einstein Telescope and/or Decigo. Therefore, we show this scenario provides an observable signal, providing a mechanism to test Affleck-Dine baryogenesis.

Doubly peaked induced stochastic gravitational wave background : Testing baryogenesis from primordial black holes

“…• Unique shape of the GW spectrum we find would serve as a smoking-gun signal of our scenario, making possible one-to-one correspondence between the GW spectrum and baryogenesis. This allows us to distinguish it from other non-thermal baryon asymmetries production mechanisms like Q-ball decay or Affleck-dine [138].…”

Affleck-Dine leptogenesis scenario for resonant production of sterile neutrino dark matter

“…This process induces a large value of the fluid velocity and enhances the scalar-induced gravitational waves. This mechanism of an enhancement of scalar-induced gravitational waves is called "Poltergeist" mechanism [56] and has been studied in the context of the L-ball decay [57][58][59]. Here, we evaluate the gravitational wave spectrum in our scenario and discuss the testability in future observations.…”

Gravitational wave signals from early matter domination: interpolating between fast and slow transitions

“…Such an early MD epoch can occur if the energy density of the universe is dominated by either heavy quasi-stable objects or a rapidly oscillating, but decaying, scalar field. Heavy objects can be motivated in extensions of the Standard Model (for example, moduli fields [14][15][16][17]), as part of a dark sector (for example, [18][19][20]), or as extended objects, including primordial black holes [21,22] and non-topological solitons [23,24]. Currently, there are no constraints on the existence or duration of such an epoch, provided that it ended before nucleosynthesis [25].…”

“…Since an early MD epoch can arise in such a varied array of models [21][22][23][24][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]] (for a review, see ref. [42]), detailed studies of the associated GW signal are necessary.…”