Gravitational wave signals of electroweak phase transition triggered by dark matter

Abstract

We study in this work a scenario that the universe undergoes a two step phase transition with the first step happened to the dark matter sector and the second step being the transition between the dark matter and the electroweak vacuums, where the barrier between the two vacuums, that is necessary for a strongly first order electroweak phase transition (EWPT) as required by the electroweak baryogenesis mechanism, arises at the tree-level. We illustrate this idea by working with the standard model (SM) augmented by a scalar singlet dark matter and an extra scalar singlet which mixes with the SM Higgs boson. We study the conditions for such pattern of phase transition to occur and especially for the strongly first order EWPT to take place, as well as its compatibility with the basic requirements of a successful dark matter, such as observed relic density and constraints of direct detections. We further explore the discovery possibility of this pattern EWPT by searching for the gravitational waves generated during this process in spaced based interferometer, by showing a representative benchmark point of the parameter space that the generated gravitational waves fall within the sensitivity of eLISA, DECIGO and BBO.

Non-resonant collider signatures of a singlet-driven electroweak phase transition

“…Hypothetically, it is possible for electroweak symmetry to be broken, then restored, then broken again, or for electroweak symmetry breaking to proceed via a multi-step transition [30,[57][58][59][60][61]. In all cases, the relevant transition for electroweak baryogenesis is the one with the lowest critical temperature such that the metastable phase features φ h = 0, since this is the transition that shuts off the sphalerons for the last time.…”

Gravitational waves from hidden QCD phase transition

“…Computing S 3 (T )/T for each temperature as in the above method, we can find the transition temperature T t from the condition (26), which is used for the determination of tunneling parameters α andβ given in Eqs. (27) and (30).…”

“…However, if the SM is extended, observable GW signals associated with a symmetry breaking may be produced and tested in future experiments such as LISA [12,13] and DECIGO [14][15][16] as discussed in [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”

Electroweak baryogenesis at high bubble wall velocities

“…There may be some tension between the two effects, but until recently there have been few quantitative studies including transport of the particle asymmetries [6][7][8][9][10][11]. Most works have focused on the coexistence of observable gravitational waves with the sphaleron washout condition v/T 1 [12][13][14][15][16][17][18][19][20][21][22], without taking into account the problem of reduced particle transport near the wall.…”