Probing multi-step electroweak phase transition with multi-peaked primordial gravitational waves spectra

Abstract

Multi-peaked spectra of the primordial gravitational waves are considered as a phenomenologically relevant source of information about the dynamics of sequential phase transitions in the early Universe. In particular, such signatures trace back to specific patterns of the first-order electroweak phase transition in the early Universe occurring in multiple steps. Such phenomena appear to be rather generic in multi-scalar extensions of the Standard Model. In a particularly simple extension of the Higgs sector, we have identified and studied the emergence of sequential long-and shortlasting transitions as well as their fundamental role in generation of multi-peaked structures in the primordial gravitational-wave spectrum. We discuss the potential detectability of these signatures by the next generation of gravitational-wave interferometers.

Diagrammatic structures of the Nielsen identity

“…Similar results will be derived no matter the ghost propagator emits a single or double R, or double I, since all the corresponding vertices share the same structure proportional to ξ (see (24), ( 25), (26), and their differentiated results ( 43), (…”

“…If this happens in the early universe, the bubble expanding processes might also generate the primary stochastic gravitational waves, and induce the baryon asymmetry as the bubble wall shift through the hot plasma. Within the frameset of the gauge theories and considering the ξ-dependent terms, the phase transition rates or temperatures [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], the phase patterns or vacuum stability [18][19][20], as well as the primary stochastic gravitational wave relic densities [21][22][23][24][25][26][27], the baryon asymmetry [28,29] and the (pole-)mass, mixing parameters or resonance shapes , the plasma parameters [53] are all observables which must be gauge-invariant. However practical gauge independent evaluations are far from the straightforward tasks.…”

Phase Transitions in an Expanding Universe: Stochastic Gravitational Waves in Standard and Non-Standard Histories

“…Perhaps even more significantly, many space-based detectors have been proposed, such as the Laser Interferometer Space Antenna (LISA) [9], Big Bang Observer (BBO), DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) [10], Taiji [11], and Tianqin [12]. They will come online within the next decade or so and can probe lower frequencies coming from an electroweak scale phase transition [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. 1 Precise calculations of the gravitational wave power spectrum are required to have any hope of inferring parameters of the underlying particle physics model.…”

Detection of Early-Universe Gravitational Wave Signatures and Fundamental Physics

“…For instance, new states at the electroweak scale can catalyze a strongly first order electroweak phase transition [86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102][103][104][105] and large lepton asymmetries or different quark masses can make the QCD transition strong [106][107][108][109]. Beyond this, a strong transition can occur in multistep phase transitions * [115][116][117][118][119][120], B-L breaking [15,[121][122][123][124][125][126][127] (or B/L breaking [128]), flavour physics [129,130], axions [16,131,132], GUT symmetry breaking chains [133][134][135][13...…”