NANOGrav signal and LIGO-Virgo primordial black holes from the Higgs field

Abstract

We show that the NANOGrav signal can come from the Higgs field with a noncanonical kinetic term in terms of the scalar induced gravitational waves. The scalar induced gravitational waves generated in our model are also detectable by space-based gravitational wave observatories. Primordial black holes with stellar masses that can explain LIGO-Virgo events are also produced. Therefore, the NANOGrav signal and the BHs in LIGO-Virgo events may both originate from the Higgs field.

Constraints on primordial curvature spectrum from primordial black holes and scalar-induced gravitational waves

“…The same signal is also detected by other pulsar timing array groups [116,117]. Although this process lacks quadrupolar spatial correlations, it is worth interpreting as a stochastic GW signal, which the SIGWs can explain with frequencies around 10 −9 Hz [58,67,[118][119][120].…”

“…The amplitude of the primordial curvature perturbations can be sharply enhanced if there is an ultra-slow-roll phase in the inflation model [34][35][36]. For the single field inflation models, the ultra-slow-roll phase can be realized by the canonical inflation models with an inflection point [33,[37][38][39][40][41][42][43][44], and the ultra-slow-roll phase can also be realized by many noncanonical inflation models [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64]. The speed of the enhancement of the primordial curvature perturbations of the single field inflation can not be arbitrarily fast; the steepest enhancement obeys the power law form, P ζ ∼ k 4 [65,66].…”

“…The scalar-induced gravitational waves (SIGWs), containing much information about the early Universe, have wide frequency distribution and can be detected by pulsar timing arrays (PTA) [106][107][108][109][110] and the future spacebased GW detectors such as Laser Interferometer Space Antenna (LISA) [111,112], Taiji [113], and TianQin [114]. The stochastic process with a common amplitude and a common spectral slope across pulsars detected by the North American Nanohertz Observatory for Gravitational Wave (NANOGrav) Collaboration [115] and other pulsar timing arrays [116,117] can be explained by SIGWs [58,67,[118][119][120]. In this paper, we give the constraints on the primordial curvature perturbation from the NANOGrav 12.5 years data sets by regarding the NANOGrav signals as GWs induced from the primordial curvature perturbation with the broken power law form.…”

Primordial black holes and scalar-induced gravitational waves from scalar-tensor inflation

“…However, it is not easy to achieve the big enhancement on the power spectrum while keeping the total number of e-folds around 50 − 60 [53,54]. Noncanonical kinetic terms inflation or other kinds of noncanonical inflation models were then considered [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72]. For example, with the coupling function f (φ) and potential satisfying (V φ +V 2 f φ /6)| φ=φc ≈ 0, the Gauss-Bonnet inflation model has a transient ultra-slowroll process at the critical point φ c [69,70] and succeeds in enhancing the power spectrum and produce PBHs.…”

“…These scalar-induced gravitational waves (SIGWs) have wide frequency distribution and can be detected by pulsar timing arrays (PTA) [104][105][106][107][108] and the space-based GW detectors such as Laser Interferometer Space Antenna (LISA) [109,110], Taiji [111], and TianQin [112] in the future. For example, the stochastic process with a common amplitude and a common spectral slope across pulsars detected by the North American Nanohertz Observatory for Gravitational Wave (NANOGrav) Collaboration recently [113] may be the SIGWs with nHz frequencies [68,[114][115][116][117].…”