Realisation of the ultra-slow roll phase in Galileon inflation and PBH overproduction
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| Format: | Preprint |
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2024
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| _version_ | 1866917724131688448 |
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| author | Choudhury, Sayantan Karde, Ahaskar Panda, Sudhakar Sami, M. |
| author_facet | Choudhury, Sayantan Karde, Ahaskar Panda, Sudhakar Sami, M. |
| contents | We demonstrate the explicit realisation of the ultra-slow roll phase in the framework of the effective field theory of single-field Galileon inflation. The pulsar timing array (PTA) collaboration hints at the scalar-induced gravity waves (SIGW) from the early universe as an explanation for the origin of the observed signal, which, however, leads to an enhancement in the amplitude of the scalar power spectrum giving rise to the overproduction of primordial black holes (PBHs). In the setup under consideration, we examine the generation of SIGW consistent with PTA (NANOGrav15 and EPTA) data, in addition to which we also consider the impact from QCD crossover at the nHz frequencies and address the PBH overproduction issue assuming linear approximations for the over-density without incorporating non-Gaussian effects from the comoving curvature perturbation. The framework is shown to give rise to SIGWs well consistent with the PTA signal with comfortable PBH abundance, $10^{-3} \lesssim f_{\rm PBH} < 1$, of near solar-mass black holes. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2401_10925 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Realisation of the ultra-slow roll phase in Galileon inflation and PBH overproduction Choudhury, Sayantan Karde, Ahaskar Panda, Sudhakar Sami, M. Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory We demonstrate the explicit realisation of the ultra-slow roll phase in the framework of the effective field theory of single-field Galileon inflation. The pulsar timing array (PTA) collaboration hints at the scalar-induced gravity waves (SIGW) from the early universe as an explanation for the origin of the observed signal, which, however, leads to an enhancement in the amplitude of the scalar power spectrum giving rise to the overproduction of primordial black holes (PBHs). In the setup under consideration, we examine the generation of SIGW consistent with PTA (NANOGrav15 and EPTA) data, in addition to which we also consider the impact from QCD crossover at the nHz frequencies and address the PBH overproduction issue assuming linear approximations for the over-density without incorporating non-Gaussian effects from the comoving curvature perturbation. The framework is shown to give rise to SIGWs well consistent with the PTA signal with comfortable PBH abundance, $10^{-3} \lesssim f_{\rm PBH} < 1$, of near solar-mass black holes. |
| title | Realisation of the ultra-slow roll phase in Galileon inflation and PBH overproduction |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2401.10925 |