تقرير
When FIMPs Decay into Neutrinos: The $N_\mathrm{eff}$ Story
| العنوان: | When FIMPs Decay into Neutrinos: The $N_\mathrm{eff}$ Story |
|---|---|
| المؤلفون: | Boyarsky, Alexey, Ovchynnikov, Maksym, Sabti, Nashwan, Syvolap, Vsevolod |
| المصدر: | Phys. Rev. D 104, 035006 (2021) |
| سنة النشر: | 2021 |
| المجموعة: | Astrophysics High Energy Physics - Phenomenology |
| مصطلحات موضوعية: | High Energy Physics - Phenomenology, Astrophysics - Cosmology and Nongalactic Astrophysics |
| الوصف: | The existence of feebly interacting massive particles (FIMPs) could have significant implications on the effective number of relativistic species $N_\mathrm{eff}$ in the early Universe. In this work, we investigate in detail how short-lived FIMPs that can decay into neutrinos affect $N_\mathrm{eff}$ and highlight the relevant effects that govern its evolution. We show that even if unstable FIMPs inject most of their energy into neutrinos, they may still decrease $N_{\mathrm{eff}}$, and identify neutrino spectral distortions as the driving power behind this effect. As a case study, we consider Heavy Neutral Leptons (HNLs) and indicate which regions of their parameter space increase or decrease $N_{\mathrm{eff}}$. Moreover, we derive bounds on the HNL lifetime from the Cosmic Microwave Background and comment on the possible role that HNLs could play in alleviating the Hubble tension. Comment: 13 pages, 7 figures - v2: journal version |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1103/PhysRevD.104.035006 |
| URL الوصول: | http://arxiv.org/abs/2103.09831 |
| رقم الأكسشن: | edsarx.2103.09831 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1103/PhysRevD.104.035006 |
|---|