Observable ${\rm Δ{N_{eff}}}$ in Dirac Scotogenic Model

Fuente: arXiv
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Autori principali: Borah, Debasish, Das, Pritam, Nanda, Dibyendu
Natura: Preprint
Pubblicazione: 2022
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author Borah, Debasish
Das, Pritam
Nanda, Dibyendu
author_facet Borah, Debasish
Das, Pritam
Nanda, Dibyendu
contents We study the possibility of probing the radiative Dirac seesaw model with dark sector particles going inside the loop, popularly referred to as the Dirac scotogenic model via measurements of effective relativistic degrees of freedom ${\rm Δ{N_{eff}}}$ at cosmic microwave background (CMB) experiments. The loop suppression and additional free parameters involved in neutrino mass generation allow large ($\sim\mathcal{O}(1))$ coupling of light Dirac neutrinos with the dark sector particles. Such large Yukawa coupling not only dictates the relic abundance of heavy fermion singlet dark matter but also can lead to the thermalisation of the right chiral part of Dirac neutrinos, generating additional relativistic degrees of freedom ${\rm Δ{N_{eff}}}$. We find that the parameter space consistent with dark matter phenomenology and neutrino mass bounds can also be probed at future cosmic microwave background experiments like CMB-S4 via precision measurements of ${\rm Δ{N_{eff}}}$. The same parameter space, while leading to loop-suppressed direct detection cross-section of dark matter outside future sensitivities, can also have other interesting and complementary observational prospects via charged lepton flavour violation and collider signatures.
format Preprint
id arxiv_https___arxiv_org_abs_2211_13168
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Observable ${\rm Δ{N_{eff}}}$ in Dirac Scotogenic Model
Borah, Debasish
Das, Pritam
Nanda, Dibyendu
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
We study the possibility of probing the radiative Dirac seesaw model with dark sector particles going inside the loop, popularly referred to as the Dirac scotogenic model via measurements of effective relativistic degrees of freedom ${\rm Δ{N_{eff}}}$ at cosmic microwave background (CMB) experiments. The loop suppression and additional free parameters involved in neutrino mass generation allow large ($\sim\mathcal{O}(1))$ coupling of light Dirac neutrinos with the dark sector particles. Such large Yukawa coupling not only dictates the relic abundance of heavy fermion singlet dark matter but also can lead to the thermalisation of the right chiral part of Dirac neutrinos, generating additional relativistic degrees of freedom ${\rm Δ{N_{eff}}}$. We find that the parameter space consistent with dark matter phenomenology and neutrino mass bounds can also be probed at future cosmic microwave background experiments like CMB-S4 via precision measurements of ${\rm Δ{N_{eff}}}$. The same parameter space, while leading to loop-suppressed direct detection cross-section of dark matter outside future sensitivities, can also have other interesting and complementary observational prospects via charged lepton flavour violation and collider signatures.
title Observable ${\rm Δ{N_{eff}}}$ in Dirac Scotogenic Model
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2211.13168