# Observing Dirac neutrinos in the cosmic microwave background

@article{Abazajian2019ObservingDN,
title={Observing Dirac neutrinos in the cosmic microwave background},
author={Kevork N. Abazajian and Julian Heeck},
journal={Physical Review D},
year={2019}
}
• Published 8 August 2019
• Physics
• Physical Review D
Planned CMB Stage IV experiments have the potential to measure the effective number of relativistic degrees of freedom in the early Universe, $N_\text{eff}$, with percent-level accuracy. This probes new thermalized light particles and also constrains possible new-physics interactions of Dirac neutrinos. Many Dirac-neutrino models that aim to address the Dirac stability, the smallness of neutrino masses or the matter--anti-matter asymmetry of our Universe endow the right-handed chirality…

## Figures from this paper

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

• Physics
• 2022
We study the possibility of generating light Dirac neutrino mass from a radiative seesaw mechanism with dark sector particles going inside the loop, known as the scotogenic framework. The loop

### Dirac neutrinos and $N_{{\rm eff}}$ II: the freeze-in case.

• Physics
• 2020
We discuss Dirac neutrinos whose right-handed component $\nu_R$ has new interactions that may lead to a measurable contribution to the effective number of relativistic neutrino species $N_{\rm eff}$.

### Observing left-right symmetry in the cosmic microwave background

• Physics
• 2020
We consider the possibility of probing left-right symmetric model (LRSM) via cosmic microwave background (CMB). We adopt the minimal LRSM with Higgs doublets, also known as the doublet left-right

### Dirac neutrino mass generation from a Majorana messenger

• Physics
Physical Review D
• 2020
The radiative type-I seesaw has been already implemented to explain the lightness of Majorana neutrinos with both Majorana and Dirac heavy fermions, and the lightness of Dirac neutrinos with Dirac

### Higgs phenomenology as a probe of sterile neutrinos

• Physics
Physical Review D
• 2019
Physics beyond the Standard Model can manifest itself as both new light states and heavy degrees of freedom. In this paper, we assume that the former comprise only a sterile neutrino, $N$. Therefore,

### Dark Matter and (g - 2) μ,e in radiative Dirac neutrino mass models

• Physics
Journal of Cosmology and Astroparticle Physics
• 2022
The origin of neutrino mass is a mystery, so is its nature, namely, whether neutrinos are Dirac or Majorana particles. On top of that, hints of large deviations of the muon and the electron anomalous

### Neutrino Magnetic Moments Meet Precision $N_{\rm eff}$ Measurements

• Physics
• 2022
: In the early universe, Dirac neutrino magnetic moments due to their chirality-ﬂipping nature could lead to thermal production of right-handed neutrinos, which would make a signiﬁcant contribution

### Dirac neutrinos and Neff

• Physics
Journal of Cosmology and Astroparticle Physics
• 2020
If neutrinos are Dirac particles the existence of light right-handed neutrinos νR is implied. Those would contribute to the effective number of relativistic neutrino species Neff in the early

### Naturally light Dirac and pseudo-Dirac neutrinos from left-right symmetry

• Physics
Journal of High Energy Physics
• 2022
Abstract We develop a class of left-right symmetric theories based on the gauge group SU(3)c × SU(2)L × SU(2)R × U(1) with a generalized seesaw mechanism for generating the charged fermion masses.

## References

SHOWING 1-10 OF 85 REFERENCES

### Thermal neutrino portal to sub-MeV dark matter

• Physics
Physical Review D
• 2019
Thermal relics lighter than an MeV contribute to the energy density of the universe at the time of nucleosynthesis and recombination. Constraints on extra radiation degrees of freedom typically

### Probes of the Standard Model effective field theory extended with a right-handed neutrino

• Physics
Journal of High Energy Physics
• 2019
Abstract If neutrinos are Dirac particles and, as suggested by the so far null LHC results, any new physics lies at energies well above the electroweak scale, the Standard Model effective field

### Models of neutrino mass with a low cutoff scale

• Physics
• 2005
In theories with a low quantum gravity scale, global symmetries are expected to be violated, inducing excessive proton decay or large Majorana neutrino masses. The simplest cure is to impose discrete

### The dispirited case of gauged U(1)B − L dark matter

• Physics
Journal of High Energy Physics
• 2018
A bstractWe explore the constraints and phenomenology of possibly the simplest scenario that could account at the same time for the active neutrino masses and the dark matter in the Universe within a

### Neutrino-dark matter connections in gauge theories

• Physics
Physical Review D
• 2019
We discuss the connection between the origin of neutrino masses and the properties of dark matter candidates in the context of gauge extensions of the Standard Model. We investigate minimal gauge

### Comment on Astrophysical consequences of a neutrinophilic two-Higgs-doublet model''

Several authors have pointed out that the scalar-mediated interaction of neutrinos in a neutriophilic two-Higgs-doublet model (nu2HDM) can be as strong as electromagnetic interaction [1-3]. We show