Related papers: Observing Dirac neutrinos in the cosmic microwave …
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 $N_{\rm eff}$. We aim at a model-independent and…
If neutrinos are Dirac particles the existence of light right-handed neutrinos $\nu_{R}$ is implied. Those would contribute to the effective number of relativistic neutrino species $N_{{\rm eff}}$ in the early Universe. With pure standard…
The nature of neutrino masses and the matter-antimatter asymmetry of our universe are two of the most important open problems in particle physics today and are notoriously difficult to test with current technology. Dirac neutrinos offer a…
The existence of prolonged radiation domination prior to the Big Bang Nucleosynthesis (BBN), starting just after the inflationary epoch, is not yet established unanimously. If instead, the universe undergoes a non-standard cosmological…
Precision data from cosmology (probing the CMB decoupling epoch) and light-element abundances (probing the BBN epoch) have hinted at the presence of extra relativistic degrees of freedom, the so-called "dark radiation." We present a model…
We explore an extension of the standard $\Lambda$CDM model by including an interaction between neutrinos and dark matter, and making use of the ground based telescope data of the Cosmic Microwave Background (CMB) from the Atacama Cosmology…
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 ${\rm…
Llight-element abundances probing big bang nucleosynthesis and precision data from cosmology probing the cosmic microwave background decoupling epoch have hinted at the presence of extra relativistic degrees of freedom. This is widely…
Cosmic Microwave Background (CMB) observations have been used extensively to constrain key properties of neutrinos, such as their mass. However, these inferences are typically dependent on assumptions about the cosmological model, and in…
After the electroweak symmetry breaking, we can write down two types of mass for the Standard Model neutrinos, Dirac or Majorana. It is often said that both types of mass cannot be distinguished in neutrino oscillation phenomena. This is in…
Cosmological observations allow to measure the abundance of light relics produced in the early Universe. Most studies focus on the thermal freeze-out scenario, yet light relics produced by freeze-in are generic for models in which new light…
We consider the possibility of probing left-right symmetric model (LRSM) via cosmic microwave background (CMB). We adopt the minimal LRSM with Higgs doublets, also known as the doublet left-right model (DLRM), where all fermions including…
We propose a Dirac neutrino portal dark matter scenario by minimally extending the particle content of the Standard Model (SM) with three right handed neutrinos ($\nu_R$), a Dirac fermion dark matter candidate ($\psi$) and a complex scalar…
The gauge-extended U(1)_C \times SU(2)_L \times U(1)_{I_R} \times U(1)_L model has the attractive property of elevating the two major global symmetries of the standard model (baryon number B and lepton number L) to local gauge symmetries.…
We confront measurable neutrino degrees of freedom $N_{\rm eff}$ and summed neutrino mass in the early universe to particle physics at the energy scale beyond the standard model (BSM), in particular including the issue of neutrino mass type…
We point out a correlation between the effective number of relativistic degrees of species $\Delta N_\text{eff}$, the cosmologically measured $m_{\nu,\text{sterile}}^{\text{eff}}$, and the terrestrially measured neutrino mass sum and…
One of the primary targets of current and future cosmological observations are light thermal relics of the hot big bang. Within the Standard Model of particle physics, an important thermal relic are cosmic neutrinos, while interesting…
We propose a gauged $U(1)_{B-L}$ version of the light Dirac neutrino portal dark matter. The $U(1)_{B-L}$ symmetry provides a UV completion by naturally accommodating three right handed neutrinos from anomaly cancellation requirements…
We improve limits on $Z^\prime$ extensions of the Standard Model (SM) with light right-handed neutrinos. The presence of shared gauge interactions between the light right-handed neutrinos and other SM fermions allows for production of…
We propose a new gauged $B-L$ extension of the standard model where light neutrinos are of Dirac type, naturally acquiring sub-eV mass after electroweak symmetry breaking, without any additional global symmetries. This is realised by…