Search results for "Sterile neutrinos"
showing 10 items of 14 documents
Omnibus experiment: CPT and CP violation with sterile neutrinos
2017
The verification of the sterile neutrino hypothesis and, if confirmed, the determination of the relevant oscillation parameters is one of the goals of the neutrino physics in near future. We propose to search for the sterile neutrinos with a high statistics measurement utilizing the radioactive sources and oscillometric approach with large liquid scintillator detector like LENA, JUNO, or RENO-50. Our calculations indicate that such an experiment is realistic and could be performed in parallel to the main research plan for JUNO, LENA, or RENO-50. Assuming as the starting point the values of the oscillation parameters indicated by the current global fit (in 3 + 1 scenario) and requiring at le…
Determination of the θ23 octant in long baseline neutrino experiments within and beyond the standard model
2018
The recent data indicate that the neutrino mixing angle θ 23 deviates from the maximal-mixing value of 45°, showing two nearly degenerate solutions, one in the lower octant (LO) ( θ 23 4 5 ° ). We investigate, using numerical simulations, the prospects for determining the octant of θ 23 in the future long baseline oscillation experiments. We present our results as contour plots on the ( θ 23 − 4 5 ° , δ )–plane, where δ is the C P phase, showing the true values of θ 23 for which the octant can be experimentally determined at 3 σ , 2 σ and 1 σ confidence level. In particular, we study the impact of the possible nonunitarity of neutrino mixing on the experimental determination of θ 23 in thos…
Limits on sterile neutrino contributions to neutrinoless double beta decay
2015
Nuclear matrix elements (NME) for exchange of arbitrary mass neutrinos are calculated in the interacting boson model (IBM-2). By combining the NME with the phase space factors (PSF), expected half-lives for neutrinos of mass ${m}_{N}$ and coupling ${U}_{eN}$ are estimated. Limits on sterile neutrinos with masses in the eV, keV, MeV-GeV, and TeV range are given.
Updated CMB and x- and gamma-ray constraints on Majoron dark matter
2013
The Majoron provides an attractive dark matter candidate, directly associated with the mechanism responsible for spontaneous neutrino mass generation within the standard model SU(3)(c) circle times SU(2)(L) circle times U(1)(Y) framework. Here we update the cosmological and astrophysical constraints on Majoron dark matter coming from the cosmic microwave background and a variety of x- and gamma-ray observations.
A search for neutrino–antineutrino mass inequality by means of sterile neutrino oscillometry
2015
The investigation of the oscillation pattern induced by the sterile neutrinos might determine the oscillation parameters, and at the same time, allow to probe CPT symmetry in the leptonic sector through neutrino-antineutrino mass inequality. We propose to use a large scintillation detector like JUNO or LENA to detect electron neutrinos and electron antineutrinos from MCi electron capture or beta decay sources. Our calculations indicate that such an experiment is realistic and could be performed in parallel to the current research plans for JUNO and RENO. Requiring at least 5$\sigma$ confidence level and assuming the values of the oscillation parameters indicated by the current global fit, w…
Neff versus the lightest neutrino mass
2016
AbstractWithin the framework of low-scale Type I seesaw models with two and three extra sterile neutrinos we evaluate the production of the sterile states in the Early Universe. We explore the full parameter space and find that in the model with two extra states both of them reach thermal equilibrium with the primordial plasma. In the model with three sterile neutrinos, if the lightest active neutrino mass is below O(10−3eV) one sterile neutrino might not thermalize, while the other two always reach thermalization. Applying constrains from both extra radiation at BBN and CMB, and the dark matter allowed abundance, we show that the spectra of heavier states are severely restricted in the mas…
Self-interacting dark matter and cosmology of a light scalar mediator
2016
We consider a fermionic dark matter candidate interacting via a scalar mediator coupled with the Standard Model through a Higgs portal. We consider a general setting including both scalar and pseudoscalar interactions between the scalar and fermion, and illustrate the relevant features for dark matter abundance, direct search limits and collider constraints. The case where dark matter has a self-interaction strength $⟨{\ensuremath{\sigma}}_{V}⟩/{m}_{\ensuremath{\psi}}\ensuremath{\sim}0.1--1\text{ }\text{ }{\mathrm{cm}}^{2}/\mathrm{g}$ is strongly constrained, in particular by the big bang nucleosynthesis. We show that these constraints can be alleviated by introducing a new light sterile ne…
Determination of the θ23 octant in long baseline neutrino experiments within and beyond the standard model
2018
The recent data indicate that the neutrino mixing angle $\theta_{23}$ deviates from the maximal-mixing value of 45$^\circ$, showing two nearly degenerate solutions, one in the lower octant (LO) ($\theta_{23}45^\circ$). We investigate, using numerical simulations, the prospects for determining the octant of $\theta_{23}$ in the future long baseline oscillation experiments. We present our results as contour plots on the ($\theta_{23}-45^\circ$, $\delta$)--plane, where $\delta$ is the $CP$ phase, showing the true values of $\theta_{23}$ for which the octant can be experimentally determined at 3$\,\sigma$, 2$\,\sigma$ and 1$\,\sigma$ confidence level. In particular, we study the impact of the p…
Long-lived particles at the energy frontier: the MATHUSLA physics case
2019
We examine the theoretical motivations for long-lived particle (LLP) signals at the LHC in a comprehensive survey of Standard Model (SM) extensions. LLPs are a common prediction of a wide range of theories that address unsolved fundamental mysteries such as naturalness, dark matter, baryogenesis and neutrino masses, and represent a natural and generic possibility for physics beyond the SM (BSM). In most cases the LLP lifetime can be treated as a free parameter from the $\mu$m scale up to the Big Bang Nucleosynthesis limit of $\sim 10^7$m. Neutral LLPs with lifetimes above $\sim$ 100m are particularly difficult to probe, as the sensitivity of the LHC main detectors is limited by challenging …
Recent Probes of Standard and Non-standard Neutrino Physics With Nuclei
2019
We review standard and non-standard neutrino physics probes that are based on nuclear measurements. We pay special attention on the discussion of prospects to extract new physics at prominent rare event measurements looking for neutrino-nucleus scattering, such as the coherent elastic neutrino-nucleus scattering (CE$\nu$NS) that may involve lepton flavor violation (LFV) in neutral-currents (NC). For the latter processes several appreciably sensitive experiments are currently pursued or have been planed to operate in the near future, like the COHERENT, CONUS, CONNIE, MINER, TEXONO, RED100, vGEN, Ricochet, NUCLEUS etc. We provide a thorough discussion on phenomenological and theoretical studi…