Minimal supergravity scalar neutrino dark matter and inverse seesaw neutrino masses

We show that within the inverse seesaw mechanism for generating neutrino masses, minimal supergravity naturally provides the scalar neutrino as the lightest superparticle. We also demonstrate that such schemes naturally reconcile the small neutrino masses with the correct relic scalar neutrino dark matter abundance and accessible direct detection rates in nuclear recoil experiments. This way, inverse seesaw minimal supergravity offers a common solution to the generation of the neutrino mass and to the origin of dark matter.     

A fourth generation neutrino with a standard Higgs scalar solves both the solar neutrino and dark matter problems

Weakly interacting massive particles (WIMPs) can solve both the solar neutrino and dark matter problems. In this paper we show that a fourth generation Dirac neutrino with mass between 4–10 GeV, in conjunction with the standard, albeit light, Higgs with mass of order 400 MeV, is a candidate WIMP. We describe both the astrophysical and particle physics consequences of this new WIMP.     

New type of seesaw mechanism for neutrino masses

In a wide class of unified models there is an additional (and possibly dominant) term in the neutrino mass formula that under the simplest assumption takes the form M(nu)=(M(N)+M(T)(N))u/M(G), where M(N) is the neutrino Dirac mass matrix, and u=O(M(W)). This makes possible highly predictive models. A generalization of this form yields realistic neutrino masses and mixings more readily than the usual seesaw formula in some models. The conditions for resonant enhancement of leptogenesis can occur naturally in such models.     

Decaying warm dark matter and neutrino masses

Neutrino masses may arise from spontaneous breaking of ungauged lepton number. Because of quantum gravity effects the associated Goldstone boson - the majoron - will pick up a mass. We determine the lifetime and mass required by cosmic microwave background observations so that the massive majoron provides the observed dark matter of the Universe. The majoron decaying dark matter scenario fits nicely in models where neutrino masses arise via the seesaw mechanism, and may lead to other possible cosmological implications.     

Galactic Rotational velocities and dark neutrino matter

It has been assumed that neutrinos with non-vanishing rest mass contribute the gravitational field of our Galaxy. This contribution can be studied empirically from the orbiting velocities of galactic objects. In this way hints for the neutrino rest mass can be obtained from the rotation curve of our Galaxy.     

Probing the seesaw mechanism with neutrino data and leptogenesis

We use the current low-energy neutrino data to understand the structure of the neutrino mass matrix. Considering this information and assuming hierarchical neutrino Yukawa couplings, we use the seesaw formula to study the properties of the heavy right-handed neutrinos N_i. We find that successful baryogenesis via leptogenesis requires mass degeneracy and maximal mixing of N₁ and N₂.     

The singular seesaw mechanism with hierarchical Dirac neutrino mass

We evaluate the one-loop fermion self-energy for the gauged Thirring model in (2+1) dimensions, with one massive fermion flavor. We do this in the framework of the causal perturbation theory. In contrast to QED, the corresponding two-point function turns out to be infrared finite on the mass shell. Then, by means of a Ward identity, we derive the on-shell vertex correction and discuss the role played by causality for non-renormalizable theories. Received: 5 May 1999 / Published online: 27 January 2000     

Unifying inflation and dark matter with neutrino masses

We propose a simple model where a gauge-invariant inflaton is responsible for cosmic inflation and generates the seed for structure formation, while its relic thermal abundance explains the missing matter of the Universe in the form of cold dark matter. The inflaton self-coupling also explains the observed neutrino masses. All the virtues can be attained in a minimal extension of the standard model gauge group around the TeV scale. We can also unveil these properties of an inflaton in forthcoming space and ground based experiments.     

Magnetic dipole moment and keV neutrino dark matter

We study magnetic dipole moments of right-handed neutrinos in a keV neutrino dark matter model. This model is a simple extension of the standard model with only right-handed neutrinos and a pair of charged particles added. One of the right-handed neutrinos is the candidate of dark matter with a keV mass. Some bounds on the dark matter magnetic dipole moment and model parameters are obtained from cosmological observations.     

Scalar neutrino dark matter in the BLMSSM

The BLMSSM is an extension of the minimal supersymmetric standard model(MSSM).Its local gauge group is SU(3)_C×SU(2)_L×U(1)_Y×U(1)_B×U(1)_L.Supposing the lightest scalar neutrino is a dark matter candidate,we study the relic density and the spin independent cross section of sneutrino scattering off a nucleon.We calculate the numerical results in detail and find a suitable parameter space.The numerical discussion can confine the parameter space and provide a reference for dark matter research.     

Monochromatic neutrino signals from dark matter annihilation

Dark matter (DM) annihilations in the Sun to neutrino–antineutrino pairs are known to have potentially observable signatures in neutrino telescopes such as IceCube and KM3. We propose a model independent analysis in which the monochomatic neutrino signal from dark matter (DM) annihilations in the Sun is related to the direct detection spin-independent and spin-dependent cross sections rather than assuming cross sections from a particular model. We propagate the neutrinos from the center of the Sun to the Earth taking into account matter effects on neutrino oscillations. For DM capture in the Sun via a large spin-dependent DM capture cross section the discovery prospects of the IceCube experiment are found to be promising.     

Sneutrino dark matter in gauged inverse seesaw models for neutrinos

Extending the minimal supersymmetric standard model to explain small neutrino masses via the inverse seesaw mechanism can lead to a new light supersymmetric scalar partner which can play the role of inelastic dark matter (IDM). It is a linear combination of the superpartners of the neutral fermions in the theory (the light left-handed neutrino and two heavy standard model singlet neutrinos) which can be very light with mass in ~5-20 GeV range, as suggested by some current direct detection experiments. The IDM in this class of models has keV-scale mass splitting, which is intimately connected to the small Majorana masses of neutrinos. We predict the differential scattering rate and annual modulation of the IDM signal which can be testable at future germanium- and xenon-based detectors.     

Exploring the singlet scalar dark matter from direct detections and neutrino signals via its annihilation in the Sun

We explore the singlet scalar dark matter (DM) from direct detections and high energy neutrino signals generated by the solar DM annihilation. Two singlet scalar DM models are discussed, one is the real singlet scalar DM model as the simple extension of the standard model (SSDM-SM) with a discrete _Z2$Z_2$ symmetry, and another is the complex singlet scalar DM model as the simple extension of the left–right symmetric two Higgs bidoublet model (SSDM-2HBDM) with P and CP   symmetries. To derive the Sun capture rate, we consider the uncertainties in the hadronic matrix elements and calculate the spin-independent DM-nucleon elastic scattering cross section. We find that the predicted neutrino induced upgoing muon fluxes in the region 3.7 GeV?_mD?4.2 GeV$3.7\text{GeV}?m_D?4.2\text{GeV}$ slightly exceed the Super-Kamiokande limit in the SSDM-SM. However, this exceeded region can be excluded by the current DM direct detection experiments. For the SSDM-2HBDM, one may adjust the Yukawa couplings to avoid the direct detection limits and enhance the predicted muon fluxes. For the allowed parameter space of the SSDM-SM and SSDM-2HBDM, the produced muon fluxes in the Super-Kamiokande and muon event rates in the IceCube are less than the experiment upper bound and atmosphere background, respectively.