Test of non-standard neutrino properties with the BOREXINO source experiments

We calculate the event rates induced by high-intensity radioactive sources of (Cr) and of (Sr), to be located near the BOREXINO detector. Calculations are performed both in the standard case and assuming non-standard properties of neutrinos, including flavor oscillations, neutrino electromagnetic interactions, and deviations from the standard vector and axial couplings in the -e interaction. It is shown that, in some cases, the current limits on non-standard neutrino properties can be significantly improved. Received: 11 January 1999 / Published online: 22 March 1999     

Measuring the sterile neutrino CP phase at DUNE and T2HK

The CP phases associated with the sterile neutrino cannot be measured in the dedicated short-baseline experiments being built to test the sterile neutrino hypothesis. On the other hand, these phases can be measured in long-baseline experiments, even though the main goal of these experiments is not to test or measure sterile neutrino parameters. In particular, the sterile neutrino phase \(\delta _{24}\) affects the charged-current electron appearance data in long-baseline experiment. In this paper we show how well the sterile neutrino phase \(\delta _{24}\) can be measured by the next-generation long-baseline experiments DUNE, T2HK (and T2HKK). We also show the expected precision with which this sterile phase can be measured by combining the DUNE data with data from T2HK or T2HKK. The T2HK experiment is seen to be able to measure the sterile phase \(\delta _{24}\) to a reasonable precision. We also present the sensitivity of these experiments to the sterile mixing angles, both by themselves, as well as when DUNE is combined with T2HK or T2HKK.     

Precision measurement of neutrino oscillation parameters at INO-ICAL detector

A magnetized Iron CALorimeter (ICAL) detector at the India-based neutrino observatory (INO) is used to study neutrino oscillation sensitivity using atmospheric muon neutrino source. The ICAL detector will be able to detect muon tracks and hadron showers produced by neutrino interactions with the iron target. We have performed precision measurement analysis for the atmospheric neutrino oscillation parameters with the muon neutrino events, generated by Monte Carlo NUANCE event generator. A marginalized χ² analysis based on reconstructed neutrino energy and muon zenith angle binning scheme has been performed to determine the sensitivity for the atmospheric neutrino mixing parameters, \(\sin ^{2}\theta _{23}\) and \(| {\Delta } m^{2}_{23}|\).     

Dark matter,neutrino mass,cutoff for cosmic-ray neutrino,and the Higgs boson invisible decay from a neutrino portal interaction

We study an effective theory beyond the standard model(SM) where either of the two additional gauge singlets, a Majorana fermion and a real scalar, constitutes all or some fraction of dark matter. In particular, we focus on the masses of the two singlets in the range of O(10) MeV-O(10) GeV with a neutrino portal interaction, which plays an important role not only in particle physics but also in cosmology and astronomy. We point out that the thermal dark matter abundance can be explained by(co-)annihilation, where the dark matter with a mass greater than 2 GeV can be tested in future lepton colliders, CEPC, ILC, FCC-ee and CLIC, in the light of the Higgs boson invisible decay. When the gauge singlets are lighter than O(100) MeV, the interaction can affect the neutrino propagation in the universe due to its annihilation with cosmic background neutrino into the gauge singlets. Although in this case it can not be the dominant dark matter, the singlets are produced by the invisible decay of the Higgs boson at such a rate which is fully within reach of future lepton colliders. In particular, a high energy cutoff of cosmic-ray neutrino,which may account for the non-detection of Greisen-Zatsepin-Kuzmin(GZK) neutrino or the non-observation of the Glashow resonance, can be set. Interestingly, given the cutoff and the mass(range) of WIMPs, a neutrino mass can be"measured" kinematically.     

Experimental study of opposite-sign dimuons produced in neutrino and antineutrino interactions

A large sample of opposite-sign dimuons, produced by the interaction of neutrinos and antineutrinos in iron, is analysed. The data agree very well with the hypothesis that the extra muon is the product of charm decay. They yield information on the strength and space-time structure of the charmproducing weak current. The strange-sea structure functionxs(x) is determined. The difference between neutrino and antineutrino dimuon production is analysed to provide a value of the Kobayashi-Maskawa weak mixing angleθ ₂.     

Imprint of non-standard interactions on the CP violation measurements at long baseline experiments

By introducing an additional state feedback into classic Rikitake system, a new hyperchaotic system without equilibrium is derived. The proposed system is investigated through numerical simulations and analyses including time phase portraits, Lyapunov exponents, and Poincaré maps. Based on adaptive control and Lyapunov stability theory, we design a reduced-order projective synchronization scheme for synchronizing the hyperchaotic Rikitake system coexisting without equilibria and the original classic Rikitake system coexisting with two non-hyperbolic equilibria. Finally, numerical simulations are given to illustrate the effectiveness of the proposed synchronization scheme.     

Inclusive study of neutrino and antineutrino interactions with nuclei at energiesE_v^{( - )} \leqq 30 GeV

Neutrino and antineutrino charged current reactions are studied inclusively at energies below 30 GeV using the freon filled bubble chamber SKAT at the Serpukhov accelerator. Data are given for the nucleon structure functions and the differential spectradσ/dy. The results are compared with predictions of the Quark-Parton Model and Quantum Chromodynamics.     

Entropy, baryon asymmetry and dark matter from heavy neutrino decays

The origin of the hot phase of the early universe remains so far an unsolved puzzle. A viable option is entropy production through the decays of heavy Majorana neutrinos whose lifetimes determine the initial temperature. We show that baryogenesis and the production of dark matter are natural by-products of this mechanism. As is well known, the cosmological baryon asymmetry can be accounted for by leptogenesis for characteristic neutrino mass parameters. We find that thermal gravitino production then automatically yields the observed amount of dark matter, for the gravitino as the lightest superparticle and typical gluino masses. As an example, we consider the production of heavy Majorana neutrinos in the course of tachyonic preheating associated with spontaneous B−L breaking. A quantitative analysis leads to constraints on the superparticle masses in terms of neutrino masses: For a light neutrino mass of ¹⁰−5 eV the gravitino mass can be as small as 200 MeV, whereas a lower neutrino mass bound of 0.01 eV implies a lower bound of 9 GeV on the gravitino mass. The measurement of a light neutrino mass of 0.1 eV would rule out heavy neutrino decays as the origin of entropy, visible and dark matter.     

Limits on neutrino-antineutrino transitions from a study of high-energy neutrino interactions

We distinguish electron and positron tracks from ν_e and $\text{ν}{}_{\mathrm{<mtext>e</mtext>}}$ charged-current interactions in a large bubble chamber f ed with a neon-hydrogen mixture. No evidence is seen for an excess of $\text{ν}{}_{\mathrm{<mtext>e</mtext>}}$ interactions from primary $\text{ν}{}_{\mathrm{<mtext>e</mtext>}}$ sources secondary $\text{ν}{}_{\mathrm{\mu }}\text{→}\text{ν}{}_{\mathrm{<mtext>e</mtext>}}\text{or}$$\text{ν}{}_{\mathrm{<mtext>e</mtext>}}\text{→}\text{ν}{}_{\mathrm{<mtext>e</mtext>}}$ oscillations. Upper limits on oscillation parameters, majoron sion and lepton-number violating π and K decays are presented.     

A study of strange particles produced in neutrino neutral current interactions in the NOMAD experiment

Results of a detailed study of strange particle production in neutrino neutral current interactions are presented using the data from the NOMAD experiment. Integral yields of neutral strange particles (, Λ, ) have been measured. Decays of resonances and heavy hyperons with an identified or Λ in the final state have been analyzed. Clear signals corresponding to and Σ(1385)^± have been observed. First results on the measurements of the Λ polarization in neutral current interactions have been obtained.     

Upward muon signals at neutrino detectors as a probe of dark matter properties

We study upward muon flux at neutrino detectors such as Super-Kamiokande resulting from high-energy neutrinos produced by the dark matter annihilation/decay at the Galactic center. In particular, we distinguish showering and non-showering muons as their energy loss processes inside the detector, and show that this information is useful for discriminating dark matter models.     

MiniBooNE and LSND data: non-standard neutrino interactions in a (3+1) scheme versus (3+2) oscillations

Journal of High Energy Physics - We consider the cosmology of a model in which the dark matter is part of a nonminimal hidden sector which is not in thermal equilibrium with the standard model...     

Observation of muon pairs in neutrino interactions at Serpukhov 70 GeV accelarator

A search for dimuons produced in a spark chamber experiment in neutrino and antineutrino beams of the Serpukhov accelerator is reported. The clear dimuon signal has been observed in vN interactions. R_v = N(2ω)/N(1ω)? (6.2 ± 1.7) × 10^?3 in the energy interval 7.5 ÷ 30 GeV. From antineutrino data we conclude that in the same energy range $\text{R}{}_{\mathrm{<mtext>v</mtext>}}\text{? 1.1. × 10}{}^{\mathrm{?2}}\text{(90\% C.L.)}$.