Search results for "neutriino"
showing 10 items of 83 documents
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…
Two-neutrino ββ decay of 136Xe to the first excited 0+ state in 136Ba
2023
We calculate the nuclear matrix element for the two-neutrino $\beta\beta$ decay of $^{136}$Xe into the first excited $0^+$ state of $^{136}$Ba. We use different many-body methods: the quasiparticle random-phase approximation (QRPA) framework, the nuclear shell model, the interacting boson model (IBM-2), and an effective field theory (EFT) for $\beta$ and $\beta\beta$ decays. While the QRPA suggests a decay rate at the edge of current experimental limits, the shell model points to a half-life about two orders of magnitude longer. The predictions of the IBM-2 and the EFT lie in between, and the latter provides systematic uncertainties at leading order. An analysis of the running sum of the nu…
The first large-scale shell-model calculation of the two-neutrino double beta decay of $^{76}$Ge to the excited states in $^{76}$Se
2022
Large-scale shell-model calculations were carried out for the half-lives and branching ratios of the $2\nu\beta\beta$ decay of $^{76}$Ge to the ground state and the lowest three excited states $2_1^+$, $0_2^+$ and $2_2^+$ in $^{76}$Se. In total, the wave functions of more than 10,000 intermediate $1^+$ states in $^{76}$As were calculated in a three-step procedure allowing an efficient use of the available computer resources. In the first step, 250 lowest states, below some 5 MeV of excitation energy, were calculated without truncations within a full major shell $0f_{5/2}-1p-0g_{9/2}$ for both protons and neutrons. The wave functions of the rest of the states, up to some 30 MeV, were compute…
Neutral-current supernova-neutrino cross sections for 204,206,208Pb calculated by Skyrme quasiparticle random-phase approximation
2019
The present work constitutes a detailed study of neutral-current (NC) supernova-neutrino scattering off the stable even-even lead isotopes 204,206,208Pb. This is a continuation of our previous work [Almosly et al., Phys. Rev. C. 94, 044614 (2016)] where we investigated charged-current processes on the same nuclei. As in the previous work, we have adopted the quasiparticle random-phase approximation (QRPA) as the theory framework and use three different Skyrme interactions to build the involved nuclear wave functions. We test the Skyrme forces by computing the location of the lowest-order isovector spin-multipole giant resonances and comparing with earlier calculations. We have computed the …
High-precision electron-capture Q value measurement of 111In for electron-neutrino mass determination
2022
A precise determination of the ground state $^{111}$In ($9/2^+$) electron capture to ground state of $^{111}$Cd ($1/2^+$) $Q$ value has been performed utilizing the double Penning trap mass spectrometer, JYFLTRAP. A value of 857.63(17) keV was obtained, which is nearly a factor of 20 more precise than the value extracted from the Atomic Mass Evaluation 2020 (AME2020). The high-precision electron-capture $Q$ value measurement along with the nuclear energy level data of 866.60(6) keV, 864.8(3) keV, 855.6(10) keV, and 853.94(7) keV for $^{111}$Cd was used to determine whether the four states are energetically allowed for a potential ultra-low $Q$-value $\beta^{}$ decay or electron-capture deca…
Neutrino-nuclear responses for astro-neutrinos, single beta decays and double beta decays
2019
Abstract Neutrino–nuclear responses associated with astro-neutrinos, single beta decays and double beta decays are crucial in studies of neutrino properties of interest for astro-particle physics. The present report reviews briefly recent studies of the neutrino–nuclear responses from both experimental and theoretical points of view in order to obtain a consistent understanding of the many facets of the neutrino–nuclear responses. Subjects discussed in this review include (i) experimental studies of neutrino–nuclear responses by means of single beta decays, charge-exchange nuclear reactions, muon- photon- and neutrino–nuclear reactions, and nucleon-transfer reactions, (ii) implications of a…
Constraining the nonstandard interaction parameters in long baseline neutrino experiments
2016
In this article we investigate the prospects for probing the strength of the possible non-standard neutrino interactions (NSI) in long baseline neutrino oscillation experiments. We find that these experiments are sensitive to NSI couplings down to the level of 0.01-0.1 depending on the oscillation channel and the baseline length, as well as on the detector's fiducial mass. We also investigate the interference of the leptonic CP angle $\delta_{CP}$ with the constraining of the NSI couplings. It is found that the interference is strong in the case of the $\nu_{e}\leftrightarrow\nu_{\mu}$ and $\nu_{e}\leftrightarrow\nu_{\tau}$ transitions but not significant in other transitions. In our numeri…
Effects of triplet Higgs bosons in long baseline neutrino experiments
2018
The triplet scalars $(\Delta=\Delta^{++},\Delta^{+},\Delta^{0})$, utilized in the so-called Type-II seesaw model to explain the lightness of neutrinos, would generate nonstandard interactions (NSI) for neutrino propagating in matter. We investigate the prospects to probe these interactions in long baseline neutrino oscillation experiments. We analyze the upper bounds that the proposed DUNE experiment might set on the nonstandard parameters and numerically derive upper bounds, as function of the lightest neutrino mass, on the ratio the mass $M_\Delta$ of the triplet scalars and strength $|\lambda_\phi|$ of the coupling $\phi\phi\Delta$ of the triplet $\Delta$ and conventional Higgs doublet $…
Potential for a precision measurement of solar pp neutrinos in the Serappis experiment
2022
The European physical journal / C 82(9), 779 (2022). doi:10.1140/epjc/s10052-022-10725-y
Theia: an advanced optical neutrino detector
2020
The European physical journal. C, Particles and fields 80(5), 416 (2020). doi:10.1140/epjc/s10052-020-7977-8