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Sample records for neutrino matter oscillation

  1. Matter effects on neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Mocioiu, Irina; Shrock, Robert

    2000-12-01

    We calculate matter effects on neutrino oscillations in long baseline experiments, using actual density profiles in the Earth. We study the dependence of the signal on E/Δmatm2, the angles in the leptonic mixing matrix and the influence of Δmsol2 and CP phase on the oscillations. The results show quantitatively how matter effects can cause significant changes in the oscillation probabilities. These effects can be useful in amplifying certain neutrino oscillation signals and helping one to obtain measurements of mixing parameters and the magnitude and sign of Δmatm2.

  2. Matter Effects On Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Gordon, Michael

    An introduction to neutrino oscillations in vacuum is presented, followed by a survey of various techniques for obtaining either exact or approximate expressions for numu → nue oscillations in matter. The method developed by Arafune, Koike, and Sato uses a perturbative analysis to find an approximation for the evolution operator. The method used by Freund yields an approximate oscillation probability by diagonalizing the Hamiltonian, finding the eigenvalues and eigenvectors, and then using those to find modified mixing angles with the matter effect taken into account. The method devised by Mann, Kafka, Schneps, and Altinok produces an exact expression for the oscillation by determining explicitly the evolution operator. These methods are compared to each other using the T2K, MINOS, NOnuA, and LBNE parameters.

  3. Neutrino Oscillations in Dense Matter

    NASA Astrophysics Data System (ADS)

    Lobanov, A. E.

    2017-03-01

    A modification of the electroweak theory, where the fermions with the same electroweak quantum numbers are combined in multiplets and are treated as different quantum states of a single particle, is proposed. In this model, mixing and oscillations of particles arise as a direct consequence of the general principles of quantum field theory. The developed approach enables one to calculate the probabilities of the processes taking place in the detector at long distances from the particle source. Calculations of higher-order processes, including computation of the contributions due to radiative corrections, can be performed in the framework of the perturbation theory using the regular diagram technique. As a result, the analog to the Dirac-Schwinger equation of quantum electrodynamics describing neutrino oscillations and its spin rotation in dense matter can be obtained.

  4. Nonadiabatic three-neutrino oscillations in matter

    SciTech Connect

    DOlivo, J.C.; Oteo, J.A.

    1996-07-01

    Oscillations of three neutrinos in matter are analyzed by using the Magnus expansion for the time-evolution operator. We derive a simple expression for the electron-neutrino survival probability which is applied to the examination of the effect of a third neutrino on the nonadiabatic flavor transformations. {copyright} {ital 1996 The American Physical Society.}

  5. Resonant oscillations of massless neutrinos in matter

    NASA Astrophysics Data System (ADS)

    Valle, J. W. F.

    1987-12-01

    Oscillations of neutrinos propagating in matter do not require that neutrinos are massive, at a fundamental level. Even if neutrinos are massless as a consequence of an exact symmetry - such as total lepton number - they can oscillate into one another if the weak interaction has a small non-universal component, whose existence would signal physics beyond the standard model. The experimental constraints and theoretical plausibility of the mechanism are discussed. Coherent neutrino and antineutrino scattering could substantially affect the late thermal phase neutrino signal from a supernova explosion. I am thankful to Peter Rosen and Lincoln Wolfenstein, organizers of the Workshop on Solar and Astrophysical neutrinos, for the hospitality extended to me Aspen, where this work was partially done. I am also sincerely indebted to Sergey Petcov for help in deriving the evolution equation, Joe Schechter and Lincoln Wolfenstein for valuable discussions and to James Wilson and George Fuller for discussions on the Dynamics of supernovae.

  6. Neutrino oscillations in structured matter

    NASA Astrophysics Data System (ADS)

    Fishbane, Paul M.

    2000-11-01

    A layered material structure in a monochromatic neutrino beam produces interference effects that could be used for the measurement of features of the neutrino mass matrix. The phenomenon would be most useful at high energies.

  7. Describing oscillations of high energy neutrinos in matter precisely.

    PubMed

    Akhmedov, E K H; Maltoni, M; Smirnov, A Y U

    2005-11-18

    We present a formalism for precise description of oscillation phenomena in matter at high energies or high densities, V > Delta m(2)/2E, where V is the matter-induced potential of neutrinos. The accuracy of the approximation is determined by the quantity, where is the mixing angle in matter and is a typical change of the potential over the oscillation length (). We derive simple and physically transparent formulas for the oscillation probabilities, which are valid for arbitrary matter density profiles. They can be applied to oscillations of high-energy accelerator, atmospheric, and cosmic neutrinos in the matter of the Earth, substantially simplifying numerical calculations and providing an insight into the physics of neutrino oscillations in matter. The effect of parametric enhancement of the oscillations of high-energy neutrinos is considered.

  8. Earth matter effect on active-sterile neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Acero, Mario A.; Aguilar-Arevalo, Alexis A.; D'Olivo, J. C.

    2011-08-01

    Oscillations between active and sterile neutrinos remain as an open possibility to explain some experimental observations. In a four-neutrino mixing scheme, we use the Magnus expansion of the evolution operator to study the evolution of neutrino flavor amplitudes within the Earth. We apply this formalism to calculate the transition probabilities from active to sterile neutrinos taking into account the matter effect for a varying terrestrial density.

  9. Obtaining supernova directional information using the neutrino matter oscillation pattern

    SciTech Connect

    Scholberg, Kate; Wendell, Roger; Burgmeier, Armin

    2010-02-15

    A nearby core collapse supernova will produce a burst of neutrinos in several detectors worldwide. With reasonably high probability, the Earth will shadow the neutrino flux in one or more detectors. In such a case, for allowed oscillation parameter scenarios, the observed neutrino energy spectrum will bear the signature of oscillations in Earth matter. Because the frequency of the oscillations in energy depends on the path length traveled by the neutrinos in the Earth, an observed spectrum also contains information about the direction to the supernova. We explore here the possibility of constraining the supernova location using matter oscillation patterns observed in a detector. Good energy resolution (typical of scintillator detectors), well-known oscillation parameters, and optimistically large (but conceivable) statistics are required. Pointing by this method can be significantly improved using multiple detectors located around the globe. Although it is not competitive with neutrino-electron elastic scattering-based pointing with water Cherenkov detectors, the technique could still be useful.

  10. Describing Oscillations of High Energy Neutrinos in Matter Precisely

    SciTech Connect

    Akhmedov, E.Kh.; Maltoni, M.; Smirnov, A.Yu.

    2005-11-18

    We present a formalism for precise description of oscillation phenomena in matter at high energies or high densities, V>{delta}m{sup 2}/2E, where V is the matter-induced potential of neutrinos. The accuracy of the approximation is determined by the quantity sin{sup 2}2{theta}{sub m}{delta}V/2{pi}V, where {theta}{sub m} is the mixing angle in matter and {delta}V is a typical change of the potential over the oscillation length (l{approx}2{pi}/V). We derive simple and physically transparent formulas for the oscillation probabilities, which are valid for arbitrary matter density profiles. They can be applied to oscillations of high-energy (E>10 GeV) accelerator, atmospheric, and cosmic neutrinos in the matter of the Earth, substantially simplifying numerical calculations and providing an insight into the physics of neutrino oscillations in matter. The effect of parametric enhancement of the oscillations of high-energy neutrinos is considered.

  11. Compact perturbative expressions for neutrino oscillations in matter

    SciTech Connect

    Denton, Peter B.; Minakata, Hisakazu; Parke, Stephen J.

    2016-06-08

    We further develop and extend a recent perturbative framework for neutrino oscillations in uniform matter density so that the resulting oscillation probabilities are accurate for the complete matter potential versus baseline divided by neutrino energy plane. This extension also gives the exact oscillation probabilities in vacuum for all values of baseline divided by neutrino energy. The expansion parameter used is related to the ratio of the solar to the atmospheric $\\Delta m^2$ scales but with a unique choice of the atmospheric $\\Delta m^2$ such that certain first-order effects are taken into account in the zeroth-order Hamiltonian. Using a mixing matrix formulation, this framework has the exceptional feature that the neutrino oscillation probability in matter has the same structure as in vacuum, to all orders in the expansion parameter. It also contains all orders in the matter potential and $\\sin\\theta_{13}$. It facilitates immediate physical interpretation of the analytic results, and makes the expressions for the neutrino oscillation probabilities extremely compact and very accurate even at zeroth order in our perturbative expansion. Furthermore, the first and second order results are also given which improve the precision by approximately two or more orders of magnitude per perturbative order.

  12. Compact perturbative expressions for neutrino oscillations in matter

    DOE PAGES

    Denton, Peter B.; Minakata, Hisakazu; Parke, Stephen J.

    2016-06-08

    We further develop and extend a recent perturbative framework for neutrino oscillations in uniform matter density so that the resulting oscillation probabilities are accurate for the complete matter potential versus baseline divided by neutrino energy plane. This extension also gives the exact oscillation probabilities in vacuum for all values of baseline divided by neutrino energy. The expansion parameter used is related to the ratio of the solar to the atmosphericmore » $$\\Delta m^2$$ scales but with a unique choice of the atmospheric $$\\Delta m^2$$ such that certain first-order effects are taken into account in the zeroth-order Hamiltonian. Using a mixing matrix formulation, this framework has the exceptional feature that the neutrino oscillation probability in matter has the same structure as in vacuum, to all orders in the expansion parameter. It also contains all orders in the matter potential and $$\\sin\\theta_{13}$$. It facilitates immediate physical interpretation of the analytic results, and makes the expressions for the neutrino oscillation probabilities extremely compact and very accurate even at zeroth order in our perturbative expansion. Furthermore, the first and second order results are also given which improve the precision by approximately two or more orders of magnitude per perturbative order.« less

  13. Exact solutions for matter-enhanced neutrino oscillations

    SciTech Connect

    Balantekin, A.B. ||

    1998-07-01

    The analogy between supersymmetric quantum mechanics and matter-enhanced neutrino oscillations is exploited to obtain exact solutions for a class of electron density profiles. This integrability condition is analogous to shape invariance in supersymmetric quantum mechanics. This method seems to be the most direct way to obtain the exact survival probabilities for a number of density profiles of interest, such as linear and exponential density profiles. The resulting neutrino amplitudes can also be utilized as comparison amplitudes for the uniform semiclassical treatment of neutrino propagation in arbitrary electron density profiles. {copyright} {ital 1998} {ital The American Physical Society}

  14. Implications of fermionic dark matter on recent neutrino oscillation data

    NASA Astrophysics Data System (ADS)

    Singirala, Shivaramakrishna

    2017-04-01

    We investigate flavor phenomenology and dark matter in the context of the scotogenic model. In this model, the neutrino masses are generated through radiative corrections at the one-loop level. Considering the neutrino mixing matrix to be of tri-bimaximal form with additional perturbations to accommodate the recently observed non-zero value of the reactor mixing angle θ 13, we obtain the relation between various neutrino oscillation parameters and the model parameters. Working in a degenerate heavy neutrino mass spectrum, we obtain light neutrino masses obeying the normal hierarchy and also study the relic abundance of fermionic dark matter candidates, including coannihilation effects. A viable parameter space is thus obtained, consistent with neutrino oscillation data, relic abundance and various lepton flavor violating decays such as l α →l βγ and l α →3l β . I would like to thank Rukmani Mohanta for helpful suggestions. This work is supported by DST-Inspire Fellowship division - IF130927

  15. Simple and compact expressions for neutrino oscillation probabilities in matter

    SciTech Connect

    Minakata, Hisakazu; Parke, Stephen J.

    2016-01-29

    We reformulate perturbation theory for neutrino oscillations in matter with an expansion parameter related to the ratio of the solar to the atmospheric Δm2 scales. Unlike previous works, use a renormalized basis in which certain first-order effects are taken into account in the zeroth-order Hamiltonian. Using this perturbation theory we derive extremely compact expressions for the neutrino oscillations probabilities in matter. We find, for example, that the νe disappearance probability at this order is of a simple two flavor form with an appropriately identified mixing angle and Δm2. Furthermore, despite exceptional simplicity in their forms they accommodate all order effects θ13 and the matter potential.

  16. Simple and compact expressions for neutrino oscillation probabilities in matter

    DOE PAGES

    Minakata, Hisakazu; Parke, Stephen J.

    2016-01-29

    We reformulate perturbation theory for neutrino oscillations in matter with an expansion parameter related to the ratio of the solar to the atmospheric Δm2 scales. Unlike previous works, use a renormalized basis in which certain first-order effects are taken into account in the zeroth-order Hamiltonian. Using this perturbation theory we derive extremely compact expressions for the neutrino oscillations probabilities in matter. We find, for example, that the νe disappearance probability at this order is of a simple two flavor form with an appropriately identified mixing angle and Δm2. Furthermore, despite exceptional simplicity in their forms they accommodate all order effectsmore » θ13 and the matter potential.« less

  17. First Indication of Terrestrial Matter Effects on Solar Neutrino Oscillation

    NASA Astrophysics Data System (ADS)

    Renshaw, A.; Abe, K.; Hayato, Y.; Iyogi, K.; Kameda, J.; Kishimoto, Y.; Miura, M.; Moriyama, S.; Nakahata, M.; Nakano, Y.; Nakayama, S.; Sekiya, H.; Shiozawa, M.; Suzuki, Y.; Takeda, A.; Takenaga, Y.; Tomura, T.; Ueno, K.; Yokozawa, T.; Wendell, R. A.; Irvine, T.; Kajita, T.; Kaneyuki, K.; Lee, K. P.; Nishimura, Y.; Okumura, K.; McLachlan, T.; Labarga, L.; Berkman, S.; Tanaka, H. A.; Tobayama, S.; Kearns, E.; Raaf, J. L.; Stone, J. L.; Sulak, L. R.; Goldhabar, M.; Bays, K.; Carminati, G.; Kropp, W. R.; Mine, S.; Smy, M. B.; Sobel, H. W.; Ganezer, K. S.; Hill, J.; Keig, W. E.; Hong, N.; Kim, J. Y.; Lim, I. T.; Akiri, T.; Himmel, A.; Scholberg, K.; Walter, C. W.; Wongjirad, T.; Ishizuka, T.; Tasaka, S.; Jang, J. S.; Learned, J. G.; Matsuno, S.; Smith, S. N.; Hasegawa, T.; Ishida, T.; Ishii, T.; Kobayashi, T.; Nakadaira, T.; Nakamura, K.; Oyama, Y.; Sakashita, K.; Sekiguchi, T.; Tsukamoto, T.; Suzuki, A. T.; Takeuchi, Y.; Bronner, C.; Hirota, S.; Huang, K.; Ieki, K.; Ikeda, M.; Kikawa, T.; Minamino, A.; Nakaya, T.; Suzuki, K.; Takahashi, S.; Fukuda, Y.; Choi, K.; Itow, Y.; Mitsuka, G.; Mijakowski, P.; Hignight, J.; Imber, J.; Jung, C. K.; Yanagisawa, C.; Ishino, H.; Kibayashi, A.; Koshio, Y.; Mori, T.; Sakuda, M.; Yano, T.; Kuno, Y.; Tacik, R.; Kim, S. B.; Okazawa, H.; Choi, Y.; Nishijima, K.; Koshiba, M.; Totsuka, Y.; Yokoyama, M.; Martens, K.; Marti, Ll.; Vagins, M. R.; Martin, J. F.; de Perio, P.; Konaka, A.; Wilking, M. J.; Chen, S.; Zhang, Y.; Wilkes, R. J.; Super-Kamiokande Collaboration

    2014-03-01

    We report an indication that the elastic scattering rate of solar B8 neutrinos with electrons in the Super-Kamiokande detector is larger when the neutrinos pass through Earth during nighttime. We determine the day-night asymmetry, defined as the difference of the average day rate and average night rate divided by the average of those two rates, to be [-3.2±1.1(stat)±0.5(syst)]%, which deviates from zero by 2.7σ. Since the elastic scattering process is mostly sensitive to electron-flavored solar neutrinos, a nonzero day-night asymmetry implies that the flavor oscillations of solar neutrinos are affected by the presence of matter within the neutrinos' flight path. Super-Kamiokande's day-night asymmetry is consistent with neutrino oscillations for 4×10-5 eV2≤Δm212≤7×10-5 eV2 and large mixing values of θ12, at the 68% C.L.

  18. Efficient numerical integration of neutrino oscillations in matter

    NASA Astrophysics Data System (ADS)

    Casas, F.; D'Olivo, J. C.; Oteo, J. A.

    2016-12-01

    A special purpose solver, based on the Magnus expansion, well suited for the integration of the linear three neutrino oscillations equations in matter is proposed. The computations are speeded up to two orders of magnitude with respect to a general numerical integrator, a fact that could smooth the way for massive numerical integration concomitant with experimental data analyses. Detailed illustrations about numerical procedure and computer time costs are provided.

  19. Describing neutrino oscillations in matter with Magnus expansion

    NASA Astrophysics Data System (ADS)

    Ioannisian, A. N.; Smirnov, A. Yu.

    2009-07-01

    We present new formalism for description of the neutrino oscillations in matter with varying density. The formalism is based on the Magnus expansion and has a virtue that the unitarity of the S-matrix is maintained in each order of perturbation theory. We show that the Magnus expansion provides better convergence of series: the restoration of unitarity leads to smaller deviations from the exact results especially in the regions of large transition probabilities. Various expansions are obtained depending on a basis of neutrino states and a way one splits the Hamiltonian into the self-commuting and non-commuting parts. In particular, we develop the Magnus expansion for the adiabatic perturbation theory which gives the best approximation. We apply the formalism to the neutrino oscillations in matter of the Earth and show that for the solar oscillation parameters the second order Magnus adiabatic expansion has better than 1% accuracy for all energies and trajectories. For the atmospheric Δm and small 1-3 mixing the approximation works well (<3% accuracy for sinθ=0.01) outside the resonance region 2.7-8 GeV.

  20. Matter Effects on Neutrino Oscillations in Different Supernova Models

    NASA Astrophysics Data System (ADS)

    Xu, Jing; Hu, Li-Jun; Li, Rui-Cheng; Guo, Xin-Heng; Young, Bing-Lin

    2016-04-01

    In recent years, with the development of simulations about supernova explosion, we have a better understanding about the density profiles and the shock waves in supernovae than before. There might be a reverse shock wave, another sudden change of density except the forward shock wave, or even no shock wave, emerging in the supernova. Instead of using the expression of the crossing probability at the high resonance, PH, we have studied the matter effects on neutrino oscillations in different supernova models. In detail, we have calculated the survival probability of ve (Ps) and the conversion probability of vx (Pc) in the Schrödinger equation within a simplified two-flavor framework for a certain case, in which the neutrino transfers through the supernova matter from an initial flavor eigenstate located at the core of the supernova. Our calculations was based on the data of density in three different supernova models obtained from simulations. In our work, we do not steepen the density gradient around the border of the shock wave, which differs to what was done in most of the other simulations. It is found that the mass and the density distribution of the supernova do make a difference on the behavior of Ps and Pc. With the results of Ps and Pc, we can estimate the number of ve (and vx) remained in the beam after they go through the matter in the supernova. Supported by National Science Foundation of China under Grant Nos. 11175020 and 11275025

  1. Neutrino Oscillations as a Probe of Light Scalar Dark Matter.

    PubMed

    Berlin, Asher

    2016-12-02

    We consider a class of models involving interactions between ultralight scalar dark matter and standard model neutrinos. Such couplings modify the neutrino mass splittings and mixing angles to include additional components that vary in time periodically with a frequency and amplitude set by the mass and energy density of the dark matter. Null results from recent searches for anomalous periodicities in the solar neutrino flux strongly constrain the dark matter-neutrino coupling to be orders of magnitude below current and projected limits derived from observations of the cosmic microwave background.

  2. Neutrino Oscillations as a Probe of Light Scalar Dark Matter

    NASA Astrophysics Data System (ADS)

    Berlin, Asher

    2016-12-01

    We consider a class of models involving interactions between ultralight scalar dark matter and standard model neutrinos. Such couplings modify the neutrino mass splittings and mixing angles to include additional components that vary in time periodically with a frequency and amplitude set by the mass and energy density of the dark matter. Null results from recent searches for anomalous periodicities in the solar neutrino flux strongly constrain the dark matter-neutrino coupling to be orders of magnitude below current and projected limits derived from observations of the cosmic microwave background.

  3. Analyses of Resonances in 4- and 5-Neutrino Oscillations in Matter

    NASA Astrophysics Data System (ADS)

    Kamo, Y.; Yajima, S.; Higashida, Y.; Kubota, S.; Tokuo, S.; Fukuda, M.

    2007-04-01

    We analytically investigate the resonance conditions among n neutrinos in matter with the discriminant for the characteristic equation of the effective Hamiltonian. This discriminant is expressed in terms of the coefficients of the characteristic equation, without solving this equation. The graphical representation of the discriminant reveals the matter densities where resonance occurs. We apply the discriminant for n neutrino oscillation to the cases of 4- and 5-neutrino oscillation.

  4. First Direct Evidence for Matter Enhanced Neutrino Oscillation, Using Super-Kamiokande Solar Neutrino Data

    NASA Astrophysics Data System (ADS)

    Renshaw, Andrew Lee

    Super-Kamiokande-IV has proven to be the largest and most precise SK data set yet. The data from this fourth phase of SK are combined with data from the previous three phases to give an extracted solar neutrino flux between 4.0 and 19.5 MeV (recoil electron kinetic energy) as (2.37+/-0.015(stat.)+/-0.04(syst.)) x 106cm-2sec-1. The SK combined recoil electron energy spectrum slightly favors a distorted shape over a flat shape. Comparing the day and night solar neutrino interactions rates separately, SK measures the day/night asymmetry as (-4.2+/-1.2+/-0.8)%. A maximum likelihood fit to the amplitude of the expected solar zenith angle variation of the neutrino-electron elastic scattering rate in SK, results in a day/night asymmetry of (-3.2+/-1.1+/-0.5)%. These results give 2.8 and 2.7 sigma significance for a non-zero day/night asymmetry. This is not only the first evidence for the regeneration of electron type solar neutrinos as they travel through Earth's matter, but the first direct evidence for matter enhanced neutrino oscillation of any kind. SK solar neutrino data measures the solar mixing angle as sin2theta12 = 0.341+0.029/-0.025, and the solar neutrino mass squared splitting as Deltam2/21=(4.8 +1.8/-0.9) x 10-5 eV2. When these results are combined with data from other solar neutrino experiments and the KamLAND experiment, sin2theta12 = 0.304+/-0.013 and Deltam2/21 = (7.45 +0.20/-0.19) x 10-5 eV2 give the most precise measurements to date.

  5. Neutrino magnetic moment, CP violation, and flavor oscillations in matter

    NASA Astrophysics Data System (ADS)

    Pehlivan, Y.; Balantekin, A. B.; Kajino, Toshitaka

    2014-09-01

    We consider collective oscillations of neutrinos, which are emergent nonlinear flavor evolution phenomena instigated by neutrino-neutrino interactions in astrophysical environments with sufficiently high neutrino densities. We investigate the symmetries of the problem in the full three-flavor mixing scheme and in the exact many-body formulation by including the effects of CP violation and the neutrino magnetic moment. We show that, similar to the two-flavor scheme, several dynamical symmetries exist for three flavors in the single-angle approximation if the net electron background in the environment and the effects of the neutrino magnetic moment are negligible. Moreover, we show that these dynamical symmetries are present even when the CP symmetry is violated in neutrino oscillations. We explicitly write down the constants of motion through which these dynamical symmetries manifest themselves in terms of the generators of the SU(3) flavor transformations. We also show that the effects due to the CP-violating Dirac phase factor out of the many-body evolution operator and evolve independently of nonlinear flavor transformations if neutrino electromagnetic interactions are ignored. In the presence of a strong magnetic field, CP-violating effects can still be considered independently provided that an effective definition for the neutrino magnetic moment is used.

  6. Solar neutrino oscillations

    SciTech Connect

    Haxton, W.C.

    1993-12-31

    The special properties of solar neutrinos that render this flux so uniquely important in searches for neutrino masses and flavor mixing are reviewed. The effects of matter, including density fluctuations and turbulence, on solar neutrino oscillations are explained through analogies with more familiar atomic physics phenomena.

  7. Matter enhancement of T violation in neutrino oscillation

    NASA Astrophysics Data System (ADS)

    Yokomakura, H.; Kimura, K.; Takamura, A.

    2000-12-01

    We study the matter enhancement of T violation in neutrino oscillation with three generations. The magnitude of T violation is proportional to Jarlskog factor /J. Recently, the elegant relation, (Δm)12(Δm)23(Δm)31Jm=Δ12Δ23Δ31J, was derived, where Δij=Δm2ij/(2E) and subscript /m implies the quantities in matter. Using this relation, we reconsider how Jm changes as a function of the matter potential /a under the approximation Δm212<<Δm213. We show that the number of maxima for Jm depends on the magnitude of sin22θ13 and there are two maxima considering the constraint on sin22θ13 from the CHOOZ experiment. One maximum of Jm at a=O(Δ12) is given by J/sin2θ12, which leads to the large enhancement of Jm in the case of the SMA MSW solution. The other maximum at a=O(Δ13) is Δ12/Δ13J/ sin2θ13, and the enhancement is possible, if sin2θ13 is small enough. These maximal values are consistent with the results obtained by other methods.

  8. CP violation and matter effect in long baseline neutrino oscillation experiments

    SciTech Connect

    Arafune, J.; Koike, M.; Sato, J.

    1997-09-01

    We show simple methods of how to separate pure CP-violating effects from matter effects in long baseline neutrino oscillation experiments with three generations of neutrinos. We give compact formulas for neutrino oscillation probabilities assuming one of the three neutrino masses (presumably {nu}{sub {tau}} mass) to be much larger than the other masses and the effective mass due to the matter effect. Two methods are shown. One is to observe envelopes of the curves of oscillation probabilities as functions of neutrino energy; a merit of this method is that only a single detector is enough to determine the presence of CP violation. The other is to compare experiments with at least two different baseline lengths; this has the merit that it needs only a narrow energy range of oscillation data. {copyright} {ital 1997} {ital The American Physical Society}

  9. Solar atmosphere neutrino oscillations

    SciTech Connect

    Fogli, G.L.; Lisi, E.; Mirizzi, A.; Montanino, D.; Serpico, P.D.; /Fermilab

    2007-02-01

    The Sun is a source of high energy neutrinos (E > 10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations on the solar atmosphere neutrino fluxes observable at Earth. We find that peculiar matter oscillation effects in the Sun do exist, but are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged ''vacuum'' oscillations, dominated by a single mixing parameter (the angle {theta}{sub 23}).

  10. Neutrino Oscillations with Reactor Neutrinos

    NASA Astrophysics Data System (ADS)

    Cabrera, Anatael

    2007-06-01

    Prospect measurements of neutrino oscillations with reactor neutrinos are reviewed in this document. The following items are described: neutrinos oscillations status, reactor neutrino experimental strategy, impact of uncertainties on the neutrino oscillation sensitivity and, finally, the experiments in the field. This is the synthesis of the talk delivered during the NOW2006 conference at Otranto (Italy) during September 2006.

  11. A New Neutrino Oscillation

    SciTech Connect

    Parke, Stephen J.; /Fermilab

    2011-07-01

    Starting in the late 1960s, neutrino detectors began to see signs that neutrinos, now known to come in the flavors electron ({nu}{sub e}), muon ({nu}{sub {mu}}), and tau ({nu}{sub {tau}}), could transform from one flavor to another. The findings implied that neutrinos must have mass, since massless particles travel at the speed of light and their clocks, so to speak, don't tick, thus they cannot change. What has since been discovered is that neutrinos oscillate at two distinct scales, 500 km/GeV and 15,000 km/GeV, which are defined by the baseline (L) of the experiment (the distance the neutrino travels) divided by the neutrino energy (E). Neutrinos of one flavor can oscillate into neutrinos of another flavor at both L/E scales, but the amplitude of these oscillations is different for the two scales and depends on the initial and final flavor of the neutrinos. The neutrino states that propogate unchanged in time, the mass eigenstates {nu}1, {nu}2, {nu}3, are quantum mechanical mixtures of the electron, muon, and tau neutrino flavors, and the fraction of each flavor in a given mass eigenstate is controlled by three mixing angles and a complex phase. Two of these mixing angles are known with reasonable precision. An upper bound exists for the third angle, called {theta}{sub 13}, which controls the size of the muon neutrino to electron neutrino oscillation at an L/E of 500 km/GeV. The phase is completely unknown. The existence of this phase has important implications for the asymmetry between matter and antimatter we observe in the universe today. Experiments around the world have steadily assembled this picture of neutrino oscillation, but evidence of muon neutrino to electron neutrino oscillation at 500 km/GeV has remained elusive. Now, a paper from the T2K (Tokai to Kamioka) experiment in Japan, reports the first possible observation of muon neutrinos oscillating into electron neutrinos at 500 km/GeV. They see 6 candidate signal events, above an expected background

  12. Connecting radiative neutrino mass, neutron-antineutron oscillation, proton decay, and leptogenesis through dark matter

    NASA Astrophysics Data System (ADS)

    Gu, Pei-Hong; Ma, Ernest; Sarkar, Utpal

    2016-12-01

    The scotogenic mechanism for radiative neutrino mass is generalized to include neutron-antineutron oscillation as well as proton decay. Dark matter is stabilized by extending the notion of lepton parity to matter parity. Leptogenesis is also a possible byproduct. This framework unifies the description of all these important topics in physics beyond the standard model of particle interactions.

  13. Looking into analytical approximations for three-flavor neutrino oscillation probabilities in matter

    NASA Astrophysics Data System (ADS)

    Li, Yu-Feng; Zhang, Jue; Zhou, Shun; Zhu, Jing-yu

    2016-12-01

    Motivated by tremendous progress in neutrino oscillation experiments, we derive a new set of simple and compact formulas for three-flavor neutrino oscillation probabilities in matter of a constant density. A useful definition of the η-gauge neutrino mass-squared difference Δ∗ ≡ ηΔ31 + (1 - η)Δ32 is introduced, where Δ ji ≡ m j 2 - m i 2 for ji = 21 , 31 , 32 are the ordinary neutrino mass-squared differences and 0 ≤ η ≤ 1 is a real and positive parameter. Expanding neutrino oscillation probabilities in terms of α ≡ Δ21 /Δ∗, we demonstrate that the analytical formulas can be remarkably simplified for η = cos2 θ 12, with θ 12 being the solar mixing angle. As a by-product, the mapping from neutrino oscillation parameters in vacuum to their counterparts in matter is obtained at the order of O({α}^2) . Finally, we show that our approximate formulas are not only valid for an arbitrary neutrino energy and any baseline length, but also still maintaining a high level of accuracy.

  14. Implications of Neutrino Oscillations on the Dark-Matter World

    NASA Astrophysics Data System (ADS)

    Hwang, W.-Y. Pauchy

    2014-01-01

    According to my own belief that "The God wouldn't create a world that is so boring that a particle knows only the very feeble weak interaction.", maybe we underestimate the roles of neutrinos. We note that right-handed neutrinos play no roles, or don't exist, in the minimal Standard Model. We discuss the language to write down an extended Standard Model - using renormalizable quantum field theory as the language; to start with a certain set of basic units under a certain gauge group; in fact, to use the three right-handed neutrinos to initiate the family gauge group SUf (3). Specifically we use the left-handed and right-handed spinors to form the basic units together with SUc (3) × SUL (2) × U (1) × SUf (3) as the gauge group. The dark-matter SUf (3) world couples with the lepton world, but not with the quark world. Amazingly enough, the space of the Standard-Model Higgs Φ (1 , 2), the family Higgs triplet Φ(3, 1), and the neutral part of the mixed family Higgs Φ0 (3 , 2) undergoes the spontaneous symmetry breaking, i.e. the Standard-Model Higgs mechanism and the "project-out" family Higgs mechanism, to give rise to the weak bosons W± and Z0, one Standard-Model Higgs, the eight massive family gauge bosons, and the remaining four massive neutral family Higgs particles, and nothing more. Thus, the roles of neutrinos in this extended Standard Model are extremely interesting in connection with the dark-matter world.

  15. Quasivacuum solar neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Fogli, G. L.; Lisi, E.; Montanino, D.; Palazzo, A.

    2000-12-01

    We discuss in detail solar neutrino oscillations with δm2/E in the range [10-10,10-7] eV2/MeV. In this range, which interpolates smoothly between the so-called ``just-so'' and ``Mikheyev-Smirnov-Wolfenstein'' oscillation regimes, neutrino flavor transitions are increasingly affected by matter effects as δm2/E increases. As a consequence, the usual vacuum approximation has to be improved through the matter-induced corrections, leading to a ``quasivacuum'' oscillation regime. We perform accurate numerical calculations of such corrections, using both the true solar density profile and its exponential approximation. Matter effects are shown to be somewhat overestimated in the latter case. We also discuss the role of Earth crossing and of energy smearing. Prescriptions are given to implement the leading corrections in the quasivacuum oscillation range. Finally, the results are applied to a global analysis of solar ν data in a three-flavor framework.

  16. Generalized bottom-tau unification, neutrino oscillations and dark matter: Predictions from a lepton quarticity flavor approach

    NASA Astrophysics Data System (ADS)

    Centelles Chuliá, Salvador; Srivastava, Rahul; Valle, José W. F.

    2017-10-01

    We propose an A4 extension of the Standard Model with a Lepton Quarticity symmetry correlating dark matter stability with the Dirac nature of neutrinos. The flavor symmetry predicts (i) a generalized bottom-tau mass relation involving all families, (ii) small neutrino masses are induced a la seesaw, (iii) CP must be significantly violated in neutrino oscillations, (iv) the atmospheric angle θ23 lies in the second octant, and (v) only the normal neutrino mass ordering is realized.

  17. Analytical approximation of the neutrino oscillation matter effects at large θ 13

    NASA Astrophysics Data System (ADS)

    Agarwalla, Sanjib Kumar; Kao, Yee; Takeuchi, Tatsu

    2014-04-01

    We argue that the neutrino oscillation probabilities in matter are best understood by allowing the mixing angles and mass-squared differences in the standard parametrization to `run' with the matter effect parameter a = , where N e is the electron density in matter and E is the neutrino energy. We present simple analytical approximations to these `running' parameters. We show that for the moderately large value of θ 13, as discovered by the reactor experiments, the running of the mixing angle θ 23 and the CP violating phase δ can be neglected. It simplifies the analysis of the resulting expressions for the oscillation probabilities considerably. Approaches which attempt to directly provide approximate analytical expressions for the oscillation probabilities in matter suffer in accuracy due to their reliance on expansion in θ 13, or in simplicity when higher order terms in θ 13 are included. We demonstrate the accuracy of our method by comparing it to the exact numerical result, as well as the direct approximations of Cervera et al., Akhmedov et al., Asano and Minakata, and Freund. We also discuss the utility of our approach in figuring out the required baseline lengths and neutrino energies for the oscillation probabilities to exhibit certain desirable features.

  18. Collective neutrino oscillations and neutrino wave packets

    NASA Astrophysics Data System (ADS)

    Akhmedov, Evgeny; Kopp, Joachim; Lindner, Manfred

    2017-09-01

    Effects of decoherence by wave packet separation on collective neutrino oscillations in dense neutrino gases are considered. We estimate the length of the wave packets of neutrinos produced in core collapse supernovae and the expected neutrino coherence length, and then proceed to consider the decoherence effects within the density matrix formalism of neutrino flavour transitions. First, we demonstrate that for neutrino oscillations in vacuum the decoherence effects are described by a damping term in the equation of motion of the density matrix of a neutrino as a whole (as contrasted to that of the fixed-momentum components of the neutrino density matrix). Next, we consider neutrino oscillations in ordinary matter and dense neutrino backgrounds, both in the adiabatic and non-adiabatic regimes. In the latter case we study two specific models of adiabaticity violation—one with short-term and another with extended non-adiabaticity. It is demonstrated that, while in the adiabatic case a damping term is present in the equation of motion of the neutrino density matrix (just like in the vacuum oscillation case), no such term in general appears in the non-adiabatic regime.

  19. Precise analytical description of the Earth matter effect on oscillations of low energy neutrinos

    SciTech Connect

    Ioannisian, A.N.; Kazarian, N.A.; Smirnov, A.Yu.; Wyler, D.

    2005-02-01

    We present a formalism for the matter effects in the Earth on low energy neutrino fluxes which is both accurate and has all the advantages of a full analytic treatment. The oscillation probabilities are calculated up to the second order term in {epsilon}(x){identical_to}2V(x)E/{delta}m{sup 2}, where V(x) is the neutrino potential at position x. We show the absence of large undamped phases which makes the expansion in {epsilon} well behaved. An improved expansion is presented in terms of the variation of V(x) around a suitable mean value which allows one to treat energies up to those relevant for supernova neutrinos. We discuss also the case of three-neutrino mixing.

  20. Matter oscillations: Neutrino transformation and regeneration in the earth

    SciTech Connect

    Baltz, A.J.; Weneser, J.

    1987-01-01

    Transformation and regeneration phenomena are calculated to result from transmission through the Earth of neutrinos with E(MeV)/..delta..m/sup 2/(eV)/sup 2/ in the vicinity of 10/sup 6/ to 10/sup 7/. As a result, large time-of-night and seasonal variations are predicted for various solar neutrino experiments in this parameter range. Analagous effects are predicted for terrestrial cosmic ray and accelerator experiments.

  1. Berry phase in neutrino oscillations

    SciTech Connect

    He Xiaogang; McKellar, Bruce H.J.; Zhang Yue

    2005-09-01

    We study the Berry phase in neutrino oscillations for both Dirac and Majorana neutrinos. In order to have a Berry phase, the neutrino oscillations must occur in a varying medium, the neutrino-background interactions must depend on at least two independent densities, and also there must be CP violation. If the neutrino interactions with matter are mediated only by the standard model W and Z boson exchanges, these conditions imply that there must be at least three generations of neutrinos. The CP violating Majorana phases do not play a role in generating a Berry phase. We show that a natural way to satisfy the conditions for the generation of a Berry phase is to have sterile neutrinos with active-sterile neutrino mixing, in which case at least two active and one sterile neutrinos are required. If there are additional new CP violating flavor changing interactions, it is also possible to have a nonzero Berry phase with just two generations.

  2. Neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Nakamura, Kenzo

    2000-12-01

    The present status of neutrino oscillation experiments and prospects of forthcoming experiments are reviewed. Particular emphasis is placed on the recent results from Super-Kamiokande atmospheric neutrino and solar neutrino observations. .

  3. Connecting the leptonic unitarity triangle to neutrino oscillation with C P violation in the vacuum and in matter

    NASA Astrophysics Data System (ADS)

    He, Hong-Jian; Xu, Xun-Jie

    2017-02-01

    Leptonic unitarity triangles (LUT) provide fundamental means to geometrically describe C P violation in neutrino oscillation. In this work, we use LUT to present a new geometrical interpretation of the vacuum oscillation probability and derive a compact new oscillation formula in terms of only three independent parameters of the corresponding LUT. Then, we systematically study matter effects in the geometrical formulation of neutrino oscillation with C P violation. Including nontrivial matter effects, we derive a very compact new oscillation formula by using the LUT formulation. We further demonstrate that this geometrical formula holds well for applications to neutrino oscillations in matter, including the long baseline experiments T2K, MINOS, NO ν A , and DUNE.

  4. Matter-Induced Neutrino Oscillation in Double Universal Seesaw Model

    NASA Astrophysics Data System (ADS)

    Sogami, I. S.; Shinohara, T.; Egawa, Y.

    1992-04-01

    The Mikheyev-Smirnov-Wolfenstein effect is investigated in an extended gauge field theory in which the universal seesaw mechanism is applied singly to the charged fermion sectors to lower their masses below the electroweak energy scale and doubly to the neutral fermion sector to make neutrinos superlight. At the first seesaw approximation, neutrinos are proved to have a distinctive spectrum consisting of doubly degenerate states with smaller mass m_{S} and a singlet state with larger mas m_{L}. The lepton mixing matrix is determined definitely in terms of the masses of charged leptons and down quarks, with a very small vacuum mixing angle sin theta = 0.043 +/- 0.004. The Schrödinger-like equation describing the spatial evolution of stationary neutrino flux is solved for globally-rotated-flavor wave functions. Comparison of its nonadiabatic solution with experimental results leads to an estimation m_{L}(2) - m_{S}(2) = (6 +/- 2) x 10(-6) eV(2) for the squared mass difference and a capture rate prediction of 74 +/- 12 SNU for the SAGE gallium experiment.

  5. Symmetric formulation of neutrino oscillations in matter and its intrinsic connection to renormalization-group equations

    NASA Astrophysics Data System (ADS)

    Zhou, Shun

    2017-04-01

    In this article, we point out that the effective Hamiltonian for neutrino oscillations in matter is invariant under the transformation of the mixing angle {θ }12\\to {θ }12-π /2 and the exchange of first two neutrino masses {m}1≤ftrightarrow {m}2, if the standard parametrization of lepton flavor mixing matrix is adopted. To maintain this symmetry in perturbative calculations, we present a symmetric formulation of the effective Hamiltonian by introducing an η-gauge neutrino mass-squared difference {{{Δ }}}* \\equiv η {{{Δ }}}31+(1-η ){{{Δ }}}32 for 0≤slant η ≤slant 1, where {{{Δ }}}{ji}\\equiv {m}j2-{m}i2 for {ji}=21,31,32, and show that only η =1/2, η ={\\cos }2{θ }12 or η ={\\sin }2{θ }12 is allowed. Furthermore, we prove that η ={\\cos }2{θ }12 is the best choice to derive more accurate and compact neutrino oscillation probabilities, by implementing the approach of renromalization-group equations. The validity of this approach becomes transparent when an analogy is made between the parameter η herein and the renormalization scale μ in relativistic quantum field theories.

  6. Oscillations of solar atmosphere neutrinos

    SciTech Connect

    Fogli, G. L.; Lisi, E.; Mirizzi, A.; Montanino, D.; Serpico, P. D.

    2006-11-01

    The Sun is a source of high-energy neutrinos (E(greater-or-similar sign)10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations (in vacuum and in matter) on solar atmosphere neutrinos, and calculate their observable fluxes at Earth, as well as their event rates in a kilometer-scale detector in water or ice. We find that peculiar three-flavor oscillation effects in matter, which can occur in the energy range probed by solar atmosphere neutrinos, are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, we find that the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged vacuum oscillations, dominated by a single mixing parameter (the angle {theta}{sub 23})

  7. Neutrino Oscillation Experiments

    NASA Astrophysics Data System (ADS)

    Scholberg, Kate

    The discovery of neutrino oscillations was recognized by the 2015 Nobel Prize. Tremendous progress has been made in the past two decades on understanding of neutrino mass and mixing properties, yet there are remaining unknowns. This talk presented an overview of neutrino oscillation experiments, with emphasis on recent results from beam and reactor experiments, as well as exciting prospects for the next decades.

  8. Atmospheric Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Giacomelli, G.; Giorgini, M.

    2005-04-01

    The latest results from the Soudan 2, MACRO and SuperKamiokande experiments on atmospheric neutrino oscillations are summarised and discussed. In particular a discussion is made on the Monte Carlo simulations used for the atmospheric neutrino flux.

  9. Semiclassical treatment of matter-enhanced neutrino oscillations for an arbitrary density profile

    SciTech Connect

    Balantekin, A.B.; Beacom, J.F.

    1996-11-01

    The matter-enhanced oscillations of two neutrino flavors are studied using a uniform semiclassical approximation. Unlike some analytic studies which have focused on certain exactly solvable densities, this method can be used for an arbitrary monotonic density profile. The method is applicable to a wider range of mixing parameters than previous approximate methods for arbitrary densities. The approximation is excellent in the adiabatic regime and up to the extreme nonadiabatic limit. In particular, the range of validity for this approximation extends farther into the nonadiabatic regime than for the linear Landau-Zener result. This method also allows calculation of the source- and detector-dependent terms in the unaveraged survival probability, and analytic results for these terms are given. These interference terms may be important in studying neutrino mixing in the Sun or in supernovas. {copyright} {ital 1996 The American Physical Society.}

  10. Atmospheric neutrinos and discovery of neutrino oscillations

    PubMed Central

    Kajita, Takaaki

    2010-01-01

    Neutrino oscillation was discovered through studies of neutrinos produced by cosmic-ray interactions in the atmosphere. These neutrinos are called atmospheric neutrinos. They are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith-angle and energy dependent deficit of muon-neutrino events. Neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. Neutrino oscillations imply that neutrinos have small but non-zero masses. The small neutrino masses have profound implications to our understanding of elementary particle physics and the Universe. This article discusses the experimental discovery of neutrino oscillations. PMID:20431258

  11. Atmospheric neutrinos and discovery of neutrino oscillations.

    PubMed

    Kajita, Takaaki

    2010-01-01

    Neutrino oscillation was discovered through studies of neutrinos produced by cosmic-ray interactions in the atmosphere. These neutrinos are called atmospheric neutrinos. They are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith-angle and energy dependent deficit of muon-neutrino events. Neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. Neutrino oscillations imply that neutrinos have small but non-zero masses. The small neutrino masses have profound implications to our understanding of elementary particle physics and the Universe. This article discusses the experimental discovery of neutrino oscillations.

  12. LSND neutrino oscillation results

    SciTech Connect

    Louis, W.C.

    1996-06-01

    In the past several years, a number of experiments have searched for neutrino oscillations, where a neutrino of one type (say {bar {nu}}{sub {mu}}) spontaneously transforms into a neutrino of another type (say {bar {nu}}{sub e}). For this phenomenon to occur, neutrinos must be massive and the apparent conservation law of lepton families must be violated. In 1995 the LSND experiment published data showing candidate events that are consistent with {bar {nu}}{sub {mu}} oscillations. Additional data are reported here which provide stronger evidence for neutrino oscillations.

  13. Paradoxes of neutrino oscillations

    SciTech Connect

    Akhmedov, E. Kh.; Smirnov, A. Yu.

    2009-08-15

    Despite the theory of neutrino oscillations being rather old, some of its basic issues are still being debated in the literature. We discuss a number of such issues, including the relevance of the 'same energy' and 'same momentum' assumptions, the role of quantum-mechanical uncertainty relations in neutrino oscillations, the dependence of the coherence and localization conditions that ensure the observability of neutrino oscillations on neutrino energy and momentum uncertainties, the question of (in)dependence of the oscillation probabilities on the neutrino production and detection processes, and the applicability limits of the stationary-source approximation. We also develop a novel approach to calculation of the oscillation probability in the wave-packet approach, based on the summation/integration conventions different from the standard one, which allows a new insight into the 'same energy' vs. 'same momentum' problem. We also discuss a number of apparently paradoxical features of the theory of neutrino oscillations.

  14. Neutrino Oscillation Physics

    SciTech Connect

    Kayser, Boris

    2012-06-01

    To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also provide a brief guide to references relevant to topics other than neutrino oscillation that were covered in the lectures. Neutrinos and photons are by far the most abundant elementary particles in the universe. Thus, if we would like to comprehend the universe, we must understand the neutrinos. Of course, studying the neutrinos is challenging, since the only known forces through which these electrically-neutral leptons interact are the weak force and gravity. Consequently, interactions of neutrinos in a detector are very rare events, so that very large detectors and intense neutrino sources are needed to make experiments feasible. Nevertheless, we have confirmed that the weak interactions of neutrinos are correctly described by the Standard Model (SM) of elementary particle physics. Moreover, in the last 14 years, we have discovered that neutrinos have nonzero masses, and that leptons mix. These discoveries have been based on the observation that neutrinos can change from one 'flavor' to another - the phenomenon known as neutrino oscillation. We shall explain the physics of neutrino oscillation, deriving the probability of oscillation in a new way. We shall also provide a very brief guide to references that can be used to study some major neutrino-physics topics other than neutrino oscillation.

  15. Exploration of CPT violation via time-dependent geometric quantities embedded in neutrino oscillation through fluctuating matter

    NASA Astrophysics Data System (ADS)

    Wang, Zisheng; Pan, Hui

    2017-02-01

    We propose a new approach to explore CPT violation of neutrino oscillations through a fluctuating matter based on time-dependent geometric quantities. By mapping the neutrino oscillations onto a Poincaré sphere structure, we obtain an analytic solution of master equation and further define the geometric quantities, i.e., radius of Poincaré sphere and geometric phase. We find that the mixing process between electron and muon neutrinos can be described by the radius of Poincaré sphere that depends on the intrinsic CP-violating angle. Such a radius reveals a dynamic mechanism of CPT-violation, i.e., both spontaneous symmetry breaking and Majorana-Dirac neutrino confusion. We show that the time-dependent geometric phase can be used to find the neutrino nature and observe the CPT-violation because it is strongly enhanced under the neutrino propagation. We further show that the time-dependent geometric phase can be easily detected by simulating the neutrino oscillation based on fluctuating magnetic fields in nuclear magnetic resonance, which makes the experimental observation of CPT-violation possible in the neutrino mixing and oscillations.

  16. Magnus approximation in neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Acero, Mario A.; Aguilar-Arevalo, Alexis A.; D'Olivo, J. C.

    2011-04-01

    Oscillations between active and sterile neutrinos remain as an open possibility to explain some anomalous experimental observations. In a four-neutrino (three active plus one sterile) mixing scheme, we use the Magnus expansion of the evolution operator to study the evolution of neutrino flavor amplitudes within the Earth. We apply this formalism to calculate the transition probabilities from active to sterile neutrinos with energies of the order of a few GeV, taking into account the matter effect for a varying terrestrial density.

  17. Neutrino Mixing in Matter at Extreme High Energy

    NASA Astrophysics Data System (ADS)

    Koranga, Bipin Singh

    2017-08-01

    We have studied neutrino mixing at extreme high energy considering two flavour framework with matter effects. We analyze the atmospheric neutrino data within the simplest scheme of two neutrino oscillation. We consider as special case of matter density profile, which are relevant for neutrino oscillations. In particular, we compute to constrain a specific from of neutrino mass square difference and mixing in extreme high energy in matter. The dispersion relation for the neutrino mixing in neutrino oscillation in matter are discussed.

  18. Collective neutrino oscillations in turbulent backgrounds

    SciTech Connect

    Reid, Giles; Adams, Jenni; Seunarine, Suruj

    2011-10-15

    Using a Kolmogorov turbulence model, we investigate the effects of fluctuations in matter and neutrino density in the region near a supernova core on the flavor oscillations of neutrinos emitted in the core collapse in a single-angle, two-flavor approximation. Deviation from a smooth background neutrino density causes significant alterations in the final flavor state of the neutrino ensemble after 400 km, but even very large fluctuations in the matter density do not strongly affect the state of the neutrinos after the collective phase. In both cases, there is a strong effect on the neutrino flavor evolution at intermediate radii, with the flavor evolution becoming much more chaotic. The effect of fluctuations also depends strongly on the initial neutrino spectra. We conclude that the true neutrino fluxes arriving at Earth from core-collapse supernova could differ considerably from predictions of neutrino fluxes based on approximate models with smoothly decreasing matter and neutrino densities.

  19. CPT-Odd Resonances in Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Barger, V.; Pakvasa, S.; Weiler, T. J.; Whisnant, K.

    2000-12-01

    We consider the consequences for future neutrino factory experiments of small CPT-odd interactions in neutrino oscillations. The νμ-->νμ and ν¯μ-->ν¯μ survival probabilities at a baseline L = 732 km can test for CPT-odd contributions at orders of magnitude better sensitivity than present neutrino sector limits. Interference between the CPT-violating interaction and CPT-even mass terms in the Lagrangian can lead to a resonant enhancement of the oscillation amplitude. For oscillations in matter, a simultaneous enhancement of both neutrino and antineutrino oscillation amplitudes is possible.

  20. CPand t violation in neutrino oscillations

    SciTech Connect

    Hisakazu Minakata; Hiroshi Nunokawa; Stephen Parke

    2003-09-18

    In this short lecture, we discuss some basic phenomenological aspects of CP and T violation in neutrino oscillation. Using CP/T trajectory diagrams in the bi-probability space, we try to sketch out some essential features of the interplay between the effect of CP/T violating phase and that of the matter in neutrino oscillation.

  1. Neutrino masses, neutrino oscillations, and cosmological implications

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1982-01-01

    Theoretical concepts and motivations for considering neutrinos having finite masses are discussed and the experimental situation on searches for neutrino masses and oscillations is summarized. The solar neutrino problem, reactor, deep mine and accelerator data, tri decay experiments and double beta-decay data are considered and cosmological implications and astrophysical data relating to neutrino masses are reviewed. The neutrino oscillation solution to the solar neutrino problem, the missing mass problem in galaxy halos and galaxy cluster galaxy formation and clustering, and radiative neutrino decay and the cosmic ultraviolet background radiation are examined.

  2. Neutrino masses, mixing, moments, and matter

    SciTech Connect

    Marciano, W.J.

    1988-01-01

    The present status of neutrino masses, mixing, and electromagnetic moments is surveyed. Potential enhancements of neutrino oscillations, decay, and spin-flavor precession due to their interactions with matter are described.

  3. Neutrino Oscillations and the Sudbury Neutrino Observatory

    NASA Astrophysics Data System (ADS)

    Wark, David

    2001-04-01

    When the existence of the neutrino was almost apologetically first proposed by Wolfgang Pauli it was intended to explain the mysterious apparent absence of energy and momentum in beta decay. 70 years later the neutrino has indeed solved that mystery, but it has generated still more of its own. Are neutrinos massive? Is it possible to create a neutrino with its spin in the same direction as its momentum? What fraction of the mass of the Universe is made up of neutrinos? Are the flavour labels which we put on neutrinos, like electron and muon, really fixed or can they change? Why does no experiment see the predicted flux of neutrinos from the Sun? Why do there appear to be roughly equal numbers of muon and electron neutrinos created in our atmosphere, rather than the 2:1 ratio we would expect? Many of these questions were coupled when Bruno Pontecorvo first suggested that the shortfall in solar neutrino measurements were caused by neutrino oscillations - neutrinos spontaneously changing flavour as they travel from the Sun. 30 years later we still await definitive proof of that conjecture, and providing that proof is the reason for the Sudbury Neutrino Observatory. The talk will discuss the current state of neutrino oscillations studies, and show how the unique capabilities of the Sudbury Neutrino Observatory can provide definitive proof of whether neutrino oscillations are the long-sought answer to the solar neutrino problem.

  4. Measurement of neutrino oscillations in MACRO experiment

    NASA Technical Reports Server (NTRS)

    Musser, J.

    1985-01-01

    The possibility of investigating neutrino oscillations in the proposed MACRO experiment are considered. Its sensitivity taking into account the theoretical uncertainties coming from flux calculations, geomagnetic effects and propagation through matter, and the experimental limitations.

  5. Boxing with neutrino oscillations

    SciTech Connect

    Wagner, D.J. |; Weiler, T.J.

    1999-06-01

    We develop a characterization of neutrino oscillations based on the coefficients of the oscillating terms. These coefficients are individually observable; although they are quartic in the elements of the unitary mixing matrix, they are independent of the conventions chosen for the angle and phase parametrization of the mixing matrix. We call these reparametrization-invariant observables {open_quotes}boxes{close_quotes} because of their geometric relation to the mixing matrix, and because of their association with the Feynman box diagram that describes oscillations in field theory. The real parts of the boxes are the coefficients for the {ital CP}- or {ital T}-even oscillation modes, while the imaginary parts are the coefficients for the {ital CP}- or {ital T}-odd oscillation modes. Oscillation probabilities are linear in the boxes, so measurements can straightforwardly determine values for the boxes (which can then be manipulated to yield magnitudes of mixing matrix elements). We examine the effects of unitarity on the boxes and discuss the reduction of the number of boxes to a minimum basis set. For the three-generation case, we explicitly construct the basis. Using the box algebra, we show that {ital CP} violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. The framework presented here will facilitate general analyses of neutrino oscillations among n{ge}3 flavors. {copyright} {ital 1999} {ital The American Physical Society}

  6. Tau neutrinos favored over sterile neutrinos in atmospheric muon neutrino oscillations.

    PubMed

    Fukuda, S; Fukuda, Y; Ishitsuka, M; Kajita, T; Kameda, J; Kaneyuki, K; Kobayashi, K; Koshio, Y; Miura, M; Moriyama, S; Nakahata, M; Nakayama, S; Obayashi, Y; Okada, A; Okumura, K; Sakurai, N; Shiozawa, M; Suzuki, Y; Takeuchi, H; Takeuchi, Y; Toshito, T; Totsuka, Y; Yamada, S; Earl, M; Habig, A; Kearns, E; Messier, M D; Scholberg, K; Stone, J L; Sulak, L R; Walter, C W; Goldhaber, M; Barszczak, T; Casper, D; Gajewski, W; Kropp, W R; Mine, S; Price, L R; Smy, M; Sobel, H W; Vagins, M R; Ganezer, K S; Keig, W E; Ellsworth, R W; Tasaka, S; Kibayashi, A; Learned, J G; Matsuno, S; Takemori, D

    2000-11-06

    The previously published atmospheric neutrino data did not distinguish whether muon neutrinos were oscillating into tau neutrinos or sterile neutrinos, as both hypotheses fit the data. Using data recorded in 1100 live days of the Super-Kamiokande detector, we use three complementary data samples to study the difference in zenith angle distribution due to neutral currents and matter effects. We find no evidence favoring sterile neutrinos, and reject the hypothesis at the 99% confidence level. On the other hand, we find that oscillation between muon and tau neutrinos suffices to explain all the results in hand.

  7. Tau Neutrinos Favored over Sterile Neutrinos in Atmospheric Muon Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Fukuda, S.; Fukuda, Y.; Ishitsuka, M.; Itow, Y.; Kajita, T.; Kameda, J.; Kaneyuki, K.; Kobayashi, K.; Koshio, Y.; Miura, M.; Moriyama, S.; Nakahata, M.; Nakayama, S.; Obayashi, Y.; Okada, A.; Okumura, K.; Sakurai, N.; Shiozawa, M.; Suzuki, Y.; Takeuchi, H.; Takeuchi, Y.; Toshito, T.; Totsuka, Y.; Yamada, S.; Earl, M.; Habig, A.; Kearns, E.; Messier, M. D.; Scholberg, K.; Stone, J. L.; Sulak, L. R.; Walter, C. W.; Goldhaber, M.; Barszczak, T.; Casper, D.; Gajewski, W.; Kropp, W. R.; Mine, S.; Price, L. R.; Smy, M.; Sobel, H. W.; Vagins, M. R.; Ganezer, K. S.; Keig, W. E.; Ellsworth, R. W.; Tasaka, S.; Kibayashi, A.; Learned, J. G.; Matsuno, S.; Takemori, D.; Hayato, Y.; Ishii, T.; Kobayashi, T.; Nakamura, K.; Oyama, Y.; Sakai, A.; Sakuda, M.; Sasaki, O.; Kohama, M.; Suzuki, A. T.; Inagaki, T.; Nishikawa, K.; Haines, T. J.; Blaufuss, E.; Kim, B. K.; Sanford, R.; Svoboda, R.; Chen, M. L.; Goodman, J. A.; Guillian, G.; Sullivan, G. W.; Hill, J.; Jung, C. K.; Martens, K.; Malek, M.; Mauger, C.; McGrew, C.; Sharkey, E.; Viren, B.; Yanagisawa, C.; Kirisawa, M.; Inaba, S.; Mitsuda, C.; Miyano, K.; Okazawa, H.; Saji, C.; Takahashi, M.; Takahata, M.; Nagashima, Y.; Nitta, K.; Takita, M.; Yoshida, M.; Kim, S. B.; Ishizuka, T.; Etoh, M.; Gando, Y.; Hasegawa, T.; Inoue, K.; Ishihara, K.; Maruyama, T.; Shirai, J.; Suzuki, A.; Koshiba, M.; Hatakeyama, Y.; Ichikawa, Y.; Koike, M.; Nishijima, K.; Fujiyasu, H.; Ishino, H.; Morii, M.; Watanabe, Y.; Golebiewska, U.; Kielczewska, D.; Boyd, S. C.; Stachyra, A. L.; Wilkes, R. J.; Young, K. K.

    2000-11-01

    The previously published atmospheric neutrino data did not distinguish whether muon neutrinos were oscillating into tau neutrinos or sterile neutrinos, as both hypotheses fit the data. Using data recorded in 1100 live days of the Super-Kamiokande detector, we use three complementary data samples to study the difference in zenith angle distribution due to neutral currents and matter effects. We find no evidence favoring sterile neutrinos, and reject the hypothesis at the 99% confidence level. On the other hand, we find that oscillation between muon and tau neutrinos suffices to explain all the results in hand.

  8. Neutrino oscillations and neutrino-electron scattering

    SciTech Connect

    Kayser, B.; Rosen, S.P.

    1980-10-01

    Neutrino flavor oscillations can significantly alter the cross section for neutrino-electron scattering. As a result, such oscillations can affect the comparison between existing reactor data and theories of neutral-current processes. They may also lead to strikingly large effects in high-energy accelerator experiments.

  9. The Search for Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Gershun, Daniel

    2011-01-01

    Neutrinos offer insight into such fundamental questions as the dominance of matter over antimatter, the dynamics of supernovae, and the large scale structure of the universe. NOvA (NUMI Off-axis Neutrino Oscillations) is an experiment that will measure crucial neutrino properties using a Near Detector at Fermilab, where the neutrinos are generated in the NuMI beam, and a large Far Detector in Ash River, MN, 735 km from Fermilab. The main objective of this experiment is the measurement of the parameters associated with the oscillation of muon to electron neutrinos. Indiana University with funding from the NSF and DOE are responsible for building and testing the water-cooled heat sinks required for the thermal and environmental control of the Avalanche Photodiodes used in the light detection generated in the Liquid Scintillator. The heat sinks have a brass body with a TEC chip that cools the APD to -15 C. The water system that conducts the 5 W generated by the thermal control has been designed to withstand a maximum pressure of 100 psi. Several of the construction techniques and QC tests performed will be described.

  10. Helicity oscillations of Dirac and Majorana neutrinos

    NASA Astrophysics Data System (ADS)

    Dobrynina, Alexandra; Kartavtsev, Alexander; Raffelt, Georg

    2016-06-01

    The helicity of a Dirac neutrino with mass m evolves under the influence of a B field because it has a magnetic dipole moment proportional to m . Moreover, it was recently shown that a polarized or anisotropic medium engenders the same effect for both Dirac and Majorana neutrinos. Because a B field polarizes a background medium, it instigates helicity oscillations even for Majorana neutrinos unless the medium is symmetric between matter and antimatter. Motivated by these observations, we review the impact of a B field and of an anisotropic or polarized medium on helicity oscillations for Dirac and Majorana neutrinos from the common perspective of in-medium dispersion.

  11. Neutrino oscillations refitted

    NASA Astrophysics Data System (ADS)

    Forero, D. V.; Tórtola, M.; Valle, J. W. F.

    2014-11-01

    Here, we update our previous global fit of neutrino oscillations by including the recent results that have appeared since the Neutrino 2012 conference. These include the measurements of reactor antineutrino disappearance reported by Daya Bay and RENO, together with latest T2K and MINOS data including both disappearance and appearance channels. We also include the revised results from the third solar phase of Super-Kamiokande, SK-III, as well as new solar results from the fourth phase of Super-Kamiokande, SK-IV. We find that the preferred global determination of the atmospheric angle θ23 is consistent with maximal mixing. We also determine the impact of the new data upon all the other neutrino oscillation parameters with an emphasis on the increasing sensitivity to the C P phase, thanks to the interplay between accelerator and reactor data. In the Appendix, we present the updated results obtained after the inclusion of new reactor data presented at the Neutrino 2014 conference. We discuss their impact on the global neutrino analysis.

  12. Neutrino Oscillation Workshop

    NASA Astrophysics Data System (ADS)

    NOW 2016 is the 9th workshop of a series started in 1998 in Amsterdam. Since the year 2000, this international workshop takes place in Otranto (Lecce, Italy). NOW is locally organized by the INFN sections and Depts. of Physics of Bari and Lecce, and is one of the few "Major Conference Series" recognized by INSPIRES in the field of neutrino physics, https://inspirehep.net/info/Conferences/series The aim of the workshop is: to discuss Neutrino Oscillation Physics, in particular current experimental data and their theoretical interpretation; to outline future investigations of neutrino masses and mixings; and to explore the links with various research fields in Astroparticle Physics and Cosmology. The structure of the Workshop includes five sessions, with plenary and parallel talks on several topics of current interest. The sessions for the NOW 2016 edition are: Session I - Oscillation parameters: present Session II - Oscillation parameters: future Session III - Multimessenger astrophysics Session IV - Neutrino masses, states and interactions Session V - Particle physics in the Cosmos The NOW 2016 Proceedings have been edited by Antonio Marrone (U. of Bari and INFN, Bari), Alessandro Mirizzi (U. of Bari and INFN, Bari), and Daniele Montanino (U. of Salento and INFN, Lecce). For further information see the NOW website, http://www.ba.infn.it/now

  13. Are there atmospheric neutrino oscillations?

    SciTech Connect

    Goodman, M.C.

    1993-06-01

    The neutrino oscillation explanation ({nu}{sub {mu}} {yields} {nu}{sub {tau}}) of the atmospheric neutrino deficit is often discussed but is far from widely accepted. This paper discusses several experimental observations, and how a consistent picture pointing towards neutrino oscillations might develop.

  14. Neutrino oscillation studies with reactors

    PubMed Central

    Vogel, P.; Wen, L.J.; Zhang, C.

    2015-01-01

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos. PMID:25913819

  15. Neutrino oscillation studies with reactors.

    PubMed

    Vogel, P; Wen, L J; Zhang, C

    2015-04-27

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  16. Neutrino oscillation studies with reactors

    DOE PAGES

    Vogel, P.; Wen, L.J.; Zhang, C.

    2015-04-27

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  17. Solar neutrino experiments and neutrino oscillations

    SciTech Connect

    Cleveland, B.T.; Davis, R. Jr.; Rowley, J.K.

    1981-01-01

    This report gives the results of the Brookhaven solar neutrino experiment that is based upon the neutrino capture reaction, /sup 37/Cl(..nu..,e/sup -/)/sup 37/Ar. The experiment was built in 1967 to test the theory of solar energy production, and it is well known that the neutrino capture rate in the detector is lower than that expected from theoretical models of the sun. The results will be compared to the current solar model calculations. One possible explanation of the low solar neutrino capture rate is that the neutrinos oscillate between two or more neutrino states, a topic of particular interest to this conference. This question is discussed in relation to the /sup 37/Cl experiment, and to other solar neutrino detectors that are capable of observing the lower energy neutrinos from the sun. A radiochemical solar neutrino detector located deep underground has a very low background and is capable of detecting the monoenergetic neutrinos from megacurie sources of radioisotopes that decay by electron capture. Experiments of this nature are described that are capable of testing for neutrino oscillations with a omicronm/sup 2/ as low as 0.2 eV/sup 2/ if there is maximum mixing between two neutrino states.

  18. Solar neutrino experiments and neutrino oscillators

    NASA Astrophysics Data System (ADS)

    Cleveland, Bruce T.; Davis, Raymond; Rowley, J. K.

    1981-05-01

    This report will give the results of the Brookhaven solar neutrino experiment that is based upon the neutrino capture reaction, 37Cl (ν,e-)37Ar. The experiment was built in 1967 to test the theory of solar energy production, and it is well known that the neutrino capture rate in the detector is lower than that expected from theoretical models of the sun. The results will be compared to the current solar model calculations. One possible explanation of the low solar neutrino capture rate is that the neutrinos oscillate between two or more neutrino states, a topic of particular interest to this conference. We will discuss this question in relation to the 37Cl experiment, and to other solar neutrino detectors that are capable of observing the lower energy neutrinos from the sun. A radiochemical solar neutrino detector located deep underground has a very low background and is capable of detecting the monoenergetic neutrinos from megacurie sources of radioisotopes that decay by electron capture. Experiments of this nature will be described that are capable of testing for neutrino oscillations with a δm2 as low as 0.2 eV2 if there is maximum mixing between the neutrino states.

  19. Current trends in non-accelerator particle physics: 1, Neutrino mass and oscillation. 2, High energy neutrino astrophysics. 3, Detection of dark matter. 4, Search for strange quark matter. 5, Magnetic monopole searches

    SciTech Connect

    He, Yudong |

    1995-07-01

    This report is a compilation of papers reflecting current trends in non-accelerator particle physics, corresponding to talks that its author was invited to present at the Workshop on Tibet Cosmic Ray Experiment and Related Physics Topics held in Beijing, China, April 4--13, 1995. The papers are entitled `Neutrino Mass and Oscillation`, `High Energy Neutrino Astrophysics`, `Detection of Dark Matter`, `Search for Strange Quark Matter`, and `Magnetic Monopole Searches`. The report is introduced by a survey of the field and a brief description of each of the author`s papers.

  20. Neutrino oscillations in curved spacetime: A heuristic treatment

    SciTech Connect

    Cardall, C.Y.; Fuller, G.M.

    1997-06-01

    We discuss neutrino oscillations in curved spacetime. Our heuristic approach can accommodate matter effects and gravitational contributions to neutrino spin precession in the presence of a magnetic field. By way of illustration, we perform explicit calculations in the Schwarzschild geometry. In this case, gravitational effects on neutrino oscillations are intimately related to the redshift. We discuss how spacetime curvature could affect the resonance position and adiabaticity of matter-enhanced neutrino flavor conversion. {copyright} {ital 1997} {ital The American Physical Society}

  1. Neutrinos and dark matter

    SciTech Connect

    Ibarra, Alejandro

    2015-07-15

    Neutrinos could be key particles to unravel the nature of the dark matter of the Universe. On the one hand, sterile neutrinos in minimal extensions of the Standard Model are excellent dark matter candidates, producing potentially observable signals in the form of a line in the X-ray sky. On the other hand, the annihilation or the decay of dark matter particles produces, in many plausible dark matter scenarios, a neutrino flux that could be detected at neutrino telescopes, thus providing non-gravitational evidence for dark matter. More conservatively, the non-observation of a significant excess in the neutrino fluxes with respect to the expected astrophysical backgrounds can be used to constrain dark matter properties, such as the self-annihilation cross section, the scattering cross section with nucleons and the lifetime.

  2. LSND neutrino oscillation results

    SciTech Connect

    Louis, W.C.; LSND Collaboration

    1996-10-01

    The LSND (Liquid Scintillator Neutrino Detector) experiment at Los Alamos has conducted a search for muon antineutrino {r_arrow} electron antineutrino oscillations using muon neutrinos from antimuon decay at rest. The electron antineutrinos are detected via the reaction electron antineutrino + proton {r_arrow} positron + neutron, correlated with the 2.2-MeV gamma from neutron + proton {r_arrow} deuteron + gamma. The use of tight cuts to identify positron events with correlated gamma rays yields 22 events with positron energy between 36 and 60 MeV and only 4.6 {+-} 0.6 background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1 {times} 10{sup -8}. A chi-squared fit to the entire positron sample results in a total excess of 51.8 {sup +18.7}{sub -16.9} {+-} 8.0 events with positron energy between 20 and 60 MeV. If attributed to muon antineutrino {r_arrow} electron antineutrino oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of (0.31 {+-} 0.12 {+-} 0.05){percent}. 10 refs., 7 figs., 1 tab.

  3. Neutrino oscillations and the modulation of neutrino-electron scattering

    SciTech Connect

    Rosen, S.P.; Kayser, B.

    1981-02-01

    Neutrino flavor oscillations modulate the cross section for neutrino-electron scattering. This modulation can seriously affect the interpretation of the present data on reactor-neutrino--electron scattering, and can greatly amplify the effective cross section for accelerator neutrinos.

  4. CP and T violation tests in neutrino oscillation

    SciTech Connect

    Arafune, J.; Sato, J.

    1997-02-01

    We examine how large violation effects of CP and T are allowed in long baseline neutrino experiments. When we attribute only the atmospheric neutrino anomaly to neutrino oscillation we may have large CP-violation effects. When we attribute both the atmospheric neutrino anomaly and the solar neutrino deficit to neutrino oscillation we may have sizable T violation effects proportional to the ratio of the two mass differences; it is difficult to see CP violation since we cannot ignore the matter effect. We give a simple expression for T violation in the presence of matter. {copyright} {ital 1997} {ital The American Physical Society}

  5. LSND neutrino oscillation results

    SciTech Connect

    Louis, W.C.; LSND Collaboration

    1997-06-01

    The LSND experiment at Los Alamos has conducted searches for {anti {nu}}{sub {mu}} {r_arrow} {anti {nu}}{sub e} oscillations using {anti {nu}}{sub {mu}} from U{sup +} decay at rest and for {nu}{sub {mu}} {r_arrow} {nu}{sub e} oscillations using {nu}{sub {mu}} from {pi}{sup +} decay in flight. For the {anti {nu}}{sub {mu}} {r_arrow} {anti {nu}}{sub e} search, a total excess of 51.8{sub {minus}16.9}{sup +18.7} {+-} 8.0 events is observed with e{sup +} energy between 20 and 60 MeV, while for the {nu}{sub {mu}} {r_arrow} {nu}{sub e} search, a total excess of 18.1 {+-} 6.6 {+-} 4.0 events is observed with e{sup {minus}} energy between 60 and 200 MeV. If attributed to neutrino oscillations, these excesses correspond to oscillation probabilities (averaged over the experimental energies and spatial acceptances) of (0.31 {+-} 0.12 {+-} 0.05)% and (0.26 {+-} 0.10 {+-} 0.05)%, respectively.

  6. Geophysical searches for three-neutrino oscillations

    NASA Technical Reports Server (NTRS)

    Cudell, J. R.; Gaisser, T. K.

    1985-01-01

    The possibilities of using cosmic ray induced neutrinos to detect oscillations in deep underground experiments were considered. The matter effects are nonnegligible in the two neutrino case, they reduce a mixing angle of 45 deg to 7.5 deg for 1 GeV neutrinos of squared mass difference 10/4 eV59 going through the Earth making the oscillation totally unobservable. They produce a natural oscillation length of about 6000 km in the case of massless neutrinos. Adding a third neutrino flavor considerably modifies the oscillation pattern and suggests that scales down to 5 x 10/5 eV could be observed even when we take into account matter effects and the electron contribution to the incoming flux. The effect of matter on the probability curves for different cases are shown by varying the masses and the mixing matrix. The ratio upward upsilon + upsilon/downward upsilon + upsilon as a function of the zenith angle at Cleveland, neglecting angular smearing and energy threshold effects is predicted.

  7. Analytical approximations for matter effects on CP violation in the accelerator-based neutrino oscillations with E ≲ 1 GeV

    NASA Astrophysics Data System (ADS)

    Xing, Zhi-zhong; Zhu, Jing-yu

    2016-07-01

    Given an accelerator-based neutrino experiment with the beam energy E ≲ 1 GeV, we expand the probabilities of ν μ → ν e and {overline{ν}}_{μ}to {overline{ν}}_e oscillations in matter in terms of two small quantities Δ21 /Δ31 and A/Δ31, where Δ 21≡ m 2 2 - m 1 2 and Δ 31≡ m 3 2 - m 1 2 are the neutrino mass-squared differences, and A measures the strength of terrestrial matter effects. Our analytical approximations are numerically more accurate than those made by Freund in this energy region, and thus they are particularly applicable for the study of leptonic CP violation in the low-energy MOMENT, ESS νSM and T2K oscillation experiments. As a by-product, the new analytical approximations help us to easily understand why the matter-corrected Jarlskog parameter tilde{J} peaks at the resonance energy E ∗ ≃ 0 .14GeV (or 0 .12 GeV) for the normal (or inverted) neutrino mass hierarchy, and how the three Dirac unitarity triangles are deformed due to the terrestrial matter contamination. We also affirm that a medium-baseline neutrino oscillation experiment with the beam energy E lying in the E ∗ ≲ E ≲ 2 E ∗ range is capable of exploring leptonic CP violation with little matter-induced suppression.

  8. Neutrino Oscillations and Neutrino Masses

    NASA Astrophysics Data System (ADS)

    Fritzsch, Harald

    In 1914 James Chadwick discovered that energy and momentum were not conserved in the beta decay of atomic nuclei. For the next 16 years this phenomenon was not understood. In 1930 Wolfgang Pauli suggested in a letter to the participants of a conference in Tuebingen, that in the beta decays not only an electron was emitted, but also a neutral particle, which could not be observed. The energy and momentum of this particle would be the observed missing energy and momentum. Enrico Fermi proposed a name for this hypothetical particle: neutrino...

  9. Analyzing Atmospheric Neutrino Oscillations

    SciTech Connect

    Escamilla, J.; Ernst, D. J.; Latimer, D. C.

    2007-10-26

    We provide a pedagogic derivation of the formula needed to analyze atmospheric data and then derive, for the subset of the data that are fully-contained events, an analysis tool that is quantitative and numerically efficient. Results for the full set of neutrino oscillation data are then presented. We find the following preliminary results: 1.) the sub-dominant approximation provides reasonable values for the best fit parameters for {delta}{sub 32}, {theta}{sub 23}, and {theta}{sub 13} but does not quantitatively provide the errors for these three parameters; 2.) the size of the MSW effect is suppressed in the sub-dominant approximation; 3.) the MSW effect reduces somewhat the extracted error for {delta}{sub 32}, more so for {theta}{sub 23} and {theta}{sub 13}; 4.) atmospheric data alone constrains the allowed values of {theta}{sub 13} only in the sub-dominant approximation, the full three neutrino calculations requires CHOOZ to get a clean constraint; 5.) the linear in {theta}{sub 13} terms are not negligible; and 6.) the minimum value of {theta}{sub 13} is found to be negative, but at a statistically insignificant level.

  10. Long Baseline Neutrino Oscillations

    SciTech Connect

    Rebel, Brian; /Fermilab

    2009-10-01

    There is compelling evidence for neutrino flavor change as neutrinos propagate. The evidence for this phenomenon has been provided by several experiments observing neutrinos that traverse distances of several hundred kilometers between production and detection. This review outlines the evidence for neutrino flavor change from such experiments and describes recent results in the field.

  11. Lepton mass hierarchy and neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Fritzsch, Harald; Zhi-Zhong, Xing

    1996-02-01

    Starting from the symmetry of lepton flavor democracy, we propose and discuss a simple pattern for the mass generation and flavor mixing of the charged leptons and neutrinos. The three neutrino masses are nearly degenerate, and the flavor mixing angles can be calculated. The observed deficit of solar and atmospheric neutrinos can be interpreted as a consequence of the near degeneracy and large oscillations of νe, νμ and ντ in the vacuum. Our ansatz can also accommodate the cosmological requirement for hot dark matter and the current data on neutrinoless ββ-decay.

  12. Dissipation and θ 13 in neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Oliveira, R. L. N.; Guzzo, M. M.

    2013-05-01

    We obtain a complete survival and transition probability involving three neutrino flavors when dissipation effects in vacuum are taken into consideration. In an approach that presents decoherence and relaxation effects, we study the behavior of the probabilities obtained from complete positivity constraints. Making the von Neumann entropy increase in time, many cases can be obtained and studied with the Lindblad master equation with addition of only one or two parameters related to dissipation. New possibilities are obtained when we take into account two decoherence parameters with different magnitudes which are given by reactor and accelerator neutrino oscillation experiments. We also present a model with only one parameter that has an important symmetry property, which can be used when the effective matter potential is important. Furthermore, the dissipation effects can contribute to the appearance of neutrinos that can hide or imitate the θ 13 effects and we study these possibilities showing that dissipative effects have an important role in three-neutrino oscillations.

  13. Supernova neutrino oscillations: A simple analytical approach

    NASA Astrophysics Data System (ADS)

    Fogli, G. L.; Lisi, E.; Montanino, D.; Palazzo, A.

    2002-04-01

    Analyses of observable supernova neutrino oscillation effects require the calculation of the electron (anti)neutrino survival probability Pee along a given supernova matter density profile. We propose a simple analytical prescription for Pee, based on a double-exponential form for the crossing probability and on the concept of maximum violation of adiabaticity. In the case of two-flavor transitions, the prescription is shown to reproduce accurately, in the whole neutrino oscillation parameter space, the results of exact numerical calculations for generic (realistic or power-law) profiles. The analytical approach is then generalized to cover three-flavor transitions with (direct or inverse) mass spectrum hierarchy, and to incorporate Earth matter effects. Compact analytical expressions, explicitly showing the symmetry properties of Pee, are provided for practical calculations.

  14. Velocity-induced neutrino oscillation and its possible implications for long baseline neutrinos

    NASA Astrophysics Data System (ADS)

    Banik, Amit Dutta; Majumdar, Debasish

    2015-12-01

    If the three types of active neutrinos possess different maximum attainable velocities and the neutrino eigenstates in the velocity basis are different from those in the flavor (and mass) basis, then this will induce a flavor oscillation in addition to the normal mass-flavor oscillation. Here we study such an oscillation scenario in three neutrino framework including also the matter effect and apply our results to demonstrate its consequences for long baseline (LBL) neutrinos. We also predict the possible signatures in terms of yields in a possible LBL neutrino experiment.

  15. Detecting supernovae neutrino with Earth matter effect

    NASA Astrophysics Data System (ADS)

    Liao, Wei

    2016-12-01

    We study Earth matter effect in oscillations of supernovae neutrinos. We show that detecting Earth matter effect gives an independent measurement of spectra of supernovae neutrinos, i.e., the flavor difference of the spectra of supernovae neutrinos. We study the effect of energy resolution and angular resolution of a final electron or positron on detecting the signal of Earth matter effect. We show that varying the widths of energy bins in analysis can change the signal strength of Earth matter effect and the statistical fluctuation. A reasonable choice of energy bins can both suppress the statistical fluctuation and make a good signal strength relative to the statistical fluctuation. Neutrino detectors with good energy resolution and good angular resolution are therefore preferred so that there is more freedom to vary energy bins and to optimize the signal of Earth matter effect in analyzing events of supernovae neutrinos.

  16. Theory of neutrino oscillations with entanglement

    SciTech Connect

    Kayser, Boris; Kopp, Joachim; Robertson, R. G. Hamish; Vogel, Petr

    2010-11-01

    We show that, despite appearances, a theoretical approach to neutrino oscillation in which the neutrino and its interaction partners are entangled yields the standard result for the neutrino oscillation wavelength. We also shed some light on the question of why plane-wave approaches to the neutrino oscillation problem can yield the correct oscillation wavelength even though they do not explicitly account for the localization of the neutrino source and the detector.

  17. Prospects for detecting supernova neutrino flavor oscillations

    SciTech Connect

    Fuller, G.M.; Haxton, W.C.; McLaughlin, G.C.

    1999-04-01

    The neutrinos from a type II supernova provide perhaps our best opportunity to probe cosmologically interesting muon and/or tauon neutrino masses. This is because matter enhanced neutrino oscillations can lead to an anomalously hot {nu}{sub e} spectrum, and thus to enhanced charged current cross sections in terrestrial detectors. Two recently proposed supernova neutrino observatories, OMNIS and LAND, will detect neutrons spalled from target nuclei by neutral and charged current neutrino interactions. As this signal is not flavor specific, it is not immediately clear whether a convincing neutrino oscillation signal can be extracted from such experiments. To address this issue we examine the responses of a series of possible light and heavy mass targets, {sup 9}Be,{sup 23}Na,{sup 35}Cl, and {sup 208}Pb. We find that strategies for detecting oscillations which use only neutron count rates are problematic at best, even if cross sections are determined by ancillary experiments. Plausible uncertainties in supernova neutrino spectra tend to obscure rate enhancements due to oscillations. However, in the case of {sup 208}Pb, a signal emerges that is largely flavor specific and extraordinarily sensitive to the {nu}{sub e} temperature, the emission of two neutrons. This signal and its flavor specificity are associated with the strength and location of the first-forbidden responses for neutral and charge current reactions, aspects of the {sup 208}Pb neutrino cross section that have not been discussed previously. Hadronic spin transfer experiments might be helpful in confirming some of the nuclear structure physics underlying our conclusions. {copyright} {ital 1999} {ital The American Physical Society}

  18. Spectrometry of the Earth using Neutrino Oscillations.

    PubMed

    Rott, C; Taketa, A; Bose, D

    2015-10-22

    The unknown constituents of the interior of our home planet have provoked the human imagination and driven scientific exploration. We herein demonstrate that large neutrino detectors could be used in the near future to significantly improve our understanding of the Earth's inner chemical composition. Neutrinos, which are naturally produced in the atmosphere, traverse the Earth and undergo oscillations that depend on the Earth's electron density. The Earth's chemical composition can be determined by combining observations from large neutrino detectors with seismic measurements of the Earth's matter density. We present a method that will allow us to perform a measurement that can distinguish between composition models of the outer core. We show that the next-generation large-volume neutrino detectors can provide sufficient sensitivity to reject extreme cases of outer core composition. In the future, dedicated instruments could be capable of distinguishing between specific Earth composition models and thereby reshape our understanding of the inner Earth in previously unimagined ways.

  19. Generalized mass ordering degeneracy in neutrino oscillation experiments

    SciTech Connect

    Coloma, Pilar; Schwetz, Thomas

    2016-09-07

    Here, we consider the impact of neutral-current (NC) nonstandard neutrino interactions (NSI) on the determination of the neutrino mass ordering. We show that in the presence of NSI there is an exact degeneracy which makes it impossible to determine the neutrino mass ordering and the octant of the solar mixing angle θ12 at oscillation experiments. The degeneracy holds at the probability level and for arbitrary matter density profiles, and hence solar, atmospheric, reactor, and accelerator neutrino experiments are affected simultaneously. The degeneracy requires order-1 corrections from NSI to the NC electron neutrino-quark interaction and can be tested in electron neutrino NC scattering experiments.

  20. Generalized mass ordering degeneracy in neutrino oscillation experiments

    SciTech Connect

    Coloma, Pilar; Schwetz, Thomas

    2016-09-07

    Here, we consider the impact of neutral-current (NC) nonstandard neutrino interactions (NSI) on the determination of the neutrino mass ordering. We show that in the presence of NSI there is an exact degeneracy which makes it impossible to determine the neutrino mass ordering and the octant of the solar mixing angle θ12 at oscillation experiments. The degeneracy holds at the probability level and for arbitrary matter density profiles, and hence solar, atmospheric, reactor, and accelerator neutrino experiments are affected simultaneously. The degeneracy requires order-1 corrections from NSI to the NC electron neutrino-quark interaction and can be tested in electron neutrino NC scattering experiments.

  1. Generalized mass ordering degeneracy in neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Coloma, Pilar; Schwetz, Thomas

    2016-09-01

    We consider the impact of neutral-current (NC) nonstandard neutrino interactions (NSI) on the determination of the neutrino mass ordering. We show that in the presence of NSI there is an exact degeneracy which makes it impossible to determine the neutrino mass ordering and the octant of the solar mixing angle θ12 at oscillation experiments. The degeneracy holds at the probability level and for arbitrary matter density profiles, and hence solar, atmospheric, reactor, and accelerator neutrino experiments are affected simultaneously. The degeneracy requires order-1 corrections from NSI to the NC electron neutrino-quark interaction and can be tested in electron neutrino NC scattering experiments.

  2. Neutrino oscillations: A source of Goldstone fields

    SciTech Connect

    Bento, L.

    1998-01-01

    It is proved that true Goldstone bosons develop coherent fields whenever the associated charges of the matter particles are not conserved in a macroscopic scale. The sources of the Goldstone fields are the time rates of quantum number violation. The case of neutrino flavor oscillations is studied with application to supernovae. It is shown that if the lepton numbers break at the Fermi scale, the {nu} potentials and oscillation patterns change in the periods of largest {nu} fluxes. In this way, {bar {nu}}{sub e}{leftrightarrow}{bar {nu}}{sub {mu}} oscillations may occur in the first instants of {nu} emission. {copyright} {ital 1997} {ital The American Physical Society}

  3. An analytical treatment for three neutrino oscillations in the Earth

    NASA Astrophysics Data System (ADS)

    Aguilar-Arevalo, A. A.; D'Olivo, J. C.; Supanitsky, A. D.

    2012-08-01

    A simple, and at the same time accurate, description of the Earth matter effects on the oscillations between three neutrino flavors is given in terms of the Magnus expansion for the evolution operator.

  4. Long-baseline Neutrino Oscillation at DUNE

    NASA Astrophysics Data System (ADS)

    Worcester, Elizabeth; DUNE Collaboration Collaboration

    2017-01-01

    The Deep Underground Neutrino Experiment (DUNE) is a long-baseline neutrino oscillation experiment with primary physics goals of determining the neutrino mass hierarchy and measuring δc P with sufficient sensitivity to discover CP violation in neutrino oscillation. CP violation sensitivity in DUNE requires careful understanding of systematic uncertainty, with contributions expected from uncertainties in the neutrino flux, neutrino interactions, and detector effects. In this presentation, we will describe the expected sensitivity of DUNE to long-baseline neutrino oscillation parameters, how various aspects of the experimental design contribute to that sensitivity, and the planned strategy for constraining systematic uncertainty in these measurements.

  5. Why is the neutrino oscillation formula expanded in Δ m {21/2}/Δ m {31/2} still accurate near the solar resonance in matter?

    NASA Astrophysics Data System (ADS)

    Xu, Xun-Jie

    2015-10-01

    The conventional approximate formula for neutrino oscillation in matter which is obtained from the expansion in terms of the ratio of mass square differences α = Δ m 21 2 /Δ m 31 2 ≈ 0.03, first proposed by Cervera, et al. and Freund, turns out to be an accurate formula for accelerator neutrino experiments. Originally it required the neutrino energy to be well above the solar resonance to validate the expansion but it is found to be still very accurate when the formula is extrapolated to the resonance, which is practically important for the T2K experiment. This paper shows that the accuracy is guaranteed by cancellations of branch cut singularities and also, for the first time, analytically computes the actual error of the formula. The actual error implies that the original requirement can be safely removed in current experiments.

  6. Oscillating asymmetric dark matter

    NASA Astrophysics Data System (ADS)

    Tulin, Sean; Yu, Hai-Bo; Zurek, Kathryn M.

    2012-05-01

    We study the dynamics of dark matter (DM) particle-antiparticle oscillations within the context of asymmetric DM. Oscillations arise due to small DM number-violating Majorana-type mass terms, and can lead to recoupling of annihilation after freeze-out and washout of the DM density. Asymmetric DM oscillations "interpolate" between symmetric and asymmetric DM freeze-out scenarios, and allow for a larger DM model-building parameter space. We derive the density matrix equations for DM oscillations and freeze-out from first principles using nonequilibrium field theory, and our results are qualitatively different than in previous studies. DM dynamics exhibits particle-vs-antiparticle "flavor" effects, depending on the interaction type, analogous to neutrino oscillations in a medium. "Flavor-sensitive" DM interactions include scattering or annihilation through a new vector boson, while "flavor-blind" interactions include scattering or s-channel annihilation through a new scalar boson. In particular, we find that flavor-sensitive annihilation does not recouple when coherent oscillations begin, and that flavor-blind scattering does not lead to decoherence.

  7. Neutrino detectors for oscillation experiments

    NASA Astrophysics Data System (ADS)

    Kudenko, Y.

    2017-06-01

    A brief overview of the development of neutrino detectors for long-baseline oscillation experiments at accelerators and reactors is presented. Basic principles and main features of detectors of running accelerator experiments T2K and NOνA sensitive to a first level of CP violation and neutrino mass hierarchy, and reactor experiments Daya Bay, RENO and Double Chooz which measured the mixing angle θ13 are discussed. A variety of different experimental techniques is proposed and developed for the next generation oscillation experiments: a 20 kt scintillator detector for the reactor experiment JUNO, a 0.52 kt water-Cherenkov detector Hyper-Kamiokande, and a massive liquid argon time-projection chamber neutrino detector envisaged for the DUNE experiment. Present status of these detectors, recent progress in R&D and future prospects are summarized in this paper.

  8. Evidence for neutrino oscillations in the Sudbury Neutrino Observatory

    SciTech Connect

    Marino, Alysia Diane

    2004-01-01

    The Sudbury Neutrino Observatory (SNO) is a large-volume heavy water Cerenkov detector designed to resolve the solar neutrino problem. SNO observes charged-current interactions with electron neutrinos, neutral-current interactions with all active neutrinos, and elastic-scattering interactions primarily with electron neutrinos with some sensitivity to other flavors. This dissertation presents an analysis of the solar neutrino flux observed in SNO in the second phase of operation, while ~2 tonnes of salt (NaCl) were dissolved in the heavy water. The dataset here represents 391 live days of data. Only the events above a visible energy threshold of 5.5 MeV and inside a fiducial volume within 550 cm of the center of the detector are studied. The neutrino flux observed via the charged-current interaction is [1.71 ± 0.065(stat.)±$0.065\\atop{0.068}$(sys.)±0.02(theor.)] x 106cm-2s-1, via the elastic-scattering interaction is [2.21±0.22(stat.)±$0.12\\atop{0.11}$(sys.)±0.01(theor.)] x 106cm-2s-1, and via the neutral-current interaction is [5.05±0.23(stat.)±$0.31\\atop{0.37}$(sys.)±0.06(theor.)] x 106cm-2s-1. The electron-only flux seen via the charged-current interaction is more than 7σ below the total active flux seen via the neutral-current interaction, providing strong evidence that neutrinos are undergoing flavor transformation as they travel from the core of the Sun to the Earth. The most likely origin of the flavor transformation is matter-induced flavor oscillation.

  9. Neutrino oscillations as a probe of dark energy.

    PubMed

    Kaplan, David B; Nelson, Ann E; Weiner, Neal

    2004-08-27

    We consider a class of theories in which neutrino masses depend significantly on environment, as a result of interactions with the dark sector. Such theories of mass varying neutrinos were recently introduced to explain the origin of the cosmological dark energy density and why its magnitude is apparently coincidental with that of neutrino mass splittings. In this Letter we argue that in such theories neutrinos can exhibit different masses in matter and in vacuum, dramatically affecting neutrino oscillations. As an example of modifications to the standard picture, we consider simple models that may simultaneously account for the LSND anomaly, KamLAND, K2K, and studies of solar and atmospheric neutrinos, while providing motivation to continue to search for neutrino oscillations in short baseline experiments such as BooNE.

  10. Atmospheric neutrino oscillations with MACRO

    NASA Astrophysics Data System (ADS)

    Siolia, M.; MACRO Collaboration

    2003-07-01

    We present the latest results on the study of atmospheric neutrino oscillations with the MACRO detector at Gran Sasso. Two sub-samples of events have been analysed, both in terms of absolute flux and zenith angle distribution: high energy events (with < Eν> ⋍ 50 GeV) and low energy events (with < Ev> ⋍ 4 GeV). The high energy sample has been used also to check the νμ Hν sterile oscillation hypothesis and to estimate neutrino energies using Multiple Coulomb Scattering (MCS) informations. All these analyses are mutually consistent and strongly favour the νμ ⇌ ντ oscillation hypothesis with maximal mixing and Δm2 = 2.5 · 10 -3eV 2.

  11. Multipole expansion method for supernova neutrino oscillations

    SciTech Connect

    Duan, Huaiyu; Shalgar, Shashank E-mail: shashankshalgar@unm.edu

    2014-10-01

    We demonstrate a multipole expansion method to calculate collective neutrino oscillations in supernovae using the neutrino bulb model. We show that it is much more efficient to solve multi-angle neutrino oscillations in multipole basis than in angle basis. The multipole expansion method also provides interesting insights into multi-angle calculations that were accomplished previously in angle basis.

  12. Measuring leptonic CP violation by low energy neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Minakata, H.; Nunokawa, H.

    2000-12-01

    We uncover an interesting phenomenon that neutrino flavor transformation in slowly varying matter density imitates almost exactly that of vacuum neutrino oscillation under suitably chosen experimental parameters. It allows us to have relatively large CP violating measure ΔP≡P(νμ-->νe)- P(ν¯μ-->ν¯e) which is essentially free from matter effect contamination. We utilize this phenomenon to design a low-energy long-baseline neutrino oscillation experiment to measure the leptonic CP violating phase.

  13. Measuring neutrino oscillation parameters using $\

    SciTech Connect

    Backhouse, Christopher James

    2011-01-01

    MINOS is a long-baseline neutrino oscillation experiment. It consists of two large steel-scintillator tracking calorimeters. The near detector is situated at Fermilab, close to the production point of the NuMI muon-neutrino beam. The far detector is 735 km away, 716m underground in the Soudan mine, Northern Minnesota. The primary purpose of the MINOS experiment is to make precise measurements of the 'atmospheric' neutrino oscillation parameters (Δmatm2 and sin2atm). The oscillation signal consists of an energy-dependent deficit of vμ interactions in the far detector. The near detector is used to characterize the properties of the beam before oscillations develop. The two-detector design allows many potential sources of systematic error in the far detector to be mitigated by the near detector observations. This thesis describes the details of the vμ-disappearance analysis, and presents a new technique to estimate the hadronic energy of neutrino interactions. This estimator achieves a significant improvement in the energy resolution of the neutrino spectrum, and in the sensitivity of the neutrino oscillation fit. The systematic uncertainty on the hadronic energy scale was re-evaluated and found to be comparable to that of the energy estimator previously in use. The best-fit oscillation parameters of the vμ-disappearance analysis, incorporating this new estimator were: Δm2 = 2.32-0.08+0.12 x 10-3 eV2, sin 2 2θ > 0.90 (90% C.L.). A similar analysis, using data from a period of running where the NuMI beam was operated in a configuration producing a predominantly $\\bar{v}$μ beam, yielded somewhat different best-fit parameters Δ$\\bar{m}${sup 2} = (3.36-0.40+0.46(stat.) ± 0.06(syst.)) x 10-3eV2, sin2 2$\\bar{θ}$ = 0.86-0.12_0.11

  14. Neutrino Interaction with Background Matter in a Noninertial Frame

    NASA Astrophysics Data System (ADS)

    Dvornikov, Maxim

    We study Dirac neutrinos propagating in rotating background matter. First we derive the Dirac equation for a single massive neutrino in the noninertial frame, where matter is at rest. This equation is written in the effective curved space-time corresponding to the corotating frame. We find the exact solution of the Dirac equation. The neutrino energy levels for ultrarelativistic particles are obtained. Then we discuss several neutrino mass eigenstates, with a nonzero mixing between them, interacting with rotating background matter. We derive the effective Schrödinger equation governing neutrino flavor oscillations in rotating matter. The new resonance condition for neutrino oscillations is obtained. We also examine the correction to the resonance condition caused by the matter rotation.

  15. Atmospheric neutrinos in ice and measurement of neutrino oscillation parameters

    SciTech Connect

    Fernandez-Martinez, Enrique; Giordano, Gerardo; Mocioiu, Irina; Mena, Olga

    2010-11-01

    The main goal of the IceCube Deep Core array is to search for neutrinos of astrophysical origins. Atmospheric neutrinos are commonly considered as a background for these searches. We show that the very high statistics atmospheric neutrino data can be used to obtain precise measurements of the main oscillation parameters.

  16. Probing supernova physics with neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Minakata, H.

    2002-08-01

    We point out that solar neutrino oscillations with large mixing angle as evidenced in current solar neutrino data have a strong impact on strategies for diagnosing collapse-driven supernova (SN) through neutrino observations. Such oscillations induce a significant deformation of the energy spectra of neutrinos, thereby allowing us to obtain otherwise inaccessible features of SN neutrino spectra. We demonstrate that one can determine temperatures and luminosities of non-electron flavor neutrinos by observing bar{nu}_{e} from galactic SN in massive water Cherenkov detectors by the charged current reactions on protons.

  17. Measurement of atmospheric neutrino oscillations with the ANTARES neutrino telescope

    NASA Astrophysics Data System (ADS)

    Adrián-Martínez, S.; Al Samarai, I.; Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Astraatmadja, T.; Aubert, J.-J.; Baret, B.; Basa, S.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bogazzi, C.; Bou-Cabo, M.; Bouhou, B.; Bouwhuis, M. C.; Brunner, J.; Busto, J.; Capone, A.; Cârloganu, C.; Carr, J.; Cecchini, S.; Charif, Z.; Charvis, Ph.; Chiarusi, T.; Circella, M.; Coniglione, R.; Core, L.; Costantini, H.; Coyle, P.; Creusot, A.; Curtil, C.; de Bonis, G.; Decowski, M. P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti, Q.; Drouhin, D.; Eberl, T.; Emanuele, U.; Enzenhöfer, A.; Ernenwein, J.-P.; Escoffier, S.; Fehn, K.; Fermani, P.; Ferri, M.; Ferry, S.; Flaminio, V.; Folger, F.; Fritsch, U.; Fuda, J.-L.; Galatà, S.; Gay, P.; Geyer, K.; Giacomelli, G.; Giordano, V.; Gleixner, A.; Gómez-González, J. P.; Graf, K.; Guillard, G.; Hallewell, G.; Hamal, M.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Herold, B.; Hößl, J.; Hsu, C. C.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Katz, U.; Kavatsyuk, O.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lambard, G.; Larosa, G.; Lattuada, D.; Lefèvre, D.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martínez-Mora, J. A.; Meli, A.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Neff, M.; Nezri, E.; Palioselitis, D.; Păvălaş, G. E.; Payet, K.; Petrovic, J.; Piattelli, P.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Reed, C.; Riccobene, G.; Richardt, C.; Richter, R.; Rivière, C.; Robert, A.; Roensch, K.; Rostovtsev, A.; Ruiz-Rivas, J.; Rujoiu, M.; Russo, G. V.; Samtleben, D. F. E.; Sánchez-Losa, A.; Sapienza, P.; Schmid, J.; Schnabel, J.; Schöck, F.; Schuller, J.-P.; Schüssler, F.; Seitz, T.; Shanidze, R.; Simeone, F.; Spies, A.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Taiuti, M.; Tamburini, C.; Trovato, A.; Vallage, B.; Vallée, C.; van Elewyck, V.; Vecchi, M.; Vernin, P.; Visser, E.; Wagner, S.; Wijnker, G.; Wilms, J.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J. D.; Zúñiga, J.; ANTARES Collaboration

    2012-08-01

    The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total live time of 863 days, are used to measure the oscillation parameters of atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20 GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon neutrinos of such energies crossing the Earth. The parameters determining the oscillation of atmospheric neutrinos are extracted by fitting the event rate as a function of the ratio of the estimated neutrino energy and reconstructed flight path through the Earth. Measurement contours of the oscillation parameters in a two-flavour approximation are derived. Assuming maximal mixing, a mass difference of Δ m322 = (3.1 ± 0.9) ṡ10-3eV2 is obtained, in good agreement with the world average value.

  18. LSND neutrino oscillation results

    SciTech Connect

    White, D.H.; LSND Collaboration

    1997-11-01

    The LSND experiment at Los Alamos has conducted a search for {anti v}{sub {mu}} {yields} {anti v}{sub e} oscillations using {anti v}{sub {mu}} from {mu}{sup +} decay at rest. The {anti v}{sub e} are detected via the reaction {anti v}{sub e} p {yields} e{sup +}n, correlated with the 2.2 MeV {gamma} from n p {yields} d {gamma}. The use of tight cuts to identify e{sup +} events with correlated {gamma} rays yielded 22 events with e{sup +} energy between 36 and 60 MeV and only 4.6 {+-} 0.6 background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1 {times} 10{sup {minus}8}. A {chi}{sup 2} fit to the entire e{sup +} sample results in a total excess of 51.8{sub {minus}16.9}{sup +18.7} {+-} 8.0 events with e{sup +} energy between 20 and 60 MeV. If attributed to {anti v}{sub {mu}} {yields} {anti v}{sub e} oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of 0.31 {+-} 0.12 {+-} 0.05%.

  19. Atmospheric neutrino oscillations and tau neutrinos in ice

    SciTech Connect

    Giordano, Gerardo; Mocioiu, Irina; Mena, Olga

    2010-06-01

    The main goal of the IceCube Deep Core Array is to search for neutrinos of astrophysical origins. Atmospheric neutrinos are commonly considered as a background for these searches. We show here that cascade measurements in the Ice Cube Deep Core Array can provide strong evidence for tau neutrino appearance in atmospheric neutrino oscillations. Controlling systematic uncertainties will be the limiting factor in the analysis. A careful study of these tau neutrinos is crucial, since they constitute an irreducible background for astrophysical neutrino detection.

  20. Neutrino Oscillations: Eighty Years in Review

    NASA Astrophysics Data System (ADS)

    Bowers, Rebecca Lyn

    In order to discuss neutrino oscillations, it is necessary to have knowledge of the developments in the field spanning the last eighty years. The existence of the neutrino was posited by Wolfgang Pauli in 1930 to account for the mass defect in beta decay, and to this day physicists are still endeavoring to answer fundamental questions about this enigmatic particle. The scope of this thesis includes a historical background of neutrino physics and a discussion of neutrinos and the Standard Model; subsequent to this is a discussion of the Solar Neutrino Problem, which provided the impetus for the proposal of neutrino oscillations. Bolstering the theory of neutrino oscillations (which is developed in the body of this thesis) are neutrino detector experiments and their results; these include the Homestake experiment, SNO, Kamiokande and Super-Kamiokande, MINOS, and Double-Chooz. We also include relevant derivations, most particularly of the quantum mechanics of neutrino oscillations as treated in the wave packet formalism. We have amassed here the principle theories and experimental results -- a mere tip of the iceberg -- that have brought us to our current understanding of neutrino oscillations. We have also studied the quantum mechanics of neutrino oscillations and developed for ourselves the wave packet formalism describing the phenomenon.

  1. Subpanel on accelerator-based neutrino oscillation experiments

    SciTech Connect

    1995-09-01

    Neutrinos are among nature`s fundamental constituents, and they are also the ones about which we know least. Their role in the universe is widespread, ranging from the radioactive decay of a single atom to the explosions of supernovae and the formation of ordinary matter. Neutrinos might exhibit a striking property that has not yet been observed. Like the back-and-forth swing of a pendulum, neutrinos can oscillate to-and-from among their three types (or flavors) if nature provides certain conditions. These conditions include neutrinos having mass and a property called {open_quotes}mixing.{close_quotes} The phenomenon is referred to as neutrino oscillations. The questions of the origin of neutrino mass and mixing among the neutrino flavors are unsolved problems for which the Standard Model of particle physics holds few clues. It is likely that the next critical step in answering these questions will result from the experimental observation of neutrino oscillations. The High Energy Physics Advisory Panel (HEPAP) Subpanel on Accelerator-Based Neutrino Oscillation Experiments was charged to review the status and discovery potential of ongoing and proposed accelerator experiments on neutrino oscillations, to evaluate the opportunities for the U.S. in this area of physics, and to recommend a cost-effective plan for pursuing this physics, as appropriate. The complete charge is provided in Appendix A. The Subpanel studied these issues over several months and reviewed all the relevant and available information on the subject. In particular, the Subpanel reviewed the two proposed neutrino oscillation programs at Fermi National Accelerator Laboratory (Fermilab) and at Brookhaven National Laboratory (BNL). The conclusions of this review are enumerated in detail in Chapter 7 of this report. The recommendations given in Chapter 7 are also reproduced in this summary.

  2. Neutrino oscillations in low density medium.

    PubMed

    Ioannisian, A N; Smirnov, A Y

    2004-12-10

    We have solved the evolution equation for neutrinos in a low density medium, Vmatter potential, developing the perturbation theory in epsilon identical with2VE/Deltam(2). Simple and physically transparent formulas for the oscillation probabilities have been derived in the lowest order in epsilon which are valid for an arbitrary density profile. The formulas can be applied for propagation of the solar and supernova neutrinos in matter of the Earth, substantially simplifying numerical calculations. Using these formulas we study sensitivity of the oscillations to structures of the density profile situated at different distances d from a detector. For the mass-to-flavor transitions, e.g., nu(2)-->nu(e), we have found the attenuation effect: a decrease of the sensitivity to remote structures, d>l(nu)E/DeltaE, where l(nu) is the oscillation length and DeltaE/E is the energy resolution of a detector.

  3. FINAL NEUTRINO OSCILLATION RESULTS FROM LSND

    SciTech Connect

    W. LOUIS

    2000-10-01

    The LSND experiment provides evidence for neutrino oscillations from both the primary {bar {nu}}{sub {mu}} {r_arrow} {bar {nu}}{sub e} oscillation search and the secondary {nu}{sub {mu}} {r_arrow} {nu}{sub e} oscillation search. At present, this remains the only evidence for appearance neutrino oscillations and implies that at least one neutrino has a mass greater than 0.4 eV/c{sup 2} and that neutrinos comprise more than 1% of the mass of the universe. The MiniBooNE experiment at Fermilab, which is presently under construction, will provide a definitive test of the LSND results, and if the neutrino oscillation results are confirmed, will make a precision measurement of the oscillation parameters.

  4. Do non-relativistic neutrinos oscillate?

    NASA Astrophysics Data System (ADS)

    Akhmedov, Evgeny

    2017-07-01

    We study the question of whether oscillations between non-relativistic neutrinos or between relativistic and non-relativistic neutrinos are possible. The issues of neutrino production and propagation coherence and their impact on the above question are discussed in detail. It is demonstrated that no neutrino oscillations can occur when neutrinos that are non-relativistic in the laboratory frame are involved, except in a strongly mass-degenerate case. We also discuss how this analysis depends on the choice of the Lorentz frame. Our results are for the most part in agreement with Hinchliffe's rule.

  5. Spectrometry of the Earth using Neutrino Oscillations

    PubMed Central

    Rott, C.; Taketa, A.; Bose, D.

    2015-01-01

    The unknown constituents of the interior of our home planet have provoked the human imagination and driven scientific exploration. We herein demonstrate that large neutrino detectors could be used in the near future to significantly improve our understanding of the Earth’s inner chemical composition. Neutrinos, which are naturally produced in the atmosphere, traverse the Earth and undergo oscillations that depend on the Earth’s electron density. The Earth’s chemical composition can be determined by combining observations from large neutrino detectors with seismic measurements of the Earth’s matter density. We present a method that will allow us to perform a measurement that can distinguish between composition models of the outer core. We show that the next-generation large-volume neutrino detectors can provide sufficient sensitivity to reject extreme cases of outer core composition. In the future, dedicated instruments could be capable of distinguishing between specific Earth composition models and thereby reshape our understanding of the inner Earth in previously unimagined ways. PMID:26489447

  6. Neutrino oscillations and the seesaw origin of neutrino mass

    NASA Astrophysics Data System (ADS)

    Miranda, O. G.; Valle, J. W. F.

    2016-07-01

    The historical discovery of neutrino oscillations using solar and atmospheric neutrinos, and subsequent accelerator and reactor studies, has brought neutrino physics to the precision era. We note that CP effects in oscillation phenomena could be difficult to extract in the presence of unitarity violation. As a result upcoming dedicated leptonic CP violation studies should take into account the non-unitarity of the lepton mixing matrix. Restricting non-unitarity will shed light on the seesaw scale, and thereby guide us towards the new physics responsible for neutrino mass generation.

  7. Neutrino oscillations in the presence of super-light sterile neutrinos

    NASA Astrophysics Data System (ADS)

    Divari, Paraskevi; Vergados, John

    2016-07-01

    In this paper, we study the effect of conversion of super-light sterile neutrino (SLSN) to electron neutrino in matter like that of the Earth. In the Sun the resonance conversion between SLSN and electron neutrino via the neutral current is suppressed due to the smallness of neutron number. On the other hand, neutron number density can play an important role in the Earth, making the scenario of SLSN quite interesting. The effect of CP-violating phases on active-SLSN oscillations is also discussed. Reactor neutrino experiments with medium or short baseline may probe the scenario of SLSN.

  8. Sterile neutrinos as the origin of dark and baryonic matter.

    PubMed

    Canetti, Laurent; Drewes, Marco; Shaposhnikov, Mikhail

    2013-02-08

    We demonstrate for the first time that three sterile neutrinos alone can simultaneously explain neutrino oscillations, the observed dark matter, and the baryon asymmetry of the Universe without new physics above the Fermi scale. The key new point of our analysis is leptogenesis after sphaleron freeze-out, which leads to resonant dark matter production, evading thus the constraints on sterile neutrino dark matter from structure formation and x-ray searches. We identify the range of sterile neutrino properties that is consistent with all known constraints. We find a domain of parameters where the new particles can be found with present day experimental techniques, using upgrades to existing experimental facilities.

  9. Neutrino oscillations: From a historical perspective to the present status

    NASA Astrophysics Data System (ADS)

    Bilenky, S.

    2016-07-01

    The history of neutrino mixing and oscillations is briefly presented. Basics of neutrino mixing and oscillations and convenient formalism of neutrino oscillations in vacuum are given. The role of neutrino in the Standard Model and the Weinberg mechanism of the generation of the Majorana neutrino masses are discussed.

  10. Neutrino oscillations: from an historical perspective to the present status

    NASA Astrophysics Data System (ADS)

    Bilenky, S.

    2016-05-01

    The history of neutrino mixing and oscillations is briefly presented. Basics of neutrino mixing and oscillations and convenient formalism of neutrino oscillations in vacuum is given. The role of neutrino in the Standard Model and the Weinberg mechanism of the generation of the Majorana neutrino masses are discussed.

  11. Collective neutrino oscillations in supernovae

    SciTech Connect

    Duan, Huaiyu

    2014-06-24

    In a dense neutrino medium neutrinos can experience collective flavor transformation through the neutrino-neutrino forward scattering. In this talk we present some basic features of collective neutrino flavor transformation in the context in core-collapse supernovae. We also give some qualitative arguments for why and when this interesting phenomenon may occur and how it may affect supernova nucleosynthesis.

  12. Solar neutrino experiments and neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Cleveland, B. T.; Davis, R., Jr.; Rowley, J. K.

    A solar neutrino experiment was conducted that was based on the neutrino capture reaction, Cl-37(v,e(-))Ar-37. The experiment was built to test the theory of solar energy production. The results are compared to solar model calculations.

  13. A study of neutrino oscillations in MINOS

    SciTech Connect

    Raufer, Tobias Martin

    2007-01-01

    MINOS is a long-baseline neutrino oscillations experiment located at Fermi National Accelerator Laboratory (FNAL), USA. It makes use of the NuMI neutrino beamline and two functionally identical detectors located at distances of ~1km and ~735km from the neutrino production target respectively. The Near Detector measures the composition and energy spectrum of the neutrino beam with high precision while the Far Detector looks for evidence of neutrino oscillations. This thesis presents work conducted in two distinct areas of the MINOS experiment: analysis of neutral current and charged current interactions. While charged current events are only sensitive to muon neutrino disappearance, neutral current events can be used to distinguish oscillations into sterile neutrinos from those involving only active neutrino species. A complete, preliminary neutral current study is performed on simulated data. This is followed by a more detailed investigation of neutral current neutrino interactions in the MINOS Near Detector. A procedure identifying neutral current interactions and rejecting backgrounds due to reconstruction failures is developed. Two distinct event classification methods are investigated. The selected neutral current events in the Near Detector are used to extract corrections to the neutral current cross-section in the MINOS Monte Carlo simulation as a function of energy. The resulting correction factors are consistent with unity. The main MINOS charged current neutrino disappearance analysis is described. We present the Monte Carlo tuning procedure, event selection, extrapolation from Near to Far Detector and fit for neutrino oscillations. Systematic errors on this measurement are evaluated and discussed in detail. The data are consistent with neutrino oscillations with the following parameters: 2.74 $+0.44\\atop{-0.26}$ x 10-3 eV2 and sin2(2θ23) > 0.87 at 68% confidence level.

  14. Decoherence and oscillations of supernova neutrinos

    NASA Astrophysics Data System (ADS)

    Kersten, Jörn; Smirnov, Alexei Yu.

    2016-06-01

    Supernova neutrinos have several exceptional features which can lead to interesting physical consequences. At the production point their wave packets have an extremely small size σ x ˜ 10^{-11} cm; hence the energy uncertainty can be as large as the energy itself, σ E ˜ E, and the coherence length is short. On the way to the Earth the wave packets of mass eigenstates spread to macroscopic sizes and separate. Inside the Earth the mass eigenstates split into eigenstates in matter and oscillate again. The coherence length in the Earth is comparable with the radius of the Earth. We explore these features and their consequences. (1) We present new estimates of the wave packet size. (2) We consider the decoherence condition for the case of wave packets with spatial spread and show that it is not modified by the spread. (3) We study the coherence of neutrinos propagating in a multi-layer medium with density jumps at the borders of layers. In this case coherence can be partially restored due to a "catch-up effect", increasing the coherence length beyond the usual estimate. This catch-up effect can occur for supernova neutrinos as they cross the shock wave fronts in the exploding star or the core of the Earth.

  15. Search for direct and indirect unitarity violation in neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Luo, Shu

    2014-08-01

    If three standard neutrinos mix with other degree of freedoms like sterile neutrinos, no matter how heavy the sterile neutrino masses are, it could result in the unitarity violation in the MNSP matrix. Nevertheless, the unitarity violation induced by the existence of light or heavy sterile neutrinos can have very different effects on neutrino oscillations, we call the former case direct unitarity violation and the later case the indirect unitarity violation. We will explain in this paper the difference of these two kinds of unitarity violations, then focus on the possibilities of searching the unitarity violation in neutrino oscillation experiments, of which the precision reactor experiments with multiple baselines are discussed in detail.

  16. Supernova Neutrino Nucleosynthesis of Light Elements with Neutrino Oscillations

    SciTech Connect

    Yoshida, Takashi; Kajino, Toshitaka; Yokomakura, Hidekazu; Kimura, Keiichi; Takamura, Akira; Hartmann, Dieter H.

    2006-03-10

    Light element synthesis in supernovae through neutrino-nucleus interactions, i.e., the {nu} process, is affected by neutrino oscillations in the supernova environment. There is a resonance of 13-mixing in the O/C layer, which increases the rates of charged-current {nu}-process reactions in the outer He-rich layer. The yields of {sup 7}Li and {sup 11}B increase by about a factor of 1.9 and 1.3, respectively, for a normal mass hierarchy and an adiabatic 13-mixing resonance, compared to those without neutrino oscillations. In the case of an inverted mass hierarchy and a nonadiabatic 13-mixing resonance, the increase in the {sup 7}Li and {sup 11}B yields is much smaller. Observations of the {sup 7}Li/{sup 11}B ratio in stars showing signs of supernova enrichment could thus provide a unique test of neutrino oscillations and constrain their parameters and the mass hierarchy.

  17. Supernova neutrino nucleosynthesis of light elements with neutrino oscillations.

    PubMed

    Yoshida, Takashi; Kajino, Toshitaka; Yokomakura, Hidekazu; Kimura, Keiichi; Takamura, Akira; Hartmann, Dieter H

    2006-03-10

    Light element synthesis in supernovae through neutrino-nucleus interactions, i.e., the v process, is affected by neutrino oscillations in the supernova environment. There is a resonance of 13-mixing in the O/C layer, which increases the rates of charged-current -process reactions in the outer He-rich layer. The yields of 7Li and 11B increase by about a factor of 1.9 and 1.3, respectively, for a normal mass hierarchy and an adiabatic 13-mixing resonance, compared to those without neutrino oscillations. In the case of an inverted mass hierarchy and a nonadiabatic 13-mixing resonance, the increase in the 7Li and 11B yields is much smaller. Observations of the 7Li/11B ratio in stars showing signs of supernova enrichment could thus provide a unique test of neutrino oscillations and constrain their parameters and the mass hierarchy.

  18. Solar neutrino oscillation from large extra dimensions

    NASA Astrophysics Data System (ADS)

    Lukas, A.; Ramond, P.; Romanino, A.; Ross, G. G.

    2000-12-01

    A plausible explanation for the existence of additional light sterile neutrinos is that they correspond to modulini, fermionic partners of moduli, which propagate in new large dimensions. We discuss the phenomenological implications of such states and show that solar neutrino oscillation is well described by small angle MSW oscillation to the tower of Kaluza-Klein states associated with the modulini. In the optimal case the recoil electron energy spectrum agrees precisely with the measured one, in contrast to the single sterile neutrino case which is disfavoured. We also consider how all oscillation phenomena can be explained in a model including bulk neutrino states. In particular, we show that a naturally maximal mixing for atmospheric neutrinos can be easily obtained.

  19. Nuclear effects in neutrino oscillation experiments

    SciTech Connect

    Chauhan, S.; Athar, M. Sajjad; Singh, S. K.

    2011-10-06

    We have studied the nuclear medium effects in the neutrino(antineutrino) induced interactions in nuclei which are relevant for present neutrino oscillation experiments in the few GeV energy region. The study is specially focused on calculating the cross sections and the event rates for atmospheric and accelerator neutrino experiments. The nuclear effects are found to be important for the quasielastic lepton production and the charged current incoherent and coherent pion production processes.

  20. Neutrino signals from dark matter

    NASA Astrophysics Data System (ADS)

    Erkoca, Arif Emre

    Large-scale neutrino telescopes will be powerful tools to observe multitude of mysterious phenomena happening in the Universe. The dark matter puzzle is listed as one of them. In this study, indirect detection of dark matter via neutrino signals is presented. The upward muon, the contained muon and the hadronic shower fluxes are calculated, assuming annihilation/decay of the dark matter in the core of the astrophysical objects and in the Galactic center. Direct neutrino production and secondary neutrino production from the decay of Standard Model particles produced in the annihilation/decay of dark matter are studied. The results are contrasted to the ones previously obtained in the literature, illustrating the importance of properly treating muon propagation and energy loss for the upward muon flux. The dependence of the dark matter signals on the density profile, the dark matter mass and the detector threshold are discussed. Different dark matter models (gravitino, Kaluza-Klein and leptophilic) which can account for recent observations of some indirect searches are analyzed regarding their detection in the kilometer size neutrino detectors in the near future. Muon and shower rates and the minimum observation times in order to reach 2sigma detection significance are evaluated, with the result suggesting that the optimum cone half angles chosen about the Galactic center are about 10° (50°) for the muon (shower) events. A detailed analysis shows that for the annihilating dark matter models such as the leptophilic and Kaluza-Klein models, upward and contained muon as well as showers yield promising signals for dark matter detection in just a few years of observation, whereas for decaying dark matter models, the same observation times can only be reached with showers. The analytical results for the final fluxes are also obtained as well as parametric forms for the muon and shower fluxes for the dark matter models considered in this study.

  1. Reproducing sterile neutrinos and the behavior of flavor oscillations with superconducting-magnetic proximity effects

    NASA Astrophysics Data System (ADS)

    Baker, Thomas E.

    2016-03-01

    The physics of a superconductor subjected to a magnetic field is known to be equivalent to neutrino oscillations. Examining the properties of singlet-triplet oscillations in the magnetic field, a sterile neutrino is suggested to be represented by singlet Cooper pairs and moderates flavor oscillations between three flavor neutrinos (triplet Cooper pairs). A superconductor-exchange spring system's rotating magnetization profile is used to simulate the mass-flavor oscillations in the neutrino case and the physics of neutrino oscillations are discussed. Connecting the condensed matter system and the particle physics system with this analogy may allow for the properties of the condensed matter system to inform neutrino experiments. Support is graciously acknowledged from the Pat Beckman Memorial Scholarship from the Orange County Chapter of the Achievement Rewards for College Scientists Foundation.

  2. Lepton asymmetry and neutrino oscillations interplay

    NASA Astrophysics Data System (ADS)

    Kirilova, Daniela

    2013-03-01

    We discuss the interplay between lepton asymmetry L and ν oscillations in the early Universe. Neutrino oscillations may suppress or enhance previously existing L. On the other hand L is capable to suppress or enhance neutrino oscillations. The mechanism of L enhancement in MSW resonant ν oscillations in the early Universe is numerically analyzed. L cosmological effects through ν oscillations are discussed. We discuss how L may change the cosmological BBN constraints on neutrino and show that BBN model with ν_e leftrightarrow ν_s oscillations is extremely sensitive to L - it allows to obtain the most stringent constraints on L value. We discuss also the cosmological role of active-sterile ν mixing and L in connection with the indications about additional relativistic density in the early Universe, pointed out by BBN, CMB and LSS data and the analysis of global ν data.

  3. Neutrino mixing and oscillations in astrophysical environments

    SciTech Connect

    Balantekin, A. B.

    2014-05-02

    A brief review of the current status of neutrino mixing and oscillations in astrophysical environments, with particular emphasis on the Sun and core-collapse supernovae, is given. Implications of the existence of sterile states which mix with the active neutrinos are discussed.

  4. Neutrino interactions in neutron matter

    NASA Astrophysics Data System (ADS)

    Cipollone, Andrea

    2012-12-01

    Neutrino flow is the dominant mechanism of energy transfer in the latest stages of supernovae explosions and in compact stars. The Standard Model of particle physics and accelerator data, provide a satisfactory description of neutrino physics in vacuum up to TeV scale. Nevertheless modeling the dynamics of neutrino interaction in the nuclear environment involves severe difficulties. This thesis in mainly aimed at obtaining the weak response of infinite matter, using both the Correlated Basis Function theory and Landau Theory of Fermi liquid to take into account properly nucleon-nucleon hard core potential and long range correlation (quasi-particle, collective modes, ecc.)

  5. Impact of Neutrino Oscillation Measurements on Theory

    SciTech Connect

    Murayama, Hitoshi

    2003-11-30

    Neutrino oscillation data had been a big surprise to theorists, and indeed they have ongoing impact on theory. I review what the impact has been, and what measurements will have critical impact on theory in the future.

  6. Generalized mass ordering degeneracy in neutrino oscillation experiments

    DOE PAGES

    Coloma, Pilar; Schwetz, Thomas

    2016-09-07

    Here, we consider the impact of neutral-current (NC) nonstandard neutrino interactions (NSI) on the determination of the neutrino mass ordering. We show that in the presence of NSI there is an exact degeneracy which makes it impossible to determine the neutrino mass ordering and the octant of the solar mixing angle θ12 at oscillation experiments. The degeneracy holds at the probability level and for arbitrary matter density profiles, and hence solar, atmospheric, reactor, and accelerator neutrino experiments are affected simultaneously. The degeneracy requires order-1 corrections from NSI to the NC electron neutrino-quark interaction and can be tested in electron neutrinomore » NC scattering experiments.« less

  7. Understanding the Earth’s Composition through Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Lowell, Beverly; de Gouvêa, André

    2017-01-01

    While our understanding of the cosmos has improved dramatically in the last decades, we still only have limited knowledge of the inside of our own planet. In particular, we only have indirect information regarding the composition or size of the Earth’s core. We do, however, know neutrinos interact with electrons and therefore their oscillations change as they propagate through matter. We theoretically examine how solar neutrinos propagating through the Earth can offer a look into the composition of its layers. We investigate if neutrinos can detect the Earth’s core by numerically calculating the probability of finding an electron-neutrino and adjusting parameters such as electron density and the radius of the core. It is determined that changing both of these parameters significantly affect the probability, such that neutrinos could be used experimentally to detect the size of a hard, dense core.

  8. Is CP violation observable in long baseline neutrino oscillation experiments?

    SciTech Connect

    Tanimoto, M.

    1997-01-01

    We have studied CP violation originating from the phase of the neutrino-mixing matrix in the long baseline neutrino oscillation experiments. The direct measurement of CP violation is the difference of the transition probabilities between CP-conjugate channels. In those experiments, the CP-violating effect is not suppressed if the highest neutrino mass scale is taken to be 1{endash}5 eV, which is appropriate for the cosmological hot dark matter. Assuming the hierarchy for the neutrino masses, the upper bounds of CP violation have been calculated for three cases, in which mixings are constrained by the recent short baseline ones. The calculated upper bounds are larger than 10{sup {minus}2}, which will be observable in the long baseline accelerator experiments. The matter effect, which is not CP invariant, has been also estimated in those experiments. {copyright} {ital 1997} {ital The American Physical Society}

  9. Neutrino oscillations in a predictive SUSY GUT

    SciTech Connect

    Blazek, T.; Raby, S.; Tobe, K.

    1999-12-01

    In this paper we present a predictive SO(10) supersymmetric grand unified theory with the family symmetry U(2)xU(1) which has several nice features. We are able to fit fermion masses and mixing angles, including recent neutrino data, with nine parameters in the charged fermion sector and four in the neutrino sector. The family symmetry plays a preeminent role. (i) The model is ''natural''--we include all terms allowed by the symmetry. It restricts the number of arbitrary parameters and enforces many zeros in the effective mass matrices. (ii) Family symmetry breaking from U(2)xU(1){yields}U(1){yields} nothing generates the family hierarchy. It also constrains squark and slepton mass matrices, thus ameliorating flavor violation resulting from squark and slepton loop contributions. (iii) It naturally gives large angle {nu}{sub {mu}}-{nu}{sub {tau}} mixing describing atmospheric neutrino oscillation data and small angle {nu}{sub e}-{nu}{sub s} mixing, consistent with the small mixing angle Mikheyev-Smirnov-Wolfenstein (MSW) solution to solar neutrino data. (iv) Finally, in this paper we assume minimal family symmetry-breaking vacuum expectation values (VEV's). As a result we cannot obtain a three neutrino solution to both atmospheric and solar neutrino oscillations. In addition, the solution discussed here cannot fit liquid scintillation neutrino detector (LSND) data even though this solution requires a sterile neutrino {nu}{sub s}. It is important to note, however, that with nonminimal family symmetry-breaking VEV's, a three neutrino solution is possible with the small mixing angle MSW solution to solar neutrino data and large angle {nu}{sub {mu}}-{nu}{sub {tau}} mixing describing atmospheric neutrino oscillation data. In the four neutrino case, nonminimal family VEV's may also permit a solution for LSND. The results with nonminimal family breaking are still under investigation and will be reported in a future paper. (c) 1999 The American Physical Society.

  10. The Latest Neutrino Oscillation Results from Super-Kamiokande

    SciTech Connect

    Sobel, Henry W.

    2006-02-08

    Super-Kamiokande is the world's largest water Cherenkov detector, with a net mass of 50,000 tons. The scientific goals of the experiment include searches for proton decays, and studies of neutrinos from various sources. In this paper we review some of the latest results from our neutrino oscillations studies using atmospheric neutrinos, solar neutrinos and neutrinos from the KEK neutrino beam.

  11. Neutrino oscillations from Dirac and Majorana masses

    SciTech Connect

    Ring, D.

    1997-05-01

    We present a scenario of neutrino masses and mixing angles. Each generation includes a sterile right-handed neutrino in addition to the usual left-handed one. We assume a hierarchy in their Dirac masses similar to, but much larger than, the hierarchies in the quarks and charged leptons. In addition, we include a Majorana mass term for the sterile neutrinos only. These assumptions prove sufficient to accommodate scales of mass differences and mixing angles consistent with all existing neutrino oscillation data. {copyright} {ital 1997} {ital The American Physical Society}

  12. Measuring Neutrino Oscillations with Nuclear Reactors

    SciTech Connect

    McKeown, R. D.

    2007-10-26

    Since the first direct observations of antineutrino events by Reines and Cowan in the 1950's, nuclear reactors have been an important tool in the study of neutrino properties. More recently, the study of neutrino oscillations has been a very active area of research. The pioneering observation of oscillations by the KamLAND experiment has provided crucial information on the neutrino mixing matrix. New experiments to study the remaining unknown mixing angle are currently under development. These recent studies and potential future developments will be discussed.

  13. Neutrino oscillation above a black hole accretion disk

    SciTech Connect

    Malkus, A.; Kneller, J. P.; McLaughlin, G. C.; Surman, R.

    2015-05-15

    We examine neutrino oscillations in the context of an accretion disk surrounding a black hole. Because accretion disks produce large quantities of neutrinos, they may be home to interesting neutrino oscillation as well. We model accretion disks associated with stellar collapse for the sake of understanding neutrino oscillations. We find that the neutrino oscillations include phenomena seen in the protoneutron star setting as well as phenomena not seen elsewhere.

  14. New MACRO results on atmospheric neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Giacomelli, G.; Margiotta, A.

    2004-06-01

    The final results of the MACRO experiment on atmospheric neutrino oscillations are presented and discussed. The data concern different event topologies with average neutrino energies of ~3 and ~50 GeV. Multiple Coulomb Scattering of the high energy muons in absorbers was used to estimate the neutrino energy of each event. The angular distributions, the L/E_nu distribution, the particle ratios and the absolute fluxes all favour nu_mu --> nu_tau oscillations with maximal mixing and Delta m^2 =0.0023 eV^2. A discussion is made on the Monte Carlos used for the atmospheric neutrino flux. Some results on neutrino astrophysics are also briefly discussed.

  15. Interactions of neutrinos with matter

    NASA Astrophysics Data System (ADS)

    Vannucci, F.

    2017-07-01

    Neutrinos are elementary particles electrically neutral which belong to the family of leptons. As a consequence and in first approximation they only undergo weak processes. This gives them very special properties. They are ideal tools to study precisely the weak interactions, but there is a price to pay: neutrinos are characterized by extremely low probabilities of interactions, they easily penetrate large amount of matter without being stopped. Consequently, it is hard to perform neutrino physics measurements. In practice the difficulty is twofold: in order to accumulate enough statistics, experiments must rely on huge fluxes traversing huge detectors, the number of interactions being obviously proportional to these two factors. As a corollary, backgrounds are difficult to handle because they appear much more commonly than good events. Nevertheless, neutrino interactions have been detected from a variety of sources, both man-made and natural, from very low to very large energies. The aim of this review is to survey our current knowledge about interaction cross sections of neutrinos with matter across all pertinent energy scales. We will see that neutrino interactions cover a large range of processes: nuclear capture, inverse beta-decay, quasi-elastic scattering, resonant pion production, deep inelastic scattering and ultra-high energy interactions. All the gathered information will be used to study weak properties of matter but it will also allow to explore the properties of the neutrinos themselves. In particular, the known three different flavors of neutrinos have different behaviors inside matter and this will be relevant to give some precious understanding about their intrinsic parameters in particular their masses and mixings. As a second order process, neutrinos can undergo electromagnetic interactions. This will also be discussed. Although the corresponding phenomena are not yet experimentally proven by actual measurements, the theory is able to calculate

  16. Extrinsic and intrinsic CPT asymmetries in neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Ohlsson, Tommy; Zhou, Shun

    2015-04-01

    We reconsider the extrinsic and possible intrinsic CPT violation in neutrino oscillations, and point out an identity, i.e., AαβCP = AβαCPT + AαβT, among the CP, T, and CPT asymmetries in oscillations. For three-flavor oscillations in matter of constant density, the extrinsic CPT asymmetries AeeCPT, AeμCPT, AμeCPT, and AμμCPT caused by Earth matter effects have been calculated in the plane of different neutrino energies and baseline lengths. It is found that two analytical conditions can be implemented to describe the main structure of the contours of vanishing extrinsic CPT asymmetries. Finally, without assuming intrinsic CPT symmetry in the neutrino sector, we investigate the possibility to constrain the difference of the neutrino CP-violating phase δ and the antineutrino one δbar using a low-energy neutrino factory and the super-beam experiment ESSνSB. We find that | δ -δbar | ≲ 0.35 π in the former case and | δ -δbar | ≲ 0.7 π in the latter case can be achieved at the 3σ confidence level if δ =δbar = π / 2 is assumed.

  17. Relic neutrino decoupling with flavour oscillations revisited

    SciTech Connect

    Salas, Pablo F. de; Pastor, Sergio

    2016-07-28

    We study the decoupling process of neutrinos in the early universe in the presence of three-flavour oscillations. The evolution of the neutrino spectra is found by solving the corresponding momentum-dependent kinetic equations for the neutrino density matrix, including for the first time the proper collision integrals for both diagonal and off-diagonal elements. This improved calculation modifies the evolution of the off-diagonal elements of the neutrino density matrix and changes the deviation from equilibrium of the frozen neutrino spectra. However, it does not vary the contribution of neutrinos to the cosmological energy density in the form of radiation, usually expressed in terms of the effective number of neutrinos, N{sub eff}. We find a value of N{sub eff}=3.045, in agreement with previous theoretical calculations and consistent with the latest analysis of Planck data. This result does not depend on the ordering of neutrino masses. We also consider the effect of non-standard neutrino-electron interactions (NSI), predicted in many theoretical models where neutrinos acquire mass. For two sets of NSI parameters allowed by present data, we find that N{sub eff} can be reduced down to 3.040 or enhanced up to 3.059.

  18. Relic neutrino decoupling with flavour oscillations revisited

    NASA Astrophysics Data System (ADS)

    de Salas, Pablo F.; Pastor, Sergio

    2016-07-01

    We study the decoupling process of neutrinos in the early universe in the presence of three-flavour oscillations. The evolution of the neutrino spectra is found by solving the corresponding momentum-dependent kinetic equations for the neutrino density matrix, including for the first time the proper collision integrals for both diagonal and off-diagonal elements. This improved calculation modifies the evolution of the off-diagonal elements of the neutrino density matrix and changes the deviation from equilibrium of the frozen neutrino spectra. However, it does not vary the contribution of neutrinos to the cosmological energy density in the form of radiation, usually expressed in terms of the effective number of neutrinos, Neff. We find a value of Neff = 3.045, in agreement with previous theoretical calculations and consistent with the latest analysis of Planck data. This result does not depend on the ordering of neutrino masses. We also consider the effect of non-standard neutrino-electron interactions (NSI), predicted in many theoretical models where neutrinos acquire mass. For two sets of NSI parameters allowed by present data, we find that Neff can be reduced down to 3.040 or enhanced up to 3.059.

  19. Long-baseline neutrino oscillation experiments

    SciTech Connect

    Crane, D.; Goodman, M.

    1994-12-31

    There is no unambiguous definition for long baseline neutrino oscillation experiments. The term is generally used for accelerator neutrino oscillation experiments which are sensitive to {Delta}m{sup 2} < 1.0 eV{sup 2}, and for which the detector is not on the accelerator site. The Snowmass N2L working group met to discuss the issues facing such experiments. The Fermilab Program Advisory Committee adopted several recommendations concerning the Fermilab neutrino program at their Aspen meeting immediately prior to the Snowmass Workshop. This heightened the attention for the proposals to use Fermilab for a long-baseline neutrino experiment at the workshop. The plan for a neutrino oscillation program at Brookhaven was also thoroughly discussed. Opportunities at CERN were considered, particularly the use of detectors at the Gran Sasso laboratory. The idea to build a neutrino beam from KEK towards Superkamiokande was not discussed at the Snowmass meeting, but there has been considerable development of this idea since then. Brookhaven and KEK would use low energy neutrino beams, while FNAL and CERN would plan have medium energy beams. This report will summarize a few topics common to LBL proposals and attempt to give a snapshot of where things stand in this fast developing field.

  20. Resurrection of large lepton number asymmetries from neutrino flavor oscillations

    NASA Astrophysics Data System (ADS)

    Barenboim, Gabriela; Kinney, William H.; Park, Wan-Il

    2017-02-01

    We numerically solve the evolution equations of neutrino three-flavor density matrices, and show that, even if neutrino oscillations mix neutrino flavors, large lepton number asymmetries are still allowed in certain limits by big bang nucleosynthesis.

  1. Accelerator-based neutrino oscillation experiments

    SciTech Connect

    Harris, Deborah A.; /Fermilab

    2007-12-01

    Neutrino oscillations were first discovered by experiments looking at neutrinos coming from extra-terrestrial sources, namely the sun and the atmosphere, but we will be depending on earth-based sources to take many of the next steps in this field. This article describes what has been learned so far from accelerator-based neutrino oscillation experiments, and then describe very generally what the next accelerator-based steps are. In section 2 the article discusses how one uses an accelerator to make a neutrino beam, in particular, one made from decays in flight of charged pions. There are several different neutrino detection methods currently in use, or under development. In section 3 these are presented, with a description of the general concept, an example of such a detector, and then a brief discussion of the outstanding issues associated with this detection technique. Finally, section 4 describes how the measurements of oscillation probabilities are made. This includes a description of the near detector technique and how it can be used to make the most precise measurements of neutrino oscillations.

  2. Neutrino propagation in the Galactic dark matter halo

    NASA Astrophysics Data System (ADS)

    de Salas, P. F.; Lineros, R. A.; Tórtola, M.

    2016-12-01

    Neutrino oscillations are a widely observed and well-established phenomenon. It is also well known that deviations with respect to flavor conversion probabilities in vacuum arise due to neutrino interactions with matter. In this work, we analyze the impact of new interactions between neutrinos and the dark matter present in the Milky Way on the neutrino oscillation pattern. The dark matter-neutrino interaction is modeled by using an effective coupling proportional to the Fermi constant GF with no further restrictions on its flavor structure. For the galactic dark matter profile we consider a homogeneous distribution as well as several density profiles, estimating in all cases the size of the interaction required to get an observable effect at different neutrino energies. Our discussion is mainly focused in the PeV neutrino energy range, to be explored in observatories like IceCube and KM3NeT. The obtained results may be interpreted in terms of a light O (sub -eV - keV ) or weakly interacting massive particlelike dark matter particle or as a new interaction with a mediator of O (sub -eV - keV ) mass.

  3. MACRO results on atmospheric neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Giacomelli, G.; Margiotta, A.

    The final results of the MACRO experiment on atmospheric neutrino oscillations are presented. The data concern different event topologies with average neutrino energies of 3 and 50 GeV. Multiple Coulomb Scattering of the high energy muons was used to estimate the neutrino energy of each event. The angular distributions, the L/Eν distribution, the particle ratios and the absolute fluxes all favour νμ --> ντ oscillations with maximal mixing and Δ m2 =0.0023 \\: eV2. A discussion is made on the Monte Carlos used for the atmospheric neutrino flux. PACS: 13.15.+g ν interactions - 14.60.Pq ν mixing - 96.40.De CR composition energy spectra - 96.40.Tv ν and μ.

  4. Parametrized relativistic dynamical framework for neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Fanchi, John R.

    2017-05-01

    Mass state transitions are a key feature of parametrized relativistic dynamics (PRD). PRD is a manifestly covariant quantum theory with invariant evolution parameter. The theory has been applied to neutrino flavor oscillations between two mass states. It is generalized to transitions between three mass states and applied to the survival of electron neutrinos. The analysis shows that significant differences exist between theoretical results of the conventional model and the PRD model.

  5. Gravitational effects on the neutrino oscillation

    SciTech Connect

    Fornengo, N.; Kim, C.W.; Song, J.; Fornengo, N.; Giunti, C.; Giunti, C.

    1997-08-01

    The propagation of neutrinos in a gravitational field is studied. A method of calculating a covariant quantum-mechanical phase in a curved space-time is presented. The result is used to calculate gravitational effects on the neutrino oscillation in the presence of a gravitational field. We restrict our discussion to the case of the Schwarzschild metric. Specifically, the cases of the radial propagation and the nonradial propagation are considered. A possible application to gravitational lensing of neutrinos is also suggested. {copyright} {ital 1997} {ital The American Physical Society}

  6. A global analysis of neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Fogli, G. L.; Lisi, E.; Marrone, A.; Montanino, D.; Palazzo, A.; Rotunno, A. M.

    2013-02-01

    We present a global analysis of neutrino oscillation data, including high-precision measurements of the neutrino mixing angle θ13 at reactor experiments, which have confirmed previous indications in favor of θ13>0. Recent data presented at this Conference are also included. We focus on the correlations between θ13 and the mixing angle θ23, as well as between θ13 and the neutrino CP-violation phase δ. We find interesting indications for θ23<π/4 and possible hints for δ˜π, with no significant difference between normal and inverted mass hierarchy.

  7. Invariant box-parameterization of neutrino oscillations

    SciTech Connect

    Weiler, Thomas J.; Wagner, DJ

    1998-10-19

    The model-independent 'box' parameterization of neutrino oscillations is examined. The invariant boxes are the classical amplitudes of the individual oscillating terms. Being observables, the boxes are independent of the choice of parameterization of the mixing matrix. Emphasis is placed on the relations among the box parameters due to mixing-matrix unitarity, and on the reduction of the number of boxes to the minimum basis set. Using the box algebra, we show that CP-violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. General analyses of neutrino oscillations among n{>=}3 flavors can readily determine the boxes, which can then be manipulated to yield magnitudes of mixing matrix elements.

  8. Supernova constraints on neutrino oscillation and EoS for proto-neutron star

    SciTech Connect

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Mathews, G. J.; Nakamura, K.; Suzuki, T.

    2014-05-02

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We here discuss how to determine the neutrino temperatures and propose a method to determine still unknown neutrino oscillation parameters, mass hierarchy and θ{sub 13}, simultaneously. Combining the recent experimental constraints on θ{sub 13} with isotopic ratios of the light elements discovered in presolar grains from the Murchison meteorite, we show that our method suggests at a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  9. Neutrinos, Dark Matter and Nuclear Detection

    SciTech Connect

    Goldstein, W H; Bernstein, A; Craig, W W; Johnson, M

    2007-05-29

    Solutions to problems in nuclear non-proliferation and counter-terrorism may be found at the forefront of modern physics. Neutrino oscillation experiments, dark matter searches, and high energy astrophysics, are based on technology advances that have may also have application to nuclear detection. The detection problems share many characteristics, including energy scales, time structures, particle-type, and, of course, the combination of high backgrounds and low signal levels. This convergence of basic and applied physics is realized in non-proliferation and homeland security projects at Lawrence Livermore National Laboratory. Examples described here include reactor anti-neutrino monitoring, dual-phase noble liquid TPC development, gamma-ray telescopes, and nuclear resonance fluorescence.

  10. OPERA neutrino oscillation search: Status and perspectives

    NASA Astrophysics Data System (ADS)

    Gornushkin, Yu.

    2016-07-01

    OPERA is a long-baseline neutrino experiment at the Gran Sasso laboratory (LNGS) designed to search for ν_{{μ}}^{} → ν_{{τ}}^{} oscillations in a direct appearance mode on an event by event basis. OPERA took data in 2008-2012 with the CNGS neutrino beam from CERN. The data analysis is ongoing, with the goal of establishing ν_{{τ}}^{} appearance with a high significance. Complementary studies of the ν_{{μ}}^{} → ν_{{e}}^{} oscillations and atmospheric muons fluxes were performed as well. Current results of the experiment are presented and perspectives discussed.

  11. Effect of flavour oscillations on the detection of supernova neutrinos

    NASA Astrophysics Data System (ADS)

    Choubey, Sandhya; Majumdar, Debasish; Kar, Kamales

    1999-05-01

    Neutrinos and antineutrinos of all three flavours are emitted during the post-bounce phase of a core-collapse supernova with 0954-3899/25/5/305/img1" ALT="(img1) having average energies more than that of 0954-3899/25/5/305/img2" ALT="(img2) They can be detected by the new earthbound detectors like SNO and Super-Kamiokande which are sensitive to neutrinos of all three flavours. In this letter we consider the effect of flavour oscillations on the neutrino flux and their expected number of events at the detector. We do a three-generation analysis and for the mass and mixing schemes we first consider the threefold maximal mixing model consistent with the solar and the atmospheric neutrino data and next a scenario with one icons/Journals/Common/Delta" ALT="Delta" ALIGN="TOP"/> m2~10-11 eV2 (solar range) and the other icons/Journals/Common/Delta" ALT="Delta" ALIGN="TOP"/> m2~10-18 eV2, for which the oscillation length is of the order of the supernova distance. In both these scenarios there are no matter effects in the resultant neutrino spectrum and one is concerned with vacuum oscillations. We find that though neutrino oscillations result in a depletion in the number of icons/Journals/Common/nu" ALT="nu" ALIGN="TOP"/>e and icons/Journals/Common/barnue" ALT="bar nu_e" ALIGN="TOP"/> coming from the supernova, the actual signals at the detectors are appreciable enhanced as the icons/Journals/Common/nu" ALT="nu" ALIGN="TOP"/>e and icons/Journals/Common/barnue" ALT="bar nu_e" ALIGN="TOP"/> energy spectra become harder.

  12. Collective neutrino oscillations in nonspherical geometry

    SciTech Connect

    Dasgupta, Basudeb; Dighe, Amol; Mirizzi, Alessandro; Raffelt, Georg

    2008-08-01

    The rich phenomenology of collective neutrino oscillations has been studied only in one-dimensional or spherically symmetric systems. Motivated by the nonspherical example of coalescing neutron stars, presumably the central engines of short gamma-ray bursts, we use the Liouville equation to formulate the problem for general source geometries. Assuming the neutrino ensemble displays self-maintained coherence, the problem once more becomes effectively one-dimensional along the streamlines of the overall neutrino flux. This approach for the first time provides a formal definition of the 'single-angle approximation' frequently used for supernova neutrinos and allows for a natural generalization to nonspherical geometries. We study the explicit example of a disk-shaped source as a proxy for coalescing neutron stars.

  13. Evidence for Oscillation of Atmospheric Neutrinos

    SciTech Connect

    Fukuda, Y.; Hayakawa, T.; Ichihara, E.; Inoue, K.; Ishihara, K.; Ishino, H.; Itow, Y.; Kajita, T.; Kameda, J.; Kasuga, S.; Kobayashi, K.; Kobayashi, Y.; Koshio, Y.; Miura, M.; Nakahata, M.; Nakayama, S.; Okada, A.; Okumura, K.; Sakurai, N.; Shiozawa, M.; Suzuki, Y.; Takeuchi, Y.; Totsuka, Y.; Yamada, S.; Earl, M.; Habig, A.; Kearns, E.; Messier, M.D.; Scholberg, K.; Stone, J.L.; Sulak, L.R.; Walter, C.W.; Goldhaber, M.; Barszczxak, T.; Casper, D.; Gajewski, W.; Halverson, P.G.; Hsu, J.; Kropp, W.R.; Price, L.R.; Reines, F.; Smy, M.; Sobel, H.W.; Vagins, M.R.; Haines, T.J.; Kielczewska, D.; Ganezer, K.S.; Keig, W.E.; Ellsworth, R.W.; Tasaka, S.; Flanagan, J.W.; Kibayashi, A.; Learned, J.G.; Matsuno, S.; Stenger, V.J.; Takemori, D.; Ishii, T.; Kanzaki, J.; Kobayashi, T.; Mine, S.; Nakamura, K.; Nishikawa, K.; Oyama, Y.; Sakai, A.; Sakuda, M.; Sasaki, O.; Echigo, S.; Kohama, M.; Suzuki, A.T.; Haines, T.J.; and others

    1998-08-01

    We present an analysis of atmospheric neutrino data from a 33.0thinspthinspktonthinspthinspyr (535-day) exposure of the Super-Kamiokande detector. The data exhibit a zenith angle dependent deficit of muon neutrinos which is inconsistent with expectations based on calculations of the atmospheric neutrino flux. Experimental biases and uncertainties in the prediction of neutrino fluxes and cross sections are unable to explain our observation. The data are consistent, however, with two-flavor {nu}{sub {mu}}{leftrightarrow}{nu}{sub {tau}} oscillations with sin{sup 2}2{theta} {gt}0.82 and 5{times}10{sup {minus}4}{lt}{Delta}m{sup 2}{lt}6{times}1 0{sup {minus}3} eV{sup 2} at 90{percent} confidence level. {copyright} {ital 1998} {ital The American Physical Society }

  14. Influence of flavor oscillations on neutrino beam instabilities

    SciTech Connect

    Mendonça, J. T.; Haas, F.; Bret, A.

    2014-09-15

    We consider the collective neutrino plasma interactions and study the electron plasma instabilities produced by a nearly mono-energetic neutrino beam in a plasma. We describe the mutual interaction between neutrino flavor oscillations and electron plasma waves. We show that the neutrino flavor oscillations are not only perturbed by electron plasmas waves but also contribute to the dispersion relation and the growth rates of neutrino beam instabilities.

  15. KamLAND's precision neutrino oscillation measurements

    DOE PAGES

    Decowski, M. P.

    2016-04-13

    The KamLAND experiment started operation in the Spring of 2002 and is operational to this day. The experiment observes signals from electron antineutrinos from distant nuclear reactors. The program, spanning more than a decade, allowed the determination of LMA-MSW as the solution to the solar neutrino transformation results (under the assumption of CPT invariance) and the measurement of various neutrino oscillation parameters. In particular, the solar mass-splitting Δm221 was determined to high precision. Besides the study of neutrino oscillation, KamLAND started the investigation of geologically produced antineutrinos (geo-ν¯e). As a result, the collaboration also reported on a variety of othermore » topics related to particle and astroparticle physics.« less

  16. The OPERA long baseline neutrino oscillation experiment

    NASA Astrophysics Data System (ADS)

    Wilquet, G.

    2008-05-01

    OPERA is a long baseline neutrino oscillation experiment designed to observe the appearance of vτ in a pure vμ beam in the parameter space indicated by the atmospheric neutrinos oscillation signal. The detector is situated in the underground LNGS laboratory under 3 800 water meter equivalent at a distance of 730 km from CERN where the CNGS neutrino beam to which it is exposed originates. It consists of two identical 0.68 kilotons lead/nuclear emulsion targets, each instrumented with a tracking device and complemented by a muon spectrometer. The concept and the status of the detector are described and the first results obtained with cosmic rays and during two weeks of beam commissioning in 2006 are reported.

  17. KamLAND's precision neutrino oscillation measurements

    NASA Astrophysics Data System (ADS)

    Decowski, M. P.

    2016-07-01

    The KamLAND experiment started operation in the Spring of 2002 and is operational to this day. The experiment observes signals from electron antineutrinos from distant nuclear reactors. The program, spanning more than a decade, allowed the determination of LMA-MSW as the solution to the solar neutrino transformation results (under the assumption of CPT invariance) and the measurement of various neutrino oscillation parameters. In particular, the solar mass-splitting Δ m212 was determined to high precision. Besides the study of neutrino oscillation, KamLAND started the investigation of geologically produced antineutrinos (geo-ν‾e). The collaboration also reported on a variety of other topics related to particle and astroparticle physics.

  18. Neutrino oscillation experiments at nuclear reactors

    NASA Astrophysics Data System (ADS)

    Grassi, Marco

    2000-08-01

    The current status of the search for neutrino oscillations at reactors is reviewed, with a particular emphasis given to the final results recently published by the CHOOZ experiment. The results of the Bugey experiments and the status of the Palo Verde experiment are also discussed.

  19. Higgs Boson Mass, Neutrino Oscillations and Inflation

    SciTech Connect

    Shafi, Qaisar

    2008-11-23

    Finding the Standard Model scalar (Higgs) boson is arguably the single most important mission of the LHC. I review predictions for the Higgs boson mass based on stability and perturbativity arguments, taking into account neutrino oscillations. Primordial inflation based on the Coleman-Weinberg potential is briefly discussed.

  20. A framework for testing leptonic unitarity by neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Fong, Chee Sheng; Minakata, Hisakazu; Nunokawa, Hiroshi

    2017-02-01

    If leptonic unitarity is violated by new physics at an energy scale much lower than the electroweak scale, which we call low-scale unitarity violation, it has different characteristic features from those expected in unitarity violation at high-energy scales. They include maintaining flavor universality and absence of zero-distance flavor transition. We present a framework for testing such unitarity violation at low energies by neutrino oscillation experiments. Starting from the unitary 3 active plus N (arbitrary positive integer) sterile neutrino model we show that by restricting the active-sterile and sterile-sterile neutrino mass squared differences to ≳ 0.1 eV2 the oscillation probability in the (3 + N) model becomes insensitive to details of the sterile sector, providing a nearly model-independent framework for testing low-scale unitarity violation. Yet, the presence of the sterile sector leaves trace as a constant probability leaking term, which distinguishes low-scale unitarity violation from the high-scale one. The non-unitary mixing matrix in the active neutrino subspace is common for the both cases. We analyze how severely the unitarity violation can be constrained in ν e -row by taking a JUNO-like setting to simulate medium baseline reactor experiments. Possible modification of the features of the (3 + N) model due to matter effect is discussed to first order in the matter potential.

  1. Neutrino masses, leptogenesis, and sterile neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Tsuyuki, Takanao

    2014-07-01

    We analyze a scenario in which the lightest heavy neutrino N1 is a dark matter candidate and the second-heaviest neutrino N2 decays producing a lepton number. If N1 were in thermal equilibrium, its energy density today would be much larger than that of the observed dark matter, so we consider energy injection by the decay of N2. In this paper, we show the parameters of this scenario that give the correct abundances of dark matter and baryonic matter and also induce the observed neutrino masses. This model can explain a possible sterile neutrino dark matter signal of M1=7 keV in the x-ray observation of x-ray multi-mirror mission.

  2. Oscillations of very low energy atmospheric neutrinos

    SciTech Connect

    Peres, Orlando L. G.; Smirnov, A. Yu.

    2009-06-01

    There are several new features in the production, oscillations, and detection of the atmospheric neutrinos of low energies E < or approx. 100 MeV. The flavor ratio r of muon to electron neutrino fluxes is substantially smaller than 2 and decreases with energy, a significant part of events is due to the decay of invisible muons at rest, etc. Oscillations in a two-layer medium (atmosphere-Earth) should be taken into account. We derive analytical and semianalytical expressions for the oscillation probabilities of these 'sub-sub-GeV' neutrinos. The energy spectra of the e-like events in water Cherenkov detectors are computed, and the dependence of the spectra on the 2-3 mixing angle {theta}{sub 23}, the 1-3 mixing, and the CP-violation phase are studied. We find that variations of {theta}{sub 23} in the presently allowed region change the number of e-like events by about 15%-20% as well as lead to distortion of the energy spectrum. The 1-3 mixing and CP violation can lead to {approx}10% effects. Detailed study of the sub-sub-GeV neutrinos will be possible in future megaton-scale detectors.

  3. Short distance neutrino oscillations with Borexino

    NASA Astrophysics Data System (ADS)

    Caminata, A.; Agostini, M.; Altenmüller, K.; Appel, S.; Bellini, G.; Benziger, J.; Berton, N.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Cavalcante, P.; Chepurnov, A.; Cribier, M.; D'Angelo, D.; Davini, S.; Derbin, A.; di Noto, L.; Durero, M.; Empl, A.; Etenko, A.; Farinon, S.; Fischer, V.; Fomenko, K.; Franco, D.; Gabriele, F.; Gaffiot, J.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Göger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Houdy, Th.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Jonquères, N.; Kaiser, M.; Kobychev, V.; Korablev, D.; Korga, G.; Kryn, D.; Lachenmaier, T.; Lasserre, T.; Laubenstein, M.; Lehnert, B.; Link, J.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Maneschg, W.; Marcocci, S.; Maricic, J.; Mention, G.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Muratova, V.; Musenich, R.; Neumair, B.; Oberauer, L.; Obolensky, M.; Ortica, F.; Pallavicini, M.; Papp, L.; Perasso, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Rossi, N.; Schönert, S.; Scola, L.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Veyssière, C.; Vivier, M.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Winter, J.; Wojcik, M.; Wurm, M.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.

    2016-07-01

    The Borexino detector has convincingly shown its outstanding performances in the low energy, sub-MeV regime through its unprecedented accomplishments in the solar and geo-neutrinos detection. These performances make it the ideal tool to accomplish a state-of-the-art experiment able to test unambiguously the long-standing issue of the existence of a sterile neutrino, as suggested by the several anomalous results accumulated over the past two decades, i.e. the outputs of the LSND and Miniboone experiments, the results of the source calibration of the two Gallium solar neutrino experiments, and the recently hinted reactor anomaly. The SOX project will exploit two sources, based on Chromium and Cerium, respectively, which deployed under the experiment, in a location foreseen on purpose at the time of the construction of the detector, will emit two intense beams of neutrinos (Cr) and anti-neutrinos (Ce). Interacting in the active volume of the liquid scintillator, each beam would create an unmistakable spatial wave pattern in case of oscillation of the νe (or ν̅e) into the sterile state: such a pattern would be the smoking gun proving the existence of the new sterile member of the neutrino family. Otherwise, its absence will allow setting a very stringent limit on its existence.

  4. Resolving Standard and Nonstandard CP Violation Phases in Neutrino Oscillations

    SciTech Connect

    Gago, A. M.; Minakata, H.; Uchinami, S.; Nunokawa, H.; Zukanovich Funchal, R.

    2010-03-30

    Neutrino oscillations can exhibit extra CP violation effects, beyond those expected from the standard Kobayashi-Maskawa phase delta, if non-standard neutrino interactions are at play. We show that it is possible to disentangle the two CP violating effects by measuring muon neutrino appearance using a near-far two detector setting in a neutrino factory experiment.

  5. Effect of violation of quantum mechanics on neutrino oscillation

    SciTech Connect

    Liu, Y.; Hu, L.; Ge, M.

    1997-11-01

    The effect of quantum mechanics violation due to quantum gravity on neutrino oscillation is investigated. It is found that the mechanism introduced by Ellis, Hagelin, Nanopoulos, and Srednicki through the modification of the Liouville equation can affect neutrino oscillation behavior and may be taken as a new solution of the solar neutrino problem. {copyright} {ital 1997} {ital The American Physical Society}

  6. Coupling between ion-acoustic waves and neutrino oscillations.

    PubMed

    Haas, Fernando; Pascoal, Kellen Alves; Mendonça, José Tito

    2017-01-01

    The work investigates the coupling between ion-acoustic waves and neutrino flavor oscillations in a nonrelativistic electron-ion plasma under the influence of a mixed neutrino beam. Neutrino oscillations are mediated by the flavor polarization vector dynamics in a material medium. The linear dispersion relation around homogeneous static equilibria is developed. When resonant with the ion-acoustic mode, the neutrino flavor oscillations can transfer energy to the plasma exciting a new fast unstable mode in extreme astrophysical scenarios. The growth rate and the unstable wavelengths are determined in typical type II supernova parameters. The predictions can be useful for a new indirect probe on neutrino oscillations in nature.

  7. Coupling between ion-acoustic waves and neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Haas, Fernando; Pascoal, Kellen Alves; Mendonça, José Tito

    2017-01-01

    The work investigates the coupling between ion-acoustic waves and neutrino flavor oscillations in a nonrelativistic electron-ion plasma under the influence of a mixed neutrino beam. Neutrino oscillations are mediated by the flavor polarization vector dynamics in a material medium. The linear dispersion relation around homogeneous static equilibria is developed. When resonant with the ion-acoustic mode, the neutrino flavor oscillations can transfer energy to the plasma exciting a new fast unstable mode in extreme astrophysical scenarios. The growth rate and the unstable wavelengths are determined in typical type II supernova parameters. The predictions can be useful for a new indirect probe on neutrino oscillations in nature.

  8. Neutrino interaction with background matter in a non-inertial frame

    NASA Astrophysics Data System (ADS)

    Dvornikov, Maxim

    2015-07-01

    We study Dirac neutrinos propagating in rotating background matter. First we derive the Dirac equation for a single massive neutrino in the non-inertial frame, where matter is at rest. This equation is written in the effective curved spacetime corresponding to the co-rotating frame. We find the exact solution of the Dirac equation. The neutrino energy levels for ultrarelativistic particles are obtained. Then we discuss several neutrino mass eigenstates, with a nonzero mixing between them, interacting with rotating background matter. We derive the effective Schrödinger equation governing neutrino flavor oscillations in rotating matter. The new resonance condition for neutrino oscillations is obtained. We also examine the correction to the resonance condition caused by the matter rotation.

  9. The Status of Sterile Neutrino Dark Matter

    NASA Astrophysics Data System (ADS)

    Horiuchi, Shunsaku

    2017-01-01

    The sterile neutrino is a particle dark matter candidate with a host of observable signatures that is close to being fully tested. I will first review the implications for structure formation, comparing predictions of sterile neutrino cosmologies against observations. I will then review analyses of X-rays from dark matter concentrations in search of mono-energetic photons predicted from sterile neutrino dark matter decays. Structure formation and X-rays offer important complementary probes, and I will highlight the recent rapid progress in testing the sterile neutrino parameter space. I will also discuss implications of analyses leading to the detection of X-ray lines from clusters of galaxies and Andromeda.

  10. Neutrino propagation in color superconducting quark matter

    NASA Astrophysics Data System (ADS)

    Carter, Gregory W.; Reddy, Sanjay

    2000-11-01

    We calculate the neutrino mean free path in color superconducting quark matter, and employ it to study the cooling of matter via neutrino diffusion in the superconducting phase as compared to a free quark phase. The cooling process slows when quark matter undergoes a second order phase transition to a superconducting phase at the critical temperature Tc. Cooling subsequently accelerates as the temperature decreases below Tc. This will directly impact the early evolution of a newly born neutron star, should its core contain quark matter. Consequently, there may be observable changes in the early neutrino emission which would provide evidence for superconductivity in hot and dense matter.

  11. Radiative neutrino mass, dark matter, and leptogenesis

    SciTech Connect

    Gu Peihong; Sarkar, Utpal

    2008-05-15

    We propose an extension of the standard model, in which neutrinos are Dirac particles and their tiny masses originate from a one-loop radiative diagram. The new fields required by the neutrino mass generation also accommodate the explanation for the matter-antimatter asymmetry and dark matter in the Universe.

  12. Dark Matter Density from Heavy Neutrino Decays

    NASA Astrophysics Data System (ADS)

    Saadat, Hassan; Rostampour, Malihe

    2012-10-01

    As we know the heavy neutrino decays is a successful model for describing dark matter and also is origin of the universe entropy. In this paper we use heavy neutrino decays to calculate time-dependent dark matter density. In that case we use observational data to fixing our solutions.

  13. Implications of CHOOZ results for the decoupling of solar and atmospheric neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Bilenky, S. M.; Giunti, C.

    1998-12-01

    We have considered the results of solar and atmospheric neutrino oscillation experiments in the scheme of mixing of three neutrinos with a mass hierarchy. It is shown that (if m32-m12>10-3 eV2) the recent results of the CHOOZ experiment imply that Ue32≪1 (U is the neutrino mixing matrix), that the oscillations of solar neutrinos are described by the two-generation formalism and that the oscillations of solar and atmospheric neutrinos decouple. It is also shown that if not only Ue32≪1 but also Ue3≪1, then the oscillations of atmospheric neutrinos do not depend on matter effects and are described by the two-generation formalism. In this case, with an appropriate identification of the mixing parameters, the two-generation analyses of solar and atmospheric neutrino data provide direct information on the mixing parameters of three neutrinos. We discuss the possibility to get information on Ue32 in long-baseline neutrino oscillation experiments.

  14. Neutrino oscillations with MINOS and MINOS+

    DOE PAGES

    Whitehead, Leigh H.

    2016-03-07

    The MINOS experiment ran from 2003 until 2012 and collected a data sample including 10.71 x 1020 protons-on-target (POT) of beam neutrinos, 3.36 x 1020 POT of beam antineutrinos and an atmospheric neutrino exposure of 37.88 kt-yrs. The final measurement of the atmospheric neutrino oscillation parameters, Δm232 and θ23, came from a full three flavour oscillation analysis of the combined CCvμ and CCv¯μ beam and atmospheric samples and the CCve and CCv¯e appearance samples. This analysis yielded the most precise measurement of the atmospheric mass splitting dm^2_32 performed to date. The results are |Δm232| = [2.28 - 2.46] x 10-3more » eV2 (68%) and sin2θ23 = 0.35-0.65 (90%) in the normal hierarchy, and |Δm232| = [2.32 - 2.53]x10-3 eV2 (68%) and sin2θ23 = 0.34-0.67 (90%) in the inverted hierarchy. The successor to MINOS in the NOv A era at FNAL, MINOS+, is now collecting data mostly in the 3-10 GeV region, and an analysis of nu_mu disappearance using the first 2.99 x 1020 POT of data produced results very consistent with those from MINOS. Here, future data will further test the standard neutrino oscillation paradigm and allow for improved searches for exotic phenomena including sterile neutrinos, large extra dimensions and non-standard interactions.« less

  15. Neutrino oscillations with MINOS and MINOS+

    NASA Astrophysics Data System (ADS)

    Whitehead, L. H.

    2016-07-01

    The MINOS experiment ran from 2003 until 2012 and collected a data sample including 10.71 ×1020 protons-on-target (POT) of beam neutrinos, 3.36 ×1020 POT of beam antineutrinos and an atmospheric neutrino exposure of 37.88 kt yrs. The final measurement of the atmospheric neutrino oscillation parameters, Δ m322 and θ23, came from a full three flavour oscillation analysis of the combined CC νμ and CC ν‾μ beam and atmospheric samples and the CC νe and CC ν‾e appearance samples. This analysis yielded the most precise measurement of the atmospheric mass splitting Δ m322 performed to date. The results are | Δ m322 | = [ 2.28- 2.46 ] ×10-3 eV2 (68%) and sin2 ⁡θ23 = 0.35- 0.65 (90%) in the normal hierarchy, and | Δ m322 | = [ 2.32- 2.53 ] ×10-3 eV2 (68%) and sin2 ⁡θ23 = 0.34- 0.67 (90%) in the inverted hierarchy. The successor to MINOS in the NOνA era at FNAL, MINOS+, is now collecting data mostly in the 3- 10 GeV region, and an analysis of νμ disappearance using the first 2.99 ×1020 POT of data produced results very consistent with those from MINOS. Future data will further test the standard neutrino oscillation paradigm and allow for improved searches for exotic phenomena including sterile neutrinos, large extra dimensions and non-standard interactions.

  16. Dark matter decaying into a Fermi sea of neutrinos

    NASA Astrophysics Data System (ADS)

    Bjælde, Ole Eggers; Das, Subinoy

    2010-08-01

    We study the possible decay of a coherently oscillating scalar field, interpreted as dark matter, into light fermions. Specifically, we consider a scalar field with sub-eV mass decaying into a Fermi sea of neutrinos. We recognize the similarity between our scenario and inflationary preheating where a coherently oscillating scalar field decays into standard model particles. Like the case of fermionic preheating, we find that Pauli blocking controls the dark matter decay into the neutrino sea. The radius of the Fermi sphere depends on the expansion of the universe leading to a time varying equation of state of dark matter. This makes the scenario very rich and we show that the decay rate might be different at different cosmological epochs. We categorize this in two interesting regimes and then study the cosmological perturbations to find the impact on structure formation. We find that the decay may help in alleviating some of the standard problems related to cold dark matter.

  17. Neutrino oscillations in discrete-time quantum walk framework

    NASA Astrophysics Data System (ADS)

    Mallick, Arindam; Mandal, Sanjoy; Chandrashekar, C. M.

    2017-02-01

    Here we present neutrino oscillation in the framework of quantum walks. Starting from a one spatial dimensional discrete-time quantum walk we present a scheme of evolutions that will simulate neutrino oscillation. The set of quantum walk parameters which is required to reproduce the oscillation probability profile obtained in both, long range and short range neutrino experiment is explicitly presented. Our scheme to simulate three-generation neutrino oscillation from quantum walk evolution operators can be physically realized in any low energy experimental set-up with access to control a single six-level system, a multiparticle three-qubit or a qubit-qutrit system. We also present the entanglement between spins and position space, during neutrino propagation that will quantify the wave function delocalization around instantaneous average position of the neutrino. This work will contribute towards understanding neutrino oscillation in the framework of the quantum information perspective.

  18. High intensity neutrino oscillation facilities in Europe

    DOE PAGES

    Edgecock, T. R.; Caretta, O.; Davenne, T.; ...

    2013-02-20

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ– beams in a storage ring. The far detector in this case ismore » a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. Furthermore, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.« less

  19. High intensity neutrino oscillation facilities in Europe

    SciTech Connect

    Edgecock, T. R.; Caretta, O.; Davenne, T.; Densam, C.; Fitton, M.; Kelliher, D.; Loveridge, P.; Machida, S.; Prior, C.; Rogers, C.; Rooney, M.; Thomason, J.; Wilcox, D.; Wildner, E.; Efthymiopoulos, I.; Garoby, R.; Gilardoni, S.; Hansen, C.; Benedetto, E.; Jensen, E.; Kosmicki, A.; Martini, M.; Osborne, J.; Prior, G.; Stora, T.; Melo Mendonca, T.; Vlachoudis, V.; Waaijer, C.; Cupial, P.; Chance, A.; Longhin, A.; Payet, J.; Zito, M.; Baussan, E.; Bobeth, C.; Bouquerel, E.; Dracos, M.; Gaudiot, G.; Lepers, B.; Osswald, F.; Poussot, P.; Vassilopoulos, N.; Wurtz, J.; Zeter, V.; Bielski, J.; Kozien, M.; Lacny, L.; Skoczen, B.; Szybinski, B.; Ustrycka, A.; Wroblewski, A.; Marie-Jeanne, M.; Balint, P.; Fourel, C.; Giraud, J.; Jacob, J.; Lamy, T.; Latrasse, L.; Sortais, P.; Thuillier, T.; Mitrofanov, S.; Loiselet, M.; Keutgen, Th.; Delbar, Th.; Debray, F.; Trophine, C.; Veys, S.; Daversin, C.; Zorin, V.; Izotov, I.; Skalyga, V.; Burt, G.; Dexter, A. C.; Kravchuk, V. L.; Marchi, T.; Cinausero, M.; Gramegna, F.; De Angelis, G.; Prete, G.; Collazuol, G.; Laveder, M.; Mazzocco, M.; Mezzetto, M.; Signorini, C.; Vardaci, E.; Di Nitto, A.; Brondi, A.; La Rana, G.; Migliozzi, P.; Moro, R.; Palladino, V.; Gelli, N.; Berkovits, D.; Hass, M.; Hirsh, T. Y.; Schaumann, M.; Stahl, A.; Wehner, J.; Bross, A.; Kopp, J.; Neuffer, D.; Wands, R.; Bayes, R.; Laing, A.; Soler, P.; Agarwalla, S. K.; Cervera Villanueva, A.; Donini, A.; Ghosh, T.; Gomez Cadenas, J. J.; Hernandez, P.; Martin-Albo, J.; Mena, O.; Burguet-Castell, J.; Agostino, L.; Buizza-Avanzini, M.; Marafini, M.; Patzak, T.; Tonazzo, A.; Duchesneau, D.; Mosca, L.; Bogomilov, M.; Karadzhov, Y.; Matev, R.; Tsenov, R.; Akhmedov, E.; Blennow, M.; Lindner, M.; Schwetz, T.; Fernandez Martinez, E.; Maltoni, M.; Menendez, J.; Giunti, C.; Gonzalez Garcia, M. C.; Salvado, J.; Coloma, P.; Huber, P.; Li, T.; Lopez Pavon, J.; Orme, C.; Pascoli, S.; Meloni, D.; Tang, J.; Winter, W.; Ohlsson, T.; Zhang, H.; Scotto-Lavina, L.; Terranova, F.; Bonesini, M.; Tortora, L.; Alekou, A.; Aslaninejad, M.; Bontoiu, C.; Kurup, A.; Jenner, L. J.; Long, K.; Pasternak, J.; Pozimski, J.; Back, J. J.; Harrison, P.; Beard, K.; Bogacz, A.; Berg, J. S.; Stratakis, D.; Witte, H.; Snopok, P.; Bliss, N.; Cordwell, M.; Moss, A.; Pattalwar, S.; Apollonio, M.

    2013-02-20

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. Furthermore, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.

  20. Theory of oscillations and sterile neutrinos

    NASA Astrophysics Data System (ADS)

    Palazzo, Antonio

    2014-11-01

    We present a concise review of the theoretical status of neutrino oscillations within the (standard) 3-flavor framework and the (non-standard) 4-flavor scheme endowed with one additional sterile species (the so-called 3+1 scheme). We emphasize the slight overall preference that recently emerged for CP-violation in the 3-flavor analysis and highlight the unique role of the global data combination in the near future. After a brief introduction of the motivations for light (eV) sterile neutrinos, we discuss the bounds on their mixing with the electron neutrinos, attainable from the solar sector. The upper limit so obtained is independent of the reactor neutrino fluxes, whose calculations are affected by systematic uncertainties not completely under control. Finally, we highlight the possibility to explore sub-eV "super-light" sterile neutrinos exploiting the θ13-dedicated reactor experiments also commenting on the robustness of the 3- flavor results within the enlarged 3+1 scheme.

  1. Oscillation of Very Low Energy Atmospheric Neutrinos

    SciTech Connect

    Peres, Orlando L. G.

    2010-03-30

    We discuss the oscillation effects of sub-sub-GeV atmospheric neutrinos, the sample with energies E < or approx. 100 MeV. The energy spectra of the e-like events in water Cherenkov detectors are computed and dependence of the spectra on the 2-3 mixing angle, theta{sub 23}, the 1-3 mixing and CP-violation phase are studied.

  2. Search for neutrino oscillations at LAMPF

    SciTech Connect

    Harper, R.W.; Ling, T.Y.; Mitchell, J.W.; Romanowski, T.A.; Smith, E.S.; Timko, M.; Freedman, S.J.; Napolitano, J.; Fujikawa, B.K.; Mckeown, R.D.

    1986-01-01

    The decays of stopped pions in the LAMPF beam stop present a unique opportunity to probe neutrino oscillations in the mass region of deltam/sup 2/ approx.0.1eV/sup 2/ and mixing parameters as low was sin/sup 2/2THETA approx.10/sup -3/. The appearance of anti nu/sub e/ will be measured with high sensitivity by Experiment 645 during the run cycle that begins in the summer of 1986.

  3. LSND neutrino oscillation results and implications

    SciTech Connect

    Louis, W.C.; LSND Collaboration

    1998-03-01

    The LSND experiment at Los Alamos has conducted searches for {anti {nu}}{sub {mu}} {r_arrow} {anti {nu}}{sub e} oscillations using {anti {nu}}{sub {mu}} from {mu}{sup +} decay at rest and for {nu}{sub {mu}} {r_arrow} {nu}{sub e} oscillations using {nu}{sub {mu}} from {pi}{sup +} decay in flight. For the {anti {nu}}{sub {mu}} {r_arrow} {anti {nu}}{sub e} search, a total excess of 51.8{sub {minus}16.9}{sup +18.7} {+-} 8.0 events is observed with e{sup +} energy between 20 and 60 MeV, while for the {nu}{sub mu} {r_arrow} {nu}{sub e} search, a total excess of 18.1 {+-} 6.6 {+-} 4.0 events is observed with e{sup {minus}} energy between 60 and 200 MeV. If attributed to neutrino oscillations, these excesses correspond to oscillation probabilities (averaged over the experimental energies and spatial acceptances) of (0.31 {+-} 0.12 {+-} 0.05)% and (0.26 {+-} 0.10 {+-} 0.05)%, respectively. For the future, the BooNE experiment at Fermilab could prove that neutrino oscillations occur and make precision measurements of {Delta}m{sup 2} and sin{sup 2}2{theta}.

  4. R-Charged Black Hole and Neutrino Oscillation

    NASA Astrophysics Data System (ADS)

    Saadat, Hassan; Rostampour, Malihe

    2012-09-01

    In this paper we consider neutrino oscillation in general curved space-times. Then we calculate neutrino oscillation length in the R-charged black hole background, which is a five dimensional space-time, and compare it with the results of various backgrounds. We obtain effect of the electrical charge corresponding to the chemical potential on the oscillation length.

  5. Sterile neutrino dark matter with supersymmetry

    NASA Astrophysics Data System (ADS)

    Shakya, Bibhushan; Wells, James D.

    2017-08-01

    Sterile neutrino dark matter, a popular alternative to the WIMP paradigm, has generally been studied in non-supersymmetric setups. If the underlying theory is supersymmetric, we find that several interesting and novel dark matter features can arise. In particular, in scenarios of freeze-in production of sterile neutrino dark matter, its superpartner, the sterile sneutrino, can play a crucial role in early Universe cosmology as the dominant source of cold, warm, or hot dark matter, or of a subdominant relativistic population of sterile neutrinos that can contribute to the effective number of relativistic degrees of freedom Neff during big bang nucleosynthesis.

  6. Precision Measurements of Long-Baseline Neutrino Oscillation at LBNF

    DOE PAGES

    Worcester, Elizabeth

    2015-08-06

    In a long-baseline neutrino oscillation experiment, the primary physics objectives are to determine the neutrino mass hierarchy, to determine the octant of the neutrino mixing angle θ23, to search for CP violation in neutrino oscillation, and to precisely measure the size of any CP-violating effect that is discovered. This presentation provides a brief introduction to these measurements and reports on efforts to optimize the design of a long-baseline neutrino oscillation experiment, the status of LBNE, and the transition to an international collaboration at LBNF.

  7. Precision Measurements of Long-Baseline Neutrino Oscillation at LBNF

    SciTech Connect

    Worcester, Elizabeth

    2015-08-06

    In a long-baseline neutrino oscillation experiment, the primary physics objectives are to determine the neutrino mass hierarchy, to determine the octant of the neutrino mixing angle θ23, to search for CP violation in neutrino oscillation, and to precisely measure the size of any CP-violating effect that is discovered. This presentation provides a brief introduction to these measurements and reports on efforts to optimize the design of a long-baseline neutrino oscillation experiment, the status of LBNE, and the transition to an international collaboration at LBNF.

  8. ν-K0 Analogy, Dirac-Majorana Neutrino Duality and the Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Lipmanov, E. M.

    The intent of this paper is to convey a new primary physical idea of a Dirac-Majorana neutrino duality in relation to the topical problem of neutrino oscillations. In view of the new atmospheric, solar and the LSND neutrino oscillation data, the Pontecorvo ν - K0 oscillation analogy is generalized to the notion of neutrino duality with substantially different physical meaning ascribed to the long-baseline and the short-baseline neutrino oscillations. At the level of CP-invariance, the suggestion of dual neutrino properties defines the symmetric two-mixing-angle form of the widely discussed four-neutrino (2 +2)-mixing scheme, as a result of the lepton charge conservation selection rule and a minimum of two Dirac neutrino fields. With neutrino duality, the two-doublet structure of the Majorana neutrino mass spectrum is a vestige of the two-Dirac-neutrino origin. The fine neutrino mass doublet structure is natural because it is produced by a lepton charge symmetry violating perturbation on a zero-approximation system of two twofold mass-degenerate Dirac neutrino-antineutrino pairs. A set of inferences related to the neutrino oscillation phenomenology in vacuum is considered.

  9. Diffuse supernova neutrinos: oscillation effects, stellar cooling and progenitor mass dependence

    SciTech Connect

    Lunardini, Cecilia; Tamborra, Irene E-mail: tamborra@mpp.mpg.de

    2012-07-01

    We estimate the diffuse supernova neutrino background (DSNB) using the recent progenitor-dependent, long-term supernova simulations from the Basel group and including neutrino oscillations at several post-bounce times. Assuming multi-angle matter suppression of collective effects during the accretion phase, we find that oscillation effects are dominated by the matter-driven MSW resonances, while neutrino-neutrino collective effects contribute at the 5–10% level. The impact of the neutrino mass hierarchy, of the time-dependent neutrino spectra and of the diverse progenitor star population is 10% or less, small compared to the uncertainty of at least 25% of the normalization of the supernova rate. Therefore, assuming that the sign of the neutrino mass hierarchy will be determined within the next decade, the future detection of the DSNB will deliver approximate information on the MSW-oscillated neutrino spectra. With a reliable model for neutrino emission, its detection will be a powerful instrument to provide complementary information on the star formation rate and for learning about stellar physics.

  10. Search for muon neutrino disappearance due to sterile neutrino oscillations with the MINOS/MINOS+ experiment

    NASA Astrophysics Data System (ADS)

    Todd, J.; Chen, R.; Huang, J.; ">MINOS, neutrino oscillations have successfully explained a wide range of neutrino oscillation data. However, anomalous results, such as the electron antineutrino appearance excesses seen by LSND and MiniBooNE, can be explained by the addition of a sterile neutrino at a larger mass scale than the existing three neutrino mass states. MINOS is a two-detector, long-baseline neutrino oscillation experiment optimized to measure muon neutrino disappearance in the NuMI neutrino beam. MINOS+ is the continuation of the MINOS experiment with the NuMI beam in a medium energy configuration. In the model with one sterile neutrino flavor added to the three active neutrino flavors, a sterile neutrino causing electron antineutrino appearance at LSND and MiniBooNE would also cause muon neutrino disappearance at MINOS. The sterile neutrino signature would be seen as modulations at high energy in the charged-current muon neutrino spectrum and a depletion of events in the neutral current spectrum. These proceedings show new results from fitting neutral-current and charged-current energy spectra from MINOS and MINOS+ data to a neutrino oscillation model assuming one sterile neutrino.

  11. Axion-Assisted Production of Sterile Neutrino Dark Matter

    SciTech Connect

    Berlin, Asher; Hooper, Dan

    2016-10-12

    Sterile neutrinos can be generated in the early universe through oscillations with active neutrinos and represent a popular and well-studied candidate for our universe's dark matter. Stringent constraints from X-ray and gamma-ray line searches, however, have excluded the simplest of such models. In this letter, we propose a novel alternative to the standard scenario in which the mixing angle between the sterile and active neutrinos is a dynamical quantity, induced through interactions with a light axion-like field. As the energy density of the axion-like particles is diluted by Hubble expansion, the degree of mixing is reduced at late times, suppressing the decay rate and easily alleviating any tension with X-ray or gamma-ray constraints. We present a simple model which illustrates the phenomenology of this scenario, and also describe a framework in which the QCD axion is responsible for the production of sterile neutrinos in the early universe.

  12. Axion-assisted production of sterile neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Berlin, Asher; Hooper, Dan

    2017-04-01

    Sterile neutrinos can be generated in the early universe through oscillations with active neutrinos and represent a popular and well-studied candidate for our Universe's dark matter. Stringent constraints from X-ray and gamma-ray line searches, however, have excluded the simplest of such models. In this paper, we propose a novel alternative to the standard scenario in which the mixing angle between the sterile and active neutrinos is a dynamical quantity, induced through interactions with a light axionlike field. As the energy density of the axionlike particles is diluted by Hubble expansion, the degree of mixing is reduced at late times, suppressing the decay rate and easily alleviating any tension with X-ray or gamma-ray constraints. We present a simple model which illustrates the phenomenology of this scenario, and also describe a framework in which the QCD axion is responsible for the production of sterile neutrinos in the early universe.

  13. Can sterile neutrinos be the dark matter?

    PubMed

    Seljak, Uros; Makarov, Alexey; McDonald, Patrick; Trac, Hy

    2006-11-10

    We use the Ly-alpha forest power spectrum measured by the Sloan Digital Sky Survey and high-resolution spectroscopy observations in combination with cosmic microwave background and galaxy clustering constraints to place limits on a sterile neutrino as a dark matter candidate in the warm dark matter scenario. Such a neutrino would be created in the early Universe through mixing with an active neutrino and would suppress structure on scales smaller than its free-streaming scale. We ran a series of high-resolution hydrodynamic simulations with varying neutrino masses to describe the effect of a sterile neutrino on the Ly-alpha forest power spectrum. We find that the mass limit is m(s) >13 keV at 95% C.L. (9 keV at 99.9%), which is above the upper limit allowed by x-ray constraints, excluding this candidate from being all of the dark matter in this model.

  14. The not-so-sterile 4th neutrino: constraints on new gauge interactions from neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Kopp, Joachim; Welter, Johannes

    2014-12-01

    Sterile neutrino models with new gauge interactions in the sterile sector are phenomenologically interesting since they can lead to novel effects in neutrino oscillation experiments, in cosmology and in dark matter detectors, possibly even explaining some of the observed anomalies in these experiments. Here, we use data from neutrino oscillation experiments, in particular from MiniBooNE, MINOS and solar neutrino experiments, to constrain such models. We focus in particular on the case where the sterile sector gauge boson A ' couples also to Standard Model particles (for instance to the baryon number current) and thus induces a large Mikheyev-Smirnov-Wolfenstein potential. For eV-scale sterile neutrinos, we obtain strong constraints especially from MINOS, which restricts the strength of the new interaction to be less than ˜ 10 times that of the Standard Model weak interaction unless active-sterile neutrino mixing is very small (sin2 θ 24 ≲ 10-3). This rules out gauge forces large enough to affect short-baseline experiments like MiniBooNE and it imposes nontrivial constraints on signals from sterile neutrino scattering in dark matter experiments.

  15. Approach to the propagation of massive neutrinos in dense matter by Wigner functions

    NASA Astrophysics Data System (ADS)

    Sirera Tomas, Miguel

    The problem of massive neutrinos comes from Grant Unification Theories but also from the so called Neutrino Solar Puzzle. The solution of this puzzle seems to be in the neutrinos physics and to need that the neutrinos are particles with mass. The possible mass of the neutrinos is not only important for Solar Neutrinos but also in other astrophysical environments such as Supernovae, Neutron Stars or The Early Universe. If the neutrinos are particles with mass, or at least one of their generations, oscillations are produced in both vacuum and matter. The oscillation in matter could cause the so called MSW effect, that transforms a neutrino flavour to another. The problem of the propagation of neutrinos in matter has been dealt with by many authors who have usually solved the covariant motion equations, and sometimes by Green Functions. In this work, this has been done using statistical techniques by Wigner Functions, which do not only allow us to study the propagation ways but also to know the behavior of the neutrinos field in equilibrium. On the other hand, the astrophysical systems, that we have commented above, yield a great amount of neutrinos which spread through them and are finally emitted to space, and so it is important to have a transport equation that explain how a neutrinos distribution is spread which is not in equilibrium. It is possible to achieve this equation by motion equations of the Wigner Functions.

  16. Matter density versus distance for the neutrino beam from Fermilab to Lead, South Dakota, and comparison of oscillations with variable and constant density

    NASA Astrophysics Data System (ADS)

    Roe, Byron

    2017-06-01

    This paper is divided into two parts. In the first part, the material densities passed through for neutrinos going from FNAL to Sanford Laboratory are calculated using two recent density tables, Crustal [G. Laske, G. Masters, Z. Ma, and M. Pasyanos, Update on CRUST1.0—A 1-degree global model of Earth's crust, Geophys. Res. Abstracts 15, EGU2013-2658 (2013),; For the programs and tables, see the website: http://igppweb.ucsd.edu/ gabi/crust1.html.] and Shen-Ritzwoller [W. Shen and M. H. Ritzwoller, Crustal and uppermost mantle structure beneath the United States, J. Geophys. Res.: Solid Earth 121, 4306 (2016)], as well as the values from an older table PEMC [A. M. Dziewonski, A. L. Hales, and E. R. Lapwood, Parametrically simple earth models consistent with geophysical data, Phys. Earth Plan. Int. 10, 12 (1975); For further information see the website: http://ds.iris.edu/ds/products/emc-pem/.]. In the second part, neutrino oscillations at Sanford Laboratory are examined for the variable density table of Shen-Ritzwoller. These results are then compared with oscillation results using the mean density from the Shen-Ritzwoller tables and with one other fixed density. For the tests made here, the mean density results are quite similar to the results using the variable density vs distance.

  17. Neutrino oscillations and the Landau-Zener formula

    SciTech Connect

    Kim, C.W.; Sze, W.K.; Nussinov, S.

    1987-06-15

    We discuss solar-neutrino oscillations and the Landau-Zener probability using a heuristic picture in analogy with an electron spin in a time-dependent magnetic field. The extreme nonadiabatic resonant oscillation is also briefly investigated.

  18. Atmospheric neutrinos, ν e- ν s oscillations and a novel neutrino evolution equation

    NASA Astrophysics Data System (ADS)

    Akhmedov, Evgeny

    2016-08-01

    If a sterile neutrino ν s with an eV-scale mass and a sizeable mixing to the electron neutrino exists, as indicated by the reactor and gallium neutrino anomalies, a strong resonance enhancement of ν e -ν s oscillations of atmospheric neutrinos should occur in the TeV energy range. At these energies neutrino flavour transitions in the 3+1 scheme depend on just one neutrino mass squared difference and are fully described within a 3-flavour oscillation framework. We demonstrate that the flavour transitions of atmospheric ν e can actually be very accurately described in a 2-flavour framework, with neutrino flavour evolution governed by an inhomogeneous Schrödinger-like equation. Evolution equations of this type have not been previously considered in the theory of neutrino oscillations.

  19. Evidence for an oscillatory signature in atmospheric neutrino oscillations.

    PubMed

    Ashie, Y; Hosaka, J; Ishihara, K; Itow, Y; Kameda, J; Koshio, Y; Minamino, A; Mitsuda, C; Miura, M; Moriyama, S; Nakahata, M; Namba, T; Nambu, R; Obayashi, Y; Shiozawa, M; Suzuki, Y; Takeuchi, Y; Taki, K; Yamada, S; Ishitsuka, M; Kajita, T; Kaneyuki, K; Nakayama, S; Okada, A; Okumura, K; Ooyabu, T; Saji, C; Takenaga, Y; Desai, S; Kearns, E; Likhoded, S; Stone, J L; Sulak, L R; Walter, C W; Wang, W; Goldhaber, M; Casper, D; Cravens, J P; Gajewski, W; Kropp, W R; Liu, D W; Mine, S; Smy, M B; Sobel, H W; Sterner, C W; Vagins, M R; Ganezer, K S; Hill, J; Keig, W E; Jang, J S; Kim, J Y; Lim, I T; Ellsworth, R W; Tasaka, S; Guillian, G; Kibayashi, A; Learned, J G; Matsuno, S; Takemori, D; Messier, M D; Hayato, Y; Ichikawa, A K; Ishida, T; Ishii, T; Iwashita, T; Kobayashi, T; Maruyama, T; Nakamura, K; Nitta, K; Oyama, Y; Sakuda, M; Totsuka, Y; Suzuki, A T; Hasegawa, M; Hayashi, K; Inagaki, T; Kato, I; Maesaka, H; Morita, T; Nakaya, T; Nishikawa, K; Sasaki, T; Ueda, S; Yamamoto, S; Haines, T J; Dazeley, S; Hatakeyama, S; Svoboda, R; Blaufuss, E; Goodman, J A; Sullivan, G W; Turcan, D; Scholberg, K; Habig, A; Fukuda, Y; Jung, C K; Kato, T; Kobayashi, K; Malek, M; Mauger, C; McGrew, C; Sarrat, A; Sharkey, E; Yanagisawa, C; Toshito, T; Miyano, K; Tamura, N; Ishii, J; Kuno, Y; Nagashima, Y; Takita, M; Yoshida, M; Kim, S B; Yoo, J; Okazawa, H; Ishizuka, T; Choi, Y; Seo, H K; Gando, Y; Hasegawa, T; Inoue, K; Shirai, J; Suzuki, A; Koshiba, M; Nakajima, Y; Nishijima, K; Harada, T; Ishino, H; Nishimura, R; Watanabe, Y; Kielczewska, D; Zalipska, J; Berns, H G; Gran, R; Shiraishi, K K; Stachyra, A; Washburn, K; Wilkes, R J

    2004-09-03

    Muon neutrino disappearance probability as a function of neutrino flight length L over neutrino energy E was studied. A dip in the L/E distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed L/E distribution constrained nu(micro)<-->nu(tau) neutrino oscillation parameters; 1.9x10(-3)0.90 at 90% confidence level.

  20. N-mode coherence in collective neutrino oscillations

    SciTech Connect

    Raffelt, Georg G.

    2011-05-15

    We study two-flavor neutrino oscillations in a homogeneous and isotropic ensemble under the influence of neutrino-neutrino interactions. For any density there exist forms of collective oscillations that show self-maintained coherence. They can be classified by a number N of linearly independent functions that describe all neutrino modes as linear superpositions. What is more, the dynamics is equivalent to another ensemble with the same effective density, consisting of N modes with discrete energies E{sub i} with i=1,...,N. We use this equivalence to derive the analytic solution for two-mode (bimodal) coherence, relevant for spectral-split formation in supernova neutrinos.

  1. Future long-baseline neutrino oscillations: View from Asia

    SciTech Connect

    Hayato, Yoshinari

    2015-07-15

    Accelerator based long-baseline neutrino oscillation experiments have been playing important roles in revealing the nature of neutrinos. However, it turned out that the current experiments are not sufficient to study two major remaining problems, the CP violation in the lepton sector and the mass hierarchy of neutrinos. Therefore, several new experiments have been proposed. Among of them, two accelerator based long-baseline neutrino oscillation experiments, the J-PARC neutrino beam and Hyper-Kamiokande, and MOMENT, have been proposed in Asia. These two projects are reviewed in this article.

  2. New Ambiguity in Probing CP Violation in Neutrino Oscillations.

    PubMed

    Miranda, O G; Tórtola, M; Valle, J W F

    2016-08-05

    If neutrinos get mass via the seesaw mechanism the mixing matrix describing neutrino oscillations can be effectively nonunitary. We show that in this case the neutrino appearance probabilities involve a new CP phase ϕ associated with nonunitarity. This leads to an ambiguity in extracting the "standard" three-neutrino phase δ_{CP}, which can survive even after neutrino and antineutrino channels are combined. Its existence should be taken into account in the planning of any oscillation experiment aiming at a robust measurement of δ_{CP}.

  3. New Ambiguity in Probing C P Violation in Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Miranda, O. G.; Tórtola, M.; Valle, J. W. F.

    2016-08-01

    If neutrinos get mass via the seesaw mechanism the mixing matrix describing neutrino oscillations can be effectively nonunitary. We show that in this case the neutrino appearance probabilities involve a new C P phase ϕ associated with nonunitarity. This leads to an ambiguity in extracting the "standard" three-neutrino phase δC P, which can survive even after neutrino and antineutrino channels are combined. Its existence should be taken into account in the planning of any oscillation experiment aiming at a robust measurement of δC P.

  4. A combined view of sterile-neutrino constraints from CMB and neutrino oscillation measurements

    NASA Astrophysics Data System (ADS)

    Bridle, Sarah; Elvin-Poole, Jack; Evans, Justin; Fernandez, Susana; Guzowski, Pawel; Söldner-Rembold, Stefan

    2017-01-01

    We perform a comparative analysis of constraints on sterile neutrinos from the Planck experiment and from current and future neutrino oscillation experiments (MINOS, IceCube, SBN). For the first time, we express joint constraints on Neff and meffsterile from the CMB in the Δm2, sin2 ⁡ 2 θ parameter space used by oscillation experiments. We also show constraints from oscillation experiments in the Neff, meffsterile cosmology parameter space. In a model with a single sterile neutrino species and using standard assumptions, we find that the Planck 2015 data and the oscillation experiments measuring muon-neutrino (νμ) disappearance have similar sensitivity.

  5. Neutrino oscillations: Quantum mechanics vs. quantum field theory

    SciTech Connect

    Akhmedov, Evgeny Kh.; Kopp, Joachim

    2010-01-01

    A consistent description of neutrino oscillations requires either the quantum-mechanical (QM) wave packet approach or a quantum field theoretic (QFT) treatment. We compare these two approaches to neutrino oscillations and discuss the correspondence between them. In particular, we derive expressions for the QM neutrino wave packets from QFT and relate the free parameters of the QM framework, in particular the effective momentum uncertainty of the neutrino state, to the more fundamental parameters of the QFT approach. We include in our discussion the possibilities that some of the neutrino's interaction partners are not detected, that the neutrino is produced in the decay of an unstable parent particle, and that the overlap of the wave packets of the particles involved in the neutrino production (or detection) process is not maximal. Finally, we demonstrate how the properly normalized oscillation probabilities can be obtained in the QFT framework without an ad hoc normalization procedure employed in the QM approach.

  6. Analysis of atmospheric neutrino oscillations in three-flavor neutrinos

    NASA Astrophysics Data System (ADS)

    Teshima, T.; Sakai, T.

    2000-12-01

    We analyze the atmospheric neutrino experiments of Super-Kamiokande (830-920 live days) using the three-flavor neutrino framework with the mass hierarchy m1~m2<neutrinos and upward through-going and stopping muons zenith angle distributions taking into account the Earth matter effects thoroughly. We obtain the allowed regions of mass and mixing parameters Δm223, θ13, and θ23. In our present analysis, we used the solar neutrino small angle solution and large angle solution for Δm212 and θ12. Δm223 is restricted to 0.002-0.01 eV2 and θ13<13°, 35°<θ23<55° in 95% C.L. For θ12, there is no difference between the large angle solution and the small one. From the χ2 fit, the minimum χ2=66 (54 DOF) is obtained at Δm223=5×10-3 eV2, θ13=10°, and θ23=50°. In a two flavor mixing approximation (θ13=0), the minimum χ2=80 (54 DOF) is obtained at Δm223=3×10-3 eV2 and θ23=45°. If θ13=10° is real, the detected νe events in the K2K experiment will be about 10 times as large as events expected in the θ13=0 case.

  7. Monochromatic neutrino lines from sneutrino dark matter

    NASA Astrophysics Data System (ADS)

    Arina, Chiara; Kulkarni, Suchita; Silk, Joseph

    2015-10-01

    We investigate the possibility of observing monochromatic neutrino lines originating from annihilation of dark matter. We analyze several astrophysical sources with overdensities of dark matter that can amplify the signal. As a case study, we consider mixed left- and right-handed sneutrino dark matter. We demonstrate that in the physically viable region of the model, one can obtain a prominent monochromatic neutrino line. We propose a search strategy to observe these neutrino lines in future generations of neutrino telescopes that is especially sensitive to dwarf spheroidal galaxies. We demonstrate that the presence of massive black holes in the cores of dwarfs as well as of more massive galaxies substantially boosts any putative signal. In particular, dark matter in dwarf galaxies spiked by an intermediate massive black hole provides a powerful means of probing low-annihilation cross sections well below 10-26 cm3 s-1 that are otherwise inaccessible by any future direct detection or collider experiment.

  8. Analytical description of quasivacuum oscillations of solar neutrinos

    NASA Astrophysics Data System (ADS)

    Lisi, E.; Marrone, A.; Montanino, D.; Palazzo, A.; Petcov, S. T.

    2001-05-01

    We propose a simple prescription to calculate the solar neutrino survival probability Pee in the quasivacuum oscillation (QVO) regime. Such a prescription is obtained by matching perturbative and exact analytical results, which effectively take into account the density distribution in the Sun as provided by the standard solar model. The resulting analytical recipe for the calculation of Pee is shown to reach its highest accuracy (\\|ΔPee\\|<=2.6×10-2 in the whole QVO range) when the familiar prescription of choosing the solar density scale parameter r0 at the Mikheyev-Smirnov-Wolfenstein (MSW) resonance point is replaced by a new one, namely, when r0 is chosen at the point of ``maximal violation of adiabaticity'' (MVA) along the neutrino trajectory in the Sun. The MVA prescription admits a smooth transition from the QVO regime to the MSW transition one. We discuss in detail the phase acquired by neutrinos in the Sun, and show that it might be of relevance for the studies of relatively short time scale variations of the fluxes of the solar ν lines in the future real-time solar neutrino experiments. Finally, we elucidate the role of matter effects in the convective zone of the Sun.

  9. On a theory of neutrino oscillations with entanglement

    SciTech Connect

    Kayser, Boris; Kopp, Joachim; Roberston, R.G.Hamish; Vogel, Petr; /Caltech, Kellogg Lab

    2010-06-01

    We show that the standard expression for the neutrino oscillation length can be confirmed even in theoretical approaches that take into account entanglement between the neutrino and its interaction partners. We show this in particular for the formalism developed in arXiv:1004.1847. Finally, we shed some light on the question why plane-wave approaches to the neutrino oscillation problem can yield the correct result for the oscillation length even though they do not explicitly account for the localization of the neutrino source and the detector.

  10. Decaying warm dark matter and neutrino masses.

    PubMed

    Lattanzi, M; Valle, J W F

    2007-09-21

    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.

  11. Decaying Warm Dark Matter and Neutrino Masses

    SciTech Connect

    Lattanzi, M.; Valle, J. W. F.

    2007-09-21

    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.

  12. Neutrino oscillation tomography of the Earth with KM3NeT-ORCA

    NASA Astrophysics Data System (ADS)

    Bourret, Simon; Coelho, João A. B.; Van Elewyck, Véronique; KM3NeT collaboration

    2017-09-01

    KM3NeT-ORCA is a water-Cherenkov neutrino detector designed for studying the oscillations of atmospheric neutrinos, with the primary objective of measuring the neutrino mass ordering. Atmospheric neutrinos crossing the Earth undergo matter effects, modifying the pattern of their flavour oscillations. The study of the angular and energy distribution of neutrino events in ORCA can therefore provide tomographic information on the Earth’s interior with an independent technique, complementary to the standard geophysics methods. Preliminary estimations based on a full Monte Carlo simulation of the detector response show that after ten years of operation the electron density can be measured with a precision of 3-5% in the mantle and 7-10% in the outer core – depending on the mass ordering.

  13. Neutrino physics

    SciTech Connect

    Peccei, R. D.

    1999-10-25

    These lectures describe some aspects of the physics of massive neutrinos. After a brief introduction of neutrinos in the Standard Model, I discuss possible patterns for their masses. In particular, I show how the presence of a large Majorana mass term for the right-handed neutrinos can engender tiny neutrino masses for the observed neutrinos. If neutrinos have mass, different flavors of neutrinos can oscillate into one another. To analyze this phenomena, I develop the relevant formalism for neutrino oscillations, both in vacuum and in matter. After reviewing the existing (negative) evidence for neutrino masses coming from direct searches, I discuss evidence for, and hints of, neutrino oscillations in the atmosphere, the sun, and at accelerators. Some of the theoretical implications of these results are emphasized. I close these lectures by briefly outlining future experiments which will shed further light on atmospheric, accelerator and solar neutrino oscillations. A pedagogical discussion of Dirac and Majorana masses is contained in an appendix.

  14. Neutrino Physics

    NASA Astrophysics Data System (ADS)

    Bergström, L.; Hulth, P. O.; Botner, O.; Carlson, P.; Ohlsson, T.

    2006-03-01

    J. N. Bahcall (1934-2005) -- Preface -- List of participants -- Committees -- Nobel symposium on neutrino physics - program -- The history of neutrino oscillations / S. M. Bilenky -- Super-Kamiokande results on neutrino oscillations / Y. Suzuki -- Sudbury neutrino observatory results / A. B. McDonald -- Results from KamLAND reactor neutrino detection / A. Suzuki -- New opportunities for surprise / J. Conrad -- Solar models and solar neutrinos / J. N. Bahcall -- Atmospheric neutrino fluxes / T. K. Gaisser -- The MSW effect and matter effects in neutrino oscillations / A. Yu. Smirnov -- Three-flavour effects and CP- and T-violation in neutrino oscillations / E. Kh. Akhmedov -- Global analysis of neutrino data / M. C. Gonzalez-Garcia -- Future precision neutrino oscillation experiments and theoretical implications / M. Lindner -- Experimental prospects of neutrinoless double beta decay / E. Fiorini -- Theoretical prospects of neutrinoless double beta decay / S. T. Petcov -- Supernova neutrino oscillations / G. G. Raffelt -- High-energy neutrino astronomy / F. Halzen -- Neutrino astrophysics in the cold: Amanda, Baikal and IceCube / C. Spiering -- Status of radio and acoustic detection of ultra-high energy cosmic neutrinos and a proposal on reporting results / D. Saltzberg -- Detection of neutrino-induced air showers / A. A. Watson -- Prospect for relic neutrino searches / G. B. Gelmini -- Leptogenesis in the early universe / T. Yanagida -- Neutrinos and big bang nucleosynthesis / G. Steigman -- Extra galactic sources of high energy neutrinos / E. Waxman -- Cosmological neutrino bounds for non-cosmologists / M. Tegmark -- Neutrino intrinsic properties: the neutrino-antineutrino relation / B. Kayser -- NuTeV and neutrino properties / M. H. Shaevitz -- Absolute masses of neutrinos - experimental results and future possibilities / C. Weinheimer -- Flavor theories and neutrino masses / P. Ramond -- Neutrino mass models and leptogenesis / S. F. King -- Neutrino mass and

  15. Global analyses of neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Gonzalez-Garcia, M. C.; Maltoni, Michele; Schwetz, Thomas

    2016-07-01

    We summarize the determination of some neutrino properties from the global analysis of solar, atmospheric, reactor, and accelerator neutrino data in the framework of three-neutrino mixing as well as in some extended scenarios such as the mixing with eV-scale sterile neutrinos invoked for the interpretation of the short baseline anomalies, and the presence of non-standard neutrino interactions.

  16. Neutrino oscillations: quantum mechanics vs. quantum field theory

    NASA Astrophysics Data System (ADS)

    Akhmedov, Evgeny Kh.; Kopp, Joachim

    2010-04-01

    A consistent description of neutrino oscillations requires either the quantum-mechanical (QM) wave packet approach or a quantum field theoretic (QFT) treatment. We compare these two approaches to neutrino oscillations and discuss the correspondence between them. In particular, we derive expressions for the QM neutrino wave packets from QFT and relate the free parameters of the QM framework, in particular the effective momentum uncertainty of the neutrino state, to the more fundamental parameters of the QFT approach. We include in our discussion the possibilities that some of the neutrino’s interaction partners are not detected, that the neutrino is produced in the decay of an unstable parent particle, and that the overlap of the wave packets of the particles involved in the neutrino production (or detection) process is not maximal. Finally, we demonstrate how the properly normalized oscillation probabilities can be obtained in the QFT framework without an ad hoc normalization procedure employed in the QM approach.

  17. Optical simulation of neutrino oscillations in binary waveguide arrays.

    PubMed

    Marini, Andrea; Longhi, Stefano; Biancalana, Fabio

    2014-10-10

    We theoretically propose and investigate an optical analogue of neutrino oscillations in a pair of vertically displaced binary waveguide arrays with longitudinally modulated effective refractive index. Optical propagation is modeled through coupled-mode equations, which in the continuous limit converge to two coupled Dirac equations for fermionic particles with different mass states, analogously to neutrinos. In addition to simulating neutrino oscillation in the noninteracting regime, our optical setting enables us to explore neutrino interactions in extreme regimes that are expected to play an important role in massive supernova stars. In particular, we predict the quenching of neutrino oscillations and the existence of topological defects, i.e., neutrino solitons, which in our photonic simulator should be observable as excitation of optical gap solitons propagating along the binary arrays at high excitation intensities.

  18. Computational Analysis of the Bugey Neutrino Oscillation Experiment

    NASA Astrophysics Data System (ADS)

    Yost, Mason

    2012-03-01

    The Bugey 3-Detector neutrino experiment attempted to place a limit on δm^21,2 and 2̂(2θ1,2) by calculating neutrino fluxes from a nuclear reactor. This experiment was unusual because it utilized data taken from three different distances from the neutrino source. The experiment concluded that neutrinos did not oscillate between flavors. However, this conclusion was later contradicted and overruled by data from more accurate neutrino oscillation experiments, and recent discoveries suggest that a fourth neutrino may exist. To help determine the plausibility of a four neutrino model we are reexamining data from the Bugey experiment. Although our attempts to recreate the original experimenter's results have yielded some success, we have not yet been able to fully recreate the original experimenters' results.

  19. Accelerator, reactor, solar, and atmospheric neutrino oscillations: Beyond three generations

    SciTech Connect

    Goswami, S.

    1997-03-01

    We perform a phenomenological analysis of neutrino oscillations introducing an additional sterile neutrino. In such a scenario, more than one spectrum is possible that can accommodate three hierarchically different mass-squared differences as required by the present experiments. We considered two different spectra. Choosing the {Delta}m{sup 2}s in the ranges suitable for the LSND, atmospheric, and solar neutrino oscillations, limits on the mixing angles are derived, consistent with the most restrictive accelerator and reactor data as well as the atmospheric and solar neutrino results. We show that the present data disfavor one of these mass spectra leaving us with a very stringent choice of mass and mixing angle. The potential of the future heavy water solar neutrino experiment SNO to distinguish between the four-neutrino mixing and two-neutrino mixing cases is explored. {copyright} {ital 1997} {ital The American Physical Society}

  20. Search for sterile neutrino oscillations in muon neutrino disappearance at MINOS/MINOS+

    NASA Astrophysics Data System (ADS)

    Todd, Jacob; Minos+ Collaboration

    2017-01-01

    A wide variety of neutrino oscillation phenomena are well-described by the standard three-flavour neutrino model, but some anomalies exist. The LSND and MiniBooNE experiments have measured electron antineutrino appearance in excess of standard oscillation predictions, which points to the possibility of a sterile neutrino with higher mass than the presently known states. MINOS, a two-detector, long-baseline neutrino oscillation experiment, was optimized for the measurement of muon neutrino disappearance in the NuMI neutrino beam. A sterile neutrino responsible for the LSND and MiniBooNE excesses would cause distortions in the charged current and neutral current MINOS spectra, which permits the search for sterile neutrinos at MINOS. In close collaboration with the Daya Bay reactor neutrino experiment, MINOS has placed strong constraints on the sterile neutrino parameter space for a model with one additional sterile neutrino. Further, the extension of data collection with MINOS+, which samples the NuMI beam in a medium energy configuration, markedly increases the sensitivity of the combined MINOS and MINOS+ sample to a 3+1-flavour sterile neutrino model.

  1. Can the neutrinos from Z sup 0 -decay oscillate

    SciTech Connect

    Smirnov, A.Y. ); Zatsepin, G. )

    1992-05-10

    A common prejudice is that neutrinos produced by the decays of real or virtual Z{sup 0}-bosons do not oscillate. In this paper, the authors will show that this is incorrect even in case of the universality of interactions and of the absence of sterile neutrinos. In Z{sup 0} -decay the coherent state of neutrino pairs is produced. The oscillation picture can be observed in principle by measuring the flavors of both neutrinos from the same Z{sup 0} -decay.

  2. Untangling supernova-neutrino oscillations with β-beam data

    NASA Astrophysics Data System (ADS)

    Jachowicz, N.; McLaughlin, G. C.; Volpe, C.

    2008-05-01

    Recently, we suggested that low-energy β-beam neutrinos can be very useful for the study of supernova-neutrino interactions. In this article, we examine the use of a such experiment for the analysis of a supernova-neutrino signal. Because supernova neutrinos are oscillating, it is very likely that the terrestrial spectrum of supernova neutrinos of a given flavor will not be the same as the energy distribution with which these neutrinos were first emitted. We demonstrate the efficacy of the proposed method for untangling multiple neutrino spectra. This is an essential feature of any model aiming at gaining information about the supernova mechanism, probing proto-neutron star physics, and understanding supernova nucleosynthesis, such as the neutrino process and the r-process. We also consider the efficacy of different experimental approaches including measurements at multiple beam energies and detector configurations.

  3. Three flavor oscillation analysis of atmospheric neutrinos in Super-Kamiokande

    NASA Astrophysics Data System (ADS)

    Wendell, Roger Alexandre

    In this dissertation atmospheric neutrino data from the 50 kiloton water-Cherenkov detector, Super-Kamiokande, are studied in the context of neutrino oscillations. Data presented here are taken from the 1489-day SK-I and 803-day SK-II exposures. Super-Kamiokande's atmospheric neutrino sample exhibits a zenith angle dependent deficit of numu interactions which is well explained by maximal two-flavor numu↔nutau oscillations. This analysis extends the two-flavor framework to include all active neutrino flavors and searches for sub-dominant oscillation effects in the oscillations of atmospheric neutrinos. If the last unknown mixing angle, theta 13, is non-zero there is enhancement (suppression) of the nu mu→nue three-flavor oscillation probability in matter for several GeV neutrinos with long baselines under the normal (inverted) mass hierarchy. At Super-Kamiokande this effect would manifest itself as an increase in the high energy nue event rate coming from below the detector. Searching the SK-I, SK-II and their combined data finds no evidence of a rate excess and yields a best fit to theta 13 of zero assuming either hierarchy. This extended analysis remains consistent with the current knowledge of two-flavor atmospheric mixing finding best fit values sin2theta23 = 0.5 and Delta m2 = 2.6 x 10-3 eV2. No preference for either the normal or inverted mass hierarchy is found in the data.

  4. A Global three-parameter model for neutrino oscillations using Lorentz violation

    NASA Astrophysics Data System (ADS)

    Katori, Teppei; Kostelecky, Alan; Tayloe, Rex

    2006-10-01

    The neutrino oscillation experiment is a natural interferometer. It is sensitive to small spacetime properties without using the photon (QED) but the sensitivity is comparable with precision optical measurements (<10-19GeV). So neutrino oscillations may be seeing small spacetime effects, such as Lorentz violation. Lorentz and CPT violation are predicted phenomena from Planck scale physics and are actively studied, mainly under the Standard-Model Extension (SME) formalism, the Standard Model with Particle Lorentz Violation. We have developed a model of neutrino oscillations that has only three degrees of freedom and is consistent with existing data under the renormalizable sector of SME, and it offers an alternative to the standard 3-neutrino massive model. All classes of neutrino data are described, including solar, reactor, atmospheric, and LSND oscillations. The disappearance of solar neutrinos is obtained without matter-enhanced oscillations (MSW effect). Quantitative predictions are offered for the ongoing MiniBooNE experiment and for the future experiments OscSNS, NOvA, and T2K.

  5. Future long-baseline neutrino oscillations: View from Europe

    SciTech Connect

    Patzak, T.

    2015-07-15

    Since about a decade the european physics community interested in neutrino and neutrino-astrophysics develops a plan to conceive the next generation large underground neutrino observatory. Recently, the LAGUNA-LBNO collaboration made the outcome of the FP7 design study public which shows a clear path for the realization of such experiment. In this paper the LAGUNA and LAGUNA-LBNO Design studies, resulting in a proposal for the LBNO experiment, will be discussed. The author will focus on the long baseline neutrino oscillation search, especially on the potential to discover the neutrino mass ordering and the search for CP violation in the lepton sector.

  6. Cosmic Neutrinos

    SciTech Connect

    Quigg, Chris; /Fermilab /CERN

    2008-02-01

    I recall the place of neutrinos in the electroweak theory and summarize what we know about neutrino mass and flavor change. I next review the essential characteristics expected for relic neutrinos and survey what we can say about the neutrino contribution to the dark matter of the Universe. Then I discuss the standard-model interactions of ultrahigh-energy neutrinos, paying attention to the consequences of neutrino oscillations, and illustrate a few topics of interest to neutrino observatories. I conclude with short comments on the remote possibility of detecting relic neutrinos through annihilations of ultrahigh-energy neutrinos at the Z resonance.

  7. Neutrino propagation in matter with general interactions

    SciTech Connect

    Bergmann, S.; Grossman, Y.; Nardi, E.

    1999-11-01

    We present a general analysis of the effective potential for neutrino propagation in matter, assuming a generic set of Lorentz invariant non-derivative interactions. We find that in addition to the known vector and axial vector terms, in a polarized medium also tensor interactions can play an important role. We compute the effective potential arising from a tensor interaction. We show that the components of the tensor potential transverse to the direction of the neutrino propagation can induce a neutrino spin flip, similar to the one induced by a transverse magnetic field. {copyright} {ital 1999} {ital The American Physical Society}

  8. Dark matter and IceCube neutrinos

    NASA Astrophysics Data System (ADS)

    Biondi, R.

    2015-01-01

    We show that the excess of high energy neutrinos observed by the IceCube collaboration at energies above 100TeV might originate from baryon number violating decays of heavy shadow baryons from mirror sector, which in turn constitute Dark Matter. Due to tiny mixing between mirror and ordinary neutrinos, it is possible to explain the specific features of the IceCube events spectrum.

  9. Future long-baseline neutrino oscillations: View from North America

    NASA Astrophysics Data System (ADS)

    Wilson, Robert J.

    2015-07-01

    In late 2012 the US Department of Energy gave approval for the first phase of the Long-Baseline Neutrino Experiment (LBNE) that will conduct a broad scientific program including neutrino oscillations, neutrino scattering physics, search for baryon violation, supernova burst neutrinos and other related astrophysical phenomena. The project is now being reformulated as an international facility hosted by the United States. The facility will consist of an intense neutrino beam produced at Fermi National Accelerator Laboratory (Fermilab), a highly capable set of neutrino detectors on the Fermilab campus, and a large underground liquid argon time projection chamber at Sanford Underground Research Facility (SURF) in South Dakota 1300 km from Fermilab. With an intense beam and massive far detector, the experimental program at the facility will make detailed studies of neutrino oscillations, including measurements of the neutrino mass hierarchy and Charge-Parity symmetry violation, by measuring neutrino and anti-neutrino mixing separately. At the near site, the high-statistics neutrino scattering data will allow for many cross section measurements and precision tests of the Standard Model. This presentation will describe the configuration developed by the LBNE collaboration, the broad physics program, and the status of the formation of the international facility.

  10. Future Long-Baseline Neutrino Oscillations: View from North America

    SciTech Connect

    Wilson, R. J.

    2015-06-01

    In late 2012 the US Department of Energy gave approval for the first phase of the Long-Baseline Neutrino Experiment (LBNE), that will conduct a broad scientific program including neutrino oscillations, neutrino scattering physics, search for baryon violation, supernova burst neutrinos and other related astrophysical phenomena. The project is now being reformulated as an international facility hosted by the United States. The facility will consist of an intense neutrino beam produced at Fermi National Accelerator Laboratory (Fermilab), a highly capable set of neutrino detectors on the Fermilab campus, and a large underground liquid argon time projection chamber at Sanford Underground Research Facility (SURF) in South Dakota 1300 km from Fermilab. With an intense beam and massive far detector, the experimental program at the facility will make detailed studies of neutrino oscillations, including measurements of the neutrino mass hierarchy and Charge-Parity symmetry violation, by measuring neutrino and anti-neutrino mixing separately. At the near site, the high-statistics neutrino scattering data will allow for many cross section measurements and precision tests of the Standard Model. This presentation will describe the configuration developed by the LBNE collaboration, the broad physics program, and the status of the formation of the international facility.

  11. Future long-baseline neutrino oscillations: View from North America

    SciTech Connect

    Wilson, Robert J.

    2015-07-15

    In late 2012 the US Department of Energy gave approval for the first phase of the Long-Baseline Neutrino Experiment (LBNE) that will conduct a broad scientific program including neutrino oscillations, neutrino scattering physics, search for baryon violation, supernova burst neutrinos and other related astrophysical phenomena. The project is now being reformulated as an international facility hosted by the United States. The facility will consist of an intense neutrino beam produced at Fermi National Accelerator Laboratory (Fermilab), a highly capable set of neutrino detectors on the Fermilab campus, and a large underground liquid argon time projection chamber at Sanford Underground Research Facility (SURF) in South Dakota 1300 km from Fermilab. With an intense beam and massive far detector, the experimental program at the facility will make detailed studies of neutrino oscillations, including measurements of the neutrino mass hierarchy and Charge-Parity symmetry violation, by measuring neutrino and anti-neutrino mixing separately. At the near site, the high-statistics neutrino scattering data will allow for many cross section measurements and precision tests of the Standard Model. This presentation will describe the configuration developed by the LBNE collaboration, the broad physics program, and the status of the formation of the international facility.

  12. Neutrino oscillation, finite self-mass and general Yang-Mills symmetry

    NASA Astrophysics Data System (ADS)

    Hsu, Jong-Ping

    2016-10-01

    The conservation of lepton number is assumed to be associated with a general Yang-Mills (gYM) symmetry. New transformations involve (Lorentz) vector gauge functions and characteristic phase functions, and they form a group. General Yang-Mills fields are associated with new fourth-order equations and linear potentials. Lepton self-masses turn out to be finite and proportional to the inverse of lepton masses, which implies that neutrinos should have nonzero masses. Thus, gYM symmetry could provide an understanding of neutrino oscillations and suggests that neutrinos with masses and very weak leptonic force may play a role in dark matter.

  13. Tau neutrinos underground: Signals of νμ-->ντ oscillations with extragalactic neutrinos

    NASA Astrophysics Data System (ADS)

    Dutta, Sharada Iyer; Reno, Mary Hall; Sarcevic, Ina

    2000-12-01

    The appearance of high energy tau neutrinos due to νμ-->ντ oscillations of extragalactic neutrinos can be observed by measuring the neutrino induced upward hadronic and electromagnetic showers and upward muons. We evaluate quantitatively the tau neutrino regeneration in the Earth for a variety of extragalactic neutrino fluxes. Charged-current interactions of the upward tau neutrinos below and in the detector, and the subsequent tau decay, create muons or hadronic and electromagnetic showers. The background for these events are muon neutrino and electron neutrino charged-current and neutral-current interactions, where in addition to extragalactic neutrinos, we consider atmospheric neutrinos. We find significant signal to background ratios for the hadronic combined with electromagnetic showers with energies above 10-100 TeV initiated by the extragalactic neutrinos. We show that the tau neutrinos from point sources also have the potential for discovery above a 1 TeV threshold. A kilometer-size neutrino telescope has a very good chance of detecting the appearance of tau neutrinos when both muon and hadronic combined with electromagnetic showers are detected.

  14. Neutrino '88. Proceedings.

    NASA Astrophysics Data System (ADS)

    Schneps, J.; Kafka, T.; Mann, W. A.; Nath, P.

    Contents: 1. Neutrino mass. 2. Neutrino oscillations. 3. Double beta decay. 4. Solar neutrinos. 5. Neutrinos from supernovae. 6. Neutrino interactions at accelerators. 7. New detectors for neutrino processes. 8. Neutrino interactions at accelerators II. 9. W, Z, and the standard model. 10. "Fred Reines at 70" Fest. 11. Nucleon decay, the standard model, and beyond. 12. Neutrinos: Earth, atmosphere, Sun, and galaxies. 13. Dark matter and cosmology. 14. Theoretical topics. 15. Future prospects.

  15. Neutrino oscillation studies with IceCube-DeepCore

    NASA Astrophysics Data System (ADS)

    Aartsen, M. G.; Abraham, K.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Altmann, D.; Anderson, T.; Ansseau, I.; Archinger, M.; Arguelles, C.; Arlen, T. C.; Auffenberg, J.; Bai, X.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; Beiser, E.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Börner, M.; Bos, F.; Bose, D.; Böser, S.; Botner, O.; Braun, J.; Brayeur, L.; Bretz, H.-P.; Buzinsky, N.; Casey, J.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Clark, K.; Classen, L.; Coenders, S.; Collin, G. H.; Conrad, J. M.; Cowen, D. F.; Cruz Silva, A. H.; Daughhetee, J.; Davis, J. C.; Day, M.; de André, J. P. A. M.; De Clercq, C.; del Pino Rosendo, E.; Dembinski, H.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; di Lorenzo, V.; Dumm, J. P.; Dunkman, M.; Eberhardt, B.; Ehrhardt, T.; Eichmann, B.; Euler, S.; Evenson, P. A.; Fahey, S.; Fazely, A. R.; Feintzeig, J.; Felde, J.; Filimonov, K.; Finley, C.; Flis, S.; Fösig, C.-C.; Fuchs, T.; Gaisser, T. K.; Gaior, R.; Gallagher, J.; Gerhardt, L.; Ghorbani, K.; Gier, D.; Gladstone, L.; Glagla, M.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Góra, D.; Grant, D.; Griffith, Z.; Groß, A.; Ha, C.; Haack, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Hansen, E.; Hansmann, B.; Hanson, K.; Hebecker, D.; Heereman, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Holzapfel, K.; Homeier, A.; Hoshina, K.; Huang, F.; Huber, M.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; In, S.; Ishihara, A.; Jacobi, E.; Japaridze, G. S.; Jeong, M.; Jero, K.; Jones, B. J. P.; Jurkovic, M.; Kappes, A.; Karg, T.; Karle, A.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kemp, J.; Kheirandish, A.; Kiryluk, J.; Klein, S. R.; Kohnen, G.; Koirala, R.; Kolanoski, H.; Konietz, R.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krings, K.; Kroll, G.; Kroll, M.; Krückl, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Lanfranchi, J. L.; Larson, M. J.; Lesiak-Bzdak, M.; Leuermann, M.; Leuner, J.; Lu, L.; Lünemann, J.; Madsen, J.; Maggi, G.; Mahn, K. B. M.; Mandelartz, M.; Maruyama, R.; Mase, K.; Matis, H. S.; Maunu, R.; McNally, F.; Meagher, K.; Medici, M.; Meli, A.; Menne, T.; Merino, G.; Meures, T.; Miarecki, S.; Middell, E.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Neer, G.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke Pollmann, A.; Olivas, A.; Omairat, A.; O'Murchadha, A.; Palczewski, T.; Pandya, H.; Pankova, D. V.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Quinnan, M.; Raab, C.; Rädel, L.; Rameez, M.; Rawlins, K.; Reimann, R.; Relich, M.; Resconi, E.; Rhode, W.; Richman, M.; Richter, S.; Riedel, B.; Robertson, S.; Rongen, M.; Rott, C.; Ruhe, T.; Ryckbosch, D.; Sabbatini, L.; Sander, H.-G.; Sandrock, A.; Sandroos, J.; Sarkar, S.; Schatto, K.; Schimp, M.; Schmidt, T.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schulte, L.; Schumacher, L.; Seckel, D.; Seunarine, S.; Soldin, D.; Song, M.; Spiczak, G. M.; Spiering, C.; Stahlberg, M.; Stamatikos, M.; Stanev, T.; Stasik, A.; Steuer, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Ström, R.; Strotjohann, N. L.; Sullivan, G. W.; Sutherland, M.; Taavola, H.; Taboada, I.; Tatar, J.; Ter-Antonyan, S.; Terliuk, A.; Tešić, G.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Toscano, S.; Tosi, D.; Tselengidou, M.; Turcati, A.; Unger, E.; Usner, M.; Vallecorsa, S.; Vandenbroucke, J.; van Eijndhoven, N.; Vanheule, S.; van Santen, J.; Veenkamp, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Wallace, A.; Wallraff, M.; Wandkowsky, N.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whelan, B. J.; Wiebe, K.; Wiebusch, C. H.; Wille, L.; Williams, D. R.; Wills, L.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zoll, M.

    2016-07-01

    IceCube, a gigaton-scale neutrino detector located at the South Pole, was primarily designed to search for astrophysical neutrinos with energies of PeV and higher. This goal has been achieved with the detection of the highest energy neutrinos to date. At the other end of the energy spectrum, the DeepCore extension lowers the energy threshold of the detector to approximately 10 GeV and opens the door for oscillation studies using atmospheric neutrinos. An analysis of the disappearance of these neutrinos has been completed, with the results produced being complementary with dedicated oscillation experiments. Following a review of the detector principle and performance, the method used to make these calculations, as well as the results, is detailed. Finally, the future prospects of IceCube-DeepCore and the next generation of neutrino experiments at the South Pole (IceCube-Gen2, specifically the PINGU sub-detector) are briefly discussed.

  16. Solar oscillation frequency and solar neutrino predictions

    SciTech Connect

    Cox, A.N.

    1990-07-05

    The light and velocity variations of the Sun and solar-like stars are unique among intrinsic variable stars. Unlike all other standard classes, such as Cepheids, B stars, and white dwarfs, the pulsation driving is caused by coupling with the acoustic noise in the upper convection zone. Each global pulsation mode is just another degree of freedom for the turbulent convection, and energy is shared equally between these g{sup {minus}}-modes and the solar oscillation modes. This driving and damping, together with the normal stellar pulsation mechanisms produce extremely low amplitude solar oscillations. Actually, the surface layer radiative damping is strong, and the varying oscillation mode amplitudes manifest the stochastic convection driving and the steady damping. Thus stability calculations for solar-like pulsations are difficult and mostly inconclusive, but calculations of pulsation periods are as straightforward as for all the other classes of intrinsic variable stars. The issue that is important for the Sun is its internal structure, because the mass, radius, and luminosity are extremely well known. Conventionally, we need the pulsation constants for each of millions of modes. Unknown parameters for constructing solar models are the composition and its material pressure, energy, and opacity, as well as the convection mixing length. We treat the nuclear energy and neutrino production formulas as sufficiently well known. The presence of weakly interacting massive particles (WIMPs) orbiting the solar center affects the predicted oscillation frequencies so that they do not agree with observations as well as those for models without WIMPs. 34 refs., 4 figs.

  17. NEUTRINO PROCESSES IN PARTIALLY DEGENERATE NEUTRON MATTER

    SciTech Connect

    Bacca, S.; Hally, K.; Liebendoerfer, M.; Perego, A.; Pethick, C. J.; Schwenk, A.

    2012-10-10

    We investigate neutrino processes for conditions reached in simulations of core-collapse supernovae. In regions where neutrino-matter interactions play an important role, matter is partially degenerate, and we extend earlier work that addressed the degenerate regime. We derive expressions for the spin structure factor in neutron matter, which is a key quantity required for evaluating rates of neutrino processes. We show that, for essentially all conditions encountered in the post-bounce phase of core-collapse supernovae, it is a very good approximation to calculate the spin relaxation rates in the nondegenerate limit. We calculate spin relaxation rates based on chiral effective field theory interactions and find that they are typically a factor of two smaller than those obtained using the standard one-pion-exchange interaction alone.

  18. The Effects of Collective Neutrino Oscillations on Supernova Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Seadrow, Shaquann; Frohlich, C.; Duan, H.; Friedland, A.; McLaughlin, G.; Keohane, J. W.

    2014-01-01

    A core-collapse supernova originates from the implosion of the electron degenerate core inside a massive star. Runaway electron capture produces on the order of 1057 neutrinos containing about 1053 erg of energy in total. While the vast majority of neutrinos are eventually released, during the first few seconds these neutrinos drive both the dynamics, and likewise the nucleosynthesis, inside the supernova. Recently, our understanding of oscillations among the different flavors of neutrinos (electron, muon, and tau) has significantly improved, allowing us to ask if neutrino flavor change has a significant effect on nucleosynthesis in a core-collapse supernova. To investigate the effects of collective neutrino flavor oscillations, we use the hydrodynamic conditions from a spherically-symmetrical model of the implosion, bounce, and explosion of the 1.4 solar mass core that is inside an 8.8 solar mass star (Huedepohl et al. 2009). We select 20 mass tracers in the ejecta, varying in initial radii, and follow these trajectories for the first 9 seconds following bounce. We include these trajectories into a nuclear reaction network in order to calculate the detailed nucleosynthesis. We use three sets of neutrino reaction rates, all of which are calculated consistently with the conditions in the supernova model: (i) no collective flavor oscillations, (ii) collective oscillations for normal neutrino mass hierarchy, and (iii) collective oscillations for inverted neutrino mass hierarchy. We calculate the detailed nucleosynthesis for each trajectory for all three sets of neutrino rates. We find that the inclusion of collective oscillations (ii or iii) significantly increases the free neutron abundance; however, we obtain similar results regardless of which hierarchy is used. The increase in free neutrons also increases the subsequent rate of neutron capture, but has only a small effect on the predicted final abundances. This work was performed as part of North Carolina State

  19. Geometric phases in neutrino oscillations with nonlinear refraction

    NASA Astrophysics Data System (ADS)

    Johns, Lucas; Fuller, George M.

    2017-02-01

    Neutrinos propagating in dense astrophysical environments sustain nonlinear refractive effects due to neutrino-neutrino forward scattering. We study geometric phases in neutrino oscillations that arise out of cyclic evolution of the potential generated by these forward-scattering processes. We perform several calculations, exact and perturbative, that illustrate the robustness of such phases, and of geometric effects more broadly, in the flavor evolution of neutrinos. The scenarios we consider are highly idealized in order to make them analytically tractable, but they suggest the possible presence of complicated geometric effects in realistic astrophysical settings. We also point out that in the limit of extremely high neutrino densities, the nonlinear potential in three flavors naturally gives rise to non-Abelian geometric phases. This paper is intended to be accessible to neutrino experts and nonspecialists alike.

  20. Minimal supergravity scalar neutrino dark matter and inverse seesaw neutrino masses.

    PubMed

    Arina, C; Bazzocchi, F; Fornengo, N; Romao, J C; Valle, J W F

    2008-10-17

    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.

  1. Oscillation properties of active and sterile neutrinos and neutrino anomalies at short distances

    SciTech Connect

    Khruschov, V. V. Fomichev, S. V. Titov, O. A.

    2016-09-15

    A generalized phenomenological (3 + 2 + 1) model featuring three active and three sterile neutrinos that is intended for calculating oscillation properties of neutrinos for the case of a normal active neutrino mass hierarchy and a large splitting between the mass of one sterile neutrino and the masses of the other two sterile neutrinos is considered. A new parametrization and a specific form of the general mixing matrix are proposed for active and sterile neutrinos with allowance for possible CP violation in the lepton sector, and test values are chosen for the neutrino masses and mixing parameters. The probabilities for the transitions between different neutrino flavors are calculated, and graphs representing the probabilities for the disappearance of muon neutrinos/antineutrinos and the appearance of electron neutrinos/antineutrinos in a beam of muon neutrinos/antineutrinos versus the distance from the neutrino source for various values of admissible model parameters at neutrino energies not higher than 50 MeV, as well as versus the ratio of this distance to the neutrino energy, are plotted. It is shown that the short-distance accelerator anomaly in neutrino data (LNSD anomaly) can be explained in the case of a specific mixing matrix for active and sterile neutrinos (which belongs to the a{sub 2} type) at the chosen parameter values. The same applies to the short-distance reactor and gallium anomalies. The theoretical results obtained in the present study can be used to interpret and predict the results of ground-based neutrino experiments aimed at searches for sterile neutrinos, as well as to analyze some astrophysical observational data.

  2. Particle production with left-right neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Enomoto, Seishi; Matsuda, Tomohiro

    2016-03-01

    When the Higgs field starts oscillation after Higgs inflation, gauge bosons are produced nonperturbatively near the enhanced symmetry point (ESP). Just after the particle production, when the Higgs field is going away from the ESP, these gauge bosons gain mass and decay or annihilate into Standard Model (SM) fermions. Left-handed neutrinos can be generated in that way. If one assumes the seesaw mechanism, the mass matrix of a pair of left- and right-handed neutrinos is nondiagonal. Although their mixing in the mass eigenstates is negligible in the true vacuum, it could be significant near the edge of the Higgs oscillation, where the off-diagonal component is large. Therefore, the left-handed neutrinos generated from the gauge bosons can start neutrino oscillation between the right-handed neutrinos. We study the particle production when such left-right (L-R) neutrino oscillation is significant. For a working example, the nonthermal leptogenesis scenario after Higgs inflation is examined, which cannot be realized without the L-R neutrino oscillation. The same mechanism could be applied to other singlet particles whose abundance has been neglected.

  3. Flux Measurement at a Neutrino Factory Near Detector for Neutrino Oscillations

    SciTech Connect

    Laing, A.; Soler, F. J. P.

    2008-02-21

    It is well established that a Near Detector positioned within 1 km of the muon decay pipe at a Neutrino Factory is essential for a true determination of the neutrino flux, necessary for the neutrino oscillation signal. Here we present a method for the the extraction of the oscillation probability parameters using the Near Detector, in combination with a long baseline Far Detector and demonstrate that by using this method, the sensitivity to oscillation parameters is maintained down values of {theta}{sub 13} one order of magnitude lower than the current world limit.

  4. Barr-Freire-Zee mechanism for the hydrogen-ionizing decaying neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Tommasini, Daniele

    1992-12-01

    We consider the scenario of the hydrogen-ionizing decaying neutrino dark matter, advocated by Sciama to solve several ionization problems in astrophysics and cosmology. We show that dangerously large neutrino oscillations are expected in general in the particle physics models introduced to provide the required neutrino masses and dark matter decay lifetime. However, the implementation of a mechanism recently discovered by Barr, Freire and Zee, allows to realize this scenario free of large neutrino oscillations. Furthermore, in this case a mass scale for the light neutrinos, which can be naturally the MSW solar neutrino scale ~ 10-3 eV, is automatically associated to the value ~ 1023 s of the dark matter decay lifetime, needed to solve the ionization problems. A realization of the mechanism in the supersymmetric standard model with broken R-parity is then considered as an example. In that case, the heavy neutrino providing the dark matter is made up mainly by the standard muon neutrino νμ.

  5. Solar neutrino experiments and a test for neutrino oscillations with radioactive sources

    SciTech Connect

    Cleveland, B.T.; Davis, R. Jr.; Rowley, J.K.

    1980-01-01

    The results of the Brookhaven solar neutrino experiment are given and compared to the most recent standard solar model calculations. The observations are about a factor of 4 below theoretical expectations. In view of the uncertainties involved in the theoretical models of the sun, the discrepancy is not considered to be evidence for neutrino oscillations. The status of the development of a gallium solar neutrino detector is described. Radiochemical neutrino detectors can be used to search for ..nu../sub e/ oscillations by using megacurie sources of monoenergetic neutrinos like /sup 65/Zn. A quantitative evaluation of possible experiments using the Brookhaven chlorine solar neutrino detector and a gallium detector is given. 6 figures, 3 tables.

  6. Neutrino lines from majoron dark matter

    NASA Astrophysics Data System (ADS)

    Garcia-Cely, Camilo; Heeck, Julian

    2017-05-01

    Models with spontaneously broken global lepton number can lead to a pseudo-Goldstone boson as a long-lived dark matter candidate. Here we revisit the case of singlet majoron dark matter and discuss multiple constraints. For masses above MeV, this model could lead to a detectable flux of monochromatic mass-eigenstate neutrinos, which have flavor ratios that depend strongly on the neutrino mass hierarchy. We provide a convenient parametrization for the loop-induced majoron couplings to charged fermions that allows us to discuss three-generation effects such as lepton flavor violation. These couplings are independent of the low-energy neutrino parameters but can be constrained by the majoron decays into charged fermions.

  7. Self-induced parametric resonance in collective neutrino oscillations

    SciTech Connect

    Raffelt, Georg G.

    2008-12-15

    We identify a generic new form of collective flavor oscillations in dense neutrino gases that amounts to a self-induced parametric resonance. It occurs in a homogeneous and isotropic ensemble when a range of neutrino modes is prepared in a different flavor than the neighboring modes with lower and higher energies. The flavor content of the intermediate spectral part librates relative to the other parts with a frequency corresponding to a typical {delta}m{sup 2}/2E. This libration persists in the limit of an arbitrarily large neutrino density where one would have expected synchronized flavor oscillations.

  8. First Neutrino Oscillation Results from the NOvA experiment

    SciTech Connect

    Sachdev, Kanika

    2016-11-29

    NOvA is a long-baseline neutrino oscillation experiment on the NuMI muon neutrino beam at Fermilab. It consists of two functionally identical, nearly fully-active liquid-scintillator tracking calorimeters. The Near Detector (ND) at Fermilab is used to study the neutrino beam spectrum and composition before oscillations occur. The Far Detector in northern Minnesota, 810 km away, observes the oscillated beam and is used to extract the oscillation parameters. NOvA is designed to observe oscillations in two channels: disappearance channel ( ν μ → ν μ ) and ν e appearance channel ( ν μ → ν e ). This paper reports the measurements of both these channels based on the first NOvA data taken from February 16, 2014 till May 15, 2015

  9. Sterile neutrinos as subdominant warm dark matter

    SciTech Connect

    Palazzo, A.; Cumberbatch, D.; Slosar, A.; Silk, J.

    2007-11-15

    In light of recent findings which seem to disfavor a scenario with (warm) dark matter entirely constituted of sterile neutrinos produced via the Dodelson-Widrow mechanism, we investigate the constraints attainable for this mechanism by relaxing the usual hypothesis that the relic neutrino abundance must necessarily account for all of the dark matter. We first study how to reinterpret the limits attainable from x-ray nondetection and Lyman-{alpha} forest measurements in the case that sterile neutrinos constitute only a fraction f{sub s} of the total amount of dark matter. Then, assuming that sterile neutrinos are generated in the early universe solely through the Dodelson-Widrow mechanism, we show how the x-ray and Lyman-{alpha} results jointly constrain the mass-mixing parameters governing their production. Furthermore, we show how the same data allow us to set a robust upper limit f{sub s} < or approx. 0.7 at the 2{sigma} level, rejecting the case of dominant dark matter (f{sub s}=1) at the {approx}3{sigma} level.

  10. Neutrino Oscillation Parameter Sensitivity in Future Long-Baseline Experiments

    SciTech Connect

    Bass, Matthew

    2014-01-01

    The study of neutrino interactions and propagation has produced evidence for physics beyond the standard model and promises to continue to shed light on rare phenomena. Since the discovery of neutrino oscillations in the late 1990s there have been rapid advances in establishing the three flavor paradigm of neutrino oscillations. The 2012 discovery of a large value for the last unmeasured missing angle has opened the way for future experiments to search for charge-parity symmetry violation in the lepton sector. This thesis presents an analysis of the future sensitivity to neutrino oscillations in the three flavor paradigm for the T2K, NO A, LBNE, and T2HK experiments. The theory of the three flavor paradigm is explained and the methods to use these theoretical predictions to design long baseline neutrino experiments are described. The sensitivity to the oscillation parameters for each experiment is presented with a particular focus on the search for CP violation and the measurement of the neutrino mass hierarchy. The variations of these sensitivities with statistical considerations and experimental design optimizations taken into account are explored. The effects of systematic uncertainties in the neutrino flux, interaction, and detection predictions are also considered by incorporating more advanced simulations inputs from the LBNE experiment.

  11. B-Meson and Neutrino Oscillation: A Unified Treatment

    SciTech Connect

    Kayser, Boris; /Fermilab

    2011-10-01

    We present a unified treatment of the quantum mechanics of B-factory and neutrino oscillation experiments. While our approach obtains the usual phenomenological predictions for these experiments, it does so without having to invoke perplexing Einstein-Podolsky-Rosen correlations or non-intuitive kinematical assumptions. The quantum mechanics of mixing during propagation is at the heart of both B-factory and neutrino oscillation experiments. In this paper, we will treat both these experiments in the same way. Our treatment has several advantages. In dealing with the B-factory experiments, it avoids having to invoke real but nonetheless puzzling Einstein-Podolsky-Rosen correlations. In dealing with neutrino oscillation, our approach avoids the non-intuitive assumption that all the interfering neutrino mass eigenstates in a beam have the same energy.

  12. Neutrino oscillation effects in Soudan 2 upward-stopping muons

    NASA Astrophysics Data System (ADS)

    Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Barr, G. D.; Barrett, W. L.; Border, P. M.; Cobb, J. H.; Cockerill, D. J. A.; Courant, H.; Demuth, D. M.; Fields, T. H.; Gallagher, H. R.; Goodman, M. C.; Kafka, T.; Kasahara, S. M. S.; Litchfield, P. J.; Mann, W. A.; Marshak, M. L.; Miller, W. H.; Mualem, L.; Nelson, J. K.; Napier, A.; Oliver, W. P.; Pearce, G. F.; Peterson, E. A.; Petyt, D. A.; Ruddick, K.; Sanchez, M.; Schneps, J.; Sousa, A.; Thron, J. L.; West, N.

    2005-09-01

    Upward-going stopping muons initiated by atmospheric νμ and ν¯μ interactions in the rock below the Soudan 2 detector have been isolated, together with a companion sample of neutrino-induced single muons, created within the detector, which travel downwards and exit. The downward-going sample is consistent with the atmospheric-neutrino flux prediction, but the upward-going sample exhibits a sizable depletion. Both are consistent with previously reported Soudan 2 neutrino-oscillation results. Inclusion of the two samples in an all-event likelihood analysis, using recent 3D-atmospheric-neutrino-flux calculations, reduces both the allowed oscillation parameter region and the probability of the no-oscillation hypothesis.

  13. A measurement of neutrino oscillations with muon neutrinos in the MINOS experiment

    SciTech Connect

    Coleman, Stephen James

    2011-05-01

    Experimental evidence has established that neutrino flavor states evolve over time. A neutrino of a particular flavor that travels some distance can be detected in a different neutrino flavor state. The Main Injector Neutrino Oscillation Search (MINOS) is a long-baseline experiment that is designed to study this phenomenon, called neutrino oscillations. MINOS is based at Fermilab near Chicago, IL, and consists of two detectors: the Near Detector located at Fermilab, and the Far Detector, which is located in an old iron mine in Soudan, MN. Both detectors are exposed to a beam of muon neutrinos from the NuMI beamline, and MINOS measures the fraction of muon neutrinos that disappear after traveling the 734 km between the two detectors. One can measure the atmospheric neutrino mass splitting and mixing angle by observing the energy-dependence of this muon neutrino disappearance. MINOS has made several prior measurements of these parameters. Here I describe recently-developed techniques used to enhance our sensitivity to the oscillation parameters, and I present the results obtained when they are applied to a dataset that is twice as large as has been previously analyzed. We measure the mass splitting Δm232 = (2.32-0.08+0.12) x 10-3 eV2/c4 and the mixing angle sin2(2θ32) > 0.90 at 90% C.L. These results comprise the world's best measurement of the atmospheric neutrino mass splitting. Alternative disappearance models are also tested. The neutrino decay hypothesis is disfavored at 7.2σ and the neutrino quantum decoherence hypothesis is disfavored at 9.0σ.

  14. A measurement of neutrino oscillations with muon neutrinos in the MINOS experiment

    NASA Astrophysics Data System (ADS)

    Coleman, Stephen James

    2011-12-01

    Experimental evidence has established that neutrino flavor states evolve over time. A neutrino of a particular flavor that travels some distance can be detected in a different neutrino flavor state. The Main Injector Neutrino Oscillation Search (MINOS) is a long-baseline experiment that is designed to study this phenomenon, called neutrino oscillations. MI-NOS is based at Fermilab near Chicago, IL, and consists of two detectors: the Near Detector located at Fermilab, and the Far Detector, which is located in an old iron mine in Soudan, MN. Both detectors are exposed to a beam of muon neutrinos from the NuMI beamline, and MINOS measures the fraction of muon neutrinos that disappear after traveling the 734 km between the two detectors. One can measure the atmospheric neutrino mass splitting and mixing angle by observing the energy-dependence of this muon neutrino disappearance. MINOS has made several prior measurements of these parameters. Here I describe recently-developed techniques used to enhance our sensitivity to the oscillation parameters, and I present the results obtained when they are applied to a dataset that is twice as large as has been previously analyzed. We measure the mass splitting Dm223=(2.32+0.12 -0.08) x 10-3 eV²/c4 and the mixing angle sin²(2theta32) > 0.90 at 90% C.L. These results comprise the world's best measurement of the atmospheric neutrino mass splitting. Alternative disappearance models are also tested. The neutrino decay hypothesis is disfavored at 7.2sigma and the neutrino quantum decoherence hypothesis is disfavored at 9.0sigma.

  15. The analysis of solar models: Neutrinos and oscillations

    NASA Technical Reports Server (NTRS)

    Ulrich, R. K.; Rhodes, E. J., Jr.; Tomczyk, S.; Dumont, P. J.; Brunish, W. M.

    1983-01-01

    Tests of solar neutrino flux and solar oscillation frequencies were used to assess standard stellar structure theory. Standard and non-standard solar models are enumerated and discussed. The field of solar seismology, wherein the solar interior is studied from the measurement of solar oscillations, is introduced.

  16. Phase space picture of neutrino mixing and oscillations

    NASA Astrophysics Data System (ADS)

    Blasone, Massimo; Vittoria Gargiulo, Maria; Vitiello, Giuseppe

    2017-08-01

    We consider a simple classical model in phase-space resembling the quantum one used for the description of neutrino oscillations and investigate the possibility of defining an analogue to the mixing transformation and to the oscillation formula in terms of generalized coordinates.

  17. Landau-Zener approximations for resonant neutrino oscillations

    SciTech Connect

    Whisnant, K.

    1988-07-15

    A simple method for calculating the effects of resonant neutrino oscillations using Landau-Zener approximations is presented. For any given set of oscillation parameters, the method is to use the Landau-Zener approximation which works best in that region.

  18. Resurrection of neutrinos as dark matter

    SciTech Connect

    Schramm, D.N.

    1986-05-01

    It is shown that new observations of large scale structure in the universe (voids, foam, and large-scale velocity fields) are best understood if the dominant matter of the universe is in the form of massive (9eV less than or equal to m/sub nu/ less than or equal to 35 eV) neutrinos. Cold dark matter, even with biasing, seems unable to duplicate the combination of these observations (although a fine-tuned loophole with cold matter and percolated explosions may also marginally work.) The previous fatal problems of galaxy formation with neutrinos can be remedied by combining them with either cosmic strings or explosive galaxy formation. The former naturally gives the scale-free correlation function for galaxies, clusters, and superclusters, and gives large, but not necessarily spherical voids. The latter naturally gives spherical voids, but requires fine tuning and percolation to get the large scales and the scale-free correlation function. 39 refs.

  19. Neutrino trapping in nonstrange dense stellar matter

    SciTech Connect

    Chiapparini, M.; Duarte, S.B.

    1996-08-01

    Neutrino trapping effects on the properties of dense stellar matter in nonstrange supranuclear regime are studied with the purpose of applying to supernovae dynamical evolution. The hadronic and leptonic compositions of stellar matter are obtained in the framework of the relativistic mean-field theory coupled with the {beta}-equilibrium condition, and maintaining the charge neutrality of the stellar medium. It is shown that the matter composition depends dramatically upon the confined electronic-leptonic fraction. The softness of the equation of state and the lowering of the nuclear incompressibility values, when compared with the situation in which neutrino confinement is not considered, are the remarkable results. {copyright} {ital 1996 The American Physical Society.}

  20. Aspects of neutrino oscillation in alternative gravity theories

    SciTech Connect

    Chakraborty, Sumanta

    2015-10-01

    Neutrino spin and flavour oscillation in curved spacetime have been studied for the most general static spherically symmetric configuration. Having exploited the spherical symmetry we have confined ourselves to the equatorial plane in order to determine the spin and flavour oscillation frequency in this general set-up. Using the symmetry properties we have derived spin oscillation frequency for neutrino moving along a geodesic or in a circular orbit. Starting from the expression of neutrino spin oscillation frequency we have shown that even in this general context, in high energy limit the spin oscillation frequency for neutrino moving along circular orbit vanishes. We have verified previous results along this line by transforming to Schwarzschild coordinates under appropriate limit. This finally lends itself to the probability of neutrino helicity flip which turns out to be non-zero. While for neutrino flavour oscillation we have derived general results for oscillation phase, which subsequently have been applied to three different gravity theories. One, of them appears as low-energy approximation to string theory, where we have an additional field, namely, dilaton field coupled to Maxwell field tensor. This yields a realization of Reissner-Nordström solution in string theory at low-energy. Next one corresponds to generalization of Schwarzschild solution by introduction of quadratic curvature terms of all possible form to the Einstein-Hilbert action. Finally, we have also discussed regular black hole solutions. In all these cases the flavour oscillation probabilities can be determined for solar neutrinos and thus can be used to put bounds on the parameters of these gravity theories. While for spin oscillation probability, we have considered two cases, Gauss-Bonnet term added to the Einstein-Hilbert action and the f(R) gravity theory. In both these cases we could impose bounds on the parameters which are consistent with previous considerations. In a nutshell, in

  1. Measurement of atmospheric neutrino oscillations with IceCube.

    PubMed

    Aartsen, M G; Abbasi, R; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beatty, J J; Bechet, S; Becker Tjus, J; Becker, K-H; Bell, M; Benabderrahmane, M L; Benzvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bernhard, A; Bertrand, D; Besson, D Z; Binder, G; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose, D; Böser, S; Botner, O; Brayeur, L; Bretz, H-P; Brown, A M; Bruijn, R; Brunner, J; Carson, M; Casey, J; Casier, M; Chirkin, D; Christov, A; Christy, B; Clark, K; Clevermann, F; Coenders, S; Cohen, S; Cowen, D F; Cruz Silva, A H; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Desiati, P; de With, M; DeYoung, T; Díaz-Vélez, J C; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Golup, G; Gonzalez, J G; Goodman, J A; Góra, D; Grandmont, D T; Grant, D; Groß, A; Ha, C; Haj Ismail, A; Hallen, P; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Jagielski, K; Japaridze, G S; Jero, K; Jlelati, O; Kaminsky, B; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kiryluk, J; Kislat, F; Kläs, J; Klein, S R; Köhne, J-H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Krings, K; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lesiak-Bzdak, M; Leuermann, M; Leute, J; Lünemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Mészáros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Niederhausen, H; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Palazzo, A; Paul, L; Pepper, J A; Pérez de los Heros, C; Pfendner, C; Pieloth, D; Pinat, E; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Rädel, L; Rameez, M; Rawlins, K; Redl, P; Reimann, R; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H-G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schöneberg, S; Schönwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stößl, A; Strahler, E A; Ström, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Tešić, G; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Wasserman, R; Weaver, Ch; Wellons, M; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zoll, M

    2013-08-23

    We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored.

  2. Supernova nucleosynthesis and the physics of neutrino oscillation

    SciTech Connect

    Kajino, Toshitaka

    2012-11-20

    We studied the explosive nucleosynthesis in core-collapse supernovae and found that several isotopes of rare elements like {sup 7}Li, {sup 11}B, {sup 138}La, {sup 180}Ta and others are predominantly produced by the neutrino interactions with several abundant nuclei. These isotopes are strongly affected by the neutrino flavor oscillation due to the MSW (Mikheyev-Smirnov-Wolfenstein) effect. We here first study how to know the suitable average neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the neutrino oscillation effects on their abundances, and propose a new novel method to determine the neutrino oscillation parameters, {theta}{sub 13} and mass hierarchy, simultaneously. There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced neutrino-process {sup 11}B and {sup 7}Li encapsulated in the grains. Combining the recent experimental constraints on {theta}{sub 13}, we show that although the uncertainties are still large, our method hints at a marginal preference for an inverted neutrino mass hierarchy for the first time.

  3. Measurement of Atmospheric Neutrino Oscillations with IceCube

    NASA Astrophysics Data System (ADS)

    Aartsen, M. G.; Abbasi, R.; Abdou, Y.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Bechet, S.; Becker Tjus, J.; Becker, K.-H.; Bell, M.; Benabderrahmane, M. L.; BenZvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Bertrand, D.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohaichuk, S.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Bretz, H.-P.; Brown, A. M.; Bruijn, R.; Brunner, J.; Carson, M.; Casey, J.; Casier, M.; Chirkin, D.; Christov, A.; Christy, B.; Clark, K.; Clevermann, F.; Coenders, S.; Cohen, S.; Cowen, D. F.; Cruz Silva, A. H.; Danninger, M.; Daughhetee, J.; Davis, J. C.; De Clercq, C.; De Ridder, S.; Desiati, P.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; Dunkman, M.; Eagan, R.; Eberhardt, B.; Eisch, J.; Ellsworth, R. W.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Franckowiak, A.; Franke, R.; Frantzen, K.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Goodman, J. A.; Góra, D.; Grandmont, D. T.; Grant, D.; Groß, A.; Ha, C.; Haj Ismail, A.; Hallen, P.; Hallgren, A.; Halzen, F.; Hanson, K.; Heereman, D.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Jagielski, K.; Japaridze, G. S.; Jero, K.; Jlelati, O.; Kaminsky, B.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kiryluk, J.; Kislat, F.; Kläs, J.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krasberg, M.; Krings, K.; Kroll, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Landsman, H.; Larson, M. J.; Lesiak-Bzdak, M.; Leuermann, M.; Leute, J.; Lünemann, J.; Madsen, J.; Maruyama, R.; Mase, K.; Matis, H. S.; McNally, F.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke, A.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Palazzo, A.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Pirk, N.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rädel, L.; Rameez, M.; Rawlins, K.; Redl, P.; Reimann, R.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Riedel, B.; Rodrigues, J. P.; Rott, C.; Ruhe, T.; Ruzybayev, B.; Ryckbosch, D.; Saba, S. M.; Salameh, T.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Scheel, M.; Scheriau, F.; Schmidt, T.; Schmitz, M.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schulz, O.; Seckel, D.; Sestayo, Y.; Seunarine, S.; Sheremata, C.; Smith, M. W. E.; Soldin, D.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stasik, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Tepe, A.; Ter-Antonyan, S.; Tešić, G.; Tilav, S.; Toale, P. A.; Toscano, S.; Usner, M.; van der Drift, D.; van Eijndhoven, N.; Van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Wasserman, R.; Weaver, Ch.; Wellons, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, C.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Ziemann, J.; Zierke, S.; Zoll, M.

    2013-08-01

    We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (˜20GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm322|=(2.3-0.5+0.6)×10-3eV2 and sin⁡2(2θ23)>0.93, and maximum mixing is favored.

  4. Neutrino oscillations in a model with a source and detector

    SciTech Connect

    Kiers, K.; Weiss, N. ||

    1998-03-01

    We study the oscillations of neutrinos in a model in which the neutrino is coupled to a localized, idealized source and detector. By varying the spatial and temporal resolution of the source and detector we are able to model the full range of source and detector types ranging from coherent to incoherent. We find that this approach is useful in understanding the interface between the quantum mechanical nature of neutrino oscillations on the one hand and the production and detection systems on the other hand. This method can easily be extended to study the oscillations of other particles such as the neutral K and B mesons. We find that this approach gives a reliable way to treat the various ambiguities which arise when one examines the oscillations from a wave packet point of view. We demonstrate that the conventional oscillation formula is correct in the relativistic limit and that several recent claims of an extra factor of 2 in the oscillation length are incorrect. We also demonstrate {ital explicitly} that the oscillations of neutrinos which have separated spatially may be {open_quotes}revived{close_quotes} by a long coherent measurement. {copyright} {ital 1998} {ital The American Physical Society}

  5. The effect of short-baseline neutrino oscillations on LBNE

    SciTech Connect

    Louis, William C.

    2015-10-15

    Short-baseline neutrino oscillations can have a relatively big effect on long-baseline oscillations, due to the cross terms that arise from multiple mass scales. The existing short-baseline anomalies suggest that short-baseline oscillations can affect the ν{sub μ} → ν{sub e} appearance probabilities by up to 20-40%, depending on the values of the CP-violating parameters.

  6. Dark matter and strong electroweak phase transition in a radiative neutrino mass model

    SciTech Connect

    Ahriche, Amine; Nasri, Salah E-mail: snasri@uaeu.ac.ae

    2013-07-01

    We consider an extension of the standard model (SM) with charged singlet scalars and right handed (RH) neutrinos all at the electroweak scale. In this model, the neutrino masses are generated at three loops, which provide an explanation for their smallness, and the lightest RH neutrino, N{sub 1}, is a dark matter candidate. We find that for three generations of RH neutrinos, the model can be consistent with the neutrino oscillation data, lepton flavor violating processes, N{sub 1} can have a relic density in agreement with the recent Planck data, and the electroweak phase transition can be strongly first order. We also show that the charged scalars may enhance the branching ratio h→γγ, where as h→γZ get can get few percent suppression. We also discuss the phenomenological implications of the RH neutrinos at the collider.

  7. Axion-assisted production of sterile neutrino dark matter

    DOE PAGES

    Berlin, Asher; Hooper, Dan

    2017-04-12

    Sterile neutrinos can be generated in the early universe through oscillations with active neutrinos and represent a popular and well-studied candidate for our Universe’s dark matter. Stringent constraints from X-ray and gamma-ray line searches, however, have excluded the simplest of such models. Here in this paper, we propose a novel alternative to the standard scenario in which the mixing angle between the sterile and active neutrinos is a dynamical quantity, induced through interactions with a light axionlike field. As the energy density of the axionlike particles is diluted by Hubble expansion, the degree of mixing is reduced at late times,more » suppressing the decay rate and easily alleviating any tension with X-ray or gamma-ray constraints. Lastly, we present a simple model which illustrates the phenomenology of this scenario, and also describe a framework in which the QCD axion is responsible for the production of sterile neutrinos in the early universe.« less

  8. Constraining neutrino oscillation parameters with current solar and atmospheric data

    NASA Astrophysics Data System (ADS)

    Maltoni, M.; Schwetz, T.; Tórtola, M. A.; Valle, J. W.

    2003-01-01

    We analyze the impact of recent solar and atmospheric data on the determination of the neutrino oscillation parameters, taking into account that both the solar νe and the atmospheric νμ may convert to a mixture of active and sterile neutrinos. We use the most recent global solar neutrino data, including the 1496-day Super-K neutrino data sample, and we investigate in detail the impact of the recent Sudbury Neutrino Observatory (SNO) neutral current, spectral, and day/night data by performing also an analysis using only the charged current rate from SNO. We confirm the clear preference of the pure active large mixing angle solution of the solar neutrino problem and obtain that the LOW solution, vacuum oscillation, small mixing angle, and just-so2 solutions are disfavored with a Δχ2=9, 9, 23, 31, respectively. Furthermore, we find that the global solar data constrains the admixture of a sterile neutrino to be less than 44% at 99% C.L. A pure sterile solution is ruled out with respect to the active one at 99.997% C.L. By performing an improved fit of the atmospheric data, we also update the corresponding regions of oscillation parameters. We find that the recent atmospheric Super-K (1489-day) and MACRO data have a strong impact on constraining a sterile component in atmospheric oscillations: if the νμ is restricted to the atmospheric mass states only a sterile admixture of 16% is allowed at 99% C.L., while a bound of 35% is obtained in the unconstrained case. Pure sterile oscillations are disfavored with a Δχ2=34.6 compared to the pure active case.

  9. Long-baseline neutrino oscillation experiments in North America

    SciTech Connect

    Goodman, M. C.

    2009-03-01

    This contribution to the proceedings of the 2008 NOW Workshop summarizes current and future long-baseline neutrino oscillation experiments in the United States. Together with recent results from MINOS, a future program incorporating NOvA and a long-baseline beam from Fermilab to DUSEL represents one possible scenario for a future U.S. High Energy Physics program with a significant neutrino component. Other futures are also possible. Depending on the value of {theta}{sub 13}, we may find that the future involves serious consideration of intercontinental neutrino beams, with the concomitant additional challenges in planning within an international framework.

  10. Solar neutrino oscillations and bounds on neutrino magnetic moment and solar magnetic field

    NASA Astrophysics Data System (ADS)

    Akhmedov, E. Kh.; Pulido, Joa~O.

    2003-01-01

    If the observed deficit of solar neutrinos is due to neutrino oscillations, neutrino conversions caused by the interaction of their transition magnetic moments with the solar magnetic field (spin-flavour precession) can still be present at a subdominant level. In that case, the combined action of neutrino oscillations and spin-flavour precession can lead to a small but observable flux of electron antineutrinos coming from the sun. Non-observation of these ν¯e's could set limits on neutrino transition moment /μ and the strength and coordinate dependence of the solar magnetic field B⊥. The sensitivity of the ν¯e flux to the product μB⊥ is the strongest in the case of the vacuum oscillation (VO) solution of the solar neutrino problem; in the case of the LOW solution, it is weaker, and it is the weakest for the LMA solution. For different solutions, different characteristics of the solar magnetic field B⊥(r) are probed: for the VO solution, the ν¯e flux is determined by the integral of B⊥(r) over the solar convective zone, for LMA it is determined by the magnitude of B⊥ in the neutrino production region, and for LOW it depends on the competition between this magnitude and the derivative of B⊥(r) at the surface of the sun.

  11. Observing Muon Neutrino to Electron Neutrino Oscillations in the NOνA Experiment

    SciTech Connect

    Xin, Tian

    2016-01-01

    Neutrino oscillations offers an insight on new physics beyond the Standard Model. The three mixing angles (θ12, θ13 and θ23) and the two mass splittings (Δm2 and Αm2 ) have been measured by different neutrino oscillation experiments. Some other parameters including the mass ordering of different neutrino mass eigenstates and the CP violation phase are still unknown. NOνA is a long-baseline accelerator neutrino experiment, using neutrinos from the NuMI beam at Fermilab. The experiment is equipped with two functionally identical detectors about 810 kilometers apart and 14 mrad off the beam axis. In this configuration, the muon neutrinos from the NuMI beam reach the disappearance maximum in the far detector and a small fraction of that oscillates into electron neutrinos. The sensitivity to the mass ordering and CP viola- tion phase determination is greately enhanced. This thesis presents the νeappearance analysis using the neutrino data collected with the NOνA experiment between February 2014 and May 2015, which corresponds to 3.45 ×1020 protons-on-target (POT). The νe appearance analysis is performed by comparing the observed νe CC-like events to the estimated background at the far detector. The total background is predicted to be 0.95 events with 0.89 originated from beam events and 0.06 from cosmic ray events. The beam background is obtained by extrapolating near detector data through different oscillation channels, while the cosmic ray background is calculated based on out-of-time NuMI trigger data. A total of 6 electron neutrino candidates are observed in the end at the far detector which represents 3.3 σ excess over the predicted background. The NOνA result disfavors inverted mass hierarchy for δcp ϵ [0, 0.6π] at 90% C.L.

  12. The Effect of Neutrino Oscillations on Supernova Light Element Synthesis

    SciTech Connect

    Yoshida, Takashi; Kajino, Toshitaka; Yokomakura, Hidekazu; Kimura, Keiichi; Takamura, Akira; Hartmann, Dieter H.

    2006-07-12

    We investigate light element synthesis through the {nu}-process during supernova explosions considering neutrino oscillations and investigate the dependence of 7Li and 11B yields on neutrino oscillation parameters mass hierarchy and {theta}13. The adopted supernova explosion model for explosive nucleosynthesis corresponds to SN 1987A. The 7Li and 11B yields increase by about factors of 1.9 and 1.3 in the case of normal mass hierarchy and adiabatic 13-mixing resonance compared with the case without neutrino oscillations. In the case of inverted mass hierarchy or nonadiabatic 13-mixing resonance, the increase in 7Li and 11B yields is much smaller. Astronomical observations of 7Li/11B ratio in stars formed in regions strongly affected by prior generations of supernovae would constrain mass hierarchy and the range of {theta}13.

  13. Invariant box[endash]parameterization of neutrino oscillations

    SciTech Connect

    Weiler, T.J. ); Wagner, D. )

    1998-10-01

    The model-independent [open quotes]box[close quotes] parameterization of neutrino oscillations is examined. The invariant boxes are the classical amplitudes of the individual oscillating terms. Being observables, the boxes are independent of the choice of parameterization of the mixing matrix. Emphasis is placed on the relations among the box parameters due to mixing[endash]matrix unitarity, and on the reduction of the number of boxes to the minimum basis set. Using the box algebra, we show that CP-violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. General analyses of neutrino oscillations among n[ge]3 flavors can readily determine the boxes, which can then be manipulated to yield magnitudes of mixing matrix elements. [copyright] [ital 1998 American Institute of Physics.

  14. Invariant box{endash}parameterization of neutrino oscillations

    SciTech Connect

    Weiler, T.J.; Wagner, D.

    1998-10-01

    The model-independent {open_quotes}box{close_quotes} parameterization of neutrino oscillations is examined. The invariant boxes are the classical amplitudes of the individual oscillating terms. Being observables, the boxes are independent of the choice of parameterization of the mixing matrix. Emphasis is placed on the relations among the box parameters due to mixing{endash}matrix unitarity, and on the reduction of the number of boxes to the minimum basis set. Using the box algebra, we show that CP-violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. General analyses of neutrino oscillations among n{ge}3 flavors can readily determine the boxes, which can then be manipulated to yield magnitudes of mixing matrix elements. {copyright} {ital 1998 American Institute of Physics.}

  15. Decaying majoron dark matter and neutrino masses

    SciTech Connect

    Lattanzi, Massimiliano

    2008-01-03

    We review our recent proposal of the majoron as a suitable warm dark matter candidate. The majoron is the Goldstone boson associated to the spontaneous breaking of ungauged lepton number, one of the mechanisms proposed to give rise to neutrino masses. The majoron can acquire a mass through quantum gravity effects, and can possibly account for the observed dark matter component of the Universe. We present constraints on the majoron lifetime, mass and abundance obtained by the analysis of the cosmic microwave background data. We find that, in the case of thermal production, the limits for the majoron mass read 0.12 keV or approx. 250 Gyr. We also apply this results to a given seesaw model for the generation of neutrino masses, and find that this constraints the energy scale for the lepton number breaking phase transition to be > or approx. 10{sup 6} GeV. We thus find that the majoron decaying dark matter (DDM) scenario fits nicely in models where neutrino masses arise a la seesaw, and may lead to other possible cosmological implications.

  16. Measurement of neutrino oscillation parameters from muon neutrino disappearance with an off-axis beam.

    PubMed

    Abe, K; Adam, J; Aihara, H; Akiri, T; Andreopoulos, C; Aoki, S; Ariga, A; Ariga, T; Assylbekov, S; Autiero, D; Barbi, M; Barker, G J; Barr, G; Bass, M; Batkiewicz, M; Bay, F; Bentham, S W; Berardi, V; Berger, B E; Berkman, S; Bertram, I; Bhadra, S; Blaszczyk, F D M; Blondel, A; Bojechko, C; Bordoni, S; Boyd, S B; Brailsford, D; Bravar, A; Bronner, C; Buchanan, N; Calland, R G; Caravaca Rodríguez, J; Cartwright, S L; Castillo, R; Catanesi, M G; Cervera, A; Cherdack, D; Christodoulou, G; Clifton, A; Coleman, J; Coleman, S J; Collazuol, G; Connolly, K; Cremonesi, L; Curioni, A; Dabrowska, A; Danko, I; Das, R; Davis, S; de Perio, P; De Rosa, G; Dealtry, T; Dennis, S R; Densham, C; Di Lodovico, F; Di Luise, S; Drapier, O; Duboyski, T; Duffy, K; Dufour, F; Dumarchez, J; Dytman, S; Dziewiecki, M; Emery, S; Ereditato, A; Escudero, L; Finch, A J; Frank, E; Friend, M; Fujii, Y; Fukuda, Y; Furmanski, A P; Galymov, V; Gaudin, A; Giffin, S; Giganti, C; Gilje, K; Golan, T; Gomez-Cadenas, J J; Gonin, M; Grant, N; Gudin, D; Hadley, D R; Haesler, A; Haigh, M D; Hamilton, P; Hansen, D; Hara, T; Hartz, M; Hasegawa, T; Hastings, N C; Hayato, Y; Hearty, C; Helmer, R L; Hierholzer, M; Hignight, J; Hillairet, A; Himmel, A; Hiraki, T; Hirota, S; Holeczek, J; Horikawa, S; Huang, K; Ichikawa, A K; Ieki, K; Ieva, M; Ikeda, M; Imber, J; Insler, J; Irvine, T J; Ishida, T; Ishii, T; Ives, S J; Iyogi, K; Izmaylov, A; Jacob, A; Jamieson, B; Johnson, R A; Jo, J H; Jonsson, P; Joo, K K; Jung, C K; Kaboth, A C; Kajita, T; Kakuno, H; Kameda, J; Kanazawa, Y; Karlen, D; Karpikov, I; Kearns, E; Khabibullin, M; Khotjantsev, A; Kielczewska, D; Kikawa, T; Kilinski, A; Kim, J; Kim, S B; Kisiel, J; Kitching, P; Kobayashi, T; Kogan, G; Kolaceke, A; Konaka, A; Kormos, L L; Korzenev, A; Koseki, K; Koshio, Y; Kreslo, I; Kropp, W; Kubo, H; Kudenko, Y; Kumaratunga, S; Kurjata, R; Kutter, T; Lagoda, J; Laihem, K; Laveder, M; Lawe, M; Lazos, M; Lee, K P; Licciardi, C; Lim, I T; Lindner, T; Lister, C; Litchfield, R P; Longhin, A; Lopez, G D; Ludovici, L; Macaire, M; Magaletti, L; Mahn, K; Malek, M; Manly, S; Marino, A D; Marteau, J; Martin, J F; Maruyama, T; Marzec, J; Masliah, P; Mathie, E L; Matveev, V; Mavrokoridis, K; Mazzucato, E; McCarthy, M; McCauley, N; McFarland, K S; McGrew, C; Metelko, C; Mijakowski, P; Miller, C A; Minamino, A; Mineev, O; Mine, S; Missert, A; Miura, M; Monfregola, L; Moriyama, S; Mueller, Th A; Murakami, A; Murdoch, M; Murphy, S; Myslik, J; Nagasaki, T; Nakadaira, T; Nakahata, M; Nakai, T; Nakamura, K; Nakayama, S; Nakaya, T; Nakayoshi, K; Naples, D; Nielsen, C; Nirkko, M; Nishikawa, K; Nishimura, Y; O'Keeffe, H M; Ohta, R; Okumura, K; Okusawa, T; Oryszczak, W; Oser, S M; Otani, M; Owen, R A; Oyama, Y; Pac, M Y; Palladino, V; Paolone, V; Payne, D; Pearce, G F; Perevozchikov, O; Perkin, J D; Petrov, Y; Pinzon Guerra, E S; Pistillo, C; Plonski, P; Poplawska, E; Popov, B; Posiadala, M; Poutissou, J-M; Poutissou, R; Przewlocki, P; Quilain, B; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M A M; Redij, A; Reeves, M; Reinherz-Aronis, E; Retiere, F; Robert, A; Rodrigues, P A; Rondio, E; Roth, S; Rubbia, A; Ruterbories, D; Sacco, R; Sakashita, K; Sánchez, F; Sato, F; Scantamburlo, E; Scholberg, K; Schwehr, J; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Sgalaberna, D; Shiozawa, M; Short, S; Shustrov, Y; Sinclair, P; Smith, B; Smith, R J; Smy, M; Sobczyk, J T; Sobel, H; Sorel, M; Southwell, L; Stamoulis, P; Steinmann, J; Still, B; Suda, Y; Suzuki, A; Suzuki, K; Suzuki, S Y; Suzuki, Y; Szeglowski, T; Tacik, R; Tada, M; Takahashi, S; Takeda, A; Takeuchi, Y; Tanaka, H K; Tanaka, H A; Tanaka, M M; Taylor, I J; Terhorst, D; Terri, R; Thompson, L F; Thorley, A; Tobayama, S; Toki, W; Tomura, T; Totsuka, Y; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Ueno, K; Vacheret, A; Vagins, M; Vasseur, G; Wachala, T; Waldron, A V; Walter, C W; Wark, D; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilkinson, C; Williamson, Z; Wilson, J R; Wilson, R J; Wongjirad, T; Yamada, Y; Yamamoto, K; Yanagisawa, C; Yen, S; Yershov, N; Yokoyama, M; Yuan, T; Zalewska, A; Zalipska, J; Zambelli, L; Zaremba, K; Ziembicki, M; Zimmerman, E D; Zito, M; Zmuda, J

    2013-11-22

    The T2K Collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to 3.01×10(20) protons on target. In the absence of neutrino oscillations, 205±17 (syst) events are expected to be detected while only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum, assuming three neutrino flavors and normal mass hierarchy yields a best-fit mixing angle sin2(θ23)=0.514±0.082 and mass splitting |Δm(32)(2)|=2.44(-0.15)(+0.17)×10(-3) eV2/c4. Our result corresponds to the maximal oscillation disappearance probability.

  17. Measurement of Neutrino Oscillation Parameters from Muon Neutrino Disappearance with an Off-Axis Beam

    NASA Astrophysics Data System (ADS)

    Abe, K.; Adam, J.; Aihara, H.; Akiri, T.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Ariga, T.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bass, M.; Batkiewicz, M.; Bay, F.; Bentham, S. W.; Berardi, V.; Berger, B. E.; Berkman, S.; Bertram, I.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Curioni, A.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; de Perio, P.; De Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Duboyski, T.; Duffy, K.; Dufour, F.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery, S.; Ereditato, A.; Escudero, L.; Finch, A. J.; Frank, E.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Gaudin, A.; Giffin, S.; Giganti, C.; Gilje, K.; Golan, T.; Gomez-Cadenas, J. J.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Ives, S. J.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Johnson, R. A.; Jo, J. H.; Jonsson, P.; Joo, K. K.; Jung, C. K.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; Kim, S. B.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Kogan, G.; Kolaceke, A.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koseki, K.; Koshio, Y.; Kreslo, I.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kumaratunga, S.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Laveder, M.; Lawe, M.; Lazos, M.; Lee, K. P.; Licciardi, C.; Lim, I. T.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Lopez, G. D.; Ludovici, L.; Macaire, M.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Maruyama, T.; Marzec, J.; Masliah, P.; Mathie, E. L.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Metelko, C.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Monfregola, L.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nagasaki, T.; Nakadaira, T.; Nakahata, M.; Nakai, T.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Naples, D.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Otani, M.; Owen, R. A.; Oyama, Y.; Pac, M. Y.; Palladino, V.; Paolone, V.; Payne, D.; Pearce, G. F.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Retiere, F.; Robert, A.; Rodrigues, P. A.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smith, R. J.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Szeglowski, T.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Tanaka, M. M.; Taylor, I. J.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Ueno, K.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Walter, C. W.; Wark, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yen, S.; Yershov, N.; Yokoyama, M.; Yuan, T.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.

    2013-11-01

    The T2K Collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to 3.01×1020 protons on target. In the absence of neutrino oscillations, 205±17 (syst) events are expected to be detected while only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum, assuming three neutrino flavors and normal mass hierarchy yields a best-fit mixing angle sin⁡2(θ23)=0.514±0.082 and mass splitting |Δm322|=2.44-0.15+0.17×10-3eV2/c4. Our result corresponds to the maximal oscillation disappearance probability.

  18. A search for neutrino oscillations using the CHOOZ 1 km baseline reactor neutrino experiment

    NASA Astrophysics Data System (ADS)

    George, Jean

    1999-10-01

    Neutrino oscillation searches are an active field of research due to the implications their discovery may have for the solar neutrino anomaly as well as for the atmospheric neutrino anomaly. Their discovery may also have broad ramifications for the Standard Model of Particle Physics as a whole. Results from an oscillation search using the CHOOZ long baseline reactor neutrino experiment are presented in this thesis. These results are based on the data taken from June 1997 through April 1998 when the two reactors ran at combined thermal power levels ranging from zero power to their full power level of 8.5 GW. Electron flavored antineutrinos emanating from the reactors were detected through the inverse beta decay channel using a liquid scintillating calorimeter located at a distance of approximately 1 km from the reactor sources. The underground experimental site (300 MWE) provided natural shielding from the background of cosmic ray muons-leading to a background rate more than an order of magnitude lower than the full power signal rate. From the agreement between the detected and expected neutrino event rates no evidence for neutrino oscillations was found (at the 90% C.L.) for the oscillation parameter space governed by Δm 2 > 0.8 × 10-3 eV2 for maximal mixing and by sin2 2Θ > 0.18 for large values of Δm2.

  19. Neutrino mass hierarchy, vacuum oscillations, and vanishing |U(e3)|

    SciTech Connect

    de Gouvea, Andre; Jenkins, James; Kayser, Boris; /Fermilab

    2005-03-01

    Is the relatively isolated member of the neutrino mass spectrum heavier or lighter than the two closely-spaced members? This question--the character of the neutrino mass hierarchy--is of great theoretical interest. All previously identified experiments for addressing it via neutrino oscillations require that the currently unknown size of the U{sub e3} element of the leptonic mixing matrix (parameterized by the unknown {theta}{sub 13} mixing angle) be sufficiently large, and will utterly fail in the limit {theta}{sub 13} {yields} 0. For this reason, we explore alternative oscillation approaches that would still succeed even if {theta}{sub 13} vanishes. We identify several alternatives that require neither a nonzero |U{sub e3}| nor the presence of significant matter effects. All include multiple percent-level neutrino oscillation measurements, usually involving muon-neutrino (or antineutrino) disappearance and very long baselines. We comment on the degree of promise that these alternative approaches show.

  20. Neutrino mass hierarchy, vacuum oscillations, and vanishing vertical bar U{sub e3} vertical bar

    SciTech Connect

    Gouvea, Andre de; Jenkins, James; Kayser, Boris

    2005-06-01

    Is the relatively isolated member of the neutrino mass spectrum heavier or lighter than the two closely-spaced members? This question--the character of the neutrino mass hierarchy--is of great theoretical interest. All previously identified experiments for addressing it via neutrino oscillations require that the currently unknown size of the U{sub e3} element of the leptonic mixing matrix (parameterized by the unknown {theta}{sub 13} mixing angle) be sufficiently large, and will utterly fail in the limit {theta}{sub 13}{yields}0. For this reason, we explore alternative oscillation approaches that would still succeed even if {theta}{sub 13} vanishes. We identify several alternatives that require neither a nonzero vertical bar U{sub e3} vertical bar nor the presence of significant matter effects (even if the latter are unavoidable in the case of long-baseline, Earth-based experiments). All include multiple percent-level neutrino oscillation measurements, usually involving muon-neutrino (or antineutrino) disappearance and very long baselines. We comment on the degree of promise that these alternative approaches show.

  1. Are non-relativistic neutrinos the dark matter particles?

    NASA Astrophysics Data System (ADS)

    Nieuwenhuizen, Theo M.

    2010-06-01

    The dark matter of a spherical, relaxed galaxy cluster is modeled by isothermal, non-interacting fermions; the galaxies and X-ray gas by isothermal classical distributions. A fit to lensing data of the cluster Abell 1689 works well and yields a mass of a few eV. This low value casts doubt on the existence of a Cold Dark Matter particle. The best case is the neutrino, for which in the cluster all 12 left- and righthanded modes are available. The fit gives an average mass 1.45(h/0.70)1/2 eV, with 2% error, while neutrino oscillations bring deviations of order meV. A neutrino mass between 0.2 and 2 eV will be searched in the Katrin experiment in 2012. The ideal value is mν = Yeme = 1.4998 eV, where Ye = 23/4GF1/2me is the Yukawa coupling of the electron. It occurs for reduced Hubble constant h = 0.744 with 4% error, right on top of and slightly sharper than the presently best supernova value of Riess et al. 2009, h = 0.742 with 4.8% error. In the cluster the neutrinos have a temperature of 0.045 K and a de Broglie length of 0.20 mm. They establish a quantum structure of several million light years across, the largest known in the Universe. The virial α-particle temperature of 9.9+/-1.1 keV/kB coincides with the average one of X-rays, while also the gas profile comes out well. Active neutrinos alone with the 1.45 eV mass give some 9.5% dark matter, more than allowed by the cold dark matter papradigm. A dark matter fraction of some 19%, Ων = (h/0.70)-3/20.189 (4), occurs for 12 degrees of freedom, i. e., for 3 families of left plus right handed neutrinos. The sterile modes may be produced in the early universe if there is a small Majorana mass matrix of order meV, on top of the Dirac matrix with ~1.45 eV masses. The neutrinos are free-streaming in the early universe and play no role during the decoupling. But now they are not homogeneous anymore. They condense on the Abell 1689 cluster fairly late, at redshift z~6-8, a prediction testable in future observations

  2. The discovery reach of CP violation in neutrino oscillation with non-standard interaction effects

    NASA Astrophysics Data System (ADS)

    Rahman, Zini; Dasgupta, Arnab; Adhikari, Rathin

    2015-06-01

    We have studied the CP violation discovery reach in a neutrino oscillation experiment with superbeam, neutrino factory and monoenergetic neutrino beam from the electron capture process. For NSI satisfying model-dependent bound for shorter baselines (like CERN-Fréjus set-up) there is insignificant effect of NSI on the the discovery reach of CP violation due to δ. Particularly, for the superbeam and neutrino factory we have also considered relatively longer baselines for which there could be significant NSI effects on CP violation discovery reach for higher allowed values of NSI. For the monoenergetic beam only shorter baselines are considered to study CP violation with different nuclei as neutrino sources. Interestingly for non-standard interactions—{{\\varepsilon }eμ } and {{\\varepsilon }eτ } of neutrinos with matter during propagation in longer baselines in the superbeam, there is the possibility of better discovery reach of CP violation than that with only Standard Model interactions of neutrinos with matter. For complex NSI we have shown the CP violation discovery reach in the plane of Dirac phase δ and NSI phase {{φ }ij}. The CP violation due to some values of δ remain unobservable with present and near future experimental facilities in the superbeam and neutrino factory. However, in the presence of some ranges of off-diagonal NSI phase values there are some possibilities of discovering total CP violation for any {{δ }CP} value even at 5σ confidence level for neutrino factory. Our analysis indicates that for some values of NSI phases total CP violation may not be at all observable for any values of δ. Combination of shorter and longer baselines could indicate in some cases the presence of NSI. However, in general for NSIs ≲ 1 the CP violation discovery reach is better in neutrino factory set-ups. Using a neutrino beam from the electron capture process for nuclei 50110Sn and 152Yb, we have shown the discovery reach of CP violation in a neutrino

  3. Measuring $\\theta_{13}$ via Muon Neutrino to Electron Neutrino Oscillations in the MINOS Experiment

    SciTech Connect

    Toner, Ruth B.

    2011-01-01

    One of the primary goals in neutrino physics at the present moment is to make a measurement of the neutrino oscillation parameter $\\theta_{13}$. This parameter, in addition to being unknown, could potentially allow for the introduction of CP violation into the lepton sector. The MINOS long-baseline neutrino oscillation experiment has the ability to make a measurement of this parameter, by looking for the oscillation of muon neutrinos to electron neutrinos between a Near and Far Detector over a distance of 735 km. This thesis discusses the development of an analysis framework to search for this oscillation mode. Two major improvements to pre-existing analysis techniques have been implemented by the author. First, a novel particle ID technique based on strip topology, known as the Library Event Matching (LEM) method, is optimized for use in MINOS. Second, a multiple bin likelihood method is developed to fit the data. These two improvements, when combined, increase MINOS' sensitivity to $\\sin^2(2\\theta_{13})$ by 27\\% over previous analyses. This thesis sees a small excess over background in the Far Detector. A Frequentist interpretation of the data rules out $\\theta_{13}=0$ at 91\\%. A Bayesian interpretation of the data is also presented, placing the most stringent upper boundary on the oscillation parameter to date, at $\\sin^2(2\\theta_{13})<0.09(0.015)$ for the Normal (Inverted) Hierarchy and $\\delta_{CP}=0$.

  4. PPPC 4 DMν: a Poor Particle Physicist Cookbook for Neutrinos from Dark Matter annihilations in the Sun

    SciTech Connect

    Baratella, Pietro; Cirelli, Marco; Hektor, Andi; Pata, Joosep; Piibeleht, Morten; Strumia, Alessandro

    2014-03-27

    We provide ingredients and recipes for computing neutrino signals of TeV-scale Dark Matter (DM) annihilations in the Sun. For each annihilation channel and DM mass we present the energy spectra of neutrinos at production, including: state-of-the-art energy losses of primary particles in solar matter, secondary neutrinos, electroweak radiation. We then present the spectra after propagation to the Earth, including (vacuum and matter) flavor oscillations and interactions in solar matter. We also provide a numerical computation of the capture rate of DM particles in the Sun. These results are available in numerical form http://www.marcocirelli.net/PPPC4DMID.html.

  5. PPPC 4 DMν: a Poor Particle Physicist Cookbook for Neutrinos from Dark Matter annihilations in the Sun

    NASA Astrophysics Data System (ADS)

    Baratella, Pietro; Cirelli, Marco; Hektor, Andi; Pata, Joosep; Piibeleht, Morten; Strumia, Alessandro

    2014-03-01

    We provide ingredients and recipes for computing neutrino signals of TeV-scale Dark Matter (DM) annihilations in the Sun. For each annihilation channel and DM mass we present the energy spectra of neutrinos at production, including: state-of-the-art energy losses of primary particles in solar matter, secondary neutrinos, electroweak radiation. We then present the spectra after propagation to the Earth, including (vacuum and matter) flavor oscillations and interactions in solar matter. We also provide a numerical computation of the capture rate of DM particles in the Sun. These results are available in numerical form.

  6. PPPC 4 DMν: a Poor Particle Physicist Cookbook for Neutrinos from Dark Matter annihilations in the Sun

    SciTech Connect

    Baratella, Pietro; Cirelli, Marco; Hektor, Andi; Pata, Joosep; Piibeleht, Morten; Strumia, Alessandro E-mail: marco.cirelli@cea.fr E-mail: joosep.pata@cern.ch E-mail: alessandro.strumia@cern.ch

    2014-03-01

    We provide ingredients and recipes for computing neutrino signals of TeV-scale Dark Matter (DM) annihilations in the Sun. For each annihilation channel and DM mass we present the energy spectra of neutrinos at production, including: state-of-the-art energy losses of primary particles in solar matter, secondary neutrinos, electroweak radiation. We then present the spectra after propagation to the Earth, including (vacuum and matter) flavor oscillations and interactions in solar matter. We also provide a numerical computation of the capture rate of DM particles in the Sun. These results are available in numerical form.

  7. Intense and exciting: current and future accelerator-based measurements of neutrino oscillation

    NASA Astrophysics Data System (ADS)

    Whitehead, Lisa

    2017-01-01

    Accelerator-based experiments have been crucial in our understanding of neutrino oscillations. In this talk, I will give an overview of current accelerator-based neutrino oscillation experiments, which have observed electron neutrino appearance and made precision measurements of the parameters governing muon neutrino disappearance. I will discuss what the current set of experiments can contribute to the remaining questions in neutrino oscillation physics, including measuring the CP violating phase, determining the mass hierarchy, resolving the θ23 octant, and searching for sterile neutrinos. Finally, I will describe the plans and physics goals for future accelerator-based neutrino experiments.

  8. Neutrino oscillation constraints on neutrinoless double-beta decay

    NASA Astrophysics Data System (ADS)

    Bilenky, S. M.; Giunti, C.; Kim, C. W.; Monteno, M.

    1998-06-01

    We have studied the constraints imposed by the results of neutrino oscillation experiments on the effective Majorana mass \\|\\| that characterizes the contribution of Majorana neutrino masses to the matrix element of neutrinoless double-beta decay. We have shown that in a general scheme with three Majorana neutrinos and a hierarchy of neutrino masses (which corresponds to the standard seesaw mechanism) the results of neutrino oscillation experiments imply rather strong constraints on the parameter \\|\\|. From the results of the first reactor long-baseline experiment CHOOZ and the Bugey experiment it follows that \\|\\|<~3×10-2 eV if Δm2<~2 eV2 (Δm2 is the largest mass-squared difference). Hence, we conclude that the observation of neutrinoless double-beta decay with a probability that corresponds to \\|\\|>~10-1 eV would be a signal for a nonhierarchical neutrino mass spectrum and/or nonstandard mechanisms of lepton number violation.

  9. Leptogenesis from oscillations of heavy neutrinos with large mixing angles

    NASA Astrophysics Data System (ADS)

    Drewes, Marco; Garbrecht, Björn; Gueter, Dario; Klarić, Juraj

    2016-12-01

    The extension of the Standard Model by heavy right-handed neutrinos can simultaneously explain the observed neutrino masses via the seesaw mechanism and the baryon asymmetry of the Universe via leptogenesis. If the mass of the heavy neutrinos is below the electroweak scale, they may be found at the LHC, BELLE II, NA62, the proposed SHiP experiment or a future high-energy collider. In this mass range, the baryon asymmetry is generated via CP -violating oscillations of the heavy neutrinos during their production. We study the generation of the baryon asymmetry of the Universe in this scenario from first principles of non-equilibrium quantum field theory, including spectator processes and feedback effects. We eliminate several uncertainties from previous calcula-tions and find that the baryon asymmetry of the Universe can be explained with larger heavy neutrino mixing angles, increasing the chance for an experimental discovery. For the limiting cases of fast and strongly overdamped oscillations of right-handed neutrinos, the generation of the baryon asymmetry can be calculated analytically up to corrections of order one.

  10. Neutrino masses and scalar singlet dark matter

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Subhaditya; Jana, Sudip; Nandi, S.

    2017-03-01

    We propose a simple extension of the Standard Model (SM) which has a viable dark matter (DM) candidate and can explain the generation of tiny neutrino masses. The DM is an electroweak (EW) singlet scalar S , odd under an imposed exact Z2 symmetry, that interacts with the SM through the "Higgs portal" coupling, while all other particles are even under Z2. The model also has an EW isospin 3 /2 scalar Δ and a pair of EW isospin vectors Σ and Σ ¯, which are responsible for generating tiny neutrino mass via the effective dimension-seven operator. Thanks to the additional interactions with Δ , the scalar singlet DM S survives a large region of parameter space by relic density constraints from WMAP/Planck and direct search bounds from updated LUX data. Constraints on the model from the LHC are also discussed.

  11. Neutrino Oscillation Searches with the Soudan 2 Detector.

    NASA Astrophysics Data System (ADS)

    Gallagher, Hugh Michael

    The Soudan 2 detector is a 963 ton iron tracking calorimeter located 2341 feet underground in Soudan Mine State Park, Soudan, Minnesota. Data taken from 1989 until 1993 is analyzed to search for atmospheric neutrino oscillations. In 1.5 fiducial kiloton-years exposure, 169 neutrino events have been identified. These events are classified as to the neutrino interaction that produced them, and a comparison is made of the number of 'track' events, which are primarily caused by the quasi-elastic scattering of nu _mu, to 'shower' events, which are primarily caused by the quasi-elastic scattering of nu_{e}. This track-to-shower ratio is also calculated for a sample of Monte Carlo events which is analyzed in the same manner as the data. These are compared in the form of a 'ratio of ratios'; R = (track/shower) _{data}/(track/shower) _{MC}. The ratio of ratios is sensitive to neutrino oscillations, a value less than one can indicate that muon neutrinos are oscillating into one of the other species. The ratio of ratios measured in this data set is R = 0.75 +/- 0.16 stat. +/- 0.14 syst.

  12. First neutrino oscillation measurements in NOvA

    DOE PAGES

    Messier, M. D.

    2016-04-20

    In this study, the NOvA experiment uses the Fermilab NuMI neutrino beam and a newly constructed 14 kt detector to address several open questions in neutrino oscillations including the neutrino mass hierarchy, the precise value of the angle θ23, and the CP-violating phase δCP. The experiment has been running since 2014 and has recently released its first results from an equivalent exposure of 2.74 × 1020 protons-on-target equal to 8% of the eventual data set. Measurements of νμ → νμ oscillations find Δm232 = (2.52+0.2–0.18) × 10-3 eV2 and 0.38 < sin2θ23 < 0.65 for the normal neutrino mass hierarchy.more » The experiment has observed νμ → νe oscillations at 3.3 σ C.L. in this early data and disfavors the inverted neutrino mass hierarchy in the range 0.1π < δCP < 0.5π at the 90% C.L.« less

  13. Search for Possible Exotic Contributions to Atmospheric Neutrino Oscillations

    NASA Astrophysics Data System (ADS)

    Giacomelli, G.; Popa, V.; Sioli, M.

    Neutrino-induced upward-going muons in MACRO are analyzed in terms of relativity violating effects, keeping “standard” mass-induced oscillations as the dominant source of νμ → ντ oscillations. Stringent 90% C.L. limits are placed on the Lorentz invariance violation parameter |Δv| as a function of the mixing angle θv or on the equivalence principle violation parameter |φΔγ|.

  14. Three-neutrino mixing and combined vacuum oscillations and MSW transitions of solar neutrinos

    SciTech Connect

    Liu, Q.Y.; Petcov, S.T. |

    1997-12-01

    Assuming three-flavor neutrino mixing takes place in vacuum, we investigate the possibility that the solar {nu}{sub e} take part in MSW transitions in the Sun due to {Delta}m{sub 31}{sup 2}{approximately}(10{sup {minus}7}{minus}10{sup {minus}4}) eV{sup 2}, followed by long wavelength vacuum oscillations on the way to the Earth, triggered by {Delta}m{sub 21}{sup 2} (or {Delta}m{sub 32}{sup 2}) {approximately}(10{sup {minus}12}{minus}10{sup {minus}10}) eV{sup 2}, {Delta}m{sub 31}{sup 2} and {Delta}m{sub 21}{sup 2} ({Delta}m{sub 32}{sup 2}) being the corresponding neutrino mass squared differences. The solar {nu}{sub e} survival probability is shown to be described in this case by a simple analytic expression. Depending on whether the vacuum oscillations are due to {Delta}m{sub 21}{sup 2} or {Delta}m{sub 32}{sup 2} there are two very different types of interplay between the MSW transitions and the vacuum oscillations of the solar {nu}{sub e}. Performing an analysis of the most recently published solar neutrino data we have found several qualitatively new solutions of the solar neutrino problem of the hybrid MSW transitions + vacuum oscillations type. The solutions differ in the way the pp, {sup 7}Be and {sup 8}B neutrino fluxes are affected by the transitions in the Sun and the oscillations in vacuum. The specific features of the new solutions are discussed. One of the distinctive predictions of the hybrid MSW + vacuum oscillation solutions found is the existence of strong and very characteristic distortions of the spectrum of {sup 8}B neutrinos. {copyright} {ital 1997} {ital The American Physical Society}

  15. Neutrinos

    NASA Astrophysics Data System (ADS)

    Murthy, P. V. R.

    The astrophysics and high energy physics of neutrinos are discussed. The former includes the topics of solar neutrinos, gravitational stellar collapses, neutrinos at high and superhigh energies, and DUMAND and related topics. Experimental results from the Homestake mine chlorine-37 experiment on solar neutrinos are shown. The solar neutrino puzzle is assessed, the economic aspects of DUMAND are discussed, and expectations for related projects are examined. For high energy physics, the discussion includes DUMAND and related projects, neutrino oscillations, the resolution of the puzzles of the measurement of the stopping muon flux and of the cosmic ray event time intervals, and the proton decay experiments.

  16. Status of the Daya Bay Reactor Neutrino Oscillation Experiment

    SciTech Connect

    Daya Bay Collaboration; Lin, Cheng-Ju Stephen

    2010-12-15

    The last unknown neutrino mixing angle theta_13 is one of the fundamental parameters of nature; it is also a crucial parameter for determining the sensitivity of future long-baseline experiments aimed to study CP violation in the neutrino sector. Daya Bay is a reactor neutrino oscillation experiment designed to achieve a sensitivity on the value of sin^2(2*theta_13) to better than 0.01 at 90percent CL. The experiment consists of multiple identical detectors placed underground at different baselines to minimize systematic errors and suppress cosmogenic backgrounds. With the baseline design, the expected anti-neutrino signal at the far site is about 360 events per day and at each of the near sites is about 1500 events per day. An overview and current status of the experiment will be presented.

  17. Violation of the Leggett-Garg Inequality in neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Weiss, T. E.; Formaggio, J. A.; Kaiser, D. I.; Murskyj, M. M.

    2017-09-01

    The Leggett-Garg inequality, an analogue of Bell’s inequality involving correlations of measurements on a system at different times, stands as one of the hallmark tests of quantum mechanics against classical predictions. The phenomenon of neutrino oscillations should adhere to quantum-mechanical predictions and provide an observable violation of the Leggett-Garg inequality. We demonstrate how oscillation phenomena can be used to test for violations of the classical bound by performing measurements on an ensemble of neutrinos at distinct energies, as opposed to a single neutrino at distinct times. A study of the MINOS experiment’s data shows a greater than 6σ violation over a distance of 735 km, representing the longest distance over which either the Leggett-Garg inequality or Bell’s inequality has been tested.

  18. Violation of the Leggett-Garg Inequality in Neutrino Oscillations.

    PubMed

    Formaggio, J A; Kaiser, D I; Murskyj, M M; Weiss, T E

    2016-07-29

    The Leggett-Garg inequality, an analogue of Bell's inequality involving correlations of measurements on a system at different times, stands as one of the hallmark tests of quantum mechanics against classical predictions. The phenomenon of neutrino oscillations should adhere to quantum-mechanical predictions and provide an observable violation of the Leggett-Garg inequality. We demonstrate how oscillation phenomena can be used to test for violations of the classical bound by performing measurements on an ensemble of neutrinos at distinct energies, as opposed to a single neutrino at distinct times. A study of the MINOS experiment's data shows a greater than 6σ violation over a distance of 735 km, representing the longest distance over which either the Leggett-Garg inequality or Bell's inequality has been tested.

  19. Final atmospheric neutrino oscillation results from Soudan 2

    NASA Astrophysics Data System (ADS)

    Kafka, T.; Soudan-2 Collaboration

    2006-05-01

    The final set of Soudan-2 data has been prepared including both events with their vertex within the detector and upgoing stopping muons originating in neutrino interactions within the rock surrounding the detector. This data set was analyzed for effects of atmospheric neutrino oscillations. The resulting probability of no oscillations was found to be 3.2 × 10-5. The improved 90% CL contour in sin22θ × log10(Δm2) is given, and found to be independent of the choice of 1D or 3D neutrino flux model. The Soudan 2 allowed contour includes, but is broader than, the 90% CL contours reported by SuperK and MACRO.

  20. Three-Neutrino Oscillation Parameters: Status and Prospects

    NASA Astrophysics Data System (ADS)

    Capozzi, F.; Fogli, G. L.; Lisi, E.; Marrone, A.; Montanino, D.; Palazzo, A.

    Neutrino oscillation searches using a variety of sources (solar, atmospheric, accelerator and reactor neutrinos) have established a standard three-neutrino (3ν) mass-mixing framework and five of its parameters: the two squared mass gaps (δm2, Δm2) and the three mixing angles (θ12, θ13, θ23). At present, a single class of experiments dominates each of these parameters, while only combined analyses of various (eventually all) data sets are needed to constrain the still unknown mass hierarchy [sign(Δm2)], θ23 octant and CP-violating phase δ. We review the status of the known and unknown parameters (as emerging from a global analysis of the oscillation data), investigate the correlations and stability of the such parameters within different combinations of data sets, and discuss the near-term prospects in this field.

  1. Long-Baseline Neutrino Oscillation Experiments in Europe

    SciTech Connect

    Terranova, F.

    2005-10-12

    Long-baseline experiments will play a crucial role in the precision era of neutrino oscillation physics. In this paper we review the ongoing European programme, which is focused on CNGS, and we discuss the opportunities for new facilities based on the CERN acceleration complex.

  2. Nonstandard interactions in solar neutrino oscillations with Hyper-Kamiokande and JUNO

    NASA Astrophysics Data System (ADS)

    Liao, Jiajun; Marfatia, Danny; Whisnant, Kerry

    2017-08-01

    Measurements of the solar neutrino mass-squared difference from KamLAND and solar neutrino data are somewhat discrepant, perhaps due to nonstandard neutrino interactions in matter. We show that the zenith angle distribution of solar neutrinos at Hyper-Kamiokande and the energy spectrum of reactor antineutrinos at JUNO can conclusively confirm the discrepancy and detect new neutrino interactions.

  3. Dark matter relic abundance and light sterile neutrinos

    NASA Astrophysics Data System (ADS)

    Tang, Yi-Lei; Zhu, Shou-hua

    2017-01-01

    In this paper, we calculate the relic abundance of the dark matter particles when they can annihilate into sterile neutrinos with the mass ≲ 100 GeV in a simple model. Unlike the usual standard calculations, the sterile neutrino may fall out of the thermal equilibrium with the thermal bath before the dark matter freezes out. In such a case, if the Yukawa coupling y N between the Higgs and the sterile neutrino is small, this process gives rise to a larger ΩDM h 2 so we need a larger coupling between the dark matter and the sterile neutrino for a correct relic abundance.

  4. Experimental constraints on the neutrino oscillations and a simple model of three-flavor mixing

    SciTech Connect

    Raczka, P.A.; Szymacha, A. ); Tatur, S. )

    1994-02-01

    A simple model of neutrino mixing is considered which contains only one right-handed neutrino field coupled, via the mass term, to the three usual left-handed fields. This is the simplest model that allows for three-flavor neutrino oscillations. The existing experimental limits on the neutrino oscillations are used to obtain constraints on the two free-mixing parameters of the model. A specific sum rule relating the oscillation probabilities of different flavors is derived.

  5. Prospects for long baseline neutrino oscillation experiments

    SciTech Connect

    Goodman, M.

    1991-12-31

    Several recent development have motivated consideration of neutrino experiments located hundreds or thousand of kilometers from an accelerator. The motivations and experimental challenges for such experiments are examined. Three proposals for using the Fermilab Main Injector are compared. The requirements on mass, distance and resolution for an ``ideal`` detector for such an experimental are considered.

  6. Prospects for long baseline neutrino oscillation experiments

    SciTech Connect

    Goodman, M.

    1991-01-01

    Several recent development have motivated consideration of neutrino experiments located hundreds or thousand of kilometers from an accelerator. The motivations and experimental challenges for such experiments are examined. Three proposals for using the Fermilab Main Injector are compared. The requirements on mass, distance and resolution for an ideal'' detector for such an experimental are considered.

  7. Dirac neutrinos and dark matter stability from lepton quarticity

    NASA Astrophysics Data System (ADS)

    Centelles Chuliá, Salvador; Ma, Ernest; Srivastava, Rahul; Valle, José W. F.

    2017-04-01

    We propose to relate dark matter stability to the possible Dirac nature of neutrinos. The idea is illustrated in a simple scheme where small Dirac neutrino masses arise from a type-I seesaw mechanism as a result of a Z4 discrete lepton number symmetry. The latter implies the existence of a viable WIMP dark matter candidate, whose stability arises from the same symmetry which ensures the Diracness of neutrinos.

  8. Cosmologically safe eV-scale sterile neutrinos and improved dark matter structure.

    PubMed

    Dasgupta, Basudeb; Kopp, Joachim

    2014-01-24

    We show that sterile neutrinos with masses ≳1  eV, as motivated by several short baseline oscillation anomalies, can be consistent with cosmological constraints if they are charged under a hidden sector force mediated by a light boson. In this case, sterile neutrinos experience a large thermal potential that suppresses mixing between active and sterile neutrinos in the early Universe, even if vacuum mixing angles are large. Thus, the abundance of sterile neutrinos in the Universe remains very small, and their impact on big bang nucleosynthesis, cosmic microwave background, and large-scale structure formation is negligible. It is conceivable that the new gauge force also couples to dark matter, possibly ameliorating some of the small-scale structure problems associated with cold dark matter.

  9. A study of muon neutrino to electron neutrino oscillations in the MINOS experiment

    SciTech Connect

    Yang, Tingjun

    2009-03-01

    The observation of neutrino oscillations (neutrino changing from one flavor to another) has provided compelling evidence that the neutrinos have non-zero masses and that leptons mix, which is not part of the original Standard Model of particle physics. The theoretical framework that describes neutrino oscillation involves two mass scales (Δmatm2 and Δmsol2), three mixing angles (θ12, θ23, and θ13) and one CP violating phase (δCP). Both mass scales and two of the mixing angles (θ12 and θ23) have been measured by many neutrino experiments. The mixing angle θ13, which is believed to be very small, remains unknown. The current best limit on θ13 comes from the CHOOZ experiment: θ13 < 11° at 90% C.L. at the atmospheric mass scale. δCP is also unknown today. MINOS, the Main Injector Neutrino Oscillation Search, is a long baseline neutrino experiment based at Fermi National Accelerator Laboratory. The experiment uses a muon neutrino beam, which is measured 1 km downstream from its origin in the Near Detector at Fermilab and then 735 km later in the Far Detector at the Soudan mine. By comparing these two measurements, MINOS can obtain parameters in the atmospheric sector of neutrino oscillations. MINOS has published results on the precise measurement of Δmatm2 and θ23 through the disappearance of muon neutrinos in the Far Detector and on a search for sterile neutrinos by looking for a deficit in the number of neutral current interactions seen in the Far Detector. MINOS also has the potential to improve the limit on the neutrino mixing angle θ13 or make the first measurement of its value by searching for an electron neutrino appearance signal in the Far Detector. This is the focus of the study presented in this thesis. We developed a neural network based algorithm to

  10. Constraints on sterile neutrino oscillations using DUNE near detector

    NASA Astrophysics Data System (ADS)

    Choubey, Sandhya; Pramanik, Dipyaman

    2017-01-01

    DUNE (Deep Underground Neutrino Experiment) is a proposed long-baseline neutrino experiment in the US with a baseline of 1300 km from Fermi National Accelerator Laboratory (Fermilab) to Sanford Underground Research Facility, which will house a 40 kt Liquid Argon Time Projection Chamber (LArTPC) as the far detector. The experiment will also have a fine grained near detector for accurately measuring the initial fluxes. We show that the energy range of the fluxes and baseline of the DUNE near detector is conducive for observing νμ →νe oscillations of Δm2 ∼ eV2 scale sterile neutrinos, and hence can be effectively used for testing to very high accuracy the reported oscillation signal seen by the LSND and MiniBooNE experiments. We study the sensitivity of the DUNE near detector to sterile neutrino oscillations by varying the baseline, detector fiducial mass and systematic uncertainties. We find that the detector mass and baseline of the currently proposed near detector at DUNE will be able to test the entire LSND parameter region with good precision. The dependence of sensitivity on baseline and detector mass is seen to give interesting results, while dependence on systematic uncertainties is seen to be small.

  11. Nonstandard neutrino-neutrino refractive effects in dense neutrino gases

    SciTech Connect

    Blennow, Mattias; Mirizzi, Alessandro; Serpico, Pasquale D.; /CERN /Fermilab

    2008-10-01

    We investigate the effects of nonstandard four-fermion neutrino-neutrino interactions on the flavor evolution of dense neutrino gases. We find that in the regions where the neutrino-neutrino refractive index leads to collective flavor oscillations, the presence of new neutrino interactions can produce flavor equilibration in both normal and inverted neutrino mass hierarchy. In realistic supernova environments, these effects are significant if the nonstandard neutrino-neutrino interaction strength is comparable to the one expected in the standard case, dominating the ordinary matter potential. However, very small nonstandard neutrino-neutrino couplings are enough to trigger the usual collective neutrino flavor transformations in the inverted neutrino mass hierarchy, even if the mixing angle vanishes exactly.

  12. Neutrino masses and oscillations in an unconventional model of lepton number violation

    NASA Astrophysics Data System (ADS)

    Tamvakis, K.; Vergados, J. D.

    1985-06-01

    Radiatively generated neutrino masses are studied in the framework of a simple model which predicts large mixings for neutrinos independently of the actual value of neutrino masses. The associated phenomenology of neutrino oscillations is analysed in detail. Other lepton violating processes are also discussed.

  13. Quantum field theory results for neutrino oscillations and new physics

    SciTech Connect

    Delepine, D.; Gonzalez Macias, Vannia; Khalil, Shaaban; Lopez Castro, G.

    2009-05-01

    The CP asymmetry in neutrino oscillations, assuming new physics at production and/or detection processes, is analyzed. We compute this CP asymmetry using the standard quantum field theory within a general new physics scenario that may generate new sources of CP and flavor violation. Well-known results for the CP asymmetry are reproduced in the case of V-A operators, and additional contributions from new physics operators are derived. We apply this formalism to SUSY extensions of the standard model where the contributions from new operators could produce a CP asymmetry observable in the next generation of neutrino experiments.

  14. Studying neutrino oscillations using quasi-elastic events in MINOS

    SciTech Connect

    Kumaratunga, Sujeewa Terasita

    2008-02-01

    MINOS (Main Injector Neutrino Oscillation Search), is a long baseline neutrino experiment designed to search for neutrino oscillations using two detectors at Fermi National Accelerator Laboratory, IL (Near Detector) and Soudan, MN (Far Detector). It will study vμ → vτ oscillations and make a measurement on the oscillation parameters, Δm$2\\atop{23}$ and sin223, via a vμ beam made at Fermilab. Charge current neutrino interactions in the MINOS detectors are of three types: quasi-elastic scattering (QEL), resonance scattering (RES) and deep inelastic scattering (DIS). Of these, quasi-elastic scattering leaves the cleanest signal with just one μ and one proton in the final state, thus rendering the reconstruction of the neutrino energy more accurate. This thesis will outline a method to separate QEL events from the others in the two detectors and perform a calculation of Δm$2\\atop{23}$ and sin223 using those events. The period under consideration was May 2005 to February 2006. The number of observed quasi-elastic events with energies below 10 GeV was 29, where the expected number was 60 ± 3. A fit to the energy distribution of these events gives Δm$2\\atop{23}$ = 2.91$+0.49\\atop{-0.53}$(stat)$+0.08\\atop{-0.09}$(sys) x 10-3 eV2 and sin223 = 0.990-0.180(stat)-0.030(sys).

  15. A combined muon-neutrino and electron-neutrino oscillation search at MiniBooNE

    SciTech Connect

    Monroe, Jocelyn Rebecca

    2006-01-01

    MiniBooNE seeks to corroborate or refute the unconfirmed oscillation result from the LSND experiment. If correct, the result implies that a new kind of massive neutrino, with no weak interactions, participates in neutrino oscillations. MiniBooNE searches for vμ → ve oscillations with the Fermi National Accelerator Laboratory 8 GeV beam line, which produces a vμ beam with an average energy of ~ 0.8 GeV and an intrinsic ve content of 0.4%. The neutrino detector is a 6.1 m radius sphere filled with CH2, viewed by 1540 photo-multiplier tubes, and located 541 m downstream from the source. This work focuses on the estimation of systematic errors associated with the neutrino flux and neutrino interaction cross section predictions, and in particular, on constraining these uncertainties using in-situ MiniBooNE vμ charged current quasielastic (CCQE) scattering data. A data set with ~ 100,000 events is identified, with 91% CCQE purity. This data set is used to measure several parameters of the CCQE cross section: the axial mass, the Fermi momentum, the binding energy, and the functional dependence of the axial form factor on four-momentum transfer squared. Constraints on the vμ and ve fluxes are derived using the vμ CCQE data set. A Monte Carlo study of a combined vμ disappearance and ve appearance oscillation fit is presented, which improves the vμ → ve oscillation sensitivity of MiniBooNE with respect to a ve appearance-only fit by 1.2-1.5σ, depending on the value of Δm2.

  16. Dark matter, light mediators, and the neutrino floor

    NASA Astrophysics Data System (ADS)

    Dent, James B.; Dutta, Bhaskar; Newstead, Jayden L.; Strigari, Louis E.

    2017-03-01

    We analyze direct dark matter detection experiments for ≲100 MeV mass mediators with general interactions. We compare the nuclear recoil energy spectra from these interactions to the solar neutrino spectrum. A set of interactions that generate spectra similar to the neutrino background is identified; however, this set is distinct from those that mimic the neutrino background for ≳100 MeV mass mediators. We outline a classification scheme based on momentum dependence of the dark matter-nucleus interaction to determine how strong the discovery limit for each interaction saturates due to the neutrino background. Our results motivate experimental progress towards lower nuclear recoil energy thresholds.

  17. Towards a unified model of neutrino-nucleus reactions for neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Nakamura, S. X.; Kamano, H.; Hayato, Y.; Hirai, M.; Horiuchi, W.; Kumano, S.; Murata, T.; Saito, K.; Sakuda, M.; Sato, T.; Suzuki, Y.

    2017-05-01

    A precise description of neutrino-nucleus reactions will play a key role in addressing fundamental questions such as the leptonic CP violation and the neutrino mass hierarchy through analyzing data from next-generation neutrino oscillation experiments. The neutrino energy relevant to the neutrino-nucleus reactions spans a broad range and, accordingly, the dominant reaction mechanism varies across the energy region from quasi-elastic scattering through nucleon resonance excitations to deep inelastic scattering. This corresponds to transitions of the effective degree of freedom for theoretical description from nucleons through meson-baryon to quarks. The main purpose of this review is to report our recent efforts towards a unified description of the neutrino-nucleus reactions over the wide energy range; recent overall progress in the field is also sketched. Starting with an overview of the current status of neutrino-nucleus scattering experiments, we formulate the cross section to be commonly used for the reactions over all the energy regions. A description of the neutrino-nucleon reactions follows and, in particular, a dynamical coupled-channels model for meson productions in and beyond the Δ (1232) region is discussed in detail. We then discuss the neutrino-nucleus reactions, putting emphasis on our theoretical approaches. We start the discussion with electroweak processes in few-nucleon systems studied with the correlated Gaussian method. Then we describe quasi-elastic scattering with nuclear spectral functions, and meson productions with a Δ -hole model. Nuclear modifications of the parton distribution functions determined through a global analysis are also discussed. Finally, we discuss issues to be addressed for future developments.

  18. Towards a unified model of neutrino-nucleus reactions for neutrino oscillation experiments.

    PubMed

    Nakamura, S X; Kamano, H; Hayato, Y; Hirai, M; Horiuchi, W; Kumano, S; Murata, T; Saito, K; Sakuda, M; Sato, T; Suzuki, Y

    2017-05-01

    A precise description of neutrino-nucleus reactions will play a key role in addressing fundamental questions such as the leptonic CP violation and the neutrino mass hierarchy through analyzing data from next-generation neutrino oscillation experiments. The neutrino energy relevant to the neutrino-nucleus reactions spans a broad range and, accordingly, the dominant reaction mechanism varies across the energy region from quasi-elastic scattering through nucleon resonance excitations to deep inelastic scattering. This corresponds to transitions of the effective degree of freedom for theoretical description from nucleons through meson-baryon to quarks. The main purpose of this review is to report our recent efforts towards a unified description of the neutrino-nucleus reactions over the wide energy range; recent overall progress in the field is also sketched. Starting with an overview of the current status of neutrino-nucleus scattering experiments, we formulate the cross section to be commonly used for the reactions over all the energy regions. A description of the neutrino-nucleon reactions follows and, in particular, a dynamical coupled-channels model for meson productions in and beyond the [Formula: see text](1232) region is discussed in detail. We then discuss the neutrino-nucleus reactions, putting emphasis on our theoretical approaches. We start the discussion with electroweak processes in few-nucleon systems studied with the correlated Gaussian method. Then we describe quasi-elastic scattering with nuclear spectral functions, and meson productions with a [Formula: see text]-hole model. Nuclear modifications of the parton distribution functions determined through a global analysis are also discussed. Finally, we discuss issues to be addressed for future developments.

  19. Earth matter effects in detection of supernova neutrinos

    SciTech Connect

    Guo, X.-H.; Young Binglin

    2006-05-01

    We calculated the matter effect, including both the Earth and supernova, on the detection of neutrinos from type II supernovae at the proposed Daya Bay reactor neutrino experiment. It is found that apart from the dependence on the flip probability P{sub H} inside the supernova and the mass hierarchy of neutrinos, the amount of the Earth matter effect depends on the direction of the incoming supernova neutrinos, and reaches the biggest value when the incident angle of neutrinos is around 93 deg. In the reaction channel {nu}{sub e}+p{yields}e{sup +}+n the Earth matter effect can be as big as about 12%. For other detection processes the amount of the Earth matter effect is a few per cent.

  20. Earth matter effects in detection of supernova neutrinos

    NASA Astrophysics Data System (ADS)

    Guo, X.-H.; Young, Bing-Lin

    2006-05-01

    We calculated the matter effect, including both the Earth and supernova, on the detection of neutrinos from type II supernovae at the proposed Daya Bay reactor neutrino experiment. It is found that apart from the dependence on the flip probability PH inside the supernova and the mass hierarchy of neutrinos, the amount of the Earth matter effect depends on the direction of the incoming supernova neutrinos, and reaches the biggest value when the incident angle of neutrinos is around 93°. In the reaction channel ν¯e+p→e++n the Earth matter effect can be as big as about 12%. For other detection processes the amount of the Earth matter effect is a few per cent.

  1. Exploring Neutrino Oscillation Parameter Space with a Monte Carlo Algorithm

    NASA Astrophysics Data System (ADS)

    Espejel, Hugo; Ernst, David; Cogswell, Bernadette; Latimer, David

    2015-04-01

    The χ2 (or likelihood) function for a global analysis of neutrino oscillation data is first calculated as a function of the neutrino mixing parameters. A computational challenge is to obtain the minima or the allowed regions for the mixing parameters. The conventional approach is to calculate the χ2 (or likelihood) function on a grid for a large number of points, and then marginalize over the likelihood function. As the number of parameters increases with the number of neutrinos, making the calculation numerically efficient becomes necessary. We implement a new Monte Carlo algorithm (D. Foreman-Mackey, D. W. Hogg, D. Lang and J. Goodman, Publications of the Astronomical Society of the Pacific, 125 306 (2013)) to determine its computational efficiency at finding the minima and allowed regions. We examine a realistic example to compare the historical and the new methods.

  2. The Daya Bay Reactor Electron Anti-neutrino Oscillation Experiment

    NASA Astrophysics Data System (ADS)

    Liu, Jianglai

    2007-10-01

    The phenomenon of neutrino flavor oscillations is now well-established. Mixing among the three flavors is characterized by three mixing angles, with θ13 being the only presently unknown angle. A precise measurement of θ13 using nuclear reactors as a source of electron anti-neutrinos requires high electron anti-neutrino flux, ˜2 km baselines, as well as good shielding to reduce cosmogenic backgrounds. The Daya Bay nuclear reactor complex located in south China is an ideal site to perform such a measurement. We have proposed an experiment at Daya Bay utilizing multiple baselines (between 0.3 and 2 km) and multiple liquid scintillator detector modules. Since the formal physics proposal in 2006, much progress has been made by the collaboration in the design of the experiment. The civil construction of the experiment will begin this year. In this talk, I will give an overview of the experiment, and report on the recent progress and the project status.

  3. Neutrino interactions in hot and dense matter

    SciTech Connect

    Reddy, S.; Prakash, M.; Lattimer, J.M.

    1998-07-01

    We study the charged and neutral current weak interaction rates relevant for the determination of neutrino opacities in dense matter found in supernovae and neutron stars. We establish an efficient formalism for calculating differential cross sections and mean free paths for interacting, asymmetric nuclear matter at arbitrary degeneracy. The formalism is valid for both charged and neutral current reactions. Strong interaction corrections are incorporated through the in-medium single particle energies at the relevant density and temperature. The effects of strong interactions on the weak interaction rates are investigated using both potential and effective field-theoretical models of matter. We investigate the relative importance of charged and neutral currents for different astrophysical situations, and also examine the influence of strangeness-bearing hyperons. Our findings show that the mean free paths are significantly altered by the effects of strong interactions and the multi-component nature of dense matter. The opacities are then discussed in the context of the evolution of the core of a protoneutron star. {copyright} {ital 1998} {ital The American Physical Society}

  4. Constraining Dark Matter-Neutrino Interactions with High-Energy Astrophysical Neutrinos

    NASA Astrophysics Data System (ADS)

    Arguelles, Carlos

    2017-01-01

    IceCube has continued to observe cosmic neutrinos since their discovery. The origin of these cosmic neutrinos is still unknown. Moreover, their arrival direction is compatible with an isotropic distribution. The this observation, together with dedicated studies looking for galactic plane correlations, suggest that the observed astrophysical neutrinos are of extragalactic origin. If there is a dark matter-neutrino interaction, then the observed neutrino flux and its spatial distribution would be distorted. We perform a likelihood analysis using four years of IceCube's high energy starting events to constrain the strength dark matter neutrino interactions in the context of simplified models. Finally, we compare our results with cosmology and highlight the complementary between the two constraints.

  5. Reconciling Neutrino Oscillations with SO(10) Leptogenesis

    NASA Astrophysics Data System (ADS)

    Nezri, Emmanuel; Orloff, Jean

    We study the link between neutrino oscillations and leptogenesis in the minimal framework assuming an SO(10) see-saw mechanism with 3 families. The solar and atmospheric data then generically induce a large mass-hierarchy and a small mixing between the lightest right-handed neutrinos, which fails to produce sufficient lepton asymmetry by 5 orders of magnitudes at least. This conclusion can only be evaded in the case of solar vacuum oscillations and for a very specific value of the mixing sin2 2θe3 = 0.1, which interestingly lies at the boundary of the CHOOZ exclusion region, but should be accessible to future long baseline experiments.

  6. Quantum simulations of neutrino oscillations and the Majorana equation

    NASA Astrophysics Data System (ADS)

    Noh, Changsuk; Rodriguez-Lara, Blas; Angelakis, Dimitris

    2013-03-01

    Two recent works on quantum simulations of relativistic equations are presented. The first is on neutrino oscillations with trapped ions as a generalization of Dirac equation simulation in 1 spatial dimension. It is shown that with two or more ion qubits it is possible to mimic the flavour oscillations of neutrinos. The second part is on quantum simulations of the Majorana equation based on the earlier work by Casanova et al. (PRX 1, 021018). We show that by decoupling the equation, it is possible to simulate with a smaller number of qubits given that one can perform complete tomography, including the spatial degrees of freedom. We acknowledge the financial support by the National Research Foundation and Ministry of Education, Singapore.

  7. Kinetic equations for baryogenesis via sterile neutrino oscillation

    SciTech Connect

    Asaka, Takehiko; Eijima, Sintaro; Ishida, Hiroyuki E-mail: eijima@muse.sc.niigata-u.ac.jp

    2012-02-01

    We investigate baryogenesis in the νMSM (neutrino Minimal Standard Model), which is the SM extended by three right-handed neutrinos with masses below the electroweak scale. The baryon asymmetry of the universe can be generated by the mechanism via flavor oscillation of right-handed (sterile) neutrinos which are responsible to masses of active neutrinos confirmed by various experiments. We present the kinetic equations for the matrix of densities of leptons which describe the generation of asymmetries. Especially, the momentum dependence of the matrix of densities is taken into account. By solving these equations numerically, it is found that the momentum distribution is significantly distorted from the equilibrium one, since the production for the modes with lower momenta k << T (T is the temperature of the universe) is enhanced, while suppressed for higher modes. As a result, the most important mode for the yields of sterile neutrinos as well as the baryon asymmetry is k ≅ 2T, which is smaller than (k) inferred from the thermal average. The comparison with the previous works is also discussed.

  8. Atmospheric neutrino oscillations from upward throughgoing muon multiple scattering in MACRO

    NASA Astrophysics Data System (ADS)

    MACRO Collaboration; Ambrosio, M.; Antolini, R.; Bakari, D.; Baldini, A.; Barbarino, G. C.; Barish, B. C.; Battistoni, G.; Becherini, Y.; Bellotti, R.; Bemporad, C.; Bernardini, P.; Bilokon, H.; Bloise, C.; Bower, C.; Brigida, M.; Bussino, S.; Cafagna, F.; Calicchio, M.; Campana, D.; Carboni, M.; Caruso, R.; Cecchini, S.; Cei, F.; Chiarella, V.; Chiarusi, T.; Choudhary, B. C.; Coutu, S.; Cozzi, M.; de Cataldo, G.; Dekhissi, H.; de Marzo, C.; de Mitri, I.; Derkaoui, J.; de Vincenzi, M.; di Credico, A.; Favuzzi, C.; Forti, C.; Fusco, P.; Giacomelli, G.; Giannini, G.; Giglietto, N.; Giorgini, M.; Grassi, M.; Grillo, A.; Gustavino, C.; Habig, A.; Hanson, K.; Heinz, R.; Iarocci, E.; Katsavounidis, E.; Katsavounidis, I.; Kearns, E.; Kim, H.; Kumar, A.; Kyriazopoulou, S.; Lamanna, E.; Lane, C.; Levin, D. S.; Lipari, P.; Longo, M. J.; Loparco, F.; Maaroufi, F.; Mancarella, G.; Mandrioli, G.; Manzoor, S.; Margiotta, A.; Marini, A.; Martello, D.; Marzari-Chiesa, A.; Mazziotta, M. N.; Michael, D. G.; Mikheyev, S.; Monacelli, P.; Montaruli, T.; Monteno, M.; Mufson, S.; Musser, J.; Nicolò, D.; Nolty, R.; Orth, C.; Osteria, G.; Palamara, O.; Patera, V.; Patrizii, L.; Pazzi, R.; Peck, C. W.; Perrone, L.; Petrera, S.; Popa, V.; Rainò, A.; Reynoldson, J.; Ronga, F.; Rrhioua, A.; Satriano, C.; Scapparone, E.; Scholberg, K.; Sciubba, A.; Serra, P.; Sioli, M.; Sirri, G.; Sitta, M.; Spinelli, P.; Spinetti, M.; Spurio, M.; Steinberg, R.; Stone, J. L.; Sulak, L. R.; Surdo, A.; Tarlè, G.; Togo, V.; Vakili, M.; Walter, C. W.; Webb, R.

    2003-07-01

    The energy of atmospheric neutrinos detected by MACRO was estimated using multiple Coulomb scattering of upward throughgoing muons. This analysis allows a test of atmospheric neutrino oscillations, relying on the distortion of the muon energy distribution. These results have been combined with those coming from the upward throughgoing muon angular distribution only. Both analyses are independent of the neutrino flux normalization and provide strong evidence, above the /4σ level, in favour of neutrino oscillations.

  9. Recent results from the Bugey neutrino oscillation experiment

    NASA Astrophysics Data System (ADS)

    Cavaignac, J. F.; Hoummada, A.; Koang, D. H.; Vignon, B.; Declais, Y.; de Kerret, H.; Pessard, H.; Thenard, J. M.

    1984-11-01

    The energy spectrum of electron antineutrinos has been measured at two distances, 13.6 and 18.3 meters, from the core of a PWR power reactor at Bugey (FRANCE). About 63000 antineutrinos events have been recorded using the inverse β-decay reaction νe¯+p→n+e+. A significant difference in the counting rate between the two positions has been observed. The compatibility of the results with solutions in a two-neutrino oscillation analysis is discussed.

  10. Solar neutrinos and neutrino physics

    NASA Astrophysics Data System (ADS)

    Maltoni, Michele; Smirnov, Alexei Yu.

    2016-04-01

    Solar neutrino studies triggered and largely motivated the major developments in neutrino physics in the last 50 years. The theory of neutrino propagation in different media with matter and fields has been elaborated. It includes oscillations in vacuum and matter, resonance flavor conversion and resonance oscillations, spin and spin-flavor precession, etc. LMA MSW has been established as the true solution of the solar neutrino problem. Parameters θ_{12} and Δ m 2 21 have been measured; θ_{13} extracted from the solar data is in agreement with results from reactor experiments. Solar neutrino studies provide a sensitive way to test theory of neutrino oscillations and conversion. Characterized by long baseline, huge fluxes and low energies they are a powerful set-up to search for new physics beyond the standard 3 ν paradigm: new neutrino states, sterile neutrinos, non-standard neutrino interactions, effects of violation of fundamental symmetries, new dynamics of neutrino propagation, probes of space and time. These searches allow us to get stringent, and in some cases unique bounds on new physics. We summarize the results on physics of propagation, neutrino properties and physics beyond the standard model obtained from studies of solar neutrinos.

  11. Neutrino-nucleus interactions and the determination of oscillation parameters

    NASA Astrophysics Data System (ADS)

    Benhar, Omar; Huber, Patrick; Mariani, Camillo; Meloni, Davide

    2017-07-01

    We review the status and prospects of theoretical studies of neutrino-nucleus interactions, and discuss the influence of the treatment of nuclear effects on the determination of oscillation parameters. The models developed to describe the variety of reaction mechanisms contributing to the nuclear cross sections are analyzed, with emphasis placed on their capability to explain the large body of available electron scattering data. The impact of the uncertainties associated with the description of nuclear structure and dynamics on the determination of oscillation parameters is illustrated through examples, and possible avenues towards a better understanding of the signals detected by accelerator-based experiments are outlined.

  12. The frequency of neutral meson and neutrino oscillation

    SciTech Connect

    Kayser, B.

    1997-03-01

    Interference between the different mass eigenstate components of a neutral K meson causes its decay probability to oscillate with time. Related oscillations occur in the decay chain {phi} {yields} KK {yields} f{sub 1}f{sub 2} (where f{sub 1,2} are decay channels), in neutral B decay, in the chain {Upsilon}(4s) {yields} BB {yields} f{sub 1}F{sub 2}, and in massive neutrino propagation. Since the mass eigenstates comprising a neutral K, a neutral B, or a neutrino have different masses, they have different speeds at any given momentum. Thus, classically, they become separated in space and time. This circumstance can tempt one to evaluate their contributions to the K or B decay, or to the neutrino interaction with a detector, at different spacetime points. However, these quantum-mechanically interfering contributions must always be evaluated at precisely the same point. Evaluating them at different points can lead to predicted oscillation frequencies double their true values.

  13. Neutrino mass, dark matter, and Baryon asymmetry via TeV-scale physics without fine-tuning.

    PubMed

    Aoki, Mayumi; Kanemura, Shinya; Seto, Osamu

    2009-02-06

    We propose an extended version of the standard model, in which neutrino oscillation, dark matter, and the baryon asymmetry of the Universe can be simultaneously explained by the TeV-scale physics without assuming a large hierarchy among the mass scales. Tiny neutrino masses are generated at the three-loop level due to the exact Z2 symmetry, by which the stability of the dark matter candidate is guaranteed. The extra Higgs doublet is required not only for the tiny neutrino masses but also for successful electroweak baryogenesis. The model provides discriminative predictions especially in Higgs phenomenology, so that it is testable at current and future collider experiments.

  14. Sterile neutrino portal to Dark Matter II: exact dark symmetry

    NASA Astrophysics Data System (ADS)

    Escudero, Miguel; Rius, Nuria; Sanz, Verónica

    2017-06-01

    We analyze a simple extension of the standard model (SM) with a dark sector composed of a scalar and a fermion, both singlets under the SM gauge group but charged under a dark sector symmetry group. Sterile neutrinos, which are singlets under both groups, mediate the interactions between the dark sector and the SM particles, and generate masses for the active neutrinos via the seesaw mechanism. We explore the parameter space region where the observed Dark Matter relic abundance is determined by the annihilation into sterile neutrinos, both for fermion and scalar Dark Matter particles. The scalar Dark Matter case provides an interesting alternative to the usual Higgs portal scenario. We also study the constraints from direct Dark Matter searches and the prospects for indirect detection via sterile neutrino decays to leptons, which may be able to rule out Dark Matter masses below and around 100 GeV.

  15. Flavor evolution of supernova neutrinos in turbulent matter

    SciTech Connect

    Lund, Tina; Kneller, James P.

    2014-01-01

    The neutrino signal from the next galactic supernova carries with it an enormous amount of information on the explosion mechanism of a core-collapse supernova, as well as on the stellar progenitor and on the neutrinos themselves. In order to extract this information we need to know how the neutrino flavor evolves over time due to the interplay of neutrino self-interactions and matter effects. Additional turbulence in the supernova matter may impart its own signatures on the neutrino spectrum, and could partly obscure the imprints of collective and matter effects. We investigate the neutrino flavor evolution due to neutrino self-interactions, matter effects due to the shock wave propagation, and turbulence in three progenitors with masses of 8.8 M⊙, 10.8 M⊙ and 18.0 M⊙. In the lightest progenitor we find that the impact of moderate turbulence of the order 10% is limited and occurs only briefly early on. This makes the signatures of collective and matter interactions relatively straightforward to interpret. Similarly, with moderate turbulence the two heavier progenitors exhibit only minor changes in the neutrino spectrum, and collective and matter signatures persists. However, when the turbulence is increased to 30% and 50% the high density matter resonance features in the neutrino spectrum get obscured, while new features arise in the low density resonance channel and in the non-resonant channels. We conclude that with moderate amounts of turbulence spectral features of collective and matter interactions survive in all three progenitors. For the larger amounts of turbulence in the 10.8 M⊙ and 18.0 M⊙ progenitor new features arise, as others disappear.

  16. Dark matter vs. neutrinos: the effect of astrophysical uncertainties and timing information on the neutrino floor

    SciTech Connect

    Davis, Jonathan H.

    2015-03-09

    Future multi-tonne Direct Detection experiments will be sensitive to solar neutrino induced nuclear recoils which form an irreducible background to light Dark Matter searches. Indeed for masses around 6 GeV the spectra of neutrinos and Dark Matter are so similar that experiments are said to run into a neutrino floor, for which sensitivity increases only marginally with exposure past a certain cross section. In this work we show that this floor can be overcome using the different annual modulation expected from solar neutrinos and Dark Matter. Specifically for cross sections below the neutrino floor the DM signal is observable through a phase shift and a smaller amplitude for the time-dependent event rate. This allows the exclusion power to be improved by up to an order of magnitude for large exposures. In addition we demonstrate that, using only spectral information, the neutrino floor exists over a wider mass range than has been previously shown, since the large uncertainties in the Dark Matter velocity distribution make the signal spectrum harder to distinguish from the neutrino background. However for most velocity distributions it can still be surpassed using timing information, and so the neutrino floor is not an absolute limit on the sensitivity of Direct Detection experiments.

  17. Dark matter vs. neutrinos: the effect of astrophysical uncertainties and timing information on the neutrino floor

    SciTech Connect

    Davis, Jonathan H.

    2015-03-01

    Future multi-tonne Direct Detection experiments will be sensitive to solar neutrino induced nuclear recoils which form an irreducible background to light Dark Matter searches. Indeed for masses around 6 GeV the spectra of neutrinos and Dark Matter are so similar that experiments are said to run into a neutrino floor, for which sensitivity increases only marginally with exposure past a certain cross section. In this work we show that this floor can be overcome using the different annual modulation expected from solar neutrinos and Dark Matter. Specifically for cross sections below the neutrino floor the DM signal is observable through a phase shift and a smaller amplitude for the time-dependent event rate. This allows the exclusion power to be improved by up to an order of magnitude for large exposures. In addition we demonstrate that, using only spectral information, the neutrino floor exists over a wider mass range than has been previously shown, since the large uncertainties in the Dark Matter velocity distribution make the signal spectrum harder to distinguish from the neutrino background. However for most velocity distributions it can still be surpassed using timing information, and so the neutrino floor is not an absolute limit on the sensitivity of Direct Detection experiments.

  18. Decoherent neutrino mixing, dark energy, and matter-antimatter asymmetry

    SciTech Connect

    Barenboim, Gabriela; Mavromatos, Nick E.

    2004-11-01

    A CPT violating decoherence scenario can easily account for all the experimental evidence in the neutrino sector including Liquid Scincillator Neutrino Detector. In this work it is argued that this framework can also accommodate the dark energy content of the Universe, as well as the observed matter-antimatter asymmetry.

  19. Light dark matter detection prospects at neutrino experiments

    SciTech Connect

    Kumar, Jason; Learned, John G.; Smith, Stefanie

    2009-12-01

    We consider the prospects for the detection of relatively light dark matter through direct annihilation to neutrinos. We specifically focus on the detection possibilities of water Cherenkov and liquid scintillator neutrino detection devices. We find, in particular, that liquid scintillator detectors may potentially provide excellent detection prospects for dark matter in the 4-10 GeV mass range. These experiments can provide excellent corroborative checks of the DAMA/LIBRA annual modulation signal, but may yield results for low mass dark matter in any case. We identify important tests of the ratio of electron to muon neutrino events (and neutrino versus antineutrino events), which discriminate against background atmospheric neutrinos. In addition, the fraction of events which arise from muon neutrinos or antineutrinos (R{sub {mu}} and R{sub {mu}}) can potentially yield information about the branching fractions of hypothetical dark matter annihilations into different neutrino flavors. These results apply to neutrinos from secondary and tertiary decays as well, but will suffer from decreased detectability.

  20. Residual Symmetries Applied to Neutrino Oscillations at NO ν A and T2K

    DOE PAGES

    Hanlon, Andrew D.; Repko, Wayne W.; Dicus, Duane A.

    2014-01-01

    Tmore » he results previously obtained from the model-independent application of a generalized hidden horizontal Z 2 symmetry to the neutrino mass matrix are updated using the latest global fits for the neutrino oscillation parameters.he resulting prediction for the Dirac CP phase δ D is in agreement with recent results from2K.he distribution for the Jarlskog invariant J ν has become sharper and appears to be approaching a particular region.he approximate effects of matter on long-baseline neutrino experiments are explored, and it is shown how the weak interactions between the neutrinos and the particles that make up the Earth can help to determine the mass hierarchy. A similar strategy is employed to show how NO ν A and2K could determine the octant of θ a ( ≡ θ 23 ) . Finally, the exact effects of matter are obtained numerically in order to make comparisons with the form of the approximate solutions. From this analysis there emerge some interesting features of the effective mass eigenvalues.« less

  1. 11B and constraints on neutrino oscillations and spectra from neutrino nucleosynthesis.

    PubMed

    Austin, Sam M; Heger, Alexander; Tur, Clarisse

    2011-04-15

    We study the sensitivity to variations in the triple-alpha and 12C(α,γ)16O reaction rates, of the yield of the neutrino-process isotopes 7Li, 11B, 19F, 138La, and 180Ta in core-collapse supernovae. Compared to solar abundances, less than 15% of 7Li, about 25%-80% of 19F, and about half of 138La is produced in these stars. Over a range of ±2σ for each helium-burning rate, 11B is overproduced and the yield varies by an amount larger than the variation caused by the effects of neutrino oscillations. The total 11B yield, however, may eventually provide constraints on supernova neutrino spectra.

  2. Adiabatic and nonadiabatic perturbation theory for coherence vector description of neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Hollenberg, Sebastian; Päs, Heinrich

    2012-01-01

    The standard wave function approach for the treatment of neutrino oscillations fails in situations where quantum ensembles at a finite temperature with or without an interacting background plasma are encountered. As a first step to treat such phenomena in a novel way, we propose a unified approach to both adiabatic and nonadiabatic two-flavor oscillations in neutrino ensembles with finite temperature and generic (e.g., matter) potentials. Neglecting effects of ensemble decoherence for now, we study the evolution of a neutrino ensemble governed by the associated quantum kinetic equations, which apply to systems with finite temperature. The quantum kinetic equations are solved formally using the Magnus expansion and it is shown that a convenient choice of the quantum mechanical picture (e.g., the interaction picture) reveals suitable parameters to characterize the physics of the underlying system (e.g., an effective oscillation length). It is understood that this method also provides a promising starting point for the treatment of the more general case in which decoherence is taken into account.

  3. Neutrino oscillation physics potential of the T2K experiment

    NASA Astrophysics Data System (ADS)

    T2K Collaboration; Abe, K.; Adam, J.; Aihara, H.; Akiri, T.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bartet-Friburg, P.; Bass, M.; Batkiewicz, M.; Bay, F.; Berardi, V.; Berger, B. E.; Berkman, S.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; de Perio, P.; de Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Dewhurst, D.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Duboyski, T.; Duffy, K.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery-Schrenk, S.; Ereditato, A.; Escudero, L.; Feusels, T.; Finch, A. J.; Fiorentini, G. A.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Garcia, A.; Giffin, S.; Giganti, C.; Gilje, K.; Goeldi, D.; Golan, T.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haegel, L.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayashino, T.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Iwai, E.; Iwamoto, K.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Johnson, R. A.; Johnson, S.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kabirnezhad, M.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Katori, T.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; King, S.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Koch, L.; Koga, T.; Kolaceke, A.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koshio, Y.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Lamont, I.; Larkin, E.; Laveder, M.; Lawe, M.; Lazos, M.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Lopez, J. P.; Ludovici, L.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Martins, P.; Martynenko, S.; Maruyama, T.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Mefodiev, A.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Missert, A.; Miura, M.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nakadaira, T.; Nakahata, M.; Nakamura, K. G.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Nantais, C.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; Nowak, J.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Ovsyannikova, T.; Owen, R. A.; Oyama, Y.; Palladino, V.; Palomino, J. L.; Paolone, V.; Payne, D.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pickard, L.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala-Zezula, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Riccio, C.; Rodrigues, P. A.; Rojas, P.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schoppmann, S.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shah, R.; Shaker, F.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Tanaka, M. M.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Wakamatsu, K.; Walter, C. W.; Wark, D.; Warzycha, W.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Yoshida, K.; Yuan, T.; Yu, M.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.

    2015-04-01

    The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle θ _{13} have led to a re-evaluation of the physics potential of the T2K long-baseline neutrino oscillation experiment. Sensitivities are explored for CP violation in neutrinos, non-maximal sin ^22θ _{23}, the octant of θ _{23}, and the mass hierarchy, in addition to the measurements of δ _{CP}, sin ^2θ _{23}, and Δ m^2_{32}, for various combinations of ν-mode and bar {ν }-mode data-taking. With an exposure of 7.8× 10^{21} protons-on-target, T2K can achieve 1σ resolution of 0.050 (0.054) on sin ^2θ _{23} and 0.040 (0.045)× 10^{-3} {eV}^2 on Δ m^2_{32} for 100% (50%) neutrino beam mode running assuming sin ^2θ _{23}=0.5 and Δ m^2_{32} = 2.4× 10^{-3} eV^2. T2K will have sensitivity to the CP-violating phase δ _{CP} at 90% C.L. or better over a significant range. For example, if sin ^22θ _{23} is maximal (i.e. θ _{23}=45°) the range is -115° < δ _{CP}< -60° for normal hierarchy and +50° < δ _{CP}< +130° for inverted hierarchy. When T2K data is combined with data from the NOνA experiment, the region of oscillation parameter space where there is sensitivity to observe a non-zero δ _{CP} is substantially increased compared to if each experiment is analyzed alone.

  4. Movable detector to search for neutrino oscillations in the BNL neutrino beam

    SciTech Connect

    Bozoki, G.; Fainberg, A.; Weygand, D.; Fagg, L.; Uberall, H.; Goldberg, M.; Meadows, B.; Saenz, A.W.; Seeman, N.

    1980-01-01

    A simple, straightforward, and economic experiment utilizing a set of water Cherenkov counters is proposed to search for neutrino oscillations in the AGS neutrino beam. The detector will be movable and will be able to provide reasonable counting rates up to 2 km downstream of the pion decay tunnel. Whereas previous accelerator experiments have sought to increase the ratio l/p (with l the neutrino path length and p its momentum) by decreasing p, increasing l is suggested instead. Further, by making measurements at several different values of l with the same apparatus, many sources of systematic error are eliminated. The experiment will measure beam-associated muon- and electron-type events at each position. A change in the ratio of muon- to electron-type events as a function of position would be evidence for ..nu../sub ..mu../ + ..nu../sub e/ oscillations. Sensitivity in terms of (..delta..m)/sup 2/ (the square of the mass difference in the mass eigenstates) can be as low as 0.1 eV/sup 2/, for full mixing, which is below the most probable value found by Reines et al for ..delta..m/sup 2/ in their electron neutrino reactor experiment. This experiment would be parasitic, running behind the usual neutrino beam experiments, assuming the nominal beam energy (peaked at 1 GeV), and would thus make a minimal demand on AGS support. It is suggested that the first two measurements be made inside the Isabelle tunnel at the points of intersection with the AGS neutrino beam. No further excavations would be required, and the data could be taken before ISA equipment is installed.

  5. Self-induced suppression of collective neutrino oscillations in a supernova.

    PubMed

    Duan, Huaiyu; Friedland, Alexander

    2011-03-04

    We investigate collective flavor oscillations of supernova neutrinos at late stages of the explosion. We first show that the frequently used single-angle (averaged coupling) approximation predicts oscillations close to, or perhaps even inside, the neutrinosphere, potentially invalidating the basic neutrino transport paradigm. Fortunately, we also find that the single-angle approximation breaks down in this regime; in the full multiangle calculation, the oscillations start safely outside the transport region. The new suppression effect is traced to the interplay between the dispersion in the neutrino-neutrino interactions and the vacuum oscillation term.

  6. Two-loop Dirac neutrino mass and WIMP dark matter

    NASA Astrophysics Data System (ADS)

    Bonilla, Cesar; Ma, Ernest; Peinado, Eduardo; Valle, Jose W. F.

    2016-11-01

    We propose a "scotogenic" mechanism relating small neutrino mass and cosmological dark matter. Neutrinos are Dirac fermions with masses arising only in two-loop order through the sector responsible for dark matter. Two triality symmetries ensure both dark matter stability and strict lepton number conservation at higher orders. A global spontaneously broken U(1) symmetry leads to a physical Diracon that induces invisible Higgs decays which add up to the Higgs to dark matter mode. This enhances sensitivities to spin-independent WIMP dark matter search below mh / 2.

  7. A search for muon neutrino to electron neutrino oscillations in the MINOS Experiment

    SciTech Connect

    Ochoa Ricoux, Juan Pedro

    2009-01-01

    We perform a search for vμ → ve oscillations, a process which would manifest a nonzero value of the θ13 mixing angle, in the MINOS long-baseline neutrino oscillation experiment. The analysis consists of searching for an excess of ve charged-current candidate events over the predicted backgrounds, made mostly of neutral-current events with high electromagnetic content. A novel technique to select electron neutrino events is developed, which achieves an improved separation between the signal and the backgrounds, and which consequently yields a better reach in θ13. The backgrounds are predicted in the Far Detector from Near Detector measurements. An excess is observed in the Far Detector data over the predicted backgrounds, which is consistent with the background-only hypothesis at 1.2 standard deviations.

  8. Los Alamos Science, Number 25 -- 1997: Celebrating the Neutrino

    DOE R&D Accomplishments Database

    Cooper, N. G. ed.

    1997-01-01

    This issue is devoted to the neutrino and its remaining mysteries. It is divided into the following areas: (1) The Reines-Cowan experiment -- detecting the poltergeist; (2) The oscillating neutrino -- an introduction to neutrino masses and mixing; (3) A brief history of neutrino experiments at LAMPF; (4) A thousand eyes -- the story of LSND (Los Alamos neutrino oscillation experiment); (5) The evidence for oscillations; (6) The nature of neutrinos in muon decay and physics beyond the Standard Model; (7) Exorcising ghosts -- in pursuit of the missing solar neutrinos; (8) MSW -- a possible solution to the solar neutrino problem; (8) Neutrinos and supernovae; and (9) Dark matter and massive neutrinos.

  9. Los Alamos Science, Number 25 -- 1997: Celebrating the neutrino

    SciTech Connect

    Cooper, N.G.

    1997-12-31

    This issue is devoted to the neutrino and its remaining mysteries. It is divided into the following areas: (1) The Reines-Cowan experiment -- detecting the poltergeist; (2) The oscillating neutrino -- an introduction to neutrino masses and mixing; (3) A brief history of neutrino experiments at LAMPF; (4) A thousand eyes -- the story of LSND (Los Alamos neutrino oscillation experiment); (5) The evidence for oscillations; (6) The nature of neutrinos in muon decay and physics beyond the Standard Model; (7) Exorcising ghosts -- in pursuit of the missing solar neutrinos; (8) MSW -- a possible solution to the solar neutrino problem; (8) Neutrinos and supernovae; and (9) Dark matter and massive neutrinos.

  10. Collaborative Research: Neutrinos & Nucleosynthesis in Hot Dense Matter

    SciTech Connect

    Reddy, Sanjay

    2013-09-06

    It is now firmly established that neutrinos, which are copiously produced in the hot and dense core of the supernova, play a role in the supernova explosion mechanism and in the synthesis of heavy elements through a phenomena known as r-process nucleosynthesis. They are also detectable in terrestrial neutrino experiments, and serve as a probe of the extreme environment and complex dynamics encountered in the supernova. The major goal of the UW research activity relevant to this project was to calculate the neutrino interaction rates in hot and dense matter of relevance to core collapse supernova. These serve as key input physics in large scale computer simulations of the supernova dynamics and nucleosynthesis being pursued at national laboratories here in the United States and by other groups in Europe and Japan. Our calculations show that neutrino production and scattering rate are altered by the nuclear interactions and that these modifications have important implications for nucleosynthesis and terrestrial neutrino detection. The calculation of neutrino rates in dense matter are difficult because nucleons in the dense matter are strongly coupled. A neutrino interacts with several nucleons and the quantum interference between scattering off different nucleons depends on the nature of correlations between them in dense matter. To describe these correlations we used analytic methods based on mean field theory and hydrodynamics, and computational methods such as Quantum Monte Carlo. We found that due to nuclear effects neutrino production rates at relevant temperatures are enhanced, and that electron neutrinos are more easily absorbed than anti-electron neutrinos in dense matter. The latter, was shown to favor synthesis of heavy neutron-rich elements in the supernova.

  11. Neutrino probes of the nature of light dark matter

    SciTech Connect

    Agarwalla, Sanjib Kumar; Mena, Olga; Blennow, Mattias; Martinez, Enrique Fernandez E-mail: blennow@mppmu.mpg.de E-mail: omena@ific.uv.es

    2011-09-01

    Dark matter particles gravitationally trapped inside the Sun may annihilate into Standard Model particles, producing a flux of neutrinos. The prospects of detecting these neutrinos in future multi-kt neutrino detectors designed for other physics searches are explored here. We study the capabilities of a 34/100 kt liquid argon detector and a 100 kt magnetized iron calorimeter detector. These detectors are expected to determine the energy and the direction of the incoming neutrino with unprecedented precision allowing for tests of the dark matter nature at very low dark matter masses, in the range of 10–25 GeV. By suppressing the atmospheric background with angular cuts, these techniques would be sensitive to dark matter-nucleon spin-dependent cross sections at the fb level, reaching down to a few ab for the most favorable annihilation channels and detector technology.

  12. Neutrinos from dark matter annihilations at the galactic center

    SciTech Connect

    Bertone, Gianfranco; Orloff, Jean; Silk, Joseph

    2004-09-15

    We discuss the prospects for detection of high energy neutrinos from dark matter (DM) annihilation at the galactic center (GC). Despite the large uncertainties associated with our poor knowledge of the distribution of dark matter in the innermost regions of the Galaxy, we determine an upper limit on the neutrino flux by requiring that the associated gamma-ray emission does not exceed the observed flux. We conclude that a neutrino flux from the GC will not be observable by Antares if dark matter is made of neutralinos with mass smaller than 650 GeV, while for heavier neutralinos, corresponding to models that will soon be probed by HESS (high energy stereoscopic system), the upper limit on the neutrino flux is barely above the Antares sensitivity. The detection of a larger flux would either require an alternative explanation, in terms of astrophysical processes, or the adoption of other dark matter candidates, disfavouring the case for neutralinos.

  13. Neutrino Oscillations, the Higgs Boson, and the Private Higgs Model

    NASA Astrophysics Data System (ADS)

    BenTov, Jonathan

    "CESR, PEP, PETRA, ISABELLE, p-bar p colliders, LEP, the tevatron, and ep machines are at various levels of design or construction. They will study the properties of b-matter, see weak intermediaries, and perhaps find the t-quark and the Higgs boson. Never before was there such a bestiary waiting to be discovered; and what surprises will be found!" - S. L. Glashow ("The Future of Elementary Particle Physics," Quarks and Leptons, NATO Advanced Study Institutes Series Volume 61, 1980, pp 687-713) The situation in 1980 was clearly different from the present situation in 2013, in which we face the very real possibilty that no new degrees of freedom will ever again be within reach of a collider. In an intriguing twist of fate, this very fact results in a sharp paradox for fundamental physics: the Higgs mass should be MP/m h ˜ 1017 times larger than it actually is, and the vacuum energy density of the universe should be (M P/A)4 ˜ (1031)4 times larger than it actually is, and apparently nature refuses to give us any more clues as to why. These together are what I would call the main problem of 21st century physics: despite all of the predictive success of particle physics so far, we must find a way to suitably modify the rules of quantum field theory, lest we accept the unproductive defeatist attitude that our universe is simply fine-tuned. In the meantime, there is much interesting work to be done in more "traditional" particle physics: we have learned that neutrinos actually have tiny but nonzero masses, which is clear and unambiguous evidence for physics beyond the Standard Model. I will allocate the first third of this document to phenomena related to neutrino oscillations. In particular, I would like to argue that some of the apparent differences between neutrino mixing and quark mixing are to an extent illusory, and actually many aspects of the two sectors can be understood in a coherent framework for extending the Standard Model. The remaining two-thirds of this

  14. How neutrino oscillations can induce an effective neutrino number of less than three during big bang nucleosynthesis

    SciTech Connect

    Foot, R.; Volkas, R.R.

    1997-11-01

    Ordinary-sterile neutrino oscillations can generate significant neutrino asymmetry in the early Universe. In this paper we extend this work by computing the evolution of neutrino asymmetries and light element abundances during the big bang nucleosynthesis (BBN) epoch. We show that a significant electron-neutrino asymmetry can be generated in a way that is approximately independent of the oscillation parameters {delta}m{sup 2} and sin{sup 2}2{theta} for a range of parameters in an interesting class of models. The numerical value of the asymmetry leads to the {ital prediction} that the effective number of neutrino flavors during BBN is either about 2.5 or 3.4, depending on the sign of the asymmetry. Interestingly, one class of primordial deuterium abundance data favors an effective number of neutrino flavors during the epoch of BBN of less than 3. {copyright} {ital 1997} {ital The American Physical Society}

  15. Neutrinos and Nucleosynthesis in Hot and Dense Matter

    SciTech Connect

    Fuller, George

    2016-01-14

    The Topical Collaboration for Neutrinos and Nucleosynthesis in Hot and Dense matter brought together researchers from a variety of nuclear science specialties and a number of institutions to address nuclear physics and neutrino physics problems associated with dense matter and the origin of the elements. See attached final technical reports for (1) the UCSD award and (2) a copy of the report for the whole TC

  16. Solar neutrino physics with low-threshold dark matter detectors

    NASA Astrophysics Data System (ADS)

    Billard, J.; Strigari, L. E.; Figueroa-Feliciano, E.

    2015-05-01

    Dark matter detectors will soon be sensitive to Solar neutrinos via two distinct channels: coherent neutrino-nucleus and neutrino-electron elastic scatterings. We establish an analysis method for extracting Solar model properties and neutrino properties from these measurements, including the possible effects of sterile neutrinos which have been hinted at by some reactor experiments and cosmological measurements. Even including sterile neutrinos, through the coherent scattering channel, a 1 ton-year exposure with a low-threshold background free Germanium detector could improve on the current measurement of the normalization of the B 8 Solar neutrino flux down to 3% or less. Combining with the neutrino-electron elastic scattering data will provide constraints on both the high- and low-energy survival probability and will improve on the uncertainty on the active-to-sterile mixing angle by a factor of 2. This sensitivity to active-to-sterile transitions is competitive and complementary to forthcoming dedicated short baseline sterile neutrino searches with nuclear decays. Finally, we show that such solar neutrino physics potentials can be reached as long as the signal-to-noise ratio is better than 0.1.

  17. Earth matter effects on supernova neutrinos in large-volume detectors

    NASA Astrophysics Data System (ADS)

    Borriello, Enrico

    2013-04-01

    Neutrino oscillations in the Earth matter may introduce peculiar modulations in the supernova (SN) neutrino spectra. The detection of this effect has been proposed as diagnostic tool for the neutrino mass hierarchy. We perform an updated study on the observability of this effect at large next-generation underground detectors (i.e., 0.4 Mton water Cherenkov, 50 kton scintillation and 100 kton liquid Argon detectors) based on neutrino fluxes from state-of-the-art SN simulations and accounting for statistical fluctuations via Montecarlo simulations. Since the average energies predicted by recent simulations are lower than previously expected and a tendency towards the equalization of the neutrino fluxes appears during the SN cooling phase, the detection of the Earth matter effect will be more challenging than expected from previous studies. We find that none of the proposed detectors shall be able to detect the Earth modulation for the neutrino signal of a typical galactic SN at 10 kpc. It should be observable in a 100 kton liquid Argon detector for a SN at few kpc and all three detectors would clearly see the Earth signature for very close-by stars only (d˜200 pc).

  18. The case for mixed dark matter from sterile neutrinos

    NASA Astrophysics Data System (ADS)

    Lello, Louis; Boyanovsky, Daniel

    2016-06-01

    Sterile neutrinos are SU(2) singlets that mix with active neutrinos via a mass matrix, its diagonalization leads to mass eigenstates that couple via standard model vertices. We study the cosmological production of heavy neutrinos via standard model charged and neutral current vertices under a minimal set of assumptions: i) the mass basis contains a hierarchy of heavy neutrinos, ii) these have very small mixing angles with the active (flavor) neutrinos, iii) standard model particles, including light (active-like) neutrinos are in thermal equilibrium. If kinematically allowed, the same weak interaction processes that produce active-like neutrinos also produce the heavier species. We introduce the quantum kinetic equations that describe their production, freeze out and decay and discuss the various processes that lead to their production in a wide range of temperatures assessing their feasibility as dark matter candidates. The final distribution function at freeze-out is a mixture of the result of the various production processes. We identify processes in which finite temperature collective excitations may lead to the production of the heavy species. As a specific example, we consider the production of heavy neutrinos in the mass range Mh lesssim 140 MeV from pion decay shortly after the QCD crossover including finite temperature corrections to the pion form factors and mass. We consider the different decay channels that allow for the production of heavy neutrinos showing that their frozen distribution functions exhibit effects from ``kinematic entanglement'' and argue for their viability as mixed dark matter candidates. We discuss abundance, phase space density and stability constraints and argue that heavy neutrinos with lifetime τ> 1/H0 freeze out of local thermal equilibrium, and conjecture that those with lifetimes τ ll 1/H0 may undergo cascade decay into lighter DM candidates and/or inject non-LTE neutrinos into the cosmic neutrino background. We provide a

  19. Impact of massive neutrinos on the nonlinear matter power spectrum.

    PubMed

    Saito, Shun; Takada, Masahiro; Taruya, Atsushi

    2008-05-16

    We present the first attempt to analytically study the nonlinear matter power spectrum for a mixed dark matter model containing neutrinos of total mass ~0.1 eV, based on cosmological perturbation theory. The suppression in the power spectrum amplitudes due to massive neutrinos is enhanced in the weakly nonlinear regime. We demonstrate that, thanks to this enhanced effect, the use of such a nonlinear model may enable a precision of sigma(m(nu,tot)) ~ 0.07 eV in constraining the total neutrino mass for the planned galaxy redshift survey, a factor of 2 improvement compared to the linear regime.

  20. Neutrino scattering rates in neutron star matter with {delta} isobars

    SciTech Connect

    Chen Yanjun; Guo Hua; Liu Yuxin

    2007-03-15

    We take the {delta}-isobar degrees of freedom into account in neutron star matter and evaluate their contributions to neutrino scattering cross sections and mean free paths. The neutron star matter is described by means of an effective hadronic model in the relativistic mean-field approximation. It is found that {delta} isobars may be present in neutron stars. The electron chemical potential does not decrease and the neutrino abundance does not increase with the increase of the density when neutrinos are trapped in the matter with {delta} isobars. The large vector coupling constant between the {delta}{sup -} and neutrino and the high spin of the {delta} influence significantly the neutrino scattering cross section and lead the contribution of the {delta}{sup -} to the dominance of the scattering rates. In neutrino-trapped case, the presence of {delta}s causes the neutrino mean free path to decrease drastically compared to that in the matter in which baryons are only nucleons.

  1. Discovering asymmetric dark matter with anti-neutrinos

    SciTech Connect

    Feldstein, Brian; Fitzpatrick, A. Liam E-mail: fitzpatr@physics.bu.edu

    2010-09-01

    We discuss possible signatures of Asymmetric Dark Matter (ADM) through dark matter decays to neutrinos. We specifically focus on scenarios in which the Standard Model (SM) baryon asymmetry is transferred to the dark sector (DS) through higher dimensional operators in chemical equilibrium. In such cases, the dark matter (DM) carries lepton and/or baryon number, and we point out that for a wide range of quantum number assignments, by far the strongest constraints on dark matter decays come from decays to neutrinos through the ''neutrino portal'' operator HL. Together with the facts that ADM favors lighter DM masses ∼ a few GeV and that the decays would lead only to anti-neutrinos and no neutrinos (or vice versa), the detection of such decays at neutrino telescopes would provide compelling evidence for ADM. We discuss current and future bounds on models where the DM decays to neutrinos through operators of dimension ≤ 6. For dimension 6 operators, the scale suppressing the decay is bounded to be ∼>10{sup 12}–10{sup 13} GeV.

  2. Summary: Neutrinos and nonaccelerator physics

    SciTech Connect

    Hoffman, C.M.

    1991-01-01

    This paper contains brief synopsis of the following major topics discussed in the neutrino and nonaccelerator parallel sessions: dark matter; neutrino oscillations at accelerators and reactors; gamma-ray astronomy; double beta decay; solar neutrinos; and the possible existence of a 17-KeV neutrino. (LSP)

  3. Minimal seesaw model for atmospheric and solar neutrino oscillations

    SciTech Connect

    Ma, E.; Roy, D.P. |

    1999-05-01

    We present a minimal seesaw model based on an extension of the standard model (SM) which includes an additional U(1), with gauge charge B{minus} (3) /(2) (L{sub {mu}}+L{sub {tau}}). The requirement of anomaly cancellation implies the existence of two right-handed singlet neutrinos, carrying this gauge charge, which have normal Dirac couplings to {nu}{sub {mu}} and {nu}{sub {tau}} but suppressed ones to {nu}{sub e}. Assuming the U(1) symmetry breaking scale to be 10{sup 12}{minus}10{sup 16} GeV, this model can naturally account for the large (small) mixing solutions to the atmospheric (solar) neutrino oscillations. {copyright} {ital 1999} {ital The American Physical Society}

  4. Gravitationally induced neutrino oscillation phases in static spacetimes

    SciTech Connect

    Bhattacharya, T.; Habib, S.; Mottola, E.

    1999-03-01

    We critically examine the recent claim of a {open_quotes}new effect{close_quotes} of gravitationally induced quantum mechanical phases in neutrino oscillations. Because this claim has generated some discussion in the literature we present here a straightforward calculation of the phase and clarify some of the conceptual issues involved, particularly in relation to the equivalence principle. When expressed in terms of the asymptotic energy of the neutrinos E and Schwarzschild radial coordinates r, the lowest order at which such a gravitational effect appears is (GM{Delta}m{sup 4}/{h_bar}E{sup 3})ln(r{sub B}/r{sub A}). {copyright} {ital 1999} {ital The American Physical Society}

  5. Search for exotic contributions to atmospheric neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Sioli, M.

    2006-11-01

    The energy spectrum of neutrino-induced upward-going muons in MACRO has been analyzed in terms of effects of violating relativity principles, keeping standard mass-induced atmospheric neutrino oscillations as the dominant source of ν μ → ν τ transitions. The data disfavor these exotic possibilities even at a subdominant level, and stringent 90% C.L. limits are placed on the Lorentz invariance violation parameter |Δ υ| < 6 × 10-24 at sin(2ϑυ) = 0 and |Δ υ| < (2.5-5) × 10-26 at sin(2ϑυ) = ±1. These limits can also be reinterpreted as upper bounds on the parameters describing violation of the equivalence principle.

  6. Lifting degeneracies in the oscillation parameters by a neutrino factory

    NASA Astrophysics Data System (ADS)

    Aoki, Mayumi; Hagiwara, Kaoru; Okamura, Naotoshi

    2005-01-01

    We study the potential of a very long baseline neutrino oscillation experiment with a neutrino factory and a large segmented water-Čerenkov calorimeter detector in resolving the degeneracies in the neutrino oscillation parameters; the sign of the larger mass-squared difference δm132, the sign of |Uμ 3 | 2 (≡sin2θATM) - 1 / 2, and a possible two-fold ambiguity in the determination of the CP phase δMNS. We find that the above problems can be resolved even if the particle charges are not measured. The following results are obtained in our exploratory study for a neutrino factory which delivers 1021 decaying μ+ and μ- at 10 GeV and a 100 kton detector which is placed 2100 km away and is capable of measuring the event energy and distinguishing e± from μ±, but not their charges. The sign of δm132 can be determined for 4|Ue 3 | 2 (1 -|Ue 3 | 2) ≡sin2 2θRCT ≳ 0.008. That of sin2θATM - 1 / 2 can be resolved for sin2 2θATM = 0.96 when sin2 2θRCT ≳ 0.06. The CP-violating phase δMNS can be uniquely constrained for sin2 2θRCT ≳ 0.02 if its true value is around 90° or 270°, while it can be constrained for sin2 2θRCT ≳ 0.03 if its true value is around 0° or 180°.

  7. Supernovae and neutron stars: playgrounds of dense matter and neutrinos

    NASA Astrophysics Data System (ADS)

    Sumiyoshi, Kohsuke

    2017-06-01

    Core-collapse supernovae are vital as the birthplace of compact objects, where one expects various phases of the dense matter. The current status of supernova studies with the nuclear data for dense matter and neutrino reactions is overviewed with a focus on recent progress of the neutrino-radiation hydrodynamics in two- an three-dimensions and remaining mysteries. In addition to its importance for the explosion mechanism, the equation of state is also essential to predict the neutrino bursts, which can be used to probe deep inside the compact objects. It is valuable to discuss variations of the extreme conditions for hyperons and quarks in central objects during explosive phenomena by looking into the pattern of neutrino signals in relation with dynamics and dense matter.

  8. Results from the Palo Verde neutrino oscillation experiment

    SciTech Connect

    Boehm, F.; Busenitz, J.; Cook, B.; Gratta, G.; Henrikson, H.; Kornis, J.; Lawrence, D.; Lee, K. B.; McKinny, K.; Miller, L.

    2000-10-01

    The {nu}(bar sign){sub e} flux and spectrum have been measured at a distance of about 800 m from the reactors of the Palo Verde Nuclear Generating Station using a segmented Gd-loaded liquid scintillator detector. Correlated positron-neutron events from the reaction {nu}(bar sign){sub e}p{yields}e{sup +}n were recorded for a period of 200 d including 55 d with one of the three reactors off for refueling. Backgrounds were accounted for by making use of the reactor-on and reactor-off cycles, and also with a novel technique based on the difference between signal and background under reversal of the e{sup +} and n portions of the events. A detailed description of the detector calibration, background subtraction, and data analysis is presented here. Results from the experiment show no evidence for neutrino oscillations. {nu}(bar sign){sub e}{yields}{nu}(bar sign){sub x} oscillations were excluded at 90% C.L. for {delta}m{sup 2}>1.12x10{sup -3} eV{sup 2} for full mixing and sin{sup 2}2{theta}>0.21 for large {delta}m{sup 2}. These results support the conclusion that the observed atmospheric neutrino oscillations do not involve {nu}{sub e}. (c) 2000 The American Physical Society.

  9. Status of three-neutrino oscillation parameters, circa 2013

    NASA Astrophysics Data System (ADS)

    Capozzi, F.; Fogli, G. L.; Lisi, E.; Marrone, A.; Montanino, D.; Palazzo, A.

    2014-05-01

    The standard three-neutrino (3ν) oscillation framework is being increasingly refined by results coming from different sets of experiments, using neutrinos from solar, atmospheric, accelerator and reactor sources. At present, each of the known oscillation parameters [the two squared mass gaps (δm2,Δm2) and the three mixing angles (θ12,θ13,θ23)] is dominantly determined by a single class of experiments. Conversely, the unknown parameters (the mass hierarchy, the θ23 octant and the CP-violating phase δ) can currently be constrained only through a combined analysis of various (eventually all) classes of experiments. In the light of recent new results coming from reactor and accelerator experiments, and of their interplay with solar and atmospheric data, we update the estimated Nσ ranges of the known 3ν parameters and revisit the status of the unknown ones. Concerning the hierarchy, no significant difference emerges between normal and inverted mass ordering. A slight overall preference is found for θ23 in the first octant and for nonzero CP violation with sinδ<0; however, for both parameters, such preference exceeds 1σ only for normal hierarchy. We also discuss the correlations and stability of the oscillation parameters within different combinations of data sets.

  10. Precision Measurement of Neutrino Oscillation Parameters with KamLAND

    SciTech Connect

    O'Donnell, Thomas

    2011-12-01

    This dissertation describes a measurement of the neutrino oscillation parameters m2 21, θ12 and constraints on θ13 based on a study of reactor antineutrinos at a baseline of ~ 180 km with the KamLAND detector. The data presented here was collected between April 2002 and November 2009, and amounts to a total exposure of 2.64 ± 0.07 × 1032 proton-years. For this exposure we expect 2140 ± 74(syst) antineutrino candidates from reactors, assuming standard model neutrino behavior, and 350±88(syst) candidates from background. The number observed is 1614. The ratio of background-subtracted candidates observed to expected is (NObs - NBkg)/ (NExp) = 0.59 ± 0.02(stat) ± 0.045(syst) which confirms reactor neutrino disappearance at greater than 5σ significance. Interpreting this deficit as being due to neutrino oscillation, the best-fit oscillation parameters from a three-flavor analysis are m2 21= 7.60+0.20 -0.19×10-5eV2, θ12 = 32.5 ± 2.9 degrees and sin2 θ13 = 0.025+0.035 -0.035, the 95% confidence-level upper limit on sin2 θ13 is sin2 θ13 < 0.083. Assuming CPT invariance, a combined analysis of KamLAND and solar neutrino data yields best-fit values: m2 21 = 7.60+0.20 -0.20 × 10-5eV2, θ12 = 33.5+1.0 -1.1 degrees, and sin2 θ13 = 0.013 ± 0.028 or sin2 θ13 < 0.06 at the 95% confidence level.

  11. Physics from solar neutrinos in dark matter direct detection experiments

    NASA Astrophysics Data System (ADS)

    Cerdeño, David G.; Fairbairn, Malcolm; Jubb, Thomas; Machado, Pedro A. N.; Vincent, Aaron C.; Bœhm, Céline

    2016-05-01

    The next generation of dark matter direct detection experiments will be sensitive to both coherent neutrino-nucleus and neutrino-electron scattering. This will enable them to explore aspects of solar physics, perform the lowest energy measurement of the weak angle sin2 θ W to date, and probe contributions from new theories with light mediators. In this article, we compute the projected nuclear and electron recoil rates expected in several dark matter direct detection experiments due to solar neutrinos, and use these estimates to quantify errors on future measurements of the neutrino fluxes, weak mixing angle and solar observables, as well as to constrain new physics in the neutrino sector. Our analysis shows that the combined rates of solar neutrino events in second generation experiments (SuperCDMS and LZ) can yield a measurement of the pp flux to 2.5% accuracy via electron recoil, and slightly improve the 8B flux determination. Assuming a low-mass argon phase, projected tonne-scale experiments like DARWIN can reduce the uncertainty on both the pp and boron-8 neutrino fluxes to below 1%. Finally, we use current results from LUX, SuperCDMS and CDMSlite to set bounds on new interactions between neutrinos and electrons or nuclei, and show that future direct detection experiments can be used to set complementary constraints on the parameter space associated with light mediators.

  12. Status of three-neutrino oscillations after the SNO-salt data

    NASA Astrophysics Data System (ADS)

    Maltoni, M.; Schwetz, T.; Tórtola, M. A.; Valle, J. W.

    2003-12-01

    We perform a global analysis of neutrino oscillation data in the framework of three neutrinos, including the recent improved measurement of the neutral current events at the Sudbury Neutrino Observatory. In addition to all current solar neutrino data, we take into account the reactor neutrino data from KamLAND and CHOOZ, the atmospheric neutrino data from Super-Kamiokande and MACRO, as well as the first spectral data from the K2K long baseline accelerator experiment. The up-to-date best-fit values and allowed ranges of the three-flavor oscillation parameters are determined from these data. Furthermore, we discuss in detail the status of the small parameters α≡Δm2sol/Δm2atm and sin2 θ13, which fix the possible strength of CP-violating effects in neutrino oscillations.

  13. Experimental evidence of electron neutrino oscillations and validation of MSW-LMA model with Borexino

    NASA Astrophysics Data System (ADS)

    Avanzini, M. Buizza

    2011-04-01

    We report the real time measurements of 7Be and 8B solar neutrino fluxes performed with the Borexino experiment at the Laboratori Nazionali del Gran Sasso. The achievement of these measurements was possible thanks to the excellent levels of the radiopurity reached. The measurement of the 7Be in real time is the first direct measurements of the survival probability for solar electron neutrinos in the vacuum region. For 8B we reached a threshold energy of 3MeV which is the lowest achieved so far in real time. For the first time, the same apparatus can measure two different oscillation regions (vacuum-driven and matter-enhanced) predicted by the MSW-LMA model. Borexino also quotes the ratio between the survival probabilities, corresponding to 1.93 ± 0.75, and validates the presence of the transition region between the two oscillation regimes, according to the MSW-LMA solution.In addition, a preliminary result on the Day-Night Asymmetry (ADN) for the 7Be neutrino flux is presented and corresponds to 0.007 ± 0.073. This measurement makes Borexino able to give once more an independent confirmation of the MSW-LMA solution.

  14. Recent results from the Bugey neutrino oscillation experiment

    SciTech Connect

    Cavaignac, J.F.; Hoummada, A.; Koang, D.H.; Vignon, B.; Declais, Y.; de Kerret, H.; Pessard, H.; Thenard, J.M.

    1984-11-15

    The energy spectrum of electron antineutrinos has been measured at two distances, 13.6 and 18.3 meters, from the core of a PWR power reactor at Bugey (FRANCE). About 63000 antineutrinos events have been recorded using the inverse ..beta..-decay reaction ..nu../sub e//sub $-bar//sub +p//sub ..-->..//sub n+e<+/. A significant difference in the counting rate between the two positions has been observed. The compatibility of the results with solutions in a two-neutrino oscillation analysis is discussed.

  15. Limits on neutrino oscillations from the CHOOZ experiment

    NASA Astrophysics Data System (ADS)

    Apollonio, M.; Baldini, A.

    1999-11-01

    We present new results based on the entire CHOOZ data sample. We find (at 90% confidence level) no evidence for neutrino oscillations in the anti_nue disappearance mode, for the parameter region given by approximately Delta m**2 > 7 x 10**-4 eV^2 for maximum mixing, and sin**2(2 theta) = 0.10 for large Delta m**2. Lower sensitivity results, based only on the comparison of the positron spectra from the two different-distance nuclear reactors, are also presented; these are independent of the absolute normalization of the anti_nue flux, the cross section, the number of target protons and the detector efficiencies.

  16. Reconciling solar and terrestrial neutrino oscillation evidence with minimum sacrifice

    SciTech Connect

    Fogli, G.L.; Lisi, E.; Montanino, D.; Scioscia, G.

    1997-10-01

    The present possible evidence in favor of neutrino masses and mixings from solar, atmospheric, and accelerator experiments cannot all be reconciled in a three-family framework, unless some data are excluded. We grade all possible three-family scenarios according to their compatibility with the available data. A recently proposed scenario appears to emerge naturally as the most likely solution to all oscillation evidence, with the only exception being the angular dependence of multi-GeV atmospheric data in the Kamiokande experiment. We describe in detail the status and the phenomenological implications of this {open_quotes}minimum sacrifice{close_quotes} solution. {copyright} {ital 1997} {ital The American Physical Society}

  17. CP violations in lepton number violation processes and neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Matsuda, K.; Takeda, N.; Fukuyama, T.; Nishiura, H.

    2000-11-01

    We examine the constraints on the Maki-Nakagawa-Sakata (MNS) lepton mixing matrix from present and future experimental data of the neutrino oscillation and lepton number violation processes. We introduce a graphical representation of the CP violation phases which appear in the lepton number violation processes such as neutrinoless double beta decay, the μ--e+ conversion, and the K decay, K--->π+μ-μ-. Using this graphical representation, we derive the constraints on the CP violation phases in the lepton sector.

  18. Discussion on Lorentz invariance violation of noncommutative field theory and neutrino oscillation

    NASA Astrophysics Data System (ADS)

    Luo, Cui-Bai; Shi, Song; Du, Yi-Lun; Wang, Yong-Long; Zong, Hong-Shi

    2017-03-01

    Depending on deformed canonical anticommutation relations, massless neutrino oscillation based on Lorentz invariance violation in noncommutative field theory is discussed. It is found that the previous studies about massless neutrino oscillation within deformed canonical anticommutation relations should satisfy the condition of new Moyal product and new nonstandard commutation relations. Furthermore, comparing the Lorentz invariant violation parameters A in the previous studies with new Moyal product and new nonstandard commutation relations, we find that the orders of magnitude of noncommutative parameters (Lorentz invariant violation parameters A) is not self-consistent. This inconsistency means that the previous studies of Lorentz invariance violation in noncommutative field theory may not naturally explain massless neutrino oscillation. In other words, it should be impossible to explain neutrino oscillation by Lorentz invariance violation in noncommutative field theory. This conclusion is supported by the latest atmospheric neutrinos experimental results from the super-Kamiokande Collaboration, which show that no evidence of Lorentz invariance violation on atmospheric neutrinos was observed.

  19. Neutrino oscillations with IceCube DeepCore and PINGU

    SciTech Connect

    DeYoung, T.; Collaboration: IceCube-PINGU Collaboration

    2014-11-18

    The IceCube neutrino telescope was augmented with the DeepCore infill array, completed in the 2010/11 austral summer, to enhance its response to neutrinos below 100 GeV. At these energies, neutrino oscillation effects are visible in the flux of atmospheric neutrinos traversing path lengths comparable to the Earth's diameter. Initial measurements of muon neutrino disappearance parameters using data from DeepCore are presented, as well as an estimate of potential future precision. In addition, plans for a Precision IceCube Next Generation Upgrade (PINGU), which could permit determination of the neutrino mass hierarchy within the coming decade, are discussed.

  20. Decaying sterile neutrino dark matter in the Local Group

    NASA Astrophysics Data System (ADS)

    Bozek, Brandon; Boylan-Kolchin, Michael; Horiuchi, Shunsaku; Garrison-Kimmel, Shea; Abazajian, Kevork; Bullock, James

    2017-01-01

    The detection of a 3.55 keV X-ray line in clusters of galaxies and the Andromeda and Milky Way galaxies, while contentious, can be explained by the decay of resonantly-produced 7.1 keV sterile neutrinos. If the X-ray line is confirmed to be the result of dark matter decay, then it is the first non-gravitational signal of dark matter and groundbreaking evidence of physics beyond the standard model. We use simulations that accurately model the dark matter distribution of the Local Group in realistic sterile neutrino cosmologies to study the dark matter interpretation of the X-ray flux. We present the sterile neutrino dark matter models that are consistent with the observed M31 flux profile and discuss the predictions of these models for X-ray observations of classical Milky Way dwarf galaxies. We discuss how these results relate to Lyman-alpha forest constraints of sterile neutrino models and predictions for satellite galaxy counts in future surveys, which may be able to rule out 7.1 keV sterile neutrinos as a dark matter candidate.

  1. Supernova Neutrino Physics with Xenon Dark Matter Detectors

    NASA Astrophysics Data System (ADS)

    Reichard, Shayne; Lang, Rafael F.; McCabe, Christopher; Selvi, Marco; Tamborra, Irene

    2017-09-01

    The dark matter experiment XENON1T is operational and sensitive to all flavors of neutrinos emitted from a supernova. We show that the proportional scintillation signal (S2) allows for a clear observation of the neutrino signal and guarantees a particularly low energy threshold, while the backgrounds are rendered negligible during the SN burst. XENON1T (XENONnT and LZ; DARWIN) will be sensitive to a SN burst up to 25 (40; 70) kpc from Earth at a significance of more than 5σ, observing approximately 35 (123; 704) events from a 27 M ⊙ SN progenitor at 10 kpc. Moreover, it will be possible to measure the average neutrino energy of all flavors, to constrain the total explosion energy, and to reconstruct the SN neutrino light curve. Our results suggest that a large xenon detector such as DARWIN will be competitive with dedicated neutrino telescopes, while providing complementary information that is not otherwise accessible.

  2. Prospects of Light Sterile Neutrino Oscillation and CP Violation Searches at the Fermilab Short Baseline Neutrino Facility

    NASA Astrophysics Data System (ADS)

    Cianci, Davio; Ross-Lonergan, Mark; Karagiorgi, Georgia; Furmanski, Andy

    2017-01-01

    While current and last generation neutrino experiments have vastly improved our knowledge of the three neutrino oscillation paradigm, certain anomalous experimental signatures such as the LSND and MiniBooNE anomalies have arisen which have consistently evaded a standard three neutrino explanation. One possible scenario to explain these anomalies is the addition of one or more, mostly sterile, light neutrino mass states, leading to observable oscillations associated to new frequencies at relatively short baselines. This talk will describe how Fermilab's Short Baseline Neutrino (SBN) program will be uniquely poised to test the existence of light sterile neutrinos in scenarios including one, two or three such new states. To quantify SBN's sensitivity reach, we compare the experiment's sensitivity to current, globally-allowed parameters for sterile neutrino oscillations. We also explore the possibility of including antineutrino beam running in the SBN run plan and study its impact on the potential physics reach, in particular from the perspective of new CP-violating phases which appear in these extended oscillation scenarios.

  3. A combined study of source, detector and matter non-standard neutrino interactions at DUNE

    NASA Astrophysics Data System (ADS)

    Blennow, Mattias; Choubey, Sandhya; Ohlsson, Tommy; Pramanik, Dipyaman; Raut, Sushant K.

    2016-08-01

    We simultaneously investigate source, detector and matter non-standard neutrino interactions at the proposed DUNE experiment. Our analysis is performed using a Markov Chain Monte Carlo exploring the full parameter space. We find that the sensitivity of DUNE to the standard oscillation parameters is worsened due to the presence of non-standard neutrino interactions. In particular, there are degenerate solutions in the leptonic mixing angle θ 23 and the Dirac CP-violating phase δ. We also compute the expected sensitivities at DUNE to the non-standard interaction parameters. We find that the sensitivities to the matter non-standard interaction parameters are substantially stronger than the current bounds (up to a factor of about 15). Furthermore, we discuss correlations between the source/detector and matter non-standard interaction parameters and find a degenerate solution in θ 23. Finally, we explore the effect of statistics on our results.

  4. MiniBooNE: first results on the muon-to-electron neutrino oscillation search

    SciTech Connect

    Sorel, M.; /Columbia U.

    2007-10-01

    MiniBooNE's first results on a search for an electron neutrino excess in a muon neutrino beam are presented, together with an analysis of the data within a two neutrino {nu}{sub {mu}} {yields} {nu}{sub e} appearance-only oscillation context. MiniBooNE finds excellent agreement between data and Standard Model predictions in the oscillation analysis energy region. If neutrino and antineutrino oscillations are the same, MiniBooNE excludes at {approx} 98% confidence level the two neutrino {nu}{sub {mu}} {yields} {nu}{sub e} appearance-only oscillation interpretation of the LSND anomaly. MiniBooNE also finds a discrepancy at energies below the oscillation analysis range, which is currently not understood and under investigation.

  5. Sterile neutrino dark matter and low scale leptogenesis from a charged scalar.

    PubMed

    Frigerio, Michele; Yaguna, Carlos E

    We show that novel paths to dark matter generation and baryogenesis are open when the standard model is extended with three sterile neutrinos [Formula: see text] and a charged scalar [Formula: see text]. Specifically, we propose a new production mechanism for the dark matter particle-a multi-keV sterile neutrino, [Formula: see text]-that does not depend on the active-sterile mixing angle and does not rely on a large primordial lepton asymmetry. Instead, [Formula: see text] is produced, via freeze-in, by the decays of [Formula: see text] while it is in equilibrium in the early Universe. In addition, we demonstrate that, thanks to the couplings between the heavier sterile neutrinos [Formula: see text] and [Formula: see text], baryogenesis via leptogenesis can be realized close to the electroweak scale. The lepton asymmetry is generated either by [Formula: see text]-decays for masses [Formula: see text] TeV, or by [Formula: see text]-oscillations for [Formula: see text] GeV. Experimental signatures of this scenario include an X-ray line from dark matter decays, and the direct production of [Formula: see text] at the LHC. This model thus describes a minimal, testable scenario for neutrino masses, the baryon asymmetry, and dark matter.

  6. Asymmetric dark matter and effective number of neutrinos

    NASA Astrophysics Data System (ADS)

    Kitabayashi, Teruyuki; Kurosawa, Yoshihiro

    2016-02-01

    We study the effect of the MeV-scale asymmetric dark matter annihilation on the effective number of neutrinos Neff at the epoch of the big bang nucleosynthesis. If the asymmetric dark matter χ couples more strongly to the neutrinos ν than to the photons γ and electrons e-, Γχ γ ,χ e≪Γχ ν , or Γχ γ ,χ e≫Γχ ν, the lower mass limit on the asymmetric dark matter is about 18 MeV for Neff≃3.0 .

  7. The Higgs seesaw induced neutrino masses and dark matter

    DOE PAGES

    Cai, Yi; Chao, Wei

    2015-08-12

    In this study we propose a possible explanation of the active neutrino Majorana masses with the TeV scale new physics which also provide a dark matter candidate. We extend the Standard Model (SM) with a local U(1)' symmetry and introduce a seesaw relation for the vacuum expectation values (VEVs) of the exotic scalar singlets, which break the U(1)' spontaneously. The larger VEV is responsible for generating the Dirac mass term of the heavy neutrinos, while the smaller for the Majorana mass term. As a result active neutrino masses are generated via the modified inverse seesaw mechanism. The lightest of themore » new fermion singlets, which are introduced to cancel the U(1)' anomalies, can be a stable particle with ultra flavor symmetry and thus a plausible dark matter candidate. We explore the parameter space with constraints from the dark matter relic abundance and dark matter direct detection.« less

  8. Pragmatic approach to the little hierarchy problem: the case for dark matter and neutrino physics.

    PubMed

    Grzadkowski, Bohdan; Wudka, José

    2009-08-28

    We show that the addition of real scalars (gauge singlets) to the standard model can both ameliorate the little hierarchy problem and provide realistic dark matter candidates. To this end, the coupling of the new scalars to the standard Higgs boson must be relatively strong and their mass should be in the 1-3 TeV range, while the lowest cutoff of the (unspecified) UV completion must be > or ~ 5 TeV, depending on the Higgs boson mass and the number of singlets present. The existence of the singlets also leads to realistic, and surprisingly reach, neutrino physics. The resulting light neutrino mass spectrum and mixing angles are consistent with the constraints from the neutrino oscillations.

  9. Solar neutrinos as a probe of dark matter-neutrino interactions

    NASA Astrophysics Data System (ADS)

    Capozzi, Francesco; Shoemaker, Ian M.; Vecchi, Luca

    2017-07-01

    Sterile neutrinos at the eV scale have long been studied in the context of anomalies in short baseline neutrino experiments. Their cosmology can be made compatible with our understanding of the early Universe provided the sterile neutrino sector enjoys a nontrivial dynamics with exotic interactions, possibly providing a link to the Dark Matter (DM) puzzle. Interactions between DM and neutrinos have also been proposed to address the long-standing "missing satellites" problem in the field of large scale structure formation. Motivated by these considerations, in this paper we discuss realistic scenarios with light steriles coupled to DM . We point out that within this framework active neutrinos acquire an effective coupling to DM that manifests itself as a new matter potential in the propagation within a medium of asymmetric DM . Assuming that at least a small fraction of asymmetric DM has been captured by the Sun, we show that a sizable region of the parameter space of these scenarios can be probed by solar neutrino experiments, especially in the regime of small couplings and light mediators where all other probes become inefficient. In the latter regime these scenarios behave as familiar 3+1 models in all channels except for solar data, where a Solar Dark MSW effect takes place. Solar Dark MSW is characterized by modifications of the most energetic 8B and CNO neutrinos, whereas the other fluxes remain largely unaffected.

  10. Investigation of Neutrino Oscillations at KamLAND

    NASA Astrophysics Data System (ADS)

    Berger, Bruce

    2002-04-01

    KamLAND is a one-kiloton liquid-scintillator neutrino detector located at the site of the old Kamiokande experiment in central Japan. The experiment will have two phases. The first uses the full array of Japanese nuclear power reactors in a long-baseline antineutrino oscillation measurement. Antineutrinos can be identified in the detector though their double-coincidence signal. KamLAND expects either to measure or rule out oscillations in the ``large mixing angle" region. In the second phase of the experiment, KamLAND hopes to directly measure the solar neutrino spectrum down to lower energies than are possible in water Cherenkov detectors. This phase requires a very low background environment and high scintillator purity, and will rely heavily on the understanding of backgrounds gained in the first phase. In this talk I will summarize the physics motivation for KamLAND and review the construction, commissioning, and initial calibration of the detector. I will also present initial data from the experiment.

  11. Radiative model of neutrino mass with neutrino interacting MeV dark matter

    SciTech Connect

    Arhrib, Abdesslam; Boehm, Céline; Ma, Ernest; Yuan, Tzu-Chiang

    2016-04-26

    We consider the radiative generation of neutrino mass through the interactions of neutrinos with MeV dark matter. We construct a realistic renormalizable model with one scalar doublet (in additional to the standard model doublet) and one complex singlet together with three light singlet Majorana fermions, all transforming under a dark U(1){sub D} symmetry which breaks softly to Z{sub 2}. We study in detail the scalar sector which supports this specific scenario and its rich phenomenology.

  12. Tight bonds between sterile neutrinos and dark matter

    SciTech Connect

    Bringmann, Torsten; Hasenkamp, Jasper; Kersten, Jörn E-mail: Jasper.Hasenkamp@nyu.edu

    2014-07-01

    Despite the astonishing success of standard ΛCDM cosmology, there is mounting evidence for a tension with observations at small and intermediate scales. We introduce a simple model where both cold dark matter (DM) and sterile neutrinos are charged under a new U(1){sub X} gauge interaction. The resulting DM self-interactions resolve the tension with the observed abundances and internal density structures of dwarf galaxies. At the same time, the sterile neutrinos can account for both the small hot DM component favored by cosmological observations and the neutrino anomalies found in short-baseline experiments.

  13. Limits on muon-neutrino to tau-neutrino oscillations induced by a sterile neutrino state obtained by OPERA at the CNGS beam

    NASA Astrophysics Data System (ADS)

    Agafonova, N.; Aleksandrov, A.; Anokhina, A.; Aoki, S.; Ariga, A.; Ariga, T.; Bender, D.; Bertolin, A.; Bodnarchuk, I.; Bozza, C.; Brugnera, R.; Buonaura, A.; Buontempo, S.; Büttner, B.; Chernyavsky, M.; Chukanov, A.; Consiglio, L.; D'Ambrosio, N.; De Lellis, G.; De Serio, M.; Del Amo Sanchez, P.; Di Crescenzo, A.; Di Ferdinando, D.; Di Marco, N.; Dmitrievski, S.; Dracos, M.; Duchesneau, D.; Dusini, S.; Dzhatdoev, T.; Ebert, J.; Ereditato, A.; Fini, R. A.; Fukuda, T.; Galati, G.; Garfagnini, A.; Goldberg, J.; Gornushkin, Y.; Grella, G.; Guler, A. M.; Gustavino, C.; Hagner, C.; Hara, T.; Hollnagel, A.; Hosseini, B.; Ishiguro, K.; Jakovcic, K.; Jollet, C.; Kamiscioglu, C.; Kamiscioglu, M.; Kim, J. H.; Kim, S. H.; Kitagawa, N.; Klicek, B.; Kodama, K.; Komatsu, M.; Kose, U.; Kreslo, I.; Lauria, A.; Ljubicic, A.; Longhin, A.; Malgin, A.; Malenica, M.; Mandrioli, G.; Matsuo, T.; Matveev, V.; Mauri, N.; Medinaceli, E.; Meregaglia, A.; Mikado, S.; Monacelli, P.; Montesi, M. C.; Morishima, K.; Muciaccia, M. T.; Naganawa, N.; Naka, T.; Nakamura, M.; Nakano, T.; Nakatsuka, Y.; Niwa, K.; Ogawa, S.; Omura, T.; Ozaki, K.; Paoloni, A.; Paparella, L.; Park, B. D.; Park, I. G.; Pasqualini, L.; Pastore, A.; Patrizii, L.; Pessard, H.; Podgrudkov, D.; Polukhina, N.; Pozzato, M.; Pupilli, F.; Roda, M.; Roganova, T.; Rokujo, H.; Rosa, G.; Ryazhskaya, O.; Sato, O.; Schembri, A.; Shakirianova, I.; Shchedrina, T.; Sheshukov, A.; Shibuya, H.; Shiraishi, T.; Shoziyoev, G.; Simone, S.; Sioli, M.; Sirignano, C.; Sirri, G.; Spinetti, M.; Stanco, L.; Starkov, N.; Stellacci, S. M.; Stipcevic, M.; Strolin, P.; Takahashi, S.; Tenti, M.; Terranova, F.; Tioukov, V.; Tufanli, S.; Vilain, P.; Vladymyrov, M.; Votano, L.; Vuilleumier, J. L.; Wilquet, G.; Wonsak, B.; Yoon, C. S.; Zemskova, S.

    2015-06-01

    The OPERA experiment, exposed to the CERN to Gran Sasso ν μ beam, collected data from 2008 to 2012. Four oscillated ν τ Charged Current interaction candidates have been detected in appearance mode, which are consistent with ν μ → ν τ oscillations at the atmospheric Δ m 2 within the "standard" three-neutrino framework. In this paper, the OPERA ν τ appearance results are used to derive limits on the mixing parameters of a massive sterile neutrino.

  14. Nucleon contribution to the neutrino electromagnetic vertex in matter

    SciTech Connect

    DOlivo, J.C.; Nieves, J.F.

    1997-11-01

    We calculate the nucleon contribution to the electromagnetic vertex of a neutrino in a background of particles, including the effect of the anomalous magnetic moment of the nucleons. Explicit formulas for the form factors are given in various physical limits of practical interest. Several applications of the results are mentioned, including the effect of an external magnetic field on the dispersion relation of a neutrino in matter. {copyright} {ital 1997} {ital The American Physical Society}

  15. Density profiles of supernova matter and determination of neutrino parameters

    SciTech Connect

    Chiu, S.-H.

    2007-08-15

    The flavor conversion of supernova neutrinos can lead to observable signatures related to the unknown neutrino parameters. As one of the determinants in dictating the efficiency of resonant flavor conversion, the local density profile near the Mikheyev-Smirnov-Wolfenstein (MSW) resonance in a supernova environment is, however, not so well understood. In this analysis, variable power-law functions are adopted to represent the independent local density profiles near the locations of resonance. It is shown that the uncertain matter density profile in a supernova, the possible neutrino mass hierarchies, and the undetermined 1-3 mixing angle would result in six distinct scenarios in terms of the survival probabilities of {nu}{sub e} and {nu}{sub e}. The feasibility of probing the undetermined neutrino mass hierarchy and the 1-3 mixing angle with the supernova neutrinos is then examined using several proposed experimental observables. Given the incomplete knowledge of the supernova matter profile, the analysis is further expanded to incorporate the Earth matter effect. The possible impact due to the choice of models, which differ in the average energy and in the luminosity of neutrinos, is also addressed in the analysis.

  16. Neutrino Oscillation Physics with KamLAND: Reactor Antineutrinos and Beyond

    NASA Astrophysics Data System (ADS)

    Heeger, Karsten M.

    The discovery of flavor transformation in atmospheric, solar, and accelerator neutrinos has provided unambiguous evidence that neutrinos have mass and mix flavors. Data obtained in the past decade have revolutionized our understanding of neutrinos and provided the first evidence of physics beyond the Standard Model. In the long history of reactor neutrino physics, KamLAND has added to these recent discoveries the first direct observation of reactor overline{ν}_{e} disappearance, the evidence of spectral distortion as a signature of neutrino oscillation, and provided terrestrial confirmation for neutrino oscillation as the solution to the solar neutrino problem. With its long baseline of 175 km KamLAND makes the most precise determination of the mass splitting Δ m^{2}_{12} and, together with the solar neutrino experiments, has determined under the assumption of CPT invariance the oscillation parameters to unprecedented precision: Δ m^{2} = 7.9^{+0.6}_{-0.5} × 10^{-5} eV^{2}and tan^{2}θ = 0.40^{+0.10}_{-0.07}. Besides the measurement of the reactor overline{ν}_{e} flux, KamLAND has also observed geological antineutrinos from inside the Earth and set limits on the overline{ν}_{e} flux from the Sun. By purifying its liquid scintillator target and reducing internal detector backgrounds, KamLAND is preparing for the direct observation of low-energy, 7Be solar neutrinos that may allow the first direct test of the MSW mechanism of solar neutrino oscillation.

  17. Heavy right-handed neutrino dark matter and PeV neutrinos at IceCube

    SciTech Connect

    Dev, P.S. Bhupal; Kazanas, D.; Mohapatra, R.N.; Teplitz, V.L.; Zhang, Yongchao

    2016-08-17

    We discuss a simple non-supersymmetric model based on the electroweak gauge group SU(2){sub L}×SU(2){sup ′}×U(1){sub B−L} where the lightest of the right-handed neutrinos, which are part of the leptonic doublet of SU(2){sup ′}, play the role of a long-lived unstable dark matter with mass in the multi-PeV range. We use a resonant s-channel annihilation to obtain the correct thermal relic density and relax the unitarity bound on dark matter mass. In this model, there exists a 3-body dark matter decay mode producing tau leptons and neutrinos, which could be the source for the PeV cascade events observed in the IceCube experiment. The model can be tested with more precise flavor information of the highest-energy neutrino events in future data.

  18. Heavy Right-Handed Neutrino Dark Matter and PeV Neutrinos at IceCube

    NASA Technical Reports Server (NTRS)

    Bhupal Dev, P. S.; Kazanas, D.; Mohapatra, R. N.; Teplitz, V. L.; Zhang, Yongchao

    2016-01-01

    We discuss a simple non-supersymmetric model based on the electroweak gauge group SU(2) (sub L) times SU(2) prime times U(1) (Sub B-L) where the lightest of the right-handed neutrinos, which are part of the leptonic doublet of SU(2) prime, play the role of a long-lived unstable dark matter with mass in the multi-Peta-electronvolt range. We use a resonant s-channel annihilation to obtain the correct thermal relic density and relax the unitarity bound on dark matter mass. In this model, there exists a 3-body dark matter decay mode producing tau leptons and neutrinos, which could be the source for the Peta-electronvolt cascade events observed in the IceCube experiment. The model can be tested with more precise flavor information of the highest-energy neutrino events in future data.

  19. Doublet-triplet dark matter with neutrino masses

    NASA Astrophysics Data System (ADS)

    Betancur, Amalia; Longas, Robinson; Zapata, Oscar

    2017-08-01

    We consider a dark matter (DM) model that arises from the interplay of two renormalizable dark matter models, namely, the doublet-triplet fermion model and the doublet-triplet scalar model. Despite being excellent exponents of the weakly interacting massive particle paradigm, the physics related to DM in each of these models fails at the same time to account for neutrino masses. It turns out that from the combination of these two models it is possible to generate neutrino masses at one-loop level in the four topologies that are realizations of the Weinberg operator for neutrino masses at one loop. In this work, we combine both models focusing mostly on fermionic dark matter lying at the electroweak scale. We analyze the impact of the extra charged fields on the Higgs diphoton decay and find that, thanks to the presence of the charged scalars, it is possible to have a viable DM region at the electroweak scale.

  20. Dark matter astrophysical uncertainties and the neutrino floor

    NASA Astrophysics Data System (ADS)

    O'Hare, Ciaran A. J.

    2016-09-01

    The search for weakly interacting massive particles (WIMPs) by direct detection faces an encroaching background due to coherent neutrino-nucleus scattering. For a given WIMP mass the cross section at which neutrinos constitute a dominant background is dependent on the uncertainty on the flux of each neutrino source, principally from the Sun, supernovae or atmospheric cosmic ray collisions. However there are also considerable uncertainties with regard to the astrophysical ingredients of the predicted WIMP signal. Uncertainties in the velocity of the Sun with respect to the Milky Way dark matter halo, the local density of WIMPs, and the shape of the local WIMP speed distribution all have an effect on the expected event rate in direct detection experiments and hence will change the region of the WIMP parameter space for which neutrinos are a significant background. In this work we extend the neutrino floor calculation to account for the uncertainty in the astrophysics dependence of the WIMP signal. We show the effect of uncertainties on projected discovery limits with an emphasis on low WIMP masses (less than 10 GeV) when solar neutrino backgrounds are most important. We find that accounting for astrophysical uncertainties changes the shape of the neutrino floor as a function of WIMP mass but also causes it to appear at cross sections up to an order of magnitude larger, extremely close to existing experimental limits, indicating that neutrino backgrounds will become an issue sooner than previously thought. We also explore how neutrinos hinder the estimation of WIMP parameters and how astrophysical uncertainties impact the discrimination of WIMPs and neutrinos with the use of their respective time dependencies.

  1. Pinning down neutrino oscillation parameters in the 2-3 sector with a magnetised atmospheric neutrino detector: a new study

    NASA Astrophysics Data System (ADS)

    Mohan, Lakshmi S.; Indumathi, D.

    2017-01-01

    We determine the sensitivity to neutrino oscillation parameters from a study of atmospheric neutrinos in a magnetised detector such as the ICAL at the proposed India-based Neutrino Observatory. In such a detector, which can separately count ν _μ and overline{ν }_μ -induced events, the relatively smaller (about 5%) uncertainties on the neutrino-antineutrino flux ratios translate to a constraint in the χ ^2 analysis that results in a significant improvement in the precision with which neutrino oscillation parameters such as sin ^2θ _{23} can be determined. Such an effect is unique to all magnetisable detectors and constitutes a great advantage in determining neutrino oscillation parameters using such detectors. Such a study has been performed for the first time here. Along with an increase in the kinematic range compared to earlier analyses, this results in sensitivities to oscillation parameters in the 2-3 sector that are comparable to or better than those from accelerator experiments where the fluxes are significantly higher. For example, the 1σ precisions on sin ^2θ _{23} and |Δ {m^2_{32(31)}}| achievable for 500 kton year exposure of ICAL are {˜ }9 and {˜ }2.5%, respectively, for both normal and inverted hierarchies. The mass hierarchy sensitivity achievable with this combination when the true hierarchy is normal (inverted) for the same exposure is Δ χ ^2≈ 8.5 (Δ χ ^2≈ 9.5).

  2. Tetramaximal neutrino mixing and its implications on neutrino oscillations and collider signatures

    SciTech Connect

    Xing Zhizhong

    2008-07-01

    We propose a novel neutrino mixing pattern in terms of only two small integers 1 and 2 together with their square roots and the imaginary number i. This ansatz is referred to as the 'tetra-maximal' mixing because it can be expressed as a product of four rotation matrices, whose mixing angles are all {pi}/4 in the complex plane. It predicts {theta}{sub 12}=arctan(2-{radical}(2)){approx_equal}30.4 deg., {theta}{sub 13}=arcsin[({radical}(2)-1)/(2{radical}(2))]{approx_equal}8.4 deg., {theta}{sub 23}=45 deg. and {delta}=90 deg. in the standard parametrization, and the Jarlskog invariant of leptonic CP violation is found to be J=1/32. These results are compatible with current data and can soon be tested in a variety of neutrino oscillation experiments. Implications of the tetra-maximal neutrino mixing on the decays of doubly-charged Higgs bosons H{sup {+-}}{sup {+-}}{yields}l{sub {alpha}}{sup {+-}}l{sub {beta}}{sup {+-}} (for {alpha}, {beta}=e, {mu}, {tau}) are also discussed in the triplet seesaw mechanism at the TeV scale, which will be explored at the upcoming LHC.

  3. Neutrino phenomenology and scalar Dark Matter with A4 flavor symmetry in Inverse and type II seesaw

    NASA Astrophysics Data System (ADS)

    Mukherjee, Ananya; Das, Mrinal Kumar

    2016-12-01

    We present a TeV scale seesaw mechanism for exploring the dark matter and neutrino phenomenology in the light of recent neutrino and cosmology data. A different realization of the Inverse seesaw (ISS) mechanism with A4 flavor symmetry is being implemented as a leading contribution to the light neutrino mass matrix which usually gives rise to vanishing reactor mixing angle θ13. Using a non-diagonal form of Dirac neutrino mass matrix and 3σ values of mass square differences we parameterize the neutrino mass matrix in terms of Dirac Yukawa coupling "y". We then use type II seesaw as a perturbation which turns out to be active to have a non-vanishing reactor mixing angle without much disturbing the other neutrino oscillation parameters. Then we constrain a common parameter space satisfying the non-zero θ13, Yukawa coupling and the relic abundance of dark matter. Contributions of neutrinoless double beta decay are also included for standard as well as non-standard interaction. This study may have relevance in future neutrino and Dark Matter experiments.

  4. Dark matter signals at neutrino telescopes in effective theories

    SciTech Connect

    Catena, Riccardo

    2015-04-29

    We constrain the effective theory of one-body dark matter-nucleon interactions using neutrino telescope observations. We derive exclusion limits on the 28 coupling constants of the theory, exploring interaction operators previously considered in dark matter direct detection only, and using new nuclear response functions recently derived through nuclear structure calculations. We determine for what interactions neutrino telescopes are superior to current direct detection experiments, and show that Hydrogen is not the most important element in the exclusion limit calculation for the majority of the spin-dependent operators.

  5. Tachyon field non-minimally coupled to massive neutrino matter

    NASA Astrophysics Data System (ADS)

    Ahmad, Safia; Myrzakulov, Nurgissa; Myrzakulov, R.

    2016-07-01

    In this paper, we consider rolling tachyon, with steep run-away type of potentials non-minimally coupled to massive neutrino matter. The coupling dynamically builds up at late times as neutrino matter turns non-relativistic. In case of scaling and string inspired potentials, we have shown that non-minimal coupling leads to minimum in the field potential. Given a suitable choice of model parameters, it is shown to give rise to late-time acceleration with the desired equation of state.

  6. Measurement of neutrino oscillations with the MINOS detectors in the NuMI beam.

    PubMed

    Adamson, P; Andreopoulos, C; Arms, K E; Armstrong, R; Auty, D J; Ayres, D S; Baller, B; Barnes, P D; Barr, G; Barrett, W L; Becker, B R; Belias, A; Bernstein, R H; Bhattacharya, D; Bishai, M; Blake, A; Bock, G J; Boehm, J; Boehnlein, D J; Bogert, D; Bower, C; Buckley-Geer, E; Cavanaugh, S; Chapman, J D; Cherdack, D; Childress, S; Choudhary, B C; Cobb, J H; Coleman, S J; Culling, A J; de Jong, J K; Dierckxsens, M; Diwan, M V; Dorman, M; Dytman, S A; Escobar, C O; Evans, J J; Harris, E Falk; Feldman, G J; Frohne, M V; Gallagher, H R; Godley, A; Goodman, M C; Gouffon, P; Gran, R; Grashorn, E W; Grossman, N; Grzelak, K; Habig, A; Harris, D; Harris, P G; Hartnell, J; Hatcher, R; Heller, K; Himmel, A; Holin, A; Hylen, J; Irwin, G M; Ishitsuka, M; Jaffe, D E; James, C; Jensen, D; Kafka, T; Kasahara, S M S; Kim, J J; Kim, M S; Koizumi, G; Kopp, S; Kordosky, M; Koskinen, D J; Kotelnikov, S K; Kreymer, A; Kumaratunga, S; Lang, K; Ling, J; Litchfield, P J; Litchfield, R P; Loiacono, L; Lucas, P; Ma, J; Mann, W A; Marchionni, A; Marshak, M L; Marshall, J S; Mayer, N; McGowan, A M; Meier, J R; Merzon, G I; Messier, M D; Metelko, C J; Michael, D G; Miller, J L; Miller, W H; Mishra, S R; Moore, C D; Morfín, J; Mualem, L; Mufson, S; Murgia, S; Musser, J; Naples, D; Nelson, J K; Newman, H B; Nichol, R J; Nicholls, T C; Ochoa-Ricoux, J P; Oliver, W P; Ospanov, R; Paley, J; Paolone, V; Para, A; Patzak, T; Pavlović, Z; Pawloski, G; Pearce, G F; Peck, C W; Peterson, E A; Petyt, D A; Pittam, R; Plunkett, R K; Rahaman, A; Rameika, R A; Raufer, T M; Rebel, B; Reichenbacher, J; Rodrigues, P A; Rosenfeld, C; Rubin, H A; Ruddick, K; Ryabov, V A; Sanchez, M C; Saoulidou, N; Schneps, J; Schreiner, P; Seun, S-M; Shanahan, P; Smart, W; Smith, C; Sousa, A; Speakman, B; Stamoulis, P; Strait, M; Symes, P; Tagg, N; Talaga, R L; Tavera, M A; Thomas, J; Thompson, J; Thomson, M A; Thron, J L; Tinti, G; Trostin, I; Tsarev, V A; Tzanakos, G; Urheim, J; Vahle, P; Viren, B; Ward, C P; Ward, D R; Watabe, M; Weber, A; Webb, R C; Wehmann, A; West, N; White, C; Wojcicki, S G; Wright, D M; Yang, T; Zois, M; Zhang, K; Zwaska, R

    2008-09-26

    This Letter reports new results from the MINOS experiment based on a two-year exposure to muon neutrinos from the Fermilab NuMI beam. Our data are consistent with quantum-mechanical oscillations of neutrino flavor with mass splitting |Deltam2| = (2.43+/-0.13) x 10(-3) eV2 (68% C.L.) and mixing angle sin2(2theta) > 0.90 (90% C.L.). Our data disfavor two alternative explanations for the disappearance of neutrinos in flight: namely, neutrino decays into lighter particles and quantum decoherence of neutrinos, at the 3.7 and 5.7 standard-deviation levels, respectively.

  7. Predictive model for radiatively induced neutrino masses and mixings with dark matter.

    PubMed

    Gustafsson, Michael; No, Jose M; Rivera, Maximiliano A

    2013-05-24

    A minimal extension of the standard model to naturally generate small neutrino masses and provide a dark matter candidate is proposed. The dark matter particle is part of a new scalar doublet field that plays a crucial role in radiatively generating neutrino masses. The symmetry that stabilizes the dark matter also suppresses neutrino masses to appear first at three-loop level. Without the need of right-handed neutrinos or other very heavy new fields, this offers an attractive explanation of the hierarchy between the electroweak and neutrino mass scales. The model has distinct verifiable predictions for the neutrino masses, flavor mixing angles, colliders, and dark matter signals.

  8. Sneutrino dark matter in gauged inverse seesaw models for neutrinos.

    PubMed

    An, Haipeng; Dev, P S Bhupal; Cai, Yi; Mohapatra, R N

    2012-02-24

    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.

  9. Dark matter and exotic neutrino interactions in direct detection searches

    NASA Astrophysics Data System (ADS)

    Bertuzzo, Enrico; Deppisch, Frank F.; Kulkarni, Suchita; Perez Gonzalez, Yuber F.; Funchal, Renata Zukanovich

    2017-04-01

    We investigate the effect of new physics interacting with both Dark Matter (DM) and neutrinos at DM direct detection experiments. Working within a simplified model formalism, we consider vector and scalar mediators to determine the scattering of DM as well as the modified scattering of solar neutrinos off nuclei. Using existing data from LUX as well as the expected sensitivity of LUX-ZEPLIN and DARWIN, we set limit on the couplings of the mediators to quarks, neutrinos and DM. Given the current limits, we also assess the true DM discovery potential of direct detection experiments under the presence of exotic neutrino interactions. In the case of a vector mediator, we show that the DM discovery reach of future experiments is affected for DM masses m χ ≲ 10 GeV or DM scattering cross sections σ χ ≲ 10-47 cm2. On the other hand, a scalar mediator will not affect the discovery reach appreciably.

  10. Improved determination of sterile neutrino dark matter spectrum

    NASA Astrophysics Data System (ADS)

    Ghiglieri, J.; Laine, M.

    2015-11-01

    The putative recent indication of an unidentified 3.55 keV X-ray line in certain astrophysical sources is taken as a motivation for an improved theoretical computation of the cosmological abundance of 7.1 keV sterile neutrinos. If the line is interpreted as resulting from the decay of Warm Dark Matter, the mass and mixing angle of the sterile neutrino are known. Our computation then permits for a determination of the lepton asymmetry that is needed for producing the correct abundance via the Shi-Fuller mechanism, as well as for an estimate of the non-equilibrium spectrum of the sterile neutrinos. The latter plays a role in structure formation simulations. Results are presented for different flavour structures of the neutrino Yukawa couplings and for different types of pre-existing lepton asymmetries, accounting properly for the charge neutrality of the plasma and incorporating approximately hadronic contributions.

  11. Spectral function in electro-weak interactions and its impact on neutrino oscillation experiments

    SciTech Connect

    Jen, C.-M.

    2015-10-15

    Neutrino oscillation experiments have entered the high-precision era in the last few years. The oscillation parameters, as a measure of the neutrino properties, are extracted from the energy-dependent oscillation probability function. Different types of nuclear dynamics deeply influence the determination of neutrino energies in neutrino oscillation experiments. As a consequence, a comprehensive understanding of various nuclear dynamics interprets the scenario behind the neutrino interaction with nucleus and nuclei. The initial ground-state structure of the target nucleus is categorized in one typical nuclear dynamics, and its realistic description is generally referred as the spectral function (SF). Implementing the SF for each target nucleus into the GENIE neutrino event generator is the preliminary step necessary to obtain a reliable determination of the kinematics of all detectable final-products from neutrino interactions. At the intermedium-range of neutrino energies (∼ 1 GeV), the kinematic energy reconstruction is the vastly used approach and consists in identifying final-products as coming from the charged-current quasi-elastic-like (CCQE-like) neutrino interactions.

  12. Results of dark matter searches with the ANTARES neutrino telescope

    NASA Astrophysics Data System (ADS)

    Zornoza, J. D.; Toennis, C.

    2017-09-01

    Neutrino telescopes have a wide scientific scope. One of their main goals is the detection of dark matter, for which they have specific advantages. Neutrino telescopes offer the possibility of looking at several kinds of sources, not all of them available to other indirect searches. In this work we provide an overview of the results obtained by the ANTARES neutrino telescope, which has been taking data for almost ten years. One of the most interesting ones is the Sun, since a detection of high energy neutrinos from it would be a very clean indication of dark matter, given that no significant astrophysical backgrounds are expected, contrary to other indirect searches. Moreover, the limits from neutrino telescopes for spin-dependent cross section are the most restrictive ones. Another interesting source is the Galactic Centre, for which ANTARES has a better visibility than IceCube, due to its geographical location. This search gives limits on the annihilation cross section. Other dark matter searches carried out in ANTARES include the Earth and dwarf galaxies.

  13. Synchronization versus decoherence of neutrino oscillations at intermediate densities

    SciTech Connect

    Raffelt, Georg G.; Tamborra, Irene

    2010-12-15

    We study collective oscillations of a two-flavor neutrino system with arbitrary but fixed density. In the vacuum limit, modes with different energies quickly dephase (kinematical decoherence), whereas in the limit of infinite density they lock to each other (synchronization). For intermediate densities, we find different classes of solutions. There is always a phase transition in the sense of partial synchronization occurring only above a density threshold. For small mixing angles, partial or complete decoherence can be induced by a parametric resonance, introducing a new time scale to the problem, the final outcome depending on the spectrum and mixing angle. We derive an analytic relation that allows us to calculate the late-time degree of coherence based on the spectrum alone.

  14. Neutrino masses and mixings

    SciTech Connect

    Wolfenstein, L.

    1991-12-31

    Theoretical prejudices, cosmology, and neutrino oscillation experiments all suggest neutrino mass are far below present direct experimental limits. Four interesting scenarios and their implications are discussed: (1) a 17 keV {nu}{sub {tau}}, (2) a 30 ev {nu}{sub {tau}} making up the dark matter, (3) a 10{sup {minus}3} ev {nu}{sub {mu}} to solve the solar neutrino problem, and (4) a three-neutrino MSW solution.

  15. Cosmological nucleosynthesis and active-sterile neutrino oscillations with small mass differences: the resonant case

    NASA Astrophysics Data System (ADS)

    Kirilova, D. P.; Chizhov, M. V.

    2000-12-01

    We have provided a numerical study of the influence of the resonant active-sterile neutrino oscillations νe↔ νs, on the primordial production of helium-4. The evolution of the neutrino ensembles was followed selfconsistently with the evolution of the nucleons, using exact kinetic equations for the neutrino density matrix and the nucleon number densities in momentum space, from the time of neutrino decoupling till the freeze-out of nucleons at 0.3 MeV. The exact kinetic approach enabled us to study precisely the neutrino depletion, spectrum distortion and neutrino mixing generated asymmetry due to oscillations at each momentum mode, and to prove that their effect on nucleosynthesis is considerable. We have calculated the dependence of the primordially produced helium-4 on the oscillation parameters Yp( δm2, ϑ) for the full range of mixing parameters of the model of oscillations with small mass differences δm2≤10 -7 eV 2. We have obtained iso-helium contours on the δm2- ϑ plane. Cosmological constraints on oscillation parameters, more precise than the existing ones were extracted, due to the exact kinetic approach and the proper account for the neutrino spectrum distortion and the oscillations generated asymmetry.

  16. On possible tachyonic state of neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Makukov, Maxim A.; Mychelkin, Eduard G.; Saveliev, Vladimir L.

    2016-03-01

    We revive the historically first neutrino dark matter model, but with an additional assumption that neutrinos might exist in tachyonic almost sterile states. To this end we propose a group-theoretical algorithm for the description of tachyons. The key point is that we employ a distinct tachyon Lorentz group with another (superluminal) parametrization which does not require traditional introduction of imaginary masses and negative energies, and therefore does not lead to violation of causality and unitarity. Our dark matter model represents effectively scalar tachyonic neutrino-antineutrino conglomerate. Distributed all over the universe, such fluid behaves as stable isothermal/stiff medium which produces somewhat denser regions (‘smoothed halos’) around galaxies and clusters. It is shown to be consistent with observational effects (galactic rotation curves).

  17. Neutrino Coannihilation on Dark-Matter Relics?

    SciTech Connect

    Barenboim, Gabriela; Mena Requejo, Olga; Quigg, Chris; /Fermilab

    2006-04-01

    High-energy neutrinos may resonate with relic background neutralinos to form short-lived sneutrinos. In some circumstances, the decay chain that leads back to the lightest supersymmetric particle would yield few-GeV gamma rays or charged-particle signals. Although resonant coannihilation would occur at an appreciable rate in our galaxy, the signal in any foreseeable detector is unobservably small.

  18. Stringent neutrino flux constraints on antiquark nugget dark matter

    NASA Astrophysics Data System (ADS)

    Gorham, P. W.; Rotter, B. J.

    2017-05-01

    Strongly interacting matter in the form of nuggets of nuclear-density material is not currently excluded as a dark matter candidate in the ten gram to hundreds of kilogram mass range. A recent variation on quark nugget dark matter models postulates that a first-order imbalance between matter and antimatter at the quark-gluon phase transition in the early Universe could lead to most of the dark matter bound into heavy (baryon number B ˜1 025) antiquark nuggets in the current epoch, explaining both the dark matter preponderance and the matter-antimatter asymmetry. Interactions of these massive objects with normal matter in the Earth and Sun lead to annihilation and an associated neutrino flux in the ˜30 MeV range. We calculate these fluxes for antiquark nuggets of sufficient flux to account for the dark matter and find that current neutrino flux limits from Super-Kamiokande (SuperK) exclude these objects as major dark matter candidates at a high confidence level. Antiquark nuggets in the previously allowed mass range cannot account for more than ˜15 % of the dark matter flux.

  19. Atmospheric neutrino oscillation analysis using Fluka three-dimensional flux and Super-Kamiokande data

    NASA Astrophysics Data System (ADS)

    Kibayashi, Atsuko

    A new neutrino oscillation analysis was carried out with the atmospheric neutrino data taken by the Super-Kamiokande detector. The updated 1489 live-days of data, or 91.6 kton-yr exposure, has been compared to a new 3-dimensional atmospheric flux calculation. The resulting best-fit oscillation parameters are (sin2 2theta, Delta m2) = (1.00, 2.51 x 10-3 eV2). At 90% C.L., the allowed region parameters are sin2(2theta) > 0.90 and 1.7 x 10-3 < Deltam2 < 4.2 x 10 -3. No flux model dependence on the results were seen. Results are considered with muon-tau neutrino mixing alone. Some admixture of sterile and electron neutrinos remains permissible, but oscillations of muon to tau neutrinos, as opposed to alternative solutions, seems inescapable.

  20. Neutrino oscillation parameter sampling with MonteCUBES

    NASA Astrophysics Data System (ADS)

    Blennow, Mattias; Fernandez-Martinez, Enrique

    2010-01-01

    We present MonteCUBES ("Monte Carlo Utility Based Experiment Simulator"), a software package designed to sample the neutrino oscillation parameter space through Markov Chain Monte Carlo algorithms. MonteCUBES makes use of the GLoBES software so that the existing experiment definitions for GLoBES, describing long baseline and reactor experiments, can be used with MonteCUBES. MonteCUBES consists of two main parts: The first is a C library, written as a plug-in for GLoBES, implementing the Markov Chain Monte Carlo algorithm to sample the parameter space. The second part is a user-friendly graphical Matlab interface to easily read, analyze, plot and export the results of the parameter space sampling. Program summaryProgram title: MonteCUBES (Monte Carlo Utility Based Experiment Simulator) Catalogue identifier: AEFJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence No. of lines in distributed program, including test data, etc.: 69 634 No. of bytes in distributed program, including test data, etc.: 3 980 776 Distribution format: tar.gz Programming language: C Computer: MonteCUBES builds and installs on 32 bit and 64 bit Linux systems where GLoBES is installed Operating system: 32 bit and 64 bit Linux RAM: Typically a few MBs Classification: 11.1 External routines: GLoBES [1,2] and routines/libraries used by GLoBES Subprograms used:Cat Id ADZI_v1_0, Title GLoBES, Reference CPC 177 (2007) 439 Nature of problem: Since neutrino masses do not appear in the standard model of particle physics, many models of neutrino masses also induce other types of new physics, which could affect the outcome of neutrino oscillation experiments. In general, these new physics imply high-dimensional parameter spaces that are difficult to explore using classical methods such as multi-dimensional projections and minimizations, such as those

  1. Neutrino physics with dark matter experiments and the signature of new baryonic neutral currents

    SciTech Connect

    Pospelov, Maxim

    2011-10-15

    New neutrino states {nu}{sub b}, sterile under the standard model interactions, can be coupled to baryons via the isoscalar vector currents that are much stronger than the standard model weak interactions. If some fraction of solar neutrinos oscillate into {nu}{sub b} on their way to Earth, the coherently enhanced elastic {nu}{sub b}-nucleus scattering can generate a strong signal in the dark matter detectors. For the interaction strength a few hundred times stronger than the weak force, the elastic {nu}{sub b}-nucleus scattering via new baryonic currents may account for the existing anomalies in the direct detection dark matter experiments at low recoil. We point out that for solar-neutrino energies, the baryon-current-induced inelastic scattering is suppressed, so that the possible enhancement of a new force is not in conflict with signals at dedicated neutrino detectors. We check this explicitly by calculating the {nu}{sub b}-induced deuteron breakup, and the excitation of a 4.4 MeV {gamma} line in {sup 12}C. A stronger-than-weak force coupled to the baryonic current implies the existence of a new Abelian gauge group U(1){sub B} with a relatively light gauge boson.

  2. Probing neutrino oscillations in supersymmetric models at the Large Hadron Collider

    SciTech Connect

    Campos, F. de; Eboli, O. J. P.; Hirsch, M.; Valle, J. W. F.; Porod, W.

    2010-10-01

    The lightest supersymmetric particle may decay with branching ratios that correlate with neutrino oscillation parameters. In this case the CERN Large Hadron Collider (LHC) has the potential to probe the atmospheric neutrino mixing angle with sensitivity competitive to its low-energy determination by underground experiments. Under realistic detection assumptions, we identify the necessary conditions for the experiments at CERN's LHC to probe the simplest scenario for neutrino masses induced by minimal supergravity with bilinear R parity violation.

  3. Experimental Evidence for Atmospheric Neutrino Oscillations: MACRO, Soudan 2, and the Future

    NASA Astrophysics Data System (ADS)

    Gallagher, Hugh

    2005-06-01

    In this note I will summarize the most recent results from the MACRO and Soudan 2 experiments. Despite their limited statistics compared with SuperKamiokande these experiments provide strong confirmatory evidence, with completely different systematics, of atmospheric neutrino oscillations. I will briefly mention the additional information that the current generation of running experiments may provide and the important role atmospheric neutrinos can continue to play in the exploration of the neutrino sector.

  4. Future sensitivity of neutrino telescopes to dark matter annihilations from the cosmic diffuse neutrino signal

    SciTech Connect

    Moliné, Ángeles; Ibarra, Alejandro; Palomares-Ruiz, Sergio E-mail: ibarra@tum.de

    2015-06-01

    Cosmological observations and cold dark matter N-body simulations indicate that our Universe is populated by numerous halos, where dark matter particles annihilate, potentially producing Standard Model particles. In this paper we calculate the contribution to the diffuse neutrino background from dark matter annihilations in halos at all redshifts and we estimate the future sensitivity to the annihilation cross section of neutrino telescopes such as IceCube or ANTARES. We consider various parametrizations to describe the internal halo properties and for the halo mass function in order to bracket the theoretical uncertainty in the limits from the modeling of the cosmological annihilation flux. We find that observations of the cosmic diffuse neutrino flux at large angular distances from the galactic center lead to constraints on the dark matter annihilation cross section which are complementary to (and for some extrapolations of the astrophysical parameters, better than) those stemming from observations of the Milky Way halo, especially for neutrino telescopes not pointing directly to the Milky Way center, as is the case of IceCube.

  5. Monoenergetic neutrinos from dark matter annihilation: Issues of exposure

    SciTech Connect

    Kumar, Jason

    2016-06-21

    We consider searches for dark matter annihilation in the Sun resulting in monoenergetic neutrinos, produced either directly or through the decay of stopped pions and kaons. We find that this strategy is very successful at increasing the signal-to-background ratio, but that current experiments may be signal limited. We discuss the exposures need to fully exploit this search strategy.

  6. Neutrino masses and mixings from supersymmetry with bilinear R-parity violation: A theory for solar and atmospheric neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Hirsch, M.; Díaz, M. A.; Porod, W.; Romão, J. C.; Valle, J. W. F.

    2000-12-01

    The simplest unified extension of the minimal supersymmetric standard model with bilinear R-parity violation naturally predicts a hierarchical neutrino mass spectrum, in which one neutrino acquires mass by mixing with neutralinos, while the other two get mass radiatively. We have performed a full one-loop calculation of the neutralino-neutrino mass matrix in the bilinear R/p minimal supersymmetric standard model, taking special care to achieve a manifestly gauge invariant calculation. Moreover we have performed the renormalization of the heaviest neutrino, needed in order to get meaningful results. The atmospheric mass scale and maximal mixing angle arise from tree-level physics, while solar neutrino scale and oscillations follow from calculable one-loop corrections. If universal supergravity assumptions are made on the soft-supersymmetry breaking terms then the atmospheric scale is calculable as a function of a single R/p violating parameter by the renormalization group evolution due to the nonzero bottom quark Yukawa coupling. The solar neutrino problem must be accounted for by the small mixing angle Mikheyev-Smirnov-Wolfenstein (MSW) solution. If these assumptions are relaxed then one can implement large mixing angle solutions. The theory predicts the lightest supersymmetic particle decay to be observable at high-energy colliders, despite the smallness of neutrino masses indicated by experiment. This provides an independent way to test this solution of the atmospheric and solar neutrino anomalies.

  7. THE PHYSICS OF ELEMENTARY PARTICLES AND FIELDS: Neutrino Oscillation Induced by Chiral Phase Transition

    NASA Astrophysics Data System (ADS)

    Mu, Cheng-Fu; Sun, Gao-Feng; Zhuang, Peng-Fei

    2009-03-01

    Electric charge neutrality provides a relationship between chiral dynamics and neutrino propagation in compact stars. Due to the sudden drop of the electron density at thefirst-order chiral phase transition, the oscillation for low energy neutrinos is significant and can be regarded as a signature of chiral symmetry restoration in the core of compact stars.

  8. Closing in on resonantly produced sterile neutrino dark matter

    NASA Astrophysics Data System (ADS)

    Cherry, John F.; Horiuchi, Shunsaku

    2017-04-01

    We perform an exhaustive scan of the allowed resonant production regime for sterile neutrino dark matter in order to improve constraints for dark matter structures which arise from the nonthermal sterile neutrino energy spectra. Small-scale structure constraints are particularly sensitive to large lepton asymmetries/small mixing angles which result in relatively warmer sterile neutrino momentum distributions. We revisit Milky Way galaxy subhalo count constraints and combine them with recent searches for x-ray emission from sterile neutrino decays. Together, they rule out models outside the mass range 7.0 keV ≤mνs≤36 keV and lepton asymmetries smaller than 15 ×10-6 per unit entropy density at 95% confidence interval or greater. We also find that, while a portion of the parameter space remains unconstrained, the combination of subhalo counts and x-ray data indicates the candidate 3.55 keV x-ray line signal potentially originating from a 7.1 keV sterile neutrino decay to be disfavored at 93% confidence interval.

  9. Neutrino oscillations in the early universe: A real-time formulation

    SciTech Connect

    Ho, C.M.; Boyanovsky, D.; Vega, H.J. de

    2005-10-15

    Neutrino oscillations in the early universe prior to the epoch of primordial nucleosynthesis is studied by implementing real-time nonequilibrium field theory methods. We focus on two flavors of Dirac neutrinos, however, the formulation is general. We obtain the equations of motion for neutrino wave packets of either chirality and helicity in the plasma allowing for CP asymmetry. Contributions nonlocal in space-time to the self-energy dominate over the asymmetry for T > or approx. 3-5 MeV if the lepton and neutrino asymmetries are of the same order as the baryon asymmetry. We find a new contribution which cannot be interpreted as the usual effective potential. The mixing angles and dispersion relations in the medium depend on helicity. We find that resonant transitions are possible in the temperature range 10 < or approx. T<<100 MeV. Near a resonance in the mixing angle, the oscillation time scale in the medium as compared to the vacuum is slowed down substantially for small vacuum mixing angle. The time scale of oscillations speeds up for off-resonance high energy neutrinos for which the mixing angle becomes vanishingly small. The equations of motion reduce to the familiar oscillation formulae for negative helicity ultrarelativistic neutrinos, but include consistently both the mixing angle and the oscillation frequencies in the medium. These equations of motion also allow to study the dynamics of right handed as well as positive helicity neutrinos.

  10. Sterile Neutrino Production Through a Matter Effect Enhancement at Long Baselines

    NASA Astrophysics Data System (ADS)

    Bramante, Joseph

    2013-06-01

    If sterile neutrinos have a neutral coupling to standard model fermions, matter effect resonant transitions to sterile neutrinos and excess neutral-current events could manifest at long baseline experiments. Assuming a single sterile neutrino with a neutral coupling to fermionic matter, we re-examine bounds on sterile neutrino production at long baselines from the MINOS result Pνμ →νs < 0.22 (90% CL). We demonstrate that sterile neutrinos with a neutral vector coupling to fermionic matter could evade the MINOS limit, allowing a higher fraction of active to sterile neutrino conversion at long baselines. Scanning the parameter space of sterile neutrino matter effect fits of the LSND and MiniBooNe data, we show that in the case of a vector singlet coupling of sterile neutrinos to matter, some favored parametrizations of these fits would create neutral-current event excesses above standard model predictions at long baseline experiments (e.g. MINOS and OPERA).

  11. NEUTRINOS OSCILLATIONS WITH LONG-BASE-LINE BEAMS:. Past, Present and very near Future

    NASA Astrophysics Data System (ADS)

    Stanco, L.

    2011-03-01

    We overview the status of the studies on neutrino oscillations with accelerators at the present running experiments. Past and present results enlighten the path towards the observation of massive neutrinos and the settling of their oscillations. The very near future may still have addiction from the outcome of the on-going experiments. OPERA is chosen as a relevant example justified by the very recent results released.

  12. Neutrino Experiments: Hierarchy, CP, CPT

    NASA Astrophysics Data System (ADS)

    Gupta, Manmohan; Randhawa, Monika; Singh, Mandip

    We present an overview of our recent investigations regarding the prospects of ongoing neutrino experiments as well as future experiments in determining few of the most important unknowns in the field of neutrino physics, specifically the neutrino mass ordering and leptonic CP-violation phase. The effect of matter oscillations on the neutrino oscillation probabilities has been exploited in resolving the degeneracy between the neutrino mass ordering and the CP violation phase in the leptonic sector. Further, we estimate the extent of extrinsic CP and CPT violation in the experiments with superbeams as well as neutrino factories.

  13. A gauge model for right handed neutrinos as dark matter

    SciTech Connect

    Hernandez-Pinto, R. J.; Perez-Lorenzana, A.

    2008-07-02

    We suggest a simple extension of the electroweak group, SU(2){sub L}xU(1){sub Y}xU(1){sub B-L}, where the breaking of U(1){sub B-L} symmetry provides masses for right handed neutrinos, N, at an acceptable range for them to be Dark Matter (DM). We study the contributions to Moeller and Bhabha scattering due to B-L neutral boson to constrain its gauge coupling. We analize N decay rates to determine the number of families that should be considered as DM candidates. The decoupling temperature between active and sterile neutrinos is also calculated.

  14. A gauge model for right handed neutrinos as dark matter

    NASA Astrophysics Data System (ADS)

    Hernández-Pinto, R. J.; Pérez-Lorenzana, A.

    2008-07-01

    We suggest a simple extension of the electroweak group, SU(2)L×U(1)Y×U(1)B-L, where the breaking of U(1)B-L symmetry provides masses for right handed neutrinos, N, at an acceptable range for them to be Dark Matter (DM). We study the contributions to Mo/ller and Bhabha scattering due to B-L neutral boson to constrain its gauge coupling. We analize N decay rates to determine the number of families that should be considered as DM candidates. The decoupling temperature between active and sterile neutrinos is also calculated.

  15. Dark matter physics in neutrino specific two Higgs doublet model

    NASA Astrophysics Data System (ADS)

    Baek, Seungwon; Nomura, Takaaki

    2017-03-01

    Although the seesaw mechanism is a natural explanation for the small neutrino masses, there are cases when the Majorana mass terms for the right-handed neutrinos are not allowed due to symmetry. In that case, if neutrino-specific Higgs doublet is introduced, neutrinos become Dirac particles and their small masses can be explained by its small VEV. We show that the same symmetry, which we assume a global U(1) X , can also be used to explain the stability of dark matter. In our model, a new singlet scalar breaks the global symmetry spontaneously down to a discrete Z 2 symmetry. The dark matter particle, lightest Z 2-odd fermion, is stabilized. We discuss the phenomenology of dark matter: relic density, direct detection, and indirect detection. We find that the relic density can be explained by a novel Goldstone boson channel or by resonance channel. In the most region of parameter space considered, the direct detections is suppressed well below the current experimental bound. Our model can be further tested in indirect detection experiments such as FermiLAT gamma ray searches or neutrinoless double beta decay experiments.

  16. Prospects of light sterile neutrino oscillation and C P violation searches at the Fermilab Short Baseline Neutrino Facility

    NASA Astrophysics Data System (ADS)

    Cianci, D.; Furmanski, A.; Karagiorgi, G.; Ross-Lonergan, M.

    2017-09-01

    We investigate the ability of the short baseline neutrino (SBN) experimental program at Fermilab to test the globally-allowed (3 +N ) sterile neutrino oscillation parameter space. We explicitly consider the globally-allowed parameter space for the (3 +1 ), (3 +2 ), and (3 +3 ) sterile neutrino oscillation scenarios. We find that SBN can probe with 5 σ sensitivity more than 85%, 95% and 55% of the parameter space currently allowed at 99% confidence level for the (3 +1 ), (3 +2 ) and (3 +3 ) scenarios, respectively, with the (3 +N ) allowed space used in these studies closely resembling that of previous studies [J. M. Conrad, C. M. Ignarra, G. Karagiorgi, M. H. Shaevitz, and J. Spitz, Adv. High Energy Phys. 2013, 1 (2013)., 10.1155/2013/163897], calculated using the same methodology. In the case of the (3 +2 ) and (3 +3 ) scenarios, C P -violating phases appear in the oscillation probability terms, leading to observable differences in the appearance probabilities of neutrinos and antineutrinos. We explore SBN's sensitivity to those phases for the (3 +2 ) scenario through the currently planned neutrino beam running, and investigate potential improvements through additional antineutrino beam running. We show that, if antineutrino exposure is considered, for maximal values of the (3 +2 ) C P -violating phase ϕ54, SBN could be the first experiment to directly observe ˜2 σ hints of C P violation associated with an extended lepton sector.

  17. Can sterile neutrinos be ruled out as warm dark matter candidates?

    PubMed

    Viel, Matteo; Lesgourgues, Julien; Haehnelt, Martin G; Matarrese, Sabino; Riotto, Antonio

    2006-08-18

    We present constraints on the mass of warm dark matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the Sloan Digital Sky Survey Lyman-alpha flux power spectrum at 2.2neutrinos and mWDM greater than or similar to 2 keV (2sigma) for early decoupled thermal relics. If we combine this bound with the constraint derived from x-ray flux observations of the Coma cluster, we find that the allowed sterile neutrino mass is approximately 10 keV (in the standard production scenario). Adding constraints based on x-ray fluxes from the Andromeda galaxy, we find that dark matter particles cannot be sterile neutrinos, unless they are produced by a nonstandard mechanism (resonant oscillations, coupling with the inflation) or get diluted by a large entropy release.

  18. Can Sterile Neutrinos Be Ruled Out as Warm Dark Matter Candidates?

    SciTech Connect

    Viel, Matteo; Lesgourgues, Julien; Haehnelt, Martin G.; Matarrese, Sabino; Riotto, Antonio

    2006-08-18

    We present constraints on the mass of warm dark matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the Sloan Digital Sky Survey Lyman-{alpha} flux power spectrum at 2.2neutrinos and m{sub WDM}(greater-or-similar sign)2 keV (2{sigma}) for early decoupled thermal relics. If we combine this bound with the constraint derived from x-ray flux observations of the Coma cluster, we find that the allowed sterile neutrino mass is {approx}10 keV (in the standard production scenario). Adding constraints based on x-ray fluxes from the Andromeda galaxy, we find that dark matter particles cannot be sterile neutrinos, unless they are produced by a nonstandard mechanism (resonant oscillations, coupling with the inflaton) or get diluted by a large entropy release.

  19. A search for muon neutrino to electron neutrino oscillations at Δm2 > 0.1 eV2

    SciTech Connect

    Patterson, Ryan Benton

    2007-11-01

    The evidence is compelling that neutrinos undergo flavor change as they propagate. In recent years, experiments have observed this phenomenon of neutrino oscillations using disparate neutrino sources: the sun, fission reactors, accelerators, and secondary cosmic rays. The standard model of particle physics needs only simple extensions - neutrino masses and mixing - to accommodate all neutrino oscillation results to date, save one. The 3.8σ-significant $\\bar{v}$e excess reported by the LSND collaboration is consistent with $\\bar{v}$μ →$\\bar{v}$e oscillations with a mass-squared splitting of Δm2 ~ 1 eV2. This signal, which has not been independently verified, is inconsistent with other oscillation evidence unless more daring standard model extensions (e.g. sterile neutrinos) are considered.

  20. Cold dark matter from heavy right-handed neutrino mixing

    SciTech Connect

    Anisimov, Alexey; Di Bari, Pasquale

    2009-10-01

    We show that, within the seesaw mechanism, an almost decoupled right-handed (RH) neutrino species N{sub DM} with mass M{sub DM} > or approx. 100 GeV can play the role of dark matter (DM). The N{sub DM}'s can be produced from nonadiabatic conversions of thermalized (source) RH neutrinos with mass M{sub S} lower than M{sub DM}. This is possible if a nonrenormalizable operator is added to the minimal type I seesaw Lagrangian. The observed DM abundance can be reproduced for M{sub DM}{delta}{sup 1/4}{approx}10{sup -13}{lambda}{sub eff}{xi}, where {lambda}{sub eff} is a very high energy new physics scale, {delta}{identical_to}(M{sub DM}-M{sub S})/M{sub DM}, and {xi} < or approx. 1 is a parameter determined by the RH neutrino couplings.

  1. Role of dense matter in collective supernova neutrino transformations

    SciTech Connect

    Esteban-Pretel, A.; Pastor, S.; Mirizzi, A.; Tomas, R.; Raffelt, G. G.; Serpico, P. D.; Sigl, G.

    2008-10-15

    For neutrinos streaming from a supernova core, dense matter suppresses self-induced flavor transformations if the electron density n{sub e} significantly exceeds the neutrino density n{sub {nu}} in the conversion region. If n{sub e} is comparable to n{sub {nu}}, one finds multiangle decoherence, whereas the standard self-induced transformation behavior requires that in the transformation region n{sub {nu}} is safely above n{sub e}. This condition need not be satisfied in the early phase after the supernova core bounce. Our new multiangle effect is a subtle consequence of neutrinos traveling on different trajectories when streaming from a source that is not pointlike.

  2. Quantum-gravity decoherence effects in neutrino oscillations: Expected constraints from CNGS and J-PARC

    SciTech Connect

    Mavromatos, Nick E.; Sarkar, Sarben; Meregaglia, Anselmo; Sakharov, Alexander S.

    2008-03-01

    Quantum decoherence, the evolution of pure states into mixed states, may be a feature of quantum-gravity models. In most cases, such models lead to fewer neutrinos of all active flavors being detected in a long-baseline experiment as compared to three-flavor standard neutrino oscillations. We discuss the potential of the CNGS and J-PARC beams in constraining models of quantum-gravity induced decoherence using neutrino oscillations as a probe. We use as much as possible model-independent parametrizations, even though they are motivated by specific microscopic models, for fits to the expected experimental data which yield bounds on quantum-gravity decoherence parameters.

  3. Recent Charm Production and Neutrino Oscillation Results From the CHORUS Experiment

    SciTech Connect

    Kayis-Topaksu, A.

    2006-07-11

    CHORUS Experiment was taking data during the years of 1994-1997. In total about 100 000 charged-current(CC) neutrino interactions were located in the nuclear emulsion target and fully reconstructed. In addition to the oscillation search, measurements of charm production have been also performed. From the sample of 100 000 events based on the data acquired by new automatic scanning system, 2013 charm-decay events were selected by a pattern recognition program. A comprehensive study of charm production by neutrinos being made. We report here some of the recent results on charm production and neutrino oscillation results.

  4. Search for differences in oscillation parameters for atmospheric neutrinos and antineutrinos at Super-Kamiokande.

    PubMed

    Abe, K; Hayato, Y; Iida, T; Ikeda, M; Iyogi, K; Kameda, J; Koshio, Y; Kozuma, Y; Miura, M; Moriyama, S; Nakahata, M; Nakayama, S; Obayashi, Y; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takenaga, Y; Takeuchi, Y; Ueno, K; Ueshima, K; Watanabe, H; Yamada, S; Yokozawa, T; Ishihara, C; Kaji, H; Lee, K P; Kajita, T; Kaneyuki, K; McLachlan, T; Okumura, K; Shimizu, Y; Tanimoto, N; Martens, K; Vagins, M R; Labarga, L; Magro, L M; Dufour, F; Kearns, E; Litos, M; Raaf, J L; Stone, J L; Sulak, L R; Goldhaber, M; Bays, K; Kropp, W R; Mine, S; Regis, C; Smy, M B; Sobel, H W; Ganezer, K S; Hill, J; Keig, W E; Jang, J S; Kim, J Y; Lim, I T; Albert, J B; Scholberg, K; Walter, C W; Wendell, R; Wongjirad, T M; Tasaka, S; Learned, J G; Matsuno, S; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Nishikawa, K; Nishino, H; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, A T; Minamino, A; Nakaya, T; Fukuda, Y; Itow, Y; Mitsuka, G; Tanaka, T; Jung, C K; Taylor, I; Yanagisawa, C; Ishino, H; Kibayashi, A; Mino, S; Mori, T; Sakuda, M; Toyota, H; Kuno, Y; Kim, S B; Yang, B S; Ishizuka, T; Okazawa, H; Choi, Y; Nishijima, K; Koshiba, M; Yokoyama, M; Totsuka, Y; Chen, S; Heng, Y; Yang, Z; Zhang, H; Kielczewska, D; Mijakowski, P; Connolly, K; Dziomba, M; Wilkes, R J

    2011-12-09

    We present a search for differences in the oscillations of antineutrinos and neutrinos in the Super-Kamiokande-I, -II, and -III atmospheric neutrino sample. Under a two-flavor disappearance model with separate mixing parameters between neutrinos and antineutrinos, we find no evidence for a difference in oscillation parameters. Best-fit antineutrino mixing is found to be at (Δm2,sin2 2θ)=(2.0×10(-3)  eV2, 1.0) and is consistent with the overall Super-K measurement.

  5. The neutrino-oscillation experiment at the CHOOZ nuclear power plant

    NASA Astrophysics Data System (ADS)

    Nicolò, D.

    The CHOOZ experiment is measuring the neutrino flux from two nuclear reactors at a distance of 1 km. The aim is to search for possible overlineνe → overlineνx oscillations in a region of parameters ( Δm2 ≥ 10 -3eV 2 at full mixing) where hints at neutrino oscillations come from the measurement of the atmosferic neutrino flux. A short description of the status of the experiment (data taking and physics analysis) is given.

  6. VALOR joint oscillation analysis using multiple LAr-TPCs in the Booster Neutrino Beam at Fermilab

    NASA Astrophysics Data System (ADS)

    Andreopoulos, C.; Barry, C.; Bench, F.; Chappell, A.; Dealtry, T.; Dennis, S.; Escudero, L.; Jones, R.; Grant, N.; Roda, M.; Sgalaberna, D.; Shah, R.

    2017-09-01

    Anomalies observed by different experiments, the most significant ones being the ∼3.8 sigma νe appearance in a ∼50 MeV νµ beam from muon decay at rest observed by the LSND experiment and the ∼3.8 sigma νe and {\\bar{ν }}e appearance in a ∼1 GeV neutrino beam from pion decay in flight observed by MiniBooNE, suggest the existence of sterile neutrinos. The Short Baseline Neutrino (SBN) program at Fermilab aims to perform a sensitive search for sterile neutrinos by performing analyses of νe appearance and νµ disappearance employing three Liquid Argon Time Projection Chambers (LAr-TPCs) at different baselines. The VALOR neutrino fitting group was established within the T2K experiment and has led numerous flagship T2K oscillation analyses, and provided sensitivity and detector optimisation studies for DUNE and Hyper-K. The neutrino oscillation framework developed by this group is able to perform fits of several samples and systematic parameters within different neutrino models and experiments. Thus, VALOR is an ideal environment for the neutrino oscillation fits using multiple LAr-TPC detectors with proper treatment of correlated systematic uncertainties necessary for the SBN analyses.

  7. Accurate GPS orientation of a long baseline for Neutrino Oscillation Experiments at Fermilab

    NASA Astrophysics Data System (ADS)

    Soler, Tomás; Foote, Richard H.; Hoyle, Dixon; Bocean, Virgil

    2000-12-01

    Recent research in elementary particle physics is concentrating a great amount of effort on neutrino oscillation experiments. These studies require the accurate pointing of neutrino beams between two distant points. The Fermi National Accelerator Laboratory (Fermilab) intends to build a new particle beamline to direct a beam of muon neutrinos from its Main Injector toward a far-off (735 km away) underground detector capable of searching for non-zero neutrino mass by looking for neutrino oscillations. This paper describes the GPS work carried out to accurately position the reference ground marks at the two sites from which the spatial orientation of the baseline can be accurately determined. The effect of plate rotations on the absolute orientation of the baseline was also investigated.

  8. Vacuum oscillations and excess of high energy solar neutrino events observed in Superkamiokande

    NASA Astrophysics Data System (ADS)

    Berezinsky, V.; Fiorentini, G.; Lissia, M.

    2000-01-01

    The excess of solar-neutrino events above 13 MeV that has been recently observed by Superkamiokande can be explained by the vacuum oscillation solution to the Solar Neutrino Problem (SNP). If the boron neutrino flux is 20% smaller than the standard solar model (SSM) prediction and the chlorine signal is assumed 30% (or 3.4σ) higher than the measured one, there exists a vacuum oscillation solution to SNP that reproduces both the observed spectrum of the recoil electrons, including the high energy distortion, and the other measured neutrino rates. The most distinct signature of this solution is a semi-annual seasonal variation of the 7Be neutrino flux with maximal amplitude. While the temporal series of the GALLEX and Homestake signals suggest that such a seasonal variation could be present, future detectors (BOREXINO, LENS and probably GNO) will be able to test it.

  9. Plots and Figures from the Main Injector Neutrino Oscillation Search (MINOS) at Fermilab

    DOE Data Explorer

    MINOS, or Main Injector Neutrino Oscillation Search, is an experiment at Fermilab designed to study the phenomena known as neutrino oscillations. It uses a beam of neutrino particles produced by the NuMI beamline facility - Neutrinos at the Main Injector. The beam of neutrinos is sent through the two MINOS detectors, one at Fermilab and one in the Soudan Mine in northern Minnesota. The Minos for Scientists page provides a link to the data plots that are available to the public and also provides explanations for some of the recent results of the experiment. Another links leads to a long listing of MINOS publications in refereed journals. Photo galleries are found by checking the links on the left menu.

  10. Equation of state and neutrino opacity of dense stellar matter

    SciTech Connect

    Reddy, S.

    2004-01-01

    The properties of matter at densities similar to nuclear density plays an important role in core collapse supernova. In this talk I discuss aspects of the equation of state and weak interactions at high density. I highlight its relation to the temporal and spectral features of the neutrino emission from the newly born neutron star born in the aftermath of a core-collapse supernova. I will briefly comment on how this will impact r-process nucleosynthesis. The hot and dense neutron star (proto-neutron star) born in the aftermath of a core collapse supernova provides a promising environment for r-process nucleosynthesis. The intense temperatures and neutrino fluxes in the vicinity of the proto-neutron star is expected to result in a high entropy neutron-rich wind necessary for successful r-process nucleosynthesis. Although theoretical efforts to simulate core collapse supernova have not been able to provide a mechanism for robust explosions, several key features of the supernova dynamics and early evolution of the proto-neutron star are well understood. Large scale numerical simulations of supernova and neutron star evolution are now being pursued by several groups. Simulating core collapse supernova is challenging because it involves coupled multi-dimensional hydrodynamics and neutrino transport. The neutrinos play a key role since they are the dominant source of energy transport. It is expected that refinements in neutrino transport and better treatment of multi-dimensional effects are needed to understand the explosion mechanism. The temporal and spectral features of the neutrino emission which is emitted from the proto-neutron star is an independent diagnostic of supernova explosion dynamics and early evolution of the proto-neutron star. To accurately predict the ambient conditions just outside the newly born neutron star for the first 10-20 s, we will need to understand both the explosion mechanism and neutrino emission. In this talk I will discuss micro

  11. Special Issue on "Neutrino Oscillations: Celebrating the Nobel Prize in Physics 2015" in Nuclear Physics B

    NASA Astrophysics Data System (ADS)

    Ohlsson, Tommy

    2016-07-01

    In 2015, the Nobel Prize in Physics was awarded jointly to Takaaki Kajita from the Super-Kamiokande Collaboration and Arthur B. McDonald from the SNO Collaboration ;for the discovery of neutrino oscillations, which shows that neutrinos have mass;. Furthermore, the Daya Bay, K2K and T2K, KamLAND, SNO, and Super-Kamiokande Collaborations shared the Fundamental Physics Breakthrough Prize the same year. In order to celebrate this successful and fruitful year for neutrino oscillations, the editors and the publisher of Nuclear Physics B decided to publish a Special Issue on neutrino oscillations. We invited prominent scientists in the area of neutrino physics that relates to neutrino oscillations to write contributions for this Special Issue, which was open to both original research articles as well as review articles. The authors of this Special Issue consist of e.g. the two Nobel Laureates, International Participants of the Nobel Symposium 129 on Neutrino Physics at Haga Slott in Enköping, Sweden (August 19-24, 2004), selected active researchers, and members from large experimental collaborations with major results in the last ten years. In total, this Special Issue consists of 28 contributions. Please note that the cover of this Special Issue contains a figure from each of the 26 contributions that have figures included.

  12. Detecting asymmetric dark matter in the Sun with neutrinos

    NASA Astrophysics Data System (ADS)

    Murase, Kohta; Shoemaker, Ian M.

    2016-09-01

    Dark matter (DM) may have a relic density that is in part determined by a particle/antiparticle asymmetry, much like baryons. If this is the case, it can accumulate in stars like the Sun to sizable number densities and annihilate to Standard Model particles including neutrinos. We show that the combination of neutrino telescope and direct detection data can be used in conjunction to determine or constrain the DM asymmetry from data. Depending on the DM mass, the current neutrino data from Super-Kamiokande and IceCube give powerful constraints on asymmetric DM unless its fractional asymmetry is ≲10-2 . Future neutrino telescopes and detectors like Hyper-K and KM3NeT can search for the resulting signal of high-energy neutrinos from the center of the Sun. The observation of such a flux yields information on both the DM-nucleus cross section and also on the relative abundances of DM and anti-DM.

  13. Precision Neutrino Oscillation Measurements using Simultaneous High-Power, Low-Energy Project-X Beams

    SciTech Connect

    Bishai, M.; Diwan, M.; Kettell, S.; Stewart, J.; Viren, B.; Worcester, E.; Tschirhart, R.; Whitehead, L.

    2013-07-02

    The first phase of the long-baseline neutrino experiment, LBNE10, will use a broadband, high-energy neutrino beam with a 10-kt liquid argon TPC at 1300 km to study neutrino oscillation. In this paper, we describe potential upgrades to LBNE10 that use Project X to produce high-intensity, low-energy neutrino beams. Simultaneous, high-power operation of 8- and 60-GeV beams with a 200-kt water Cerenkov detector would provide sensitivity to nu_mu to nu_e oscillations at the second oscillation maximum. We find that with ten years of data, it would be possible to measure sin2(2theta_13) with precision comparable to that expected from reactor antineutrino disappearance and to measure the value of the CP phase, delta_CP, with an uncertainty of (5-10) degrees. This document is submitted for inclusion in Snowmass 2013.

  14. Common origin of neutrino mass, dark matter and Dirac leptogenesis

    NASA Astrophysics Data System (ADS)

    Borah, Debasish; Dasgupta, Arnab

    2016-12-01

    We study the possibility of generating tiny Dirac neutrino masses at one loop level through the scotogenic mechanism such that one of the particles going inside the loop can be a stable cold dark matter (DM) candidate. Majorana mass terms of singlet fermions as well as tree level Dirac neutrino masses are prevented by incorporating the presence of additional discrete symmetries in a minimal fashion, which also guarantee the stability of the dark matter candidate. Due to the absence of total lepton number violation, the observed baryon asymmetry of the Universe is generated through the mechanism of Dirac leptogenesis where an equal and opposite amount of leptonic asymmetry is generated in the left and right handed sectors which are prevented from equilibration due to tiny Dirac Yukawa couplings. Dark matter relic abundance is generated through its usual freeze-out at a temperature much below the scale of leptogenesis. We constrain the relevant parameter space from neutrino mass, baryon asymmetry, Planck bound on dark matter relic abundance, and latest LUX bound on spin independent DM-nucleon scattering cross section. We also discuss the charged lepton flavour violation (μ → e γ) and electric dipole moment of electron in this model in the light of the latest experimental data and constrain the parameter space of the model.

  15. Neutrinos from Kaluza-Klein dark matter in the Sun

    SciTech Connect

    Blennow, Mattias; Melbéus, Henrik; Ohlsson, Tommy E-mail: melbeus@kth.se

    2010-01-01

    We investigate indirect neutrino signals from annihilations of Kaluza-Klein dark matter in the Sun. Especially, we examine a five- as well as a six-dimensional model, and allow for the possibility that boundary localized terms could affect the spectrum to give different lightest Kaluza-Klein particles, which could constitute the dark matter. The dark matter candidates that are interesting for the purpose of indirect detection of neutrinos are the first Kaluza-Klein mode of the gauge boson and the neutral component of the gauge bosons. Using the DarkSUSY and WimpSim packages, we calculate muon fluxes at an Earth-based neutrino telescope, such as IceCube. For the five-dimensional model, the results that we obtained agree reasonably well with the results that have previously been presented in the literature, whereas for the six-dimensional model, we find that, at tree-level, the results are the same as for the five-dimensional model. Finally, if the first Kaluza-Klein mode of the gauge boson constitutes the dark matter, IceCube can constrain the parameter space. However, in the case that the neutral component of the gauge bosons is the LKP, the signal is too weak to be observed.

  16. Charged-current weak interaction processes in hot and dense matter and its impact on the spectra of neutrinos emitted from protoneutron star cooling.

    PubMed

    Martínez-Pinedo, G; Fischer, T; Lohs, A; Huther, L

    2012-12-21

    We perform three-flavor Boltzmann neutrino transport radiation hydrodynamics simulations covering a period of 3 s after the formation of a protoneutron star in a core-collapse supernova explosion. Our results show that a treatment of charged-current neutrino interactions in hot and dense matter as suggested by Reddy et al. [Phys. Rev. D 58, 013009 (1998)] has a strong impact on the luminosities and spectra of the emitted neutrinos. When compared with simulations that neglect mean-field effects on the neutrino opacities, we find that the luminosities of all neutrino flavors are reduced while the spectral differences between electron neutrinos and antineutrinos are increased. Their magnitude depends on the equation of state and in particular on the symmetry energy at subnuclear densities. These modifications reduce the proton-to-nucleon ratio of the outflow, increasing slightly their entropy. They are expected to have a substantial impact on nucleosynthesis in neutrino-driven winds, even though they do not result in conditions that favor an r process. Contrary to previous findings, our results show that the spectra of electron neutrinos remain substantially different from those of other (anti)neutrino flavors during the entire deleptonization phase of the protoneutron star. The obtained luminosity and spectral changes are also expected to have important consequences for neutrino flavor oscillations and neutrino detection on Earth.

  17. Neutrino-oscillation experiments at Brookhaven National Laboratory

    SciTech Connect

    Ahrens, L.A.; Aronson, S.A.; Connolly, P.L.; Gibbard, B.G.; Maeda, Y.; Murtagh, M.J.; Murtagh, S.J.; Terada, S.; Callas, J.; Cutts, D.

    1983-01-01

    Two groups have submitted major proposals for neutrino oscillation searches at BNL. Both are two detector experiments with a close detector at approx. = 100m and a far detector at approx. = 900m. While the details of the experiments are quite different, both groups expect to obtain nu/sub ..mu../ disappearance limits of delta m/sup 2/sin2 theta approx. = 0.1 - 0.2 for small mass difference and sin/sup 2/2 theta at the few percent level for the most sensitive delta m/sup 2/(approx. = 25eV/sup 2/). Since both detectors are designed to identify electrons as well as muons they expect to obtain significant limits on nu/sub e/ appearance (nu/sub ..mu../ ..-->.. nu/sub e/). Each has received approval for a single detector (Phase I) experiment with the two detector phase (Phase II) still pending. The present status of the single detector experiments is detailed. (WHK)

  18. Comparison of νμ->νe Oscillation calculations with matter effects

    NASA Astrophysics Data System (ADS)

    Gordon, Michael; Toki, Walter

    2013-04-01

    An introduction to neutrino oscillations in vacuum is presented, followed by a survey of various techniques for obtaining either exact or approximate expressions for νμ->νe oscillations in matter. The method devised by Mann, Kafka, Schneps, and Altinok produces an exact expression for the oscillation by determining explicitely the evolution operator. The method used by Freund yields an approximate oscillation probability by diagonalizing the Hamiltonian, finding the eigenvalues and eigenvectors, and then using those to find modified mixing angles with the matter effect taken into account. The method developed by Arafune, Koike, and Sato uses an alternate method to find an approximation of the evolution operator. These methods are compared to each other using parameters from both the T2K and LBNE experiments.

  19. Compatibility of high-{delta}m{sup 2} {nu}{sub e} and {nu}{sub e} neutrino oscillation searches

    SciTech Connect

    Aguilar-Arevalo, A. A.; Bugel, L.; Coney, L.; Conrad, J. M.; Djurcic, Z.; Karagiorgi, G.; Mahn, K. B. M.; Monroe, J.; Nguyen, V. T.; Schmitz, D.; Shaevitz, M. H.; Sorel, M.; Anderson, C. E.; Curioni, A.; Fleming, B. T.; Linden, S. K.; Soderberg, M.; Bazarko, A. O.; Laird, E. M.; Meyers, P. D.

    2008-07-01

    This article presents the compatibility of experimental data from neutrino oscillation experiments with a high-{delta}m{sup 2} two-neutrino oscillation hypothesis. Data is provided by the Bugey, Karlsruhe Rutherford Medium Energy Neutrino Experiment 2 (KARMEN2), Los Alamos Liquid Scintillator Neutrino Detector (LSND), and MiniBooNE experiments. The LSND, KARMEN2, and MiniBooNE results are 25.36% compatible within a two-neutrino oscillation hypothesis. However, the point of maximal compatibility is found in a region that is excluded by the Bugey data. A joint analysis of all four experiments, performed in the sin{sup 2}2{theta} vs {delta}m{sup 2} region common to all data, finds a maximal compatibility of 3.94%. This result does not account for additions to the neutrino oscillation model from sources such as CP violation or sterile neutrinos.

  20. Compatibility of high-Δm2 νe and ν¯e neutrino oscillation searches

    NASA Astrophysics Data System (ADS)

    Aguilar-Arevalo, A. A.; Anderson, C. E.; Bazarko, A. O.; Brice, S. J.; Brown, B. C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J. M.; Cox, D. C.; Curioni, A.; Djurcic, Z.; Finley, D. A.; Fleming, B. T.; Ford, R.; Garcia, F. G.; Garvey, G. T.; Green, C.; Green, J. A.; Hart, T. L.; Hawker, E.; Imlay, R.; Johnson, R. A.; Karagiorgi, G.; Kasper, P.; Katori, T.; Kobilarcik, T.; Kourbanis, I.; Koutsoliotas, S.; Laird, E. M.; Linden, S. K.; Link, J. M.; Liu, Y.; Liu, Y.; Louis, W. C.; Mahn, K. B. M.; Marsh, W.; Martin, P. S.; McGregor, G.; Metcalf, W.; Meyers, P. D.; Mills, F.; Mills, G. B.; Monroe, J.; Moore, C. D.; Nelson, R. H.; Nguyen, V. T.; Nienaber, P.; Ouedraogo, S.; Patterson, R. B.; Perevalov, D.; Polly, C. C.; Prebys, E.; Raaf, J. L.; Ray, H.; Roe, B. P.; Russell, A. D.; Sandberg, V.; Schirato, R.; Schmitz, D.; Shaevitz, M. H.; Shoemaker, F. C.; Smith, D.; Soderberg, M.; Sorel, M.; Spentzouris, P.; Stancu, I.; Stefanski, R. J.; Sung, M.; Tanaka, H. A.; Tayloe, R.; Tzanov, M.; van de Water, R.; Wascko, M. O.; White, D. H.; Wilking, M. J.; Yang, H. J.; Zeller, G. P.; Zimmerman, E. D.

    2008-07-01

    This article presents the compatibility of experimental data from neutrino oscillation experiments with a high-Δm2 two-neutrino oscillation hypothesis. Data is provided by the Bugey, Karlsruhe Rutherford Medium Energy Neutrino Experiment 2 (KARMEN2), Los Alamos Liquid Scintillator Neutrino Detector (LSND), and MiniBooNE experiments. The LSND, KARMEN2, and MiniBooNE results are 25.36% compatible within a two-neutrino oscillation hypothesis. However, the point of maximal compatibility is found in a region that is excluded by the Bugey data. A joint analysis of all four experiments, performed in the sin⁡22θvsΔm2 region common to all data, finds a maximal compatibility of 3.94%. This result does not account for additions to the neutrino oscillation model from sources such as CP violation or sterile neutrinos.

  1. SIMULATION OF A WIDE-BAND LOW-ENERGY NEUTRINO BEAM FOR VERY LONG BASELINE NEUTRINO OSCILLATION EXPERIMENTS.

    SciTech Connect

    BISHAI, M.; HEIM, J.; LEWIS, C.; MARINO, A.D.; VIREN, B.; YUMICEVA, F.

    2006-08-01

    We present simulations of a wide-band low-energy neutrino beam for a future very long baseline neutrino oscillation (VLBNO) program using the proton beam from the Main Injector (MI) proton accelerator at Fermi National Accelerator Laboratory (Fermilab). The target and horn designs previously developed for Brookhaven Laboratory's Alternating Gradient Synchrotron (AGS) VLBNO program are used without modifications. The neutrino flux distributions for various MI proton beam energies and new high-intensity neutrino beam-line designs possible at Fermilab are presented. The beam-line siting and design parameters are chosen to match the requirements of an on-axis beam from Fermilab to one of the two possible sites for the future Deep Underground Science and Engineering Laboratory (DUSEL). A preliminary estimate of the observable event rates and spectra at a detector located in DUSEL for different beam configurations has been performed. Our preliminary conclusions are that a 40-60 GeV 0.5 to 1 MW beam from the Fermilab Main Injector to a DUSEL site has the potential to reach the desired intensity for the next generation of neutrino oscillation experiments. Recent studies indicate that the Fermilab MI can reach a beam power of 0.5 MW at 60 GeV with incremental upgrades to the existing accelerator complex.

  2. Analysis of a three flavor neutrino oscillation fit to recent Super-Kamiokande data

    NASA Astrophysics Data System (ADS)

    Meier, Ch.; Ohlsson, T.

    2000-12-01

    We have analyzed the most recent available Super-Kamiokande data in a three flavor neutrino oscillation model. We have here neglected possible matter effects and we performed a fit to atmospheric and solar Super-Kamiokande data. We have investigated a large parameter range where the mixing angles were restricted to 0 ≤ θ_i ≤ π/2, i=1,2,3, and the mass squared differences were taken to be in the intervals 10^{-11} {eV}^2 ≤ Δ m^ 2 ≤ 10^{-2} {eV}^2 and 10^{-4} {eV}^2 ≤ Δ M^2 ≤ 10 {eV}^2, i.e., the hierarchy between the mass squared differences is not completely determined. This yielded a best solution characterized by the parameter values θ_1 ˜eq 45^circ, θ_2 ˜eq 10^circ, θ_3 ˜eq 45^circ, Δ m^2 ˜eq 4.4 × 10^{-10} {eV}^2, and Δ M^2 ˜eq 1.01 × 10^{-3} {eV}^2, which shows that the analyzed experimental data speak in favor of a bimaximal mixing scenario with one of the mass squared differences in the “just-so” domain and the other one in the range capable of providing a solution to the atmospheric neutrino problem.

  3. Topical Collaboration "Neutrinos and Nucleosynthesis in Hot and Dense Matter"

    SciTech Connect

    Allahverdi, Rouzbeh

    2015-09-18

    This is the final technical report describing contributions from the University of New Mexico to Topical Collaboration on "Neutrinos and Nucleosynthesis in Hot and Dense Matter" in the period June 2010 through May 2015. During the funding period, the University of New Mexico successfully hired Huaiyu Duan as a new faculty member with the support from DOE, who has contributed to the Topical Collaboration through his research and collaborations.

  4. Peccei-Quinn symmetry, dark matter, and neutrino mass

    SciTech Connect

    Ma, Ernest

    2014-06-24

    It is pointed out that a residual Z{sub 2} symmetry of the usual anomalous Peccei-Quinn U(1){sub PQ} symmetry (which solves the strong CP problem) may be used for an absolutely stable heavy dark-matter particle in addition to the long-lived axion. The same Z{sub 2} symmetry may also be used to generate radiative neutrino mass.

  5. A study of atmospheric neutrino oscillations in the MINOS far detector

    SciTech Connect

    Blake, Andrew

    2005-08-01

    In recent years, neutrino experiments have begun to challenge the Standard Model assumption that neutrinos are massless. There is now firm evidence that neutrinos undergo quantum mechanical oscillations between flavors. This would imply that neutrinos possess mass and that neutrino flavors are mixed by the weak interaction. Atmospheric neutrinos, produced by the interactions of cosmic rays in the earth's atmosphere, can be used to study these oscillations. The MINOS Far Detector has been collecting atmospheric neutrino data since 1st August 2003 using a 5.4 kT steel-scintillator sampling calorimeter located 700 m underground (2100 m water-equivalent) at the Soudan Underground Laboratory, Minnesota. The Far Detector is the first massive underground detector to possess a magnetic field. This makes the separation of atmospheric vμ and $\\bar{v}$μ charged current interactions possible for the first time. This thesis presents a study of atmospheric neutrino oscillations in the Far Detector, based on a total detector exposure of 316 days (3.3 kT-Yrs fiducial exposure). The separation of atmospheric neutrinos from the high background of cosmic muons is outlined. A total of 82 candidate events are observed, with an expectation of 109.9 ± 21.4 events in the absence of oscillations. Of the selected events, 40 events have a clearly identified charge, with 27 events tagged as neutrinos and 13 events tagged at anti-neutrinos. This represents the first direct observation of atmospheric vμ and $\\bar{v}$μ charged current interactions. A maximum likelihood analysis us used to determine the allowed region for the oscillation parameters Δm$2\\atop{23}$ and sin223. This disfavors the null oscillation hypothesis at the 79% confidence level. With the current low statistics, the sensitivity of the analysis is limited. The expected future sensitivity of the atmospheric neutrino analysis is discussed.

  6. Sterile neutrinos and indirect dark matter searches in IceCube

    SciTech Connect

    Argüelles, Carlos A.; Kopp, Joachim E-mail: jkopp@fnal.gov

    2012-07-01

    If light sterile neutrinos exist and mix with the active neutrino flavors, this mixing will affect the propagation of high-energy neutrinos from dark matter annihilation in the Sun. In particular, new Mikheyev-Smirnov-Wolfenstein resonances can occur, leading to almost complete conversion of some active neutrino flavors into sterile states. We demonstrate how this can weaken IceCube limits on neutrino capture and annihilation in the Sun and how potential future conflicts between IceCube constraints and direct detection or collider data might be resolved by invoking sterile neutrinos. We also point out that, if the dark matter-nucleon scattering cross section and the allowed annihilation channels are precisely measured in direct detection and collider experiments in the future, IceCube can be used to constrain sterile neutrino models using neutrinos from the dark matter annihilation.

  7. Unifying inflation and dark matter with neutrino masses.

    PubMed

    Allahverdi, Rouzbeh; Dutta, Bhaskar; Mazumdar, Anupam

    2007-12-31

    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.

  8. Neutrino Experiments

    SciTech Connect

    McKeown, R. D.

    2010-08-04

    Recent studies of neutrino oscillations have established the existence of finite neutrino masses and mixing between generations of neutrinos. The combined results from studies of atmospheric neutrinos, solar neutrinos, reactor antineutrinos and neutrinos produced at accelerators paint an intriguing picture that clearly requires modification of the standard model of particle physics. These results also provide clear motivation for future neutrino oscillation experiments as well as searches for direct neutrino mass and nuclear double-beta decay. I will discuss the program of new neutrino oscillation experiments aimed at completing our knowledge of the neutrino mixing matrix.

  9. Measurements of atmospheric muon neutrino oscillations, global analysis of the data collected with MACRO detector

    NASA Astrophysics Data System (ADS)

    MACRO Collaboration

    2004-08-01

    The final analysis of atmospheric neutrino events collected with the MACRO detector is presented. Three different classes of events, generated by neutrinos in different energy ranges, are studied looking at rates, angular distributions and estimated energies. The results are consistent for all the subsamples and indicate a flux deficit that depends on energy and path-length of neutrinos. The no-oscillation hypothesis is excluded at ~ 5σ , while the hypothesis of ν μ -> ν τ oscillation gives a satisfactory description of all data. The parameters with highest probability in a two flavor scenario are sin 2 2θ m = 1 and Δ m2 = 0.0023 {eV}2. This result is independent of the absolute normalization of the atmospheric neutrino fluxes. The data can also be used to put experimental constrain on this normalization.

  10. Earth regeneration effect in solar neutrino oscillations: An analytic approach

    SciTech Connect

    Lisi, E.; Montanino, D.

    1997-08-01

    We present a simple and accurate method for computing analytically the regeneration probability of solar neutrinos in the Earth. We apply this method to the calculation of several solar-model-independent quantities that can be measured by the SuperKamiokande and Sudbury Neutrino Observatory experiments. {copyright} {ital 1997} {ital The American Physical Society}

  11. A study of atmospheric neutrino oscillation using the icecube deepcore detector

    NASA Astrophysics Data System (ADS)

    Gladstone, Laura

    The IceCube detector at the South Pole is a cubic-kilometer-scale neutrino detector designed to observe TeV-range charged particle secondaries from neutrino interactions, and thus do neutrino astronomy. As a main background to the search for astrophysical point sources of neutrinos, IceCube also observes muons and neutrinos from the atmospheric interactions of cosmic rays. By observing a spectrum of atmospheric neutrinos and comparing it to independent predictions of atmospheric fluxes with and without oscillations, IceCube can test various values of oscillation parameters. Neutrino oscillations have been observed experimentally for several decades; IceCube is the first experiment to extend this measurement to the 10-20 GeV energy range. An initial analysis has established that IceCube can see oscillations using the 79-string detector configuration ("IC79"), which was the first year of data that included the DeepCore detector. As a follow-up, this analysis uses a less restrictive event selection and thus a higher total event count, around 3,000 for one year of data. The fit is a Poisson likelihood fit of a two-dimensional rate histogram, using both oscillated length and observed energy. The arrival zenith angle of the muon is used as a proxy for oscillation length. The error contours are dominated by systematic effects more than by statistical limitations of the data. Major systematics include uncertainties in the atmospheric neutrino flux at high energies and uncertainties in the distribution of the cosmic ray muon background. This analysis was designed to produce limits on the mixing angle θ 23 that are competitive with other current experiments, although this is still uncertain as error analysis work is ongoing. Future work will further refine the event selection and systematic error analysis; the statistical methods and software used here are expected to become the IceCube oscillations standard. This thesis also includes background information about the

  12. Active-sterile neutrino oscillations in the early Universe with full collision terms

    SciTech Connect

    Hannestad, Steen; Hansen, Rasmus Sloth; Tram, Thomas; Wong, Yvonne Y.Y.

    2015-08-11

    Sterile neutrinos are thermalised in the early Universe via oscillations with the active neutrinos for certain mixing parameters. The most detailed calculation of this thermalisation process involves the solution of the momentum-dependent quantum kinetic equations, which track the evolution of the neutrino phase space distributions. Until now the collision terms in the quantum kinetic equations have always been approximated using equilibrium distributions, but this approximation has never been checked numerically. In this work we revisit the sterile neutrino thermalisation calculation using the full collision term, and compare the results with various existing approximations in the literature. We find a better agreement than would naively be expected, but also identify some issues with these approximations that have not been appreciated previously. These include an unphysical production of neutrinos via scattering and the importance of redistributing momentum through scattering, as well as details of Pauli blocking. Finally, we devise a new approximation scheme, which improves upon some of the shortcomings of previous schemes.

  13. Active-sterile neutrino oscillations in the early Universe with full collision terms

    SciTech Connect

    Hannestad, Steen; Hansen, Rasmus Sloth; Tram, Thomas; Wong, Yvonne Y.Y. E-mail: rshansen@phys.au.dk E-mail: yvonne.y.wong@unsw.edu.au

    2015-08-01

    Sterile neutrinos are thermalised in the early Universe via oscillations with the active neutrinos for certain mixing parameters. The most detailed calculation of this thermalisation process involves the solution of the momentum-dependent quantum kinetic equations, which track the evolution of the neutrino phase space distributions. Until now the collision terms in the quantum kinetic equations have always been approximated using equilibrium distributions, but this approximation has never been checked numerically. In this work we revisit the sterile neutrino thermalisation calculation using the full collision term, and compare the results with various existing approximations in the literature. We find a better agreement than would naively be expected, but also identify some issues with these approximations that have not been appreciated previously. These include an unphysical production of neutrinos via scattering and the importance of redistributing momentum through scattering, as well as details of Pauli blocking. Finally, we devise a new approximation scheme, which improves upon some of the shortcomings of previous schemes.

  14. Hidden MeV-scale dark matter in neutrino detectors

    SciTech Connect

    Kile, Jennifer; Soni, Amarjit

    2009-12-01

    The possibility of direct detection of light fermionic dark matter in neutrino detectors is explored from a model-independent standpoint. We consider all operators of dimension six or lower which can contribute to the interaction fp{yields}e{sup +}n, where f is a dark Majorana or Dirac fermion. Constraints on these operators are then obtained from the f lifetime and its decays which produce visible {gamma} rays or electrons. We find one operator which would allow fp{yields}e{sup +}n at interesting rates in neutrino detectors, as long as m{sub f} < or approx. m{sub {pi}}. The existing constraints on light dark matter from relic density arguments, supernova cooling rates, and big-bang nucleosynthesis are then reviewed. We calculate the cross section for fp{yields}e{sup +}n in neutrino detectors implied by this operator, and find that Super-Kamiokande can probe the new physics scale {lambda} for this interaction up to O(100 TeV)

  15. Hidden MeV-scale Dark Matter in Neutrino Detectors

    SciTech Connect

    Soni, A.; Kile, J

    2009-12-30

    The possibility of direct detection of light fermionic dark matter in neutrino detectors is explored from a model-independent standpoint. We consider all operators of dimension six or lower which can contribute to the interaction fp {yields} e{sup +}n, where f is a dark Majorana or Dirac fermion. Constraints on these operators are then obtained from the f lifetime and its decays which produce visible {gamma} rays or electrons. We find one operator which would allow fp {yields} e{sup +}n at interesting rates in neutrino detectors, as long as m{sub f} {approx}< m{sub {pi}}. The existing constraints on light dark matter from relic density arguments, supernova cooling rates, and big-bang nucleosynthesis are then reviewed. We calculate the cross section for fp {yields} e{sup +}n in neutrino detectors implied by this operator, and find that Super-Kamiokande can probe the new physics scale {Lambda} for this interaction up to O(100 TeV).

  16. Distinguishing neutrino mass hierarchies using dark matter annihilation signals at IceCube

    SciTech Connect

    Allahverdi, Rouzbeh; Dutta, Bhaskar; Ghosh, Dilip Kumar; Knockel, Bradley; Saha, Ipsita

    2015-12-01

    We explore the possibility of distinguishing neutrino mass hierarchies through the neutrino signal from dark matter annihilation at neutrino telescopes. We consider a simple extension of the standard model where the neutrino masses and mixing angles are obtained via the type-II seesaw mechanism as an explicit example. We show that future extensions of IceCube neutrino telescope may detect the neutrino signal from DM annihilation at the Galactic Center and inside the Sun, and differentiate between the normal and inverted mass hierarchies, in this model.

  17. Spontaneous Oscillations in an Active Matter System

    NASA Astrophysics Data System (ADS)

    Hayes, Robert; Tsang, Boyce; Granick, Steve

    Active matter (which consumes energy to move about) can organize into dynamic structures more interesting than those possible at steady-state. Here we show spontaneous periodic self-assembly in a simple three-component system of water, oil phase, and surfactant at constant room temperature, with emphasis on one model system. Benchtop experiments show that liquid crystal oil droplets spontaneously and collectively oscillate like a `beating heart' for several hours; contract, relax, and subsequently re-contract in a petri dish at a rate of a few `beats' per minute. These oscillations, emergent from the cooperative interaction of the three components, are driven by the competition between positive and negative feedback processes. This illustration of feedback in action reveals a new way to program self-assembled structures to vary with time.

  18. Testing keV sterile neutrino dark matter in future direct detection experiments

    NASA Astrophysics Data System (ADS)

    Campos, Miguel D.; Rodejohann, Werner

    2016-11-01

    We determine constraints on sterile neutrino warm dark matter through direct detection experiments, taking XENON100, XENON1T, and DARWIN as examples. If keV-scale sterile neutrinos scatter inelastically with bound electrons of the target material, an electron recoil signal is generated. This can be used to set limits on the sterile neutrino mass and its mixing with the active sector. While not competitive with astrophysical constraints from x-ray data, the constraints are the first direct laboratory bounds on sterile neutrino warm dark matter and will be in some parts of parameter space the strongest limits on keV-scale neutrinos.

  19. Neutrino masses, leptogenesis, and dark matter in a hybrid seesaw model

    SciTech Connect

    Gu Peihong; Hirsch, M.; Valle, J. W. F.

    2009-02-01

    We suggest a hybrid seesaw model where relatively light right-handed neutrinos give no contribution to neutrino mass matrix due to a special symmetry. This allows their Yukawa couplings to the standard model particles to be relatively strong, so that the standard model Higgs boson can decay dominantly to a left- and a right-handed neutrino, leaving another stable right-handed neutrino as cold dark matter. In our model neutrino masses arise via the type-II seesaw mechanism, the Higgs triplet scalars being also responsible for the generation of the matter-antimatter asymmetry via the leptogenesis mechanism.

  20. Global three-neutrino vacuum oscillation fits to the solar and atmospheric anomalies

    SciTech Connect

    Barger, V. |; Whisnant, K.

    1999-05-01

    We determine the three-neutrino mixing and mass parameters that are allowed by the solar and atmospheric neutrino data when vacuum oscillations are responsible for both phenomena. The global fit does not appreciably change the allowed regions for the parameters obtained from effective two-neutrino fits. We discuss how measurements of the solar electron energy spectrum below 6.5 GeV in Super-Kamiokande and seasonal variations in the Super-Kamiokande, {sup 71}Ga, and BOREXINO experiments can distinguish the different solar vacuum solutions. {copyright} {ital 1999} {ital The American Physical Society}