Predictions for the Majorana CP violation phases in the neutrino mixing matrix and neutrinoless double beta decay

Science.gov (United States)

Girardi, I.; Petcov, S. T.; Titov, A. V.

2016-10-01

We obtain predictions for the Majorana phases α21 / 2 and α31 / 2 of the 3 × 3 unitary neutrino mixing matrix U = Ue† Uν, Ue and Uν being the 3 × 3 unitary matrices resulting from the diagonalisation of the charged lepton and neutrino Majorana mass matrices, respectively. We focus on forms of Ue and Uν permitting to express α21 / 2 and α31 / 2 in terms of the Dirac phase δ and the three neutrino mixing angles of the standard parametrisation of U, and the angles and the two Majorana-like phases ξ21 / 2 and ξ31 / 2 present, in general, in Uν. The concrete forms of Uν considered are fixed by, or associated with, symmetries (tri-bimaximal, bimaximal, etc.), so that the angles in Uν are fixed. For each of these forms and forms of Ue that allow to reproduce the measured values of the three neutrino mixing angles θ12, θ23 and θ13, we derive predictions for phase differences (α21 / 2 -ξ21 / 2), (α31 / 2 -ξ31 / 2), etc., which are completely determined by the values of the mixing angles. We show that the requirement of generalised CP invariance of the neutrino Majorana mass term implies ξ21 = 0 or π and ξ31 = 0 or π. For these values of ξ21 and ξ31 and the best fit values of θ12, θ23 and θ13, we present predictions for the effective Majorana mass in neutrinoless double beta decay for both neutrino mass spectra with normal and inverted ordering.

Neutrino tri-bi-maximal mixing from a non-Abelian discrete family symmetry

CERN Document Server

Varzielas, I M; Ross, Graham G

2007-01-01

The observed neutrino mixing, having a near maximal atmospheric neutrino mixing angle and a large solar mixing angle, is close to tri-bi-maximal. We argue that this structure suggests a family symmetric origin in which the magnitude of the mixing angles are related to the existence of a discrete non-Abelian family symmetry. We construct a model in which the family symmetry is the non-Abelian discrete group $\\Delta(27)$, a subgroup of $SU(3)$ in which the tri-bi-maximal mixing directly follows from the vacuum structure enforced by the discrete symmetry. In addition to the lepton mixing angles, the model accounts for the observed quark and lepton masses and the CKM matrix. The structure is also consistent with an underlying stage of Grand Unification.

Neutrino Mass and Flavour Models

International Nuclear Information System (INIS)

King, Stephen F.

2010-01-01

We survey some of the recent promising developments in the search for the theory behind neutrino mass and tri-bimaximal mixing, and indeed all fermion masses and mixing. We focus in particular on models with discrete family symmetry and unification, and show how such models can also solve the SUSY flavour and CP problems. We also discuss the theoretical implications of the measurement of a non-zero reactor angle, as hinted at by recent experimental measurements.

Gauge theory model of the neutrino and new physics beyond the standard model

International Nuclear Information System (INIS)

Wu Yueliang

2008-01-01

Majorana features of neutrinos and SO(3) gauge symmetry of three families enable us to construct a gauge model of neutrino for understanding naturally the observed smallness of neutrino masses and the nearly tri-bimaximal neutrino mixing when combining together with the mechanism of approximate global U(1) family symmetry. The vacuum structure of SO(3) symmetry breaking is found to play an important role. The mixing angle θ 13 and CP-violating phases governed by the vacuum of spontaneous symmetry breaking are in general nonzero and testable experimentally at the allowed sensitivity. The model predicts the existence of vectorlike SO(3) triplet charged leptons and vectorlike SO(3) triplet Majorana neutrinos as well as SO(3) tri-triplet Higgs bosons, some of them can be light and explored at the colliders LHC and ILC

Seesaw neutrino masses with large mixings from dimensional deconstruction

International Nuclear Information System (INIS)

Balaji, K.R.S.; Lindner, Manfred; Seidl, Gerhart

2003-01-01

We demonstrate a dynamical origin for the dimension-five seesaw operator in dimensional deconstruction models. Light neutrino masses arise from the seesaw scale which corresponds to the inverse lattice spacing. It is shown that the deconstructing limit naturally prefers maximal leptonic mixing. Higher-order corrections which are allowed by gauge invariance can transform the bimaximal into a bilarge mixing. These terms may appear to be nonrenormalizable at scales smaller than the deconstruction scale

Deviation from bimaximal mixing and leptonic CP phases in S4 family symmetry and generalized CP

International Nuclear Information System (INIS)

Li, Cai-Chang; Ding, Gui-Jun

2015-01-01

The lepton flavor mixing matrix having one row or one column in common with the bimaximal mixing up to permutations is still compatible with the present neutrino oscillation data. We provide a thorough exploration of generating such a mixing matrix from S 4 family symmetry and generalized CP symmetry H CP . Supposing that S 4 ⋊H CP is broken down to Z 2 ST 2 SU ×H CP ν in the neutrino sector and Z 4 TST 2 U ⋊H CP l in the charged lepton sector, one column of the PMNS matrix would be of the form (1/2,1/√2,1/2) T up to permutations, both Dirac CP phase and Majorana CP phases are trivial to accommodate the observed lepton mixing angles. The phenomenological implications of the remnant symmetry K 4 (TST 2 ,T 2 U) ×H CP ν in the neutrino sector and Z 2 SU ×H CP l in the charged lepton sector are studied. One row of PMNS matrix is determined to be (1/2,1/2,−i/√2), and all the three leptonic CP phases can only be trivial to fit the measured values of the mixing angles. Two models based on S 4 family symmetry and generalized CP are constructed to implement these model independent predictions enforced by remnant symmetry. The correct mass hierarchy among the charged leptons is achieved. The vacuum alignment and higher order corrections are discussed.

Perturbative estimates of lepton mixing angles in unified models

International Nuclear Information System (INIS)

Antusch, Stefan; King, Stephen F.; Malinsky, Michal

2009-01-01

Many unified models predict two large neutrino mixing angles, with the charged lepton mixing angles being small and quark-like, and the neutrino masses being hierarchical. Assuming this, we present simple approximate analytic formulae giving the lepton mixing angles in terms of the underlying high energy neutrino mixing angles together with small perturbations due to both charged lepton corrections and renormalisation group (RG) effects, including also the effects of third family canonical normalization (CN). We apply the perturbative formulae to the ubiquitous case of tri-bimaximal neutrino mixing at the unification scale, in order to predict the theoretical corrections to mixing angle predictions and sum rule relations, and give a general discussion of all limiting cases. We also discuss the implications for the sum rule relations of the measurement of a non-zero reactor angle, as hinted at by recent experimental measurements.

Neutrino 2012: Outlook – theory

Energy Technology Data Exchange (ETDEWEB)

Smirnov, A.Yu. [International Center for Theoretical Physics, Trieste (Italy)

2013-02-15

Ongoing developments in theory and phenomenology are related to the measured large value of 1–3 mixing and indications of significant deviation of the 2–3 mixing from maximal one. “Race” for the mass hierarchy has started and there is good chance that multi-megaton scale atmospheric neutrino detectors with low threshold (e.g. PINGU) will establish the type of hierarchy. Two IceCube candidates of the PeV cosmic neutrinos if confirmed, is the beginning of new era of high energy neutrino astronomy. Accumulation of data on solar neutrinos (energy spectrum, D-N asymmetry, value of Δm{sub 21}{sup 2}) may uncover some new physics. The Tri-bimaximal mixing is disfavored and the existing discrete symmetry paradigm may change. The confirmed QLC prediction, θ{sub 13}≈θ{sub C}/√(2), testifies for GUT, seesaw and some symmetry at very high scales. However, the same value of 1–3 mixing can be obtained in various ways which have different implications. The situation in lepton sector changes from special (with specific neutrino symmetries, etc.) to normal, closer to that in the quark sector. Sterile neutrinos are challenge for neutrino physics but also opportunity with many interesting phenomenological consequences. Further studies of possible connections between neutrinos and the dark sector of the Universe may lead to breakthrough both in particle physics and cosmology.

Naturalness of nearly degenerate neutrinos

International Nuclear Information System (INIS)

Casas, J.A.; Espinosa, J.R.; Ibarra, A.; Navarro, I.

1999-01-01

If neutrinos are to play a relevant cosmological role, they must be essentially degenerate. We study whether radiative corrections can or cannot be responsible for the small mass splittings, in agreement with all the available experimental data. We perform an exhaustive exploration of the bimaximal mixing scenario, finding that (i) the vacuum oscillations solution to the solar neutrino problem is always excluded; (ii) if the mass matrix is produced by a see-saw mechanism, there are large regions of the parameter space consistent with the large angle MSW solution, providing a natural origin for the Δm sol 2 atm 2 hierarchy; (iii) the bimaximal structure becomes then stable under radiative corrections. We also provide analytical expressions for the mass splittings and mixing angles and present a particularly simple see-saw ansatz consistent with all observations

Quark-lepton complementarity relation and neutrino mass hierarchy

International Nuclear Information System (INIS)

Ferrandis, Javier; Pakvasa, Sandip

2005-01-01

Latest measurements have revealed that the deviation from a maximal solar mixing angle is approximately the Cabibbo angle [i.e., quark-lepton complementarity (QLC) relation]. We argue that it is not plausible that this deviation from maximality, be it a coincidence or not, comes from the charged lepton mixing. Consequently we have calculated the required corrections to the exactly bimaximal neutrino mass matrix ansatz necessary to account for the solar mass difference and the solar mixing angle. We point out that the relative size of these two corrections depends strongly on the hierarchy case under consideration. We find that the inverted hierarchy case with opposite CP parities, which is known to guarantee the renormalization group equations stability of the solar mixing angle, offers the most plausible scenario for a high-energy origin of a QLC-corrected bimaximal neutrino mass matrix. This possibility may allow us to explain the QLC relation in connection with the origin of the charged fermion mass matrices

Discrete Symmetries and Neutrino Mass Perturbations for θ$_{13}$

CERN Document Server

Hall, L J

2013-01-01

The recent measurement of the third lepton mixing angle, \\theta_{13}, has shown that, although small compared to \\theta_{12} and \\theta_{23}, it is much larger than anticipated in schemes that generate Tri-Bi-Maximal (TBM) or Golden Ratio (GR) mixing. We develop a model-independent formalism for perturbations away from exact TBM or GR mixing in the neutrino sector. Each resulting perturbation scheme reflects an underlying symmetry structure and involves a single complex parameter. We show that such perturbations can readily fit the observed value of \\theta_{13}, which is then correlated with a change in the other mixing angles. We also determine the implication for the lepton CP violating phases. For comparison we determine the predictions for Bi-Maximal mixing corrected by charged lepton mixing and we discuss the accuracy that will be needed to distinguish between the various schemes.

Study of experimentally undetermined neutrino parameters in the light of baryogenesis considering type I and type II Seesaw models

International Nuclear Information System (INIS)

Kalita, Rupam

2017-01-01

We study to connect all the experimentally undetermined neutrino parameters namely lightest neutrino mass, neutrino CP phases and baryon asymmetry of the Universe within the framework of a model where both type I and type II seesaw mechanisms can contribute to tiny neutrino masses. In this work we study the effects of Dirac and Majorana neutrino phases in the origin of matter-antimatter asymmetry through the mechanism of leptogenesis. Type I seesaw mass matrix considered to a tri-bimaximal (TBM) type neutrino mixing which always gives non zero reactor mixing angle. The type II seesaw mass matrix is then considered in such a way that the necessary deviation from TBM mixing and the best fit values of neutrino parameters can be obtained when both type I and type II seesaw contributions are taken into account. We consider different contribution from type I and type II seesaw mechanism to study the effects of neutrino CP phases in the baryon asymmetry of the universe. We further study to connect all these experimentally undetermined neutrino parameters by considering various contribution of type I and type II seesaw. (author)

Impact of Ue3 on neutrino models

International Nuclear Information System (INIS)

Tanimoto, M.

2004-01-01

We have discussed the impact of U e3 on the model of the neutrino mass matrix. In order to get the small U e3 , some flavor symmetry is required. Typical two models are investigated. The first one is the model in which the bi-maximal mixing is realized at the symmetric limit. The second one is the texture zeros of the neutrino mass matrix. (author)

Renormalisation group analysis of single right-handed neutrino dominance

International Nuclear Information System (INIS)

King, S.F.; Nimai Singh, N.

2000-01-01

We perform a renormalisation group (RG) analysis of neutrino masses and mixing angles in the see-saw mechanism in the minimal supersymmetric standard model with three right-handed neutrinos, including the effects of the heavy neutrino thresholds. We focus on the case that one of the right-handed neutrinos provides the dominant contribution to the 23 block of the light Majorana matrix, causing its determinant to approximately vanish and giving an automatic neutrino mass hierarchy, so-called single right-handed neutrino dominance which may arise from a U(1) family symmetry. In these models radiative corrections can increase atmospheric and solar neutrino mixing by up to about 10% and 5%, respectively, and may help to achieve bi-maximal mixing. Significantly we find that the radiative corrections over the heavy neutrino threshold region are at least as important as those usually considered from the lightest right-handed neutrino down to low energies

Nearly degenerate neutrinos, supersymmetry and radiative corrections

International Nuclear Information System (INIS)

Casas, J.A.; Espinosa, J.R.; Ibarra, A.; Navarro, I.

2000-01-01

If neutrinos are to play a relevant cosmological role, they must be essentially degenerate with a mass matrix of the bimaximal mixing type. We study this scenario in the MSSM framework, finding that if neutrino masses are produced by a see-saw mechanism, the radiative corrections give rise to mass splittings and mixing angles that can accommodate the atmospheric and the (large angle MSW) solar neutrino oscillations. This provides a natural origin for the Δm 2 sol 2 atm hierarchy. On the other hand, the vacuum oscillation solution to the solar neutrino problem is always excluded. We discuss also in the SUSY scenario other possible effects of radiative corrections involving the new neutrino Yukawa couplings, including implications for triviality limits on the Majorana mass, the infrared fixed point value of the top Yukawa coupling, and gauge coupling and bottom-tau unification

Unified parametrization for quark and lepton mixing angles

International Nuclear Information System (INIS)

Rodejohann, Werner

2009-01-01

We propose a new parametrization for the quark and lepton mixing matrices: the two 12-mixing angles (the Cabibbo angle and the angle responsible for solar neutrino oscillations) are at zeroth order π/12 and π/5, respectively. The resulting 12-elements in the CKM and PMNS matrices, V us and U e2 , are in this order irrational but simple algebraic numbers. We note that the cosine of π/5 is the golden ratio divided by two. The difference between π/5 and the observed best-fit value of solar neutrino mixing is of the same order as the difference between the observed value and the one for tri-bimaximal mixing. In order to reproduce the central values of current fits, corrections to the zeroth order expressions are necessary. They are small and of the same order and sign for quarks and leptons. We parametrize the perturbations to the CKM and PMNS matrices in a 'triminimal' way, i.e., with three small rotations in an order corresponding to the order of the rotations in the PDG-description of mixing matrices

A new family symmetry for SO(10) GUTs

International Nuclear Information System (INIS)

King, Stephen F.; Luhn, Christoph

2009-01-01

We argue that the projective special linear group PSL 2 (7), also known as Σ(168), has unique features which make it the most suitable discrete family symmetry for describing quark and lepton masses and mixing in the framework of SO(10) type unified models. In such models flavon fields in the sextet representation of PSL 2 (7) play a crucial role both in obtaining tri-bimaximal neutrino mixing as well as in generating the third family charged fermion Yukawa couplings. In preparation for physical applications, we derive the triplet representation of PSL 2 (7) in the basis S,T,U,V where S,T,U are the familiar triplet generators of S 4 in the diagonal charged lepton basis where T is diagonal. We also derive an analogous basis for the real sextet representation and identify the vacuum alignments which lead to tri-bimaximal neutrino mixing and large third family charged fermion Yukawa couplings.

Fermion masses and flavor mixings in a model with S4 flavor symmetry

International Nuclear Information System (INIS)

Ding Guijun

2010-01-01

We present a supersymmetric model of quark and lepton based on S 4 xZ 3 xZ 4 flavor symmetry. The S 4 symmetry is broken down to Klein four and Z 3 subgroups in the neutrino and the charged lepton sectors, respectively. Tri-Bimaximal mixing and the charged lepton mass hierarchies are reproduced simultaneously at leading order. Moreover, a realistic pattern of quark masses and mixing angles is generated with the exception of the mixing angle between the first two generations, which requires a small accidental enhancement. It is remarkable that the mass hierarchies are controlled by the spontaneous breaking of flavor symmetry in our model. The next to leading order contributions are studied, all the fermion masses and mixing angles receive corrections of relative order λ c 2 with respect to the leading order results. The phenomenological consequences of the model are analyzed, the neutrino mass spectrum can be normal hierarchy or inverted hierarchy, and the combined measurement of the 0ν2β decay effective mass m ββ and the lightest neutrino mass can distinguish the normal hierarchy from the inverted hierarchy.

A4 family symmetry and quark-lepton unification

International Nuclear Information System (INIS)

King, Stephen F.; Malinsky, Michal

2007-01-01

We present a model of quark and lepton masses and mixings based on A 4 family symmetry, a discrete subgroup of an SO(3) flavour symmetry, together with Pati-Salam unification. It accommodates tri-bimaximal neutrino mixing via constrained sequential dominance with a particularly simple vacuum alignment mechanism emerging through the effective D-term contributions to the scalar potential

Possible energy dependence of Θ13 in neutrino oscillations

International Nuclear Information System (INIS)

Klinkhamer, Frans R.

2005-01-01

A simple three-flavor neutrino-oscillation model is discussed which has both nonzero mass differences and timelike Fermi-point splittings, together with a combined bi-maximal and trimaximal mixing pattern. One possible consequence would be new effects in ν μ →ν e oscillations, characterized by an energy-dependent effective mixing angle Θ 13 . Future experiments such as T2K and NOνA, and perhaps even the current MINOS experiment, could look for these effects

μ-τ symmetry in Zee-Babu model

International Nuclear Information System (INIS)

Araki, Takeshi; Geng, C.Q.

2010-01-01

We study the Zee-Babu two-loop neutrino mass generation model and look for a possible flavor symmetry behind the tri-bimaximal neutrino mixing. We find that there probably exists the μ-τ symmetry in the case of the normal neutrino mass hierarchy, whereas there may not be in the inverted hierarchy case. We also propose a specific model based on a Froggatt-Nielsen-like Z 5 symmetry to naturally accomplish the μ-τ symmetry on the neutrino mass matrix for the normal hierarchy case.

Status of the Gribov-Pontecorvo Solution to the Solar Neutrino Problem

CERN Document Server

Berezinsky, Veniamin Sergeevich; Peña-Garay, C

2001-01-01

We discuss the status of the Gribov--Pontecorvo (GP) solution to the solar neutrino problem. This solution naturally appears in bimaximal neutrino mixing and reduces the solar and atmospheric neutrino problems to vacuum oscillations of three active neutrinos. The GP solution predicts an energy-independent suppression of the solar neutrino flux. It is disfavoured by the rate of the Homestake detector, but its statistical significance greatly improves, when the chlorine rate and the boron neutrino flux are slightly rescaled, and when the Super-Kamiokande neutrino spectrum is included in the analysis. Our results show that rescaling of the chlorine signal by only 10% is sufficient for the GP solution to exist, if the boron--neutrino flux is taken 10 -- 20% lower than the SSM prediction. The regions allowed for the GP solution in the parameter space are found and observational signatures of this solution are discussed.

Theory of Neutrino Masses and Mixing

CERN Document Server

González-Garciá, M Concepción

2003-01-01

In this talk I will review our present knowledge on neutrino masses and mixing trying to emphasize what has been definitively proved and what is in the process of being probed. I will also discuss the most important theoretical implications of these results: the existence of new physics, the estimate of the scale of this new physics as well as some other possible consequences such as leptogenesis origin of the baryon asymmetry.

Renormalisation group improved leptogenesis in family symmetry models

International Nuclear Information System (INIS)

Cooper, Iain K.; King, Stephen F.; Luhn, Christoph

2012-01-01

We study renormalisation group (RG) corrections relevant for leptogenesis in the case of family symmetry models such as the Altarelli-Feruglio A 4 model of tri-bimaximal lepton mixing or its extension to tri-maximal mixing. Such corrections are particularly relevant since in large classes of family symmetry models, to leading order, the CP violating parameters of leptogenesis would be identically zero at the family symmetry breaking scale, due to the form dominance property. We find that RG corrections violate form dominance and enable such models to yield viable leptogenesis at the scale of right-handed neutrino masses. More generally, the results of this paper show that RG corrections to leptogenesis cannot be ignored for any family symmetry model involving sizeable neutrino and τ Yukawa couplings.

Neutrino mixing and big bang nucleosynthesis

Science.gov (United States)

Bell, Nicole

2003-04-01

We analyse active-active neutrino mixing in the early universe and show that transformation of neutrino-antineutrino asymmetries between flavours is unavoidable when neutrino mixing angles are large. This process is a standard Mikheyev-Smirnov-Wolfenstein flavour transformation, modified by the synchronisation of momentum states which results from neutrino-neutrino forward scattering. The new constraints placed on neutrino asymmetries eliminate the possibility of degenerate big bang nucleosynthesis.Implications of active-sterile neutrino mixing will also be reviewed.

The Charged Lepton Mass Matrix and Non-zero θ13 with TeV Scale New Physics.

Science.gov (United States)

Rashed, Ahmed; Datta, Alakabha

2012-03-01

We provide an explicit structure of the charged lepton mass matrix which is 2-3 symmetric except for a single breaking of this symmetry by the muon mass. We identify a flavor symmetric limit for the mass matrices where the first generation is decoupled from the other two in the charged lepton sector while in the neutrino sector the third generation is decoupled from the first two generations. The leptonic mixing in the symmetric limit can be, among other structures, the bi-maximal (BM) or the tri-bimaximal (TBM) mixing. Symmetry breaking effects are included both in the charged lepton and the neutrino sector to produce corrections to the leptonic mixing and explain the recent θ13 measurements. A model that extends the SM by three right handed neutrinos, an extra Higgs doublet, and two singlet scalars is introduced to generate the leptonic mixing.[4pt] This work was supported in part by the US-Egypt Joint Board on Scientific and Technological Co-operation award (Project ID: 1855) administered by the US Department of Agriculture, summer grant from the College of Liberal Arts, University of Mississippi and in part by the National Science Foundation under Grant No. 1068052 and 1066293 and the hospitality of the Aspen Center for Physics.

Common origin of soft μ−τ and CP breaking in neutrino seesaw and the origin of matter

International Nuclear Information System (INIS)

Ge, Shao-Feng; He, Hong-Jian; Yin, Fu-Rong

2010-01-01

Neutrino oscillation data strongly support μ – τ symmetry as a good approximate flavor symmetry of the neutrino sector, which has to appear in any viable theory for neutrino mass-generation. The μ – τ breaking is not only small, but also the source of Dirac CP-violation. We conjecture that both discrete μ – τ and CP symmetries are fundamental symmetries of the seesaw Lagrangian (respected by interaction terms), and they are only softly broken, arising from a common origin via a unique dimension-3 Majorana mass-term of the heavy right-handed neutrinos. From this conceptually attractive and simple construction, we can predict the soft μ – τ breaking at low energies, leading to quantitative correlations between the apparently two small deviations θ 23 −45° and θ 13 −0°. This nontrivially connects the on-going measurements of mixing angle θ 23 with the upcoming experimental probes of θ 13 . We find that any deviation of θ 23 −45° must put a lower limit on θ 13 . Furthermore, we deduce the low energy Dirac and Majorana CP violations from a common soft-breaking phase associated with μ – τ breaking in the neutrino seesaw. Finally, from the soft CP breaking in neutrino seesaw we derive the cosmological CP violation for the baryon asymmetry via leptogenesis. We fully reconstruct the leptogenesis CP-asymmetry from the low energy Dirac CP phase and establish a direct link between the cosmological CP-violation and the low energy Jarlskog invariant. We predict new lower and upper bounds on the θ 13 mixing angle, 1°∼ 13 ∼ 12 by its group-parameter, and includes the conventional tri-bimaximal mixing as a special case, allowing deviations from it

Neutrino mixing and future accelerator neutrino experiments

International Nuclear Information System (INIS)

Bilenky, S.M.

1992-01-01

No evidence for neutrino mixing has been obtained in experiments searching for oscillations with neutrinos from accelerators and reactors. The possible reason is that neutrino masses are too small to produce any sizable effects in the experiments with terrestrial neutrinos. We put forward here the point of view that the reason for that can be traced to the presence of a hierarchy of neutrino masses as well as strength of couplings between lepton families. (orig.)

Massive neutrinos flavor mixing of leptons and neutrino oscillations

CERN Document Server

2015-01-01

Since the discovery of neutrino oscillations neutrino physics has become an interesting field of research in physics. They imply that neutrino must have a small mass and that the neutrinos, coupled to the charged leptons, are mixtures of the mass eigenstates, analogous to the flavor mixing of the quarks. The mixing angles for the quarks are small, but for the leptons two of the mixing angles are large. The masses of the three neutrinos must be very small, less than 1 eV, but from the oscillation experiments we only know the mass differences — the absolute masses are still unknown. Also we do not know, if the masses of the neutrinos are Dirac masses, as the masses of the charged leptons and of the quarks, or whether they are Majorana masses. In this volume, an overview of the present state of research in neutrino physics is given by well-known experimentalists and theorists. The contents — originated from talks and discussions at a recent conference addressing some of the most pressing open questions in n...

Solar neutrinos and the MSW effect for three-neutrino mixing

Science.gov (United States)

Shi, X.; Schramm, David N.

1991-01-01

Researchers considered three-neutrino Mikheyev-Smirnov-Wolfenstein (MSW) mixing, assuming m sub 3 is much greater than m sub 2 is greater than m sub 1 as expected from theoretical consideration if neutrinos have mass. They calculated the corresponding mixing parameter space allowed by the Cl-37 and Kamiokande 2 experiments. They also calculated the expected depletion for the Ga-71 experiment. They explored a range of theoretical uncertainty due to possible astrophysical effects by varying the B-8 neutrino flux and redoing the MSW mixing calculation.

Mixing of fourth-generation neutrinos

International Nuclear Information System (INIS)

Nussinov, S.

1987-01-01

This paper reviews some of the constraints on the mixing of massive decaying neutrinos. Some of the possible implications for neutrino physics of the recent supernova, and in particular the apparent overabundance of neutrino energy, are discussed

Features of neutrino mixing

Science.gov (United States)

Chiu, S. H.; Kuo, T. K.

2018-03-01

The elements (squared) of the neutrino mixing matrix are found to satisfy, as functions of the induced mass, a set of differential equations. They show clearly the dominance of pole terms when the neutrino masses "cross." Using the known vacuum mixing parameters as initial conditions, it is found that these equations have very good approximate solutions, for all values of the induced mass. The results are applicable to long baseline experiments.

SUSY S4×SU(5) revisited

International Nuclear Information System (INIS)

Hagedorn, Claudia; King, Stephen F.; Luhn, Christoph

2012-01-01

Following the recent results from Daya Bay and RENO, which measure the lepton mixing angle θ 13 l ≈0.15, we revisit a supersymmetric (SUSY) S 4 ×SU(5) model, which predicts tri-bimaximal (TB) mixing in the neutrino sector with θ 13 l being too small in its original version. We show that introducing one additional S 4 singlet flavon into the model gives rise to a sizable θ 13 l via an operator which leads to the breaking of one of the two Z 2 symmetries preserved in the neutrino sector at leading order (LO). The results of the original model for fermion masses, quark mixing and the solar mixing angle are maintained to good precision. The atmospheric and solar mixing angle deviations from TB mixing are subject to simple sum rule bounds.

Neutrino mixing and lepton CP-phase in neutrino oscillations

International Nuclear Information System (INIS)

Ryzhikh, D.A.; Ter-Martirosyan, K.A.

2001-01-01

One studied oscillations of the Dirac neutrinos belonging to three generations in vacuum with regard to the effect of the lepton CP-breaking phase on them in the matrix of lepton mixing (analogue of the quark CP-phase). In the general form one obtained formulae for probabilities of transition of neutrino of one kind to another at oscillations depending on three angles of mixing and on CP-phase. It was pointed that when measuring oscillation average probabilities of transition of neutrino of one kind to another one might in principle, restore the value of lepton CP-phase. Manifestation of CP-phase in the form of deviation of the values of probabilities of direct neutrino transition from reverse one is the effect practically escaping observation [ru

Lepton mixing and the 'solar neutrino puzzle'

International Nuclear Information System (INIS)

Bilenky, S.M.; Pontecorvo, B.

1977-01-01

The results of the well-known solar neutrino experiments in which the Cl-Ar method was employed are discussed; the results of this experiment gave a too-small neutrino signal and were referred to as the 'solar neutrino puzzle'. A number of explanations have been offered to account for the results, but it is stated that the explanation in terms of lepton mixing and neutrino sterility is attractive in terms of present day elementary particle physics and much more natural than the other explanations offered. Headings are as follows: neutrino oscillations and lepton charge, oscillations and solar neutrino experiments, lepton mixing according to old and present ideas, neutrino oscillations and the 'solar neutrino puzzle'. (U.K.)

Neutrino masses and mixings: Big Bang and Supernova nucleosynthesis and neutrino dark matter

International Nuclear Information System (INIS)

Fuller, George M.

1999-01-01

The existence of small mixings between light active and sterile neutrino species could have implications for Big Bang and Supernova Heavy Element Nucleosynthesis. As well, such mixing would force us to abandon cherished constraints on light neutrino Dark Matter. Two proposed 4-neutrino mass and mixing schemes, for example, can both accomodate existing experimental results and lead to elegant solutions to the neutron-deficit problem for r-Process nucleosynthesis from neutrino-heated supernova ejecta. Each of these solutions is based on matter-enhanced (MSW) active-sterile neutrino transformation. In plausible extensions of these schemes to the early universe, Shi and Fuller have shown that relatively light mass (∼200 eV to ∼10 keV) sterile neutrinos produced via active-sterile MSW conversion can have a ''cold'' energy spectrum. Neutrinos produced in this way circumvent the principal problem of light neutrino dark matter and would be, essentially, Cold Dark Matter

Neutrino mixing in a grand unified theory

International Nuclear Information System (INIS)

Milton, K.; Tanaka, K.

1980-01-01

Neutrino mixing in a grand unified theory in which the neutrino mass matrix is determined by the Gell-Mann-Ramond-Slansky mechanism was investigated. With an arbitrary real right-handed Majorana mass matrix which incorporates three neutrino mass scales, the effects of the up-quark mass matrix are found to be dominant and as a result no significant mixing of ν/sub e/ occurs, while ν/sub μ/ - ν/sub γ/ mixing can be substantial

Three neutrino flavors: Oscillations, mixing, and the solar-neutrino problem

International Nuclear Information System (INIS)

Pantaleone, J.

1991-01-01

An analytical, quantitative description of solar-neutrino propagation is presented which includes three flavors, matter dependence, and long-wavelength effects. Using the derived expression for the electron-neutrino survival probability, it is demonstrated that mixing is possible between the two-flavor Mikheyev-Smirnov-Wolfenstein and two-flavor long-wavelength solutions to the solar-neutrino problem. However, adiabatic conversion of a neutrino mass eigenstate tends to suppress all subsequent long-wavelength effects such as ''seasonal'' variations in the solar-neutrino flux

Neutrino Masses and Mixings and Astrophysics

Science.gov (United States)

Fuller, George M.

1998-10-01

Here we discuss the implications of light neutrino masses and neutrino flavor/type mixing for dark matter, big bang nucleosynthesis, and models of heavy element nucleosynthesis in super novae. We will also argue the other way and discuss possible constraints on neutrino physics from these astrophysical considerations.

Neutrino mixing, flavor states and dark energy

International Nuclear Information System (INIS)

Blasone, M.; Capolupo, A.; Capozziello, S.; Vitiello, G.

2008-01-01

We shortly summarize the quantum field theory formalism for the neutrino mixing and report on recent results showing that the vacuum condensate induced by neutrino mixing can be interpreted as a dark energy component of the Universe

Neutrino masses and mixing

International Nuclear Information System (INIS)

Fogli, G.

1998-01-01

The paper presents an analysis of the solar neutrino problem in terms of both Mikheyev-Smirnov-Wolfenstein (MSW) and vacuum neutrino oscillations, with the inclusion of the data collected by the SuperKamiokande experiment during 306.3 days of operation. In particular, the observed energy spectrum of the recoil electrons from 8 B neutrino scattering is discussed in detail and used to constrain the mass-mixing parameter space. Going to the atmospheric neutrino anomaly, the paper performs both a two- and three-flavor analysis of the most recent SuperKamiokande atmospheric neutrino data. The variations of the zenith distributions of ν events in the presence of flavor oscillations are investigated. It is seen that fits to the SK data, with and without the addition of the CHOOZ constrains, strongly limit the parameter space. Detailed bounds in triangle graphs are reported

Neutrino masses and mixing: evidence and implications

International Nuclear Information System (INIS)

Gonzalez-Garcia, M.C.; Nir, Yosef

2003-01-01

Measurements of various features of the fluxes of atmospheric and solar neutrinos have provided evidence for neutrino oscillations and therefore for neutrino masses and mixing. The authors review the phenomenology of neutrino oscillations in vacuum and in matter. They present the existing evidence from solar and atmospheric neutrinos as well as the results from laboratory searches, including the final status of the Liquid Scintillator Neutrino Detector (LSND) experiment. The theoretical inputs that are used to interpret the experimental results are described in terms of neutrino oscillations. The allowed ranges for the mass and mixing parameters are derived in two frameworks: First, each set of observations is analyzed separately in a two-neutrino framework; Second, the data from solar and atmospheric neutrinos are analyzed in a three-active-neutrino framework. The theoretical implications of these results are then discussed, including the existence of new physics, the estimate of the scale of this new physics, and the lessons for grand unified theories, for models of extra dimensions and singlet fermions in the bulk, and for flavor models

Neutrino mass and mixing in the seesaw playground

International Nuclear Information System (INIS)

King, Stephen F.

2016-01-01

We discuss neutrino mass and mixing in the framework of the classic seesaw mechanism, involving right-handed neutrinos with large Majorana masses, which provides an appealing way to understand the smallness of neutrino masses. However, with many input parameters, the seesaw mechanism is in general not predictive. We focus on natural implementations of the seesaw mechanism, in which large cancellations do not occur, where one of the right-handed neutrinos is dominantly responsible for the atmospheric neutrino mass, while a second right-handed neutrino accounts for the solar neutrino mass, leading to an effective two right-handed neutrino model. We discuss recent attempts to predict lepton mixing and CP violation within such natural frameworks, focusing on the Littlest Seesaw and its distinctive predictions.

Two Light Sterile Neutrinos that Mix Maximally with Each Other and Moderately with Three Active Neutrinos

International Nuclear Information System (INIS)

Krolikowski, W.

2004-01-01

Since the 3+1 neutrino models with one light sterile neutrino turn out to be not very effective, at least two light sterile neutrinos may be needed to reconcile the solar and atmospheric neutrino experiments with the LSND result, if this is confirmed by the ongoing MiniBooNE experiment (and when the CPT invariance is assumed to hold for neutrino oscillations). We present an attractive 3+2 neutrino model, where two light sterile neutrinos mix maximally with each other, in analogy to the observed maximal mixing of muon and tauon active neutrinos. But, while the mixing of ν e and (ν μ - ν τ )/√2 is observed as large (though not maximal), the mixing of ν e with the corresponding combination of two light sterile neutrinos is expected to be only moderate because of the reported smallness of LSND oscillation amplitude. The presented model turns out, however, not to be more effective in explaining the hypothetic LSND result than the simplest 3+1 neutrino model. On the other hand, in the considered 3+2 model, the deviations from conventional oscillations of three active neutrinos appear to be minimal within a larger class of 3+2 models. (author)

Hierarchical Neutrino Masses and Mixing in Flipped-SU(5)

CERN Document Server

Rizos, J

2010-01-01

We consider the problem of neutrino masses and mixing in the framework of flipped SU(5). The right-handed neutrino mass, generated through the operation of a seesaw mechanism by a sector of gauge singlets, leads naturally, at a subsequent level, to the standard seesaw mechanism resulting into three light neutrino states with masses of the desired phenomenological order of magnitude. In this framework we study simple Ansatze for the singlet couplings for which hierarchical neutrino masses emerge naturally, parametrized in terms of the Cabbibo parameter. The resulting neutrino mixing matrices are characterized by a hierarchical structure, in which theta-(13) is always predicted to be the smallest. Finally, we discuss a possible factorized parametrization of the neutrino mass that, in addition to Cabbibo mixing, encodes also mixing due to the singlet sector.

Introduction to models of neutrino masses and mixings

International Nuclear Information System (INIS)

Joshipura, Anjan S.

2004-01-01

This review contains an introduction to models of neutrino masses for non-experts. Topics discussed are i) different types of neutrino masses ii) structure of neutrino masses and mixing needed to understand neutrino oscillation results iii) mechanism to generate neutrino masses in gauge theories and iv) discussion of generic scenarios proposed to realize the required neutrino mass structures. (author)

Hierarchical neutrino masses and mixing in flipped-SU(5)

Energy Technology Data Exchange (ETDEWEB)

Rizos, J. [Physics Department, University of Ioannina, 45110 Ioannina (Greece); Tamvakis, K., E-mail: tamvakis@uoi.g [Physics Department, University of Ioannina, 45110 Ioannina (Greece); Physics Department, CERN, CH-1211, Geneva 23 (Switzerland)

2010-02-22

We consider the problem of neutrino masses and mixing in the framework of flipped SU(5). The right-handed neutrino mass, generated through the operation of a seesaw mechanism by a sector of gauge singlets, leads naturally, at a subsequent level, to the standard seesaw mechanism resulting into three light neutrino states with masses of the desired phenomenological order of magnitude. In this framework we study simple Ansaetze for the singlet couplings for which hierarchical neutrino masses emerge naturally as lambda{sup n}:lambda:1 or lambda{sup n}:lambda{sup 2}:1, parametrized in terms of the Cabbibo parameter. The resulting neutrino mixing matrices are characterized by a hierarchical structure, in which theta{sub 13} is always predicted to be the smallest. Finally, we discuss a possible factorized parametrization of the neutrino mass that, in addition to Cabbibo mixing, encodes also mixing due to the singlet sector.

Discrete symmetries and solar neutrino mixing

Energy Technology Data Exchange (ETDEWEB)

Kapetanakis, D.; Mayr, P.; Nilles, H.P. (Physik Dept., Technische Univ. Muenchen, Garching (Germany) Max-Planck-Inst. fuer Physik, Werner-Heisenberg-Inst., Muenchen (Germany))

1992-05-21

We study the question of resonant solar neutrino mixing in the framework of the supersymmetric extension of the standard model. Discrete symmetries that are consistent with solar neutrino mixing and proton stability are classified. In the minimal model they are shown to lead to two distinct patterns of allowed dimension-four operators. Imposing anomaly freedom, only three different discrete Z{sub N}-symmetries (with N=2, 3, 6) are found to be phenomenologically acceptable. (orig.).

Discrete symmetries and solar neutrino mixing

International Nuclear Information System (INIS)

Kapetanakis, D.; Mayr, P.; Nilles, H.P.

1992-01-01

We study the question of resonant solar neutrino mixing in the framework of the supersymmetric extension of the standard model. Discrete symmetries that are consistent with solar neutrino mixing and proton stability are classified. In the minimal model they are shown to lead to two distinct patterns of allowed dimension-four operators. Imposing anomaly freedom, only three different discrete Z N -symmetries (with N=2, 3, 6) are found to be phenomenologically acceptable. (orig.)

On flavor violation for massive and mixed neutrinos

International Nuclear Information System (INIS)

Blasone, M.; Capolupo, A.; Ji, C.R.; Vitiello, G.

2009-01-01

We discuss flavor charges and states for interacting mixed neutrinos in QFT. We show that the Pontecorvo states are not eigenstates of the flavor charges. This implies that their use in describing the flavor neutrinos produces a violation of lepton charge conservation in the production/detection vertices. The flavor states defined as eigenstates of the flavor charges give the correct representation of mixed neutrinos in charged current weak interaction processes.

Neutrino mixing, oscillations and decoherence in astrophysics and cosmology

Science.gov (United States)

Ho, Chiu Man

2007-08-01

This thesis focuses on a finite-temperature field-theoretical treatment of neutrino oscillations in hot and dense media. By implementing the methods of real-time non-equilibrium field theory, we study the dynamics of neutrino mixing, oscillations, decoherence and relaxation in astrophysical and cosmological environments. We first study neutrino oscillations in the early universe in the temperature regime prior to the epoch of Big Bang Nucleosynthesis (BBN). The dispersion relations and mixing angles in the medium are found to be helicity-dependent, and a resonance like the Mikheyev-Smirnov- Wolfenstein (MSW) effect is realized. The oscillation time scales are found to be longer near a resonance and shorter for off-resonance high-energy neutrinos. We then investigate the space-time propagation of neutrino wave-packets just before BBN. A phenomenon of " frozen coherence " is found to occur if the longitudinal dispersion catches up with the progressive separation between the mass eigenstates, before the coherence time limit has been reached. However, the transverse dispersion occurs at a much shorter scale than all other possible time scales in the medium, resulting in a large suppression in the transition probabilities from electron-neutrino to muon-neutrino. We also explore the possibility of charged lepton mixing as a consequence of neutrino mixing in the early Universe. We find that charged leptons, like electrons and muons, can mix and oscillate resonantly if there is a large lepton asymmetry in the neutrino sector. We study sterile neutrino production in the early Universe via active-sterile oscillations. We provide a quantum field theoretical reassessment of the quantum Zeno suppression on the active-to-sterile transition probability and its time average. We determine the complete conditions for quantum Zeno suppression. Finally, we examine the interplay between neutrino mixing, oscillations and equilibration in a thermal medium, and the corresponding non

Neutrino mixing in SO(10)

International Nuclear Information System (INIS)

Milton, K.; Hama, S.; Nandi, S.; Tanaka, K.

1980-01-01

Neutrino mixing angles were computed in terms of upquark mass ratios in a grand unified field theory based on the gauge group SO(10) supplemented by a discrete symmetry. Only large ν/sub μ/ - ν/sub tau/ mixing were found

Particle Physics Seminar: Towards 3+1 Neutrino Mixing

CERN Multimedia

Geneva University

2011-01-01

GENEVA UNIVERSITY Ecole de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92 Wednesday  12 October  2011 PARTICLE PHYSICS SEMINAR at 17.00 hrs – Stückelberg Auditorium “Towards 3+1 Neutrino Mixing” Par Prof. Carlo Giunti, INFN Torino I will review the recent experimental indications in favor of  short-baseline neutrino oscillations. I will discuss their interpretation in the framework of neutrino mixing schemes with one or more sterile neutrinos which have masses around the eV scale. Taking into account also cosmological constraints, I will present arguments in favor of 3+1 neutrino mixing with one sterile neutrino at the eV scale. Information : http://dpnc.unige.ch/seminaire/annonce.html Organizer : G. Pasztor

Eighty years of neutrino physics

International Nuclear Information System (INIS)

Roy, D.P.

2009-01-01

This is a pedagogical overview of neutrino physics from the invention of neutrino by Pauli in 1930 to the precise measurement of neutrino mass and mixing parameters via neutrino oscillation experiments in recent years. I have tried to pitch it at the level of undergraduate students, occasionally cutting corners to avoid the use of advanced mathematical tools. I hope it will be useful in introducing this exciting field to a broad group of young physicists. (author)

Softly Broken Lepton Numbers: an Approach to Maximal Neutrino Mixing

International Nuclear Information System (INIS)

Grimus, W.; Lavoura, L.

2001-01-01

We discuss models where the U(1) symmetries of lepton numbers are responsible for maximal neutrino mixing. We pay particular attention to an extension of the Standard Model (SM) with three right-handed neutrino singlets in which we require that the three lepton numbers L e , L μ , and L τ be separately conserved in the Yukawa couplings, but assume that they are softly broken by the Majorana mass matrix M R of the neutrino singlets. In this framework, where lepton-number breaking occurs at a scale much higher than the electroweak scale, deviations from family lepton number conservation are calculable, i.e., finite, and lepton mixing stems exclusively from M R . We show that in this framework either maximal atmospheric neutrino mixing or maximal solar neutrino mixing or both can be imposed by invoking symmetries. In this way those maximal mixings are stable against radiative corrections. The model which achieves maximal (or nearly maximal) solar neutrino mixing assumes that there are two different scales in M R and that the lepton number (dash)L=L e -L μ -L τ 1 is conserved in between them. We work out the difference between this model and the conventional scenario where (approximate) (dash)L invariance is imposed directly on the mass matrix of the light neutrinos. (author)

Flavor democracy and type-II seesaw realization of bilarge neutrino mixing

International Nuclear Information System (INIS)

Rodejohann, Werner; Xing Zhizhong

2004-01-01

We generalize the democratic neutrino mixing ansatz by incorporating the type-II seesaw mechanism with S(3) flavor symmetry. For only the triplet mass term or only the conventional seesaw term large neutrino mixing can be achieved only by assuming an unnatural suppression of the flavor democracy contribution. We show that bilarge neutrino mixing can naturally appear if the flavor democracy term is strongly suppressed due to significant cancellation between the conventional seesaw and triplet mass terms. Explicit S(3) symmetry breaking yields successful neutrino phenomenology and various testable correlations between the neutrino mass and mixing parameters. Among the results are a normal neutrino mass ordering, 0.005= e3 vertical bar = 2 2θ 23 >=0.005, positive J CP and moderate cancellation in the effective mass of the neutrinoless double beta decay

The case for mixed dark matter from sterile neutrinos

International Nuclear Information System (INIS)

Lello, Louis; Boyanovsky, Daniel

2016-01-01

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 M h ∼< 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/ H 0 freeze out of local thermal equilibrium, and conjecture that those with lifetimes τ || 1/ H 0 may undergo cascade decay into lighter DM candidates and/or inject non-LTE neutrinos into the cosmic neutrino

The case for mixed dark matter from sterile neutrinos

Energy Technology Data Exchange (ETDEWEB)

Lello, Louis; Boyanovsky, Daniel, E-mail: lal81@pitt.edu, E-mail: boyan@pitt.edu [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States)

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 M {sub h} ∼< 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/ H {sub 0} freeze out of local thermal equilibrium, and conjecture that those with lifetimes τ || 1/ H {sub 0} may undergo cascade decay into lighter DM candidates and/or inject non-LTE neutrinos into the

Lepton mixing and the ''solar neutrino puzzle''

International Nuclear Information System (INIS)

Bilenky, S.M.; Pontecorvo, B.

1977-01-01

The results of the well known solar neutrino experiment of Davis et al. are discussed, in which the Cl-Ar method is used. The result of the experiment, a too small neutrino signal (the so-called ''solar neutrino puzzle'), has been tentatively accounted for in a number of quite exotic explanations. It appears that the explanation in terms of lepton mixing and neutrino sterility is quite attractive from the point of view of present day elementary particle physics and is much more natural than the other explanations of the ''puzzle''

A supersymmetric grand unified theory of flavour with PSL2(7)xSO(10)

International Nuclear Information System (INIS)

King, Stephen F.; Luhn, Christoph

2010-01-01

We construct a realistic Supersymmetric Grand Unified Theory of Flavour based on PSL 2 (7)xSO(10), where the quarks and leptons in the 16 of SO(10) are assigned to the complex triplet representation of PSL 2 (7), while the flavons are assigned to a combination of sextets and anti-triplets of PSL 2 (7). Using a D-term vacuum alignment mechanism, we require the flavon sextets of PSL 2 (7) to be aligned along the 3-3 direction leading to the third family Yukawa couplings, while the flavon anti-triplets describe the remaining Yukawa couplings. Other sextets are aligned along the neutrino flavour symmetry preserving directions leading to tri-bimaximal neutrino mixing via a type II see-saw mechanism, with predictions for neutrinoless double beta decay and cosmology.

Discrete Symmetry Approach to Lepton Flavour, Neutrino Mixing and Leptonic CP Violation, and Neutrino Related Physics Beyond the Standard Theory

OpenAIRE

Girardi, Ivan

2016-01-01

The experimental evidences of neutrino oscillation, caused by non-zero neutrino masses and neutrino mixing, which were obtained in the experiments with solar, atmospheric, accelerator and reactor neutrinos, opened new field of research in elementary particle physics. The principal goal is to understand at fundamental level the mechanism giving rise to non-zero neutrino masses and neutrino mixing. The open fundamental questions include those of the nature — Dirac or Majorana — of massive neutr...

Bilarge neutrino mixing and mass of the lightest neutrino from third generation dominance in a democratic approach

International Nuclear Information System (INIS)

Dermisek, Radovan

2004-01-01

We show that both small mixing in the quark sector and large mixing in the lepton sector can be obtained from a simple assumption of universality of Yukawa couplings and the right-handed neutrino Majorana mass matrix in leading order. We discuss conditions under which bilarge mixing in the lepton sector is achieved with a minimal amount of fine-tuning requirements for possible models. From knowledge of the solar and atmospheric mixing angles we determine the allowed values of sin θ 13 . If embedded into grand unified theories, the third generation Yukawa coupling unification is a generic feature while masses of the first two generations of charged fermions depend on small perturbations. In the neutrino sector, the heavier two neutrinos are model dependent, while the mass of the lightest neutrino in this approach does not depend on perturbations in the leading order. The right-handed neutrino mass scale can be identified with the GUT scale in which case the mass of the lightest neutrino is given as (m top 2 /M GUT )sin 2 θ 23 sin 2 θ 12 in the limit sin θ 13 ≅0. Discussing symmetries we make a connection with hierarchical models and show that the basis independent characteristic of this scenario is a strong dominance of the third generation right-handed neutrino, M 1 ,M 2 -4 M 3 , M 3 =M GUT

Search for the sterile neutrino mixing with the ICAL detector at INO

Energy Technology Data Exchange (ETDEWEB)

Behera, S.P. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India); Homi Bhabha National Institute, Mumbai (India); Ghosh, Anushree [Universidad Tecnica Federico Santa Maria, Departamento de Fisica, Valparaiso (Chile); Choubey, Sandhya [Harish-Chandra Research Institute, Allahabad (India); Datar, V.M. [INO Cell, Tata Institute of Fundamental Research, Mumbai (India); Mishra, D.K. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India); Mohanty, A.K. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India); Homi Bhabha National Institute, Mumbai (India); Saha Institute of Nuclear Physics, Kolkata (India)

2017-05-15

The study has been carried out on the prospects of probing the sterile neutrino mixing with the magnetized iron calorimeter (ICAL) at the India-based Neutrino Observatory (INO), using atmospheric neutrinos as a source. The so-called 3 + 1 scenario is considered for active-sterile neutrino mixing and lead to projected exclusion curves in the sterile neutrino mass and mixing angle plane. The analysis is performed using the neutrino event generator NUANCE, modified for ICAL, and folded with the detector resolutions obtained by the INO collaboration from a full GEANT4-based detector simulation. A comparison has been made between the results obtained from the analysis considering only the energy and zenith angle of the muon and combined with the hadron energy due to the neutrino induced event. A small improvement has been observed with the addition of the hadron information to the muon. In the analysis we consider neutrinos coming from all zenith angles and the Earth matter effects are also included. The inclusion of events from all zenith angles improves the sensitivity to sterile neutrino mixing by about 35% over the result obtained using only down-going events. The improvement mainly stems from the impact of Earth matter effects on active-sterile mixing. The expected precision of ICAL on the active-sterile mixing is explored and the allowed confidence level (C.L.) contours presented. At the assumed true value of 10 {sup circle} for the sterile mixing angles and marginalization over Δm{sup 2}{sub 41} and the sterile mixing angles, the upper bound at 90% C.L. (from two-parameter plots) is around 20 {sup circle} for θ{sub 14} and θ{sub 34}, and about 12 {sup circle} for θ{sub 24}. (orig.)

Neutrino Mass Models: impact of non-zero reactor angle

International Nuclear Information System (INIS)

King, Stephen F.

2011-01-01

In this talk neutrino mass models are reviewed and the impact of a non-zero reactor angle and other deviations from tri-bi maximal mixing are discussed. We propose some benchmark models, where the only way to discriminate between them is by high precision neutrino oscillation experiments.

Introduction to the physics of massive and mixed neutrinos

CERN Document Server

Bilenky, Samoil

2018-01-01

Small neutrino masses are the first signs of new physics beyond the Standard Model of particle physics. Since the first edition of this textbook appeared in 2010, the Nobel Prize has been awarded "for the discovery of neutrino oscillations, which shows that neutrinos have mass". The measurement of the small neutrino mixing angle $\\theta_{13}$ in 2012, launched the precision stage of the investigation of neutrino oscillations. This measurement now allows such fundamental problems as the three-neutrino mass spectrum - is it normal or inverted? – and the $CP$ violation in the lepton sector to be tackled. In order to understand the origin of small neutrino masses, it remains crucial to reveal the nature of neutrinos with definite masses: are they Dirac neutrinos possessing a conserved lepton number, which distinguishes neutrinos and antineutrinos, or are they Majorana neutrinos with identical neutrinos and antineutrinos? Experiments searching for the neutrinoless double beta decay are presently under way to ans...

Bounds on neutrino mixing with exotic singlet neutrinos E

Indian Academy of Sciences (India)

1Department of Physics, Government College, Sawai Madhopur 322 001, India. 2Department of Physics ... ZZ (where a = e,µ or τ) with the inclusion of neutrino mixing. The threshold of the process Ôs ..... JKS thanks University Grants Commission and NKS thanks DST for financial assistance. References. [1] P Langacker ...

New limits on neutrino magnetic moment through nonvanishing 13-mixing

Science.gov (United States)

Guzzo, M. M.; de Holanda, P. C.; Peres, O. L. G.

2018-05-01

The relatively large value of the neutrino mixing angle θ13 set by recent measurements allows us to use solar neutrinos to set a limit on the neutrino magnetic moment involving the second and third flavor families, μ23. The existence of a random magnetic field in the solar convective zone can produce a significant antineutrino flux when a nonvanishing neutrino magnetic moment is assumed. Even if we consider a vanishing neutrino magnetic moment involving the first family, electron antineutrinos are indirectly produced through the mixing between the first and third families and μ23≠0 . Using KamLAND limits on the solar flux of electron antineutrino, we set the limit μ23behavior of solar magnetic fields. This is the first time that a limit on μ23 has been established in the literature directly from neutrino interactions with magnetic fields, and, interestingly enough, is comparable with the limits on the neutrino magnetic moment involving the first family and with the ones coming from modifications to the electroweak cross section.

On entanglement in neutrino mixing and oscillations

International Nuclear Information System (INIS)

Blasone, Massimo; Dell'Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio

2010-01-01

We report on recent results about entanglement in the context of particle mixing and oscillations. We study in detail single-particle entanglement arising in two-flavor neutrino mixing. The analysis is performed first in the context of Quantum Mechanics, and then for the case of Quantum Field Theory.

On entanglement in neutrino mixing and oscillations

Energy Technology Data Exchange (ETDEWEB)

Blasone, Massimo; Dell' Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio, E-mail: blasone@sa.infn.i [Dipartimento di Matematica e Informatica, Universita degli Studi di Salerno, Via Ponte don Melillo, I-84084 Fisciano (Italy)

2010-06-01

We report on recent results about entanglement in the context of particle mixing and oscillations. We study in detail single-particle entanglement arising in two-flavor neutrino mixing. The analysis is performed first in the context of Quantum Mechanics, and then for the case of Quantum Field Theory.

Pattern of neutrino mixing in grand unified theories

International Nuclear Information System (INIS)

Milton, K.; Tanaka, K.

1981-01-01

It was found previously in SO(10) grand unified theories that if the neutrinos have a Dirac mass and a right-handed Majorana mass (approx. 10 15 GeV) but no left-handed Majorana mass, there is small ν/sub e/ mixing but ν/sub μ/ - ν/sub tau/ mixing can be substantial. This problem is reexamined on the basis of a formalism that assumes that the up, down, lepton, and neutrino mass matrices arise from a single complex 10 and a single 126 Higgs boson. This formalism determines the Majorana mass matrix in terms of quark mass matrices. Adopting three different sets of quark mass matrices that produce acceptable fermion mass ratios and Cabbibo mixing produces results consistent with the above; however, in the optimum case, ν/sub e/ - ν/sub μ/ mixing can be of the order of the Cabbibo angle

Origins of tiny neutrino mass and large flavor mixings

International Nuclear Information System (INIS)

Haba, Naoyuki

2015-01-01

Active neutrino masses are extremely smaller than those of other quarks and leptons, and there are large flavor mixings in the lepton sector, contrary to the quark sector. They are great mysteries in the standard model, but also excellent hints of new physics beyond the standard model. Thus, questions 'What is an origin of tiny neutrino mass?' and 'What is an origin of large lepton flavor mixings?' are very important. In this paper, we overview various attempts to solve these big questions. (author)

Large neutrino mixings in MSSM and SUSY GUTs: Democratic approach

International Nuclear Information System (INIS)

Shafi, Qaisar; Tavartkiladze, Zurab

2003-01-01

We show how, with aid from a U (1) flavor symmetry, the hierarchical structure in the charged fermion sector and a democratic approach for neutrinos that yields large solar and atmospheric neutrino mixings can be simultaneously realized in the MSSM framework. In SU(5), due to the unified multiplets, we encounter difficulties. Namely, democracy for the neutrinos leads to a wrong hierarchical pattern for charged fermion masses and mixings. We discuss how this is overcome in flipped SU(5). We then proceed to an example based on 5D SUSY SU(5) GUT in which the neutrino democracy idea can be realized. A crucial role is played by bulk states, the so-called 'copies', which are split by compactifying the fifth dimension on an S(1)/Z2 x Z'2 orbifold

Unified triminimal parametrizations of quark and lepton mixing matrices

International Nuclear Information System (INIS)

He Xiaogang; Li Shiwen; Ma Boqiang

2009-01-01

We present a detailed study on triminimal parametrizations of quark and lepton mixing matrices with different basis matrices. We start with a general discussion on the triminimal expansion of the mixing matrix and on possible unified quark and lepton parametrization using quark-lepton complementarity. We then consider several interesting basis matrices and compare the triminimal parametrizations with the Wolfenstein-like parametrizations. The usual Wolfenstein parametrization for quark mixing is a triminimal expansion around the unit matrix as the basis. The corresponding quark-lepton complementarity lepton mixing matrix is a triminimal expansion around the bimaximal basis. Current neutrino oscillation data show that the lepton mixing matrix is very well represented by the tribimaximal mixing. It is natural to take it as an expanding basis. The corresponding zeroth order basis for quark mixing in this case makes the triminimal expansion converge much faster than the usual Wolfenstein parametrization. The triminimal expansion based on tribimaximal mixing can be converted to the Wolfenstein-like parametrizations discussed in the literature. We thus have a unified description between different kinds of parametrizations for quark and lepton sectors: the standard parametrizations, the Wolfenstein-like parametrizations, and the triminimal parametrizations.

Models of neutrino mass and mixing

International Nuclear Information System (INIS)

Ma, Ernest

2000-01-01

There are two basic theoretical approaches to obtaining neutrino mass and mixing. In the minimalist approach, one adds just enough new stuff to the Minimal Standard Model to get m ν ≠0 and U αi ≠1. In the holistic approach, one uses a general framework or principle to enlarge the Minimal Standard Model such that, among other things, m ν ≠0 and U αi ≠1. In both cases, there are important side effects besides neutrino oscillations. I discuss a number of examples, including the possibility of leptogenesis from R parity nonconservation in supersymmetry

Prospects for experiments on neutrino masses and mixing via neutrino oscillations at future accelerators

International Nuclear Information System (INIS)

Lanou, R.E. Jr.

1982-01-01

A study is made of the requirements necessary for improvement in our knowledge of limits in mass and mixing parameters for neutrinos via oscillation phenomena at accelerators. It is concluded that increased neutrino event rate (flux x energy) at modest energy machines (e.g., AGS and LAMPF) is the single most important requirement. This will permit smaller E/L ratios and refinement of systematics

Role of neutrino mixing in accelerated proton decay

Science.gov (United States)

Blasone, M.; Lambiase, G.; Luciano, G. G.; Petruzziello, L.

2018-05-01

The decay of accelerated protons has been analyzed both in the laboratory frame (where the proton is accelerated) and in the comoving frame (where the proton is at rest and interacts with the Fulling-Davies-Unruh thermal bath of electrons and neutrinos). The equality between the two rates has been exhibited as an evidence of the necessity of Fulling-Davies-Unruh effect for the consistency of quantum field theory formalism. Recently, it has been argued that neutrino mixing can spoil such a result, potentially opening new scenarios in neutrino physics. In the present paper, we analyze in detail this problem, and we find that, assuming flavor neutrinos to be fundamental and working within a certain approximation, the agreement can be restored.

Unifying leptogenesis, dark matter and high-energy neutrinos with right-handed neutrino mixing via Higgs portal

Energy Technology Data Exchange (ETDEWEB)

Bari, Pasquale Di; Ludl, Patrick Otto [Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Palomares-Ruiz, Sergio [Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València,Apartado de Correos 22085, E-46071 Valencia (Spain)

2016-11-21

We revisit a model in which neutrino masses and mixing are described by a two right-handed (RH) neutrino seesaw scenario, implying a strictly hierarchical light neutrino spectrum. A third decoupled RH neutrino, N{sub DM} with mass M{sub DM}, plays the role of cold dark matter (DM) and is produced by the mixing with a source RH neutrino, N{sub S} with mass M{sub S}, induced by Higgs portal interactions. The same interactions are also responsible for N{sub DM} decays. We discuss in detail the constraints coming from DM abundance and stability conditions showing that in the hierarchical case, for M{sub DM}≫M{sub S}, there is an allowed window on M{sub DM} values necessarily implying a contribution, from DM decays, to the high-energy neutrino flux recently detected by IceCube. We also show how the model can explain the matter-antimatter asymmetry of the Universe via leptogenesis in the quasi-degenerate limit. In this case, the DM mass should be within the range 300 GeV ≲M{sub S}neutrino flux and show the predicted event spectrum for two exemplary cases. Although DM decays, with a relatively hard spectrum, cannot account for all the IceCube high-energy data, we illustrate how this extra source of high-energy neutrinos could reasonably explain some potential features in the observed spectrum. In this way, this represents a unified scenario for leptogenesis and DM that could be tested during the next years with more high-energy neutrino events.

Neutrino bi-large mixings and family

International Nuclear Information System (INIS)

Bando, Masako; Obara, Midori

2004-01-01

After a brief review of quark-lepton relations in grand unified theories (GUT), we show that the Pati-Salam relation with only one type of Higgs field configuration with ''four zero symmetric texture'' can reproduce two large neutrino mixings as well as observed mass differences. This is quite in contrast to the case of SU(5) where bi-large mixings essentially come from the charged lepton sector with non-symmetric charged lepton mass matrix. (author)

A model of radiative neutrino masses. Mixing and a possible fourth generation

International Nuclear Information System (INIS)

Babu, K.S.; Ma, E.; Pantaleone, J.

1989-01-01

We consider the phenomenological consequences of a recently proposed model with four lepton generations such that the three known neutrinos have radiatively induced Majorana masses. Mixing among generations in the presence of a heavy fourth neutrino necessitates a reevaluation of the usual experimental tests of the standard model. One interesting possibility is to have a τ lifetime longer than predicted by the standard three-generation model. Another is to have neutrino masses and mixing angles in the range needed for a natural explanation of the solar-neutrino puzzle in terms of the Mikheyev-Smirnov-Wolfenstein effect. (orig.)

Implications of neutrino masses and mixing for weak processes

International Nuclear Information System (INIS)

Shrock, R.E.

1981-01-01

A general theory is presented of weak processes involving neutrinos which consistently incorporates the possibility of nonzero neutrino masses and associated lepton mixing. The theory leads to new tests for and bounds on such masses and mixing. These tests make use of (π,K)/sub l2/ decay, nuclear β decay, and μ and tau decays, among others. New experiments at SIN and KEK to apply the tests are mentioned. Further, some implications are discussed for (1) the analysis of the spectral parameters in leptonic decays to determine the Lorentz structure of the weak leptonic couplings; (2) fundamental weak interaction constants such as G/sub μ/, G/sub V/', f/sub π/, f/sub K/, V/sub uq/, q = d or s, m/sub W/, and m/sub Z/; and (3) neutrino propagation

LSND versus MiniBooNE: Sterile neutrinos with energy dependent masses and mixing?

CERN Document Server

Schwetz, Thomas

2008-01-01

Standard active-sterile neutrino oscillations do not provide a satisfactory description of the LSND evidence for neutrino oscillations together with the constraints from MiniBooNE and other null-result short-baseline oscillation experiments. However, if the mass or the mixing of the sterile neutrino depends in an exotic way on its energy all data become consistent. I explore the phenomenological consequences of the assumption that either the mass or the mixing scales with the neutrino energy as $1/E_\

Measurement of day and night neutrino energy spectra at SNO and constraints on neutrino mixing parameters

International Nuclear Information System (INIS)

Ahmad, Q.R.; Bullard, T.V.; Cox, G.A.; Duba, C.A.; Formaggio, J.A.; Germani, J.V.; Hamian, A.A.; Hazama, R.; Heeger, K.M.; Howe, M.; Kazkaz, K.; Manor, J.; Meijer Drees, R.; Orrell, J.L.; Schaffer, K.K.; Smith, M.W.E.; Steiger, T.D.; Stonehill, L.C.; Allen, R.C.; Buehler, G.

2002-01-01

The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted 8 B spectrum, the night minus day rate is 14.0%±6.3% +1.5 -1.4 % of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the ν e asymmetry is found to be 7.0%±4.9% +1.3 -1.2 % . A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the large mixing angle solution

Exact and approximate formulas for neutrino mixing and oscillations with non-standard interactions

International Nuclear Information System (INIS)

Meloni, Davide; Ohlsson, Tommy; Zhang, He

2009-01-01

We present, both exactly and approximately, a complete set of mappings between the vacuum (or fundamental) leptonic mixing parameters and the effective ones in matter with non-standard neutrino interaction (NSI) effects included. Within the three-flavor neutrino framework and a constant matter density profile, a full set of sum rules is established, which enables us to reconstruct the moduli of the effective leptonic mixing matrix elements, in terms of the vacuum mixing parameters in order to reproduce the neutrino oscillation probabilities for future long-baseline experiments. Very compact, but quite accurate, approximate mappings are obtained based on series expansions in the neutrino mass hierarchy parameter η ≡ Δm 2 21 /Δm 2 31 , the vacuum leptonic mixing parameter s 13 ≡ sin θ 13 , and the NSI parameters ε αβ . A detailed numerical analysis about how the NSIs affect the smallest leptonic mixing angle θ 13 , the deviation of the leptonic mixing angle θ 23 from its maximal mixing value, and the transition probabilities useful for future experiments are performed using our analytical results.

Fully constrained Majorana neutrino mass matrices using Σ(72 x 3)

Energy Technology Data Exchange (ETDEWEB)

Krishnan, R.; Harrison, P.F. [Warwick Univ., Coventry (United Kingdom); Scott, W.G. [Rutherford Appleton Laboratory, Chilton, Didcot (United Kingdom)

2018-01-15

In 2002, two neutrino mixing ansatze having trimaximally mixed middle (ν{sub 2}) columns, namely tri-chi-maximal mixing (TχM) and tri-phi-maximal mixing (TφM), were proposed. In 2012, it was shown that TχM with χ = ± (π)/(16) as well as TφM with φ = ± (π)/(16) leads to the solution, sin{sup 2} θ{sub 13} = (2)/(3) sin{sup 2} (π)/(16), consistent with the latest measurements of the reactor mixing angle, θ{sub 13}. To obtain TχM{sub (χ=±(π)/(16))} and TφM{sub (φ=±(π)/(16))}, the type I see-saw framework with fully constrained Majorana neutrino mass matrices was utilised. These mass matrices also resulted in the neutrino mass ratios, m{sub 1}: m{sub 2}: m{sub 3} = ((2+√2))/(1+√(2(2+√2))): 1: ((2+√2))/(-1+√(2(2+√2))). In this paper we construct a flavour model based on the discrete group Σ(72 x 3) and obtain the aforementioned results. A Majorana neutrino mass matrix (a symmetric 3 x 3 matrix with six complex degrees of freedom) is conveniently mapped into a flavon field transforming as the complex six-dimensional representation of Σ(72 x 3). Specific vacuum alignments of the flavons are used to arrive at the desired mass matrices. (orig.)

A neutrino mass-mixing sum rule from SO(10) and neutrinoless double beta decay

Energy Technology Data Exchange (ETDEWEB)

Buccella, F. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Chianese, M. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Mangano, G. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Miele, G.; Morisi, S.; Santorelli, P. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II,Complesso University Monte S. Angelo, I-80126 Napoli (Italy)

2017-04-03

Minimal SO(10) grand unified models provide phenomenological predictions for neutrino mass patterns and mixing. These are the outcome of the interplay of several features, namely: i) the seesaw mechanism; ii) the presence of an intermediate scale where B-L gauge symmetry is broken and the right-handed neutrinos acquire a Majorana mass; iii) a symmetric Dirac neutrino mass matrix whose pattern is close to the up-type quark one. In this framework two natural characteristics emerge. Normal neutrino mass hierarchy is the only allowed, and there is an approximate relation involving both light-neutrino masses and mixing parameters. This differs from what occurring when horizontal flavour symmetries are invoked. In this case, in fact, neutrino mixing or mass relations have been separately obtained in literature. In this paper we discuss an example of such comprehensive mixing-mass relation in a specific realization of SO(10) and, in particular, analyse its impact on the expected neutrinoless double beta decay effective mass parameter 〈m{sub ee}〉, and on the neutrino mass scale. Remarkably a lower limit for the lightest neutrino mass is obtained (m{sub lightest}≳7.5×10{sup −4} eV, at 3 σ level).

Neutrino Mixing and Masses from a Minimum Principle

CERN Document Server

Alonso, R; Isidori, G; Maiani, L

2013-01-01

We analyze the structure of quark and lepton mass matrices under the hypothesis that they are determined from a minimum principle applied to a generic potential invariant under the $\\left[SU(3)\\right]^5\\otimes \\mathcal O(3)$ flavor symmetry, acting on Standard Model fermions and right-handed neutrinos. Unlike the quark case, we show that hierarchical masses for charged leptons are naturally accompanied by degenerate Majorana neutrinos with one mixing angle close to maximal, a second potentially large, a third one necessarily small, and one maximal relative Majorana phase. Adding small perturbations the predicted structure for the neutrino mass matrix is in excellent agreement with present observations and could be tested in the near future via neutrino-less double beta decay and cosmological measurements. The generalization of these results to arbitrary sew-saw models is also discussed.

Maximal neutrino mixing from a minimal flavor symmetry

International Nuclear Information System (INIS)

Aranda, Alfredo; Carone, Christopher D.; Lebed, Richard F.

2000-01-01

We study a number of models, based on a non-Abelian discrete group, that successfully reproduce the simple and predictive Yukawa textures usually associated with U(2) theories of flavor. These models allow for solutions to the solar and atmospheric neutrino problems that do not require altering successful predictions for the charged fermions or introducing sterile neutrinos. Although Yukawa matrices are hierarchical in the models we consider, the mixing between second- and third-generation neutrinos is naturally large. We first present a quantitative analysis of a minimal model proposed in earlier work, consisting of a global fit to fermion masses and mixing angles, including the most important renormalization group effects. We then propose two new variant models: The first reproduces all important features of the SU(5)xU(2) unified theory with neither SU(5) nor U(2). The second demonstrates that discrete subgroups of SU(2) can be used in constructing viable supersymmetric theories of flavor without scalar universality even though SU(2) by itself cannot. (c) 2000 The American Physical Society

Large mixing of light and heavy neutrinos in seesaw models and the LHC

International Nuclear Information System (INIS)

He Xiaogang; Oh, Sechul; Tandean, Jusak; Wen, C.-C.

2009-01-01

In the type-I seesaw model the size of mixing between light and heavy neutrinos, ν and N, respectively, is of order the square root of their mass ratio, (m ν /m N ) 1/2 , with only one generation of the neutrinos. Since the light-neutrino mass must be less than an eV or so, the mixing would be very small, even for a heavy-neutrino mass of order a few hundred GeV. This would make it unlikely to test the model directly at the LHC, as the amplitude for producing the heavy neutrino is proportional to the mixing size. However, it has been realized for some time that, with more than one generation of light and heavy neutrinos, the mixing can be significantly larger in certain situations. In this paper we explore this possibility further and consider specific examples in detail in the context of type-I seesaw. We study its implications for the single production of the heavy neutrinos at the LHC via the main channel qq ' →W*→lN involving an ordinary charged lepton l. We then extend the discussion to the type-III seesaw model, which has richer phenomenology due to presence of the charged partners of the heavy neutrinos, and examine the implications for the single production of these heavy leptons at the LHC. In the latter model the new kinds of solutions that we find also make it possible to have sizable flavor-changing neutral-current effects in processes involving ordinary charged leptons.

Neutrino mixing: from the broken μ-τ symmetry to the broken Friedberg–Lee symmetry

International Nuclear Information System (INIS)

Xing, Zhizhong

2007-01-01

I argue that the observed flavor structures of leptons and quarks might imply the existence of certain flavor symmetries. The latter should be a good starting point to build realistic models towards deeper understanding of the fermion mass spectra and flavor mixing patterns. The μ-τ permutation symmetry serves for such an example to interpret the almost maximal atmospheric neutrino mixing angle (θ 23 ~ 45°) and the strongly suppressed CHOOZ neutrino mixing angle (θ 13 < 10°). In this talk I like to highlight a new kind of flavor symmetry, the Friedberg–Lee symmetry, for the effective Majorana neutrino mass operator. Luo and I have shown that this symmetry can be broken in an oblique way, such that the lightest neutrino remains massless but an experimentally-favored neutrino mixing pattern is achievable. We get a novel prediction for θ 13 in the CP-conserving case: sinθ 13 = tanθ 12 |(1 - tanθ 23 )/(1 + tanθ 23 )|. Our scenario can simply be generalized to accommodate CP violation and be combined with the seesaw mechanism. Finally I stress the importance of probing possible effects of μ-τ symmetry breaking either in terrestrial neutrino oscillation experiments or with ultrahigh-energy cosmic neutrino telescopes. (author)

Remarks on ''Neutrino masses and mixing angles in a predictive theory of fermion masses''

International Nuclear Information System (INIS)

Lavoura, L.; Silva, J.P.

1994-01-01

In the extension of the Dimopoulos-Hall-Raby model of the fermion mass matrices to the neutrino sector, there is an entry in the up-quark and neutrino Dirac mass matrices which can be assumed to arise from the Yukawa coupling of a 120, instead of a 10 or a 126, of SO(10). Although this assumption leads to an extra undetermined complex parameter in the model, the resulting lepton mixing matrix exhibits the remarkable feature that the ν τ does not mix with the other two neutrinos. Making a reasonable assumption about the extra parameter, we are able to fit the large-mixing-angle MSW solution of the solar-neutrino problem, and we obtain m ντ ∼10 eV, the right mass range to close the Universe. Other possibilities for explaining the solar-neutrino deficit are also discussed

Neutrino Physics: what we have learned so far and what

Energy Technology Data Exchange (ETDEWEB)

Nunokawa, Hiroshi [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil)

2013-07-01

Full text: In the last 15 years, after the discovery of neutrino oscillation by the Super-Kamiokande collaboration in 1998, an enormous progress has been made in neutrino physics. Thanks to the recent results from reactor experiments which finally measured the angle theta13 whose value was not known for a long time, we now know all the mixing angles in the standard three flavor scheme. Yet there are several unknowns and open questions about neutrinos. I will try to discuss what we have learned so far and what we would like to know more about neutrinos.we would like to know more about neutrinos.

Neutrinos

CERN Multimedia

CERN. Geneva

2004-01-01

The Standard Model predicts that the neutrinos are massless and do not mix. Generic extensions of the Standard Model predict that neutrinos are massive (but, very likely, much lighter than the charged fermions). Therefore, the search for neutrino masses and mixing tests the Standard Model and probes new phasics. Measurements of various features of the fluxes of atmospheric, solar and, more recently, reactor neutrinos have provided evidence for neutrino oscillations and therefore for neutrino masses and mixing. These results have significant theoretical implications: new physics exists, and its scale can be estimated. There are interesting lessons for grand unified theories and for models of extra dimensions. The measured neutrino flavor parameters pose a challenge to flavor models.

Addendum to 'Update on neutrino mixing in the early universe'

International Nuclear Information System (INIS)

Di Bari, P.

2003-01-01

In the light of the recent WMAP results we update the constraints on a class of nonstandard big bang nucleosynthesis (BBN) models with a simultaneous combination of nonstandard neutrino distributions and an extra effective number of neutrinos in the expansion rate. These models can be described in terms of the two parameters ΔN ν tot , constrained by the primordial helium abundance Y p measurement, and ΔN ν ρ , constrained by a combination of cosmic microwave background and primordial deuterium data. Small deviations from standard big bang nucleosynthesis are suggested. Different nonstandard scenarios can be distinguished by a measurement of the difference ΔN ν f ν =ΔN ν tot -ΔN ν ρ . From the current data we estimate ΔN ν f ν ≅-1.4 -1.4 +0.9 , mildly disfavoring solutions with a low expansion rate, characterized by ΔN ν f ν =0 and negative ΔN ν ρ . Active-sterile neutrino mixing could be a viable explanation only for high values of Y p > or approx. 0.24. The existence of large positive neutrino chemical potentials ξ i ∼0.05, implying ΔN ν ρ ≅0, would be a possible explanation of the data within the analyzed class of nonstandard BBN models. Interestingly, it would also provide a way to evade the cosmological bounds for ''class A 3+1'' four neutrino mixing models. A scenario with a decaying sterile neutrino is also considered

Measuring the deviation of the 2-3 lepton mixing from maximal with atmospheric neutrinos

CERN Document Server

González-Garciá, M C; Smirnov, A Yu

2004-01-01

The measurement of the deviation of the 2-3 leptonic mixing from maximal, D_23 = 1/2 - sin^2(theta_23), is one of the key issues for understanding the origin of the neutrino masses and mixing. In the three-neutrino context we study the dependence of various observables in the atmospheric neutrinos on D_23. We perform a global three-neutrino analysis of the atmospheric and reactor neutrino data taking into account the effects of both the oscillations driven by the "solar" parameters (Delta_m_21^2 and theta_12) and the 1-3 mixing. The departure from the one-dominant mass scale approximation results into the shift of the 2-3 mixing from maximal by Delta_sin^2(theta_23) ~ 0.04, so that D_23 ~ 0.04 +- 0.07 (1 sigma). Though value of the shift is not statistically significant, the tendency is robust. The shift is induced by the excess of the e-like events in the sub-GeV sample. We show that future large scale water Cherenkov detectors can determine D_23 with accuracy of a few percent, comparable with the sensitivit...

Renormalization-group equations of neutrino masses and flavor mixing parameters in matter

Science.gov (United States)

Xing, Zhi-zhong; Zhou, Shun; Zhou, Ye-Ling

2018-05-01

We borrow the general idea of renormalization-group equations (RGEs) to understand how neutrino masses and flavor mixing parameters evolve when neutrinos propagate in a medium, highlighting a meaningful possibility that the genuine flavor quantities in vacuum can be extrapolated from their matter-corrected counterparts to be measured in some realistic neutrino oscillation experiments. Taking the matter parameter a≡ 2√{2}{G}F{N}_eE to be an arbitrary scale-like variable with N e being the net electron number density and E being the neutrino beam energy, we derive a complete set of differential equations for the effective neutrino mixing matrix V and the effective neutrino masses {\\tilde{m}}_i (for i = 1 , 2 , 3). Given the standard parametrization of V , the RGEs for {{\\tilde{θ}}_{12}, {\\tilde{θ}}_{13}, {\\tilde{θ}}_{23}, \\tilde{δ}} in matter are formulated for the first time. We demonstrate some useful differential invariants which retain the same form from vacuum to matter, including the well-known Naumov and Toshev relations. The RGEs of the partial μ- τ asymmetries, the off-diagonal asymmetries and the sides of unitarity triangles of V are also obtained as a by-product.

Neutrino physics: Summary talk

International Nuclear Information System (INIS)

Marciano, W.J.

1989-04-01

This paper is organized as follows: First, I describe the state of neutrino phenomenology. Emphasis is placed on sin 2 θ W , its present status and future prospects. In addition, some signatures of ''new physics'' are described. Then, kaon physics at Fermilab is briefly discussed. I concentrate on the interesting rare decay K L → π 0 e + e - which may be a clean probe direct CP violation. Neutrino mass, mixing, and electromagnetic moments are surveyed. There, I describe the present state and future direction of accelerator based experiments. Finally, I conclude with an outlook on the future. Throughout this summary, I have drawn from and incorporated ideas discussed by other speakers at this workshop. However, I have tried to combine their ideas with my own perspective on neutrino physics and where it is headed. 49 refs., 3 figs., 4 tabs

Non-unitary neutrino mixing and CP violation in the minimal inverse seesaw model

International Nuclear Information System (INIS)

Malinsky, Michal; Ohlsson, Tommy; Xing, Zhi-zhong; Zhang He

2009-01-01

We propose a simplified version of the inverse seesaw model, in which only two pairs of the gauge-singlet neutrinos are introduced, to interpret the observed neutrino mass hierarchy and lepton flavor mixing at or below the TeV scale. This 'minimal' inverse seesaw scenario (MISS) is technically natural and experimentally testable. In particular, we show that the effective parameters describing the non-unitary neutrino mixing matrix are strongly correlated in the MISS, and thus, their upper bounds can be constrained by current experimental data in a more restrictive way. The Jarlskog invariants of non-unitary CP violation are calculated, and the discovery potential of such new CP-violating effects in the near detector of a neutrino factory is discussed.

Neutrino masses and mixings

International Nuclear Information System (INIS)

Wolfenstein, L.

1991-01-01

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 ν τ , (2) a 30 ev ν τ making up the dark matter, (3) a 10 -3 ev ν μ to solve the solar neutrino problem, and (4) a three-neutrino MSW solution

GUT and flavor models for neutrino masses and mixing

Science.gov (United States)

Meloni, Davide

2017-10-01

In the recent years experiments have established the existence of neutrino oscillations and most of the oscillation parameters have been measured with a good accuracy. However, in spite of many interesting ideas, no real illumination was sparked on the problem of flavor in the lepton sector. In this review, we discuss the state of the art of models for neutrino masses and mixings formulated in the context of flavor symmetries, with particular emphasis on the role played by grand unified gauge groups.

Large neutrino mixing from renormalization group evolution

International Nuclear Information System (INIS)

Balaji, K.R.S.; Mohapatra, R.N.; Parida, M.K.; Paschos, E.A.

2000-10-01

The renormalization group evolution equation for two neutrino mixing is known to exhibit nontrivial fixed point structure corresponding to maximal mixing at the weak scale. The presence of the fixed point provides a natural explanation of the observed maximal mixing of ν μ - ν τ , if the ν μ and ν τ are assumed to be quasi-degenerate at the seesaw scale without constraining the mixing angles at that scale. In particular, it allows them to be similar to the quark mixings as in generic grand unified theories. We discuss implementation of this program in the case of MSSM and find that the predicted mixing remains stable and close to its maximal value, for all energies below the O(TeV) SUSY scale. We also discuss how a particular realization of this idea can be tested in neutrinoless double beta decay experiments. (author)

Leptogenesis from oscillations of heavy neutrinos with large mixing angles

Energy Technology Data Exchange (ETDEWEB)

Drewes, Marco; Garbrecht, Björn [Physik-Department T70, Technische Universität München,James-Franck-Straße, 85748 Garching (Germany); Gueter, Dario [Physik-Department T70, Technische Universität München,James-Franck-Straße, 85748 Garching (Germany); Max-Planck-Institut für Physik (Werner-Heisenberg-Institut),Föhringer Ring 6, 80805 München (Germany); Excellence Cluster Universe, Technische Universität München,Boltzmannstraße 2, 85748 Garching (Germany); Klarić, Juraj [Physik-Department T70, Technische Universität München,James-Franck-Straße, 85748 Garching (Germany)

2016-12-29

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 calculations 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.

Doubly perturbed S3 neutrinos and the s13 mixing parameter

International Nuclear Information System (INIS)

Jora, Renata; Schechter, Joseph; Shahid, M. Naeem

2010-01-01

We further study a predictive model for the masses and mixing matrix of three Majorana neutrinos. At zeroth order the model yielded degenerate neutrinos and a generalized tribimaximal mixing matrix. At first order the mass splitting was incorporated and the tribimaximal mixing matrix emerged with very small corrections but with a zero value for the parameter s 13 . In the present paper a different, assumed weaker, perturbation is included which gives a nonzero value for s 13 and further corrections to other quantities. These corrections are worked out and their consequences discussed under the simplifying assumption that the conventional CP violation phase vanishes. It is shown that the existing measurements of the parameter s 23 provide strong bounds on s 13 in this model.

Neutrino masses and oscillations

Energy Technology Data Exchange (ETDEWEB)

Smirnov, A Yu

1996-11-01

New effects related to refraction of neutrinos in different media are reviewed and implication of the effects to neutrino mass and mixing are discussed. Patterns of neutrino masses and mixing implied by existing hints/bounds are described. Recent results on neutrino mass generation are presented. They include neutrino masses in SO(10) GUT`s and models with anomalous U(1), generation of neutrino mass via neutrino-neutralino mixing, models of sterile neutrino. (author). 95 refs, 9 figs.

Neutrino emissivity in the quark-hadron mixed phase of neutron stars

Energy Technology Data Exchange (ETDEWEB)

Spinella, William M. [Computational Science Research Center San Diego State University, San Diego, CA (United States); San Diego State University, Department of Physics, San Diego, CA (United States); Weber, Fridolin [San Diego State University, Department of Physics, San Diego, CA (United States); University of California San Diego, Center for Astrophysics and Space Sciences, La Jolla, CA (United States); Contrera, Gustavo A. [CONICET, Buenos Aires (Argentina); CONICET - Dept. de Fisica, UNLP, IFLP, La Plata (Argentina); Universidad Nacional de La Plata, Grupo de Gravitacion, Astrofisica y Cosmologia, Facultad de Ciencias Astronomicas y Geofisicas, La Plata (Argentina); Orsaria, Milva G. [CONICET, Buenos Aires (Argentina); Universidad Nacional de La Plata, Grupo de Gravitacion, Astrofisica y Cosmologia, Facultad de Ciencias Astronomicas y Geofisicas, La Plata (Argentina)

2016-03-15

Numerous theoretical studies using various equation of state models have shown that quark matter may exist at the extreme densities in the cores of high-mass neutron stars. It has also been shown that a phase transition from hadronic matter to quark matter would result in an extended mixed phase region that would segregate phases by net charge to minimize the total energy of the phase, leading to the formation of a crystalline lattice. The existence of quark matter in the core of a neutron star may have significant consequences for its thermal evolution, which for thousands of years is facilitated primarily by neutrino emission. In this work we investigate the effect a crystalline quark-hadron mixed phase can have on the neutrino emissivity from the core. To this end we calculate the equation of state using the relativistic mean-field approximation to model hadronic matter and a nonlocal extension of the three-flavor Nambu-Jona-Lasinio model for quark matter. Next we determine the extent of the quark-hadron mixed phase and its crystalline structure using the Glendenning construction, allowing for the formation of spherical blob, rod, and slab rare phase geometries. Finally we calculate the neutrino emissivity due to electron-lattice interactions utilizing the formalism developed for the analogous process in neutron star crusts. We find that the contribution to the neutrino emissivity due to the presence of a crystalline quark-hadron mixed phase is substantial compared to other mechanisms at fairly low temperatures (

Neutrino mixing and oscillation in a grand unified field theory SO(10)

International Nuclear Information System (INIS)

Tanaka, K.

1980-01-01

The investigation shows that it is very difficult to achieve neutrino mixing of other than the V/sub μ/-ν/sub tau/ type in any minimal SO(10) model in which neutrino masses are generated by the Gell-Mann-Ramond-Slansky mechanism, because of the severe constraints placed on the mass matrix by quark phenomenology

A note on the mixings of heavy neutrinos and muon decays

International Nuclear Information System (INIS)

Kalyniak, P.; Ng, J.N.

1982-11-01

The authors set limits on the mixing of heavy neutrinos into the muon family /U sub(μi)/sup(2) for neutrino masses in the range of 30 to 70 MeV/c 2 . Both the Michel parameter and the e + spectrum are used. This complements limits from leptonic decays of pseudoscalar mesons. They also give indications of how current experiments can be used to improve these limits

Search for active-sterile neutrino mixing using neutral-current interactions in NOvA

Science.gov (United States)

Adamson, P.; Aliaga, L.; Ambrose, D.; Anfimov, N.; Antoshkin, A.; Arrieta-Diaz, E.; Augsten, K.; Aurisano, A.; Backhouse, C.; Baird, M.; Bambah, B. A.; Bays, K.; Behera, B.; Bending, S.; Bernstein, R.; Bhatnagar, V.; Bhuyan, B.; Bian, J.; Blackburn, T.; Bolshakova, A.; Bromberg, C.; Brown, J.; Brunetti, G.; Buchanan, N.; Butkevich, A.; Bychkov, V.; Campbell, M.; Catano-Mur, E.; Childress, S.; Choudhary, B. C.; Chowdhury, B.; Coan, T. E.; Coelho, J. A. B.; Colo, M.; Cooper, J.; Corwin, L.; Cremonesi, L.; Cronin-Hennessy, D.; Davies, G. S.; Davies, J. P.; Derwent, P. F.; Dharmapalan, R.; Ding, P.; Djurcic, Z.; Dukes, E. C.; Duyang, H.; Edayath, S.; Ehrlich, R.; Feldman, G. J.; Frank, M. J.; Gabrielyan, M.; Gallagher, H. R.; Germani, S.; Ghosh, T.; Giri, A.; Gomes, R. A.; Goodman, M. C.; Grichine, V.; Groh, M.; Group, R.; Grover, D.; Guo, B.; Habig, A.; Hartnell, J.; Hatcher, R.; Hatzikoutelis, A.; Heller, K.; Himmel, A.; Holin, A.; Howard, B.; Hylen, J.; Jediny, F.; Judah, M.; Kafka, G. K.; Kalra, D.; Kasahara, S. M. S.; Kasetti, S.; Keloth, R.; Kolupaeva, L.; Kotelnikov, S.; Kourbanis, I.; Kreymer, A.; Kumar, A.; Kurbanov, S.; Lackey, T.; Lang, K.; Lee, W. M.; Lin, S.; Lokajicek, M.; Lozier, J.; Luchuk, S.; Maan, K.; Magill, S.; Mann, W. A.; Marshak, M. L.; Matera, K.; Matveev, V.; Méndez, D. P.; Messier, M. D.; Meyer, H.; Miao, T.; Miller, W. H.; Mishra, S. R.; Mohanta, R.; Moren, A.; Mualem, L.; Muether, M.; Mufson, S.; Murphy, R.; Musser, J.; Nelson, J. K.; Nichol, R.; Niner, E.; Norman, A.; Nosek, T.; Oksuzian, Y.; Olshevskiy, A.; Olson, T.; Paley, J.; Patterson, R. B.; Pawloski, G.; Pershey, D.; Petrova, O.; Petti, R.; Phan-Budd, S.; Plunkett, R. K.; Poling, R.; Potukuchi, B.; Principato, C.; Psihas, F.; Radovic, A.; Rameika, R. A.; Rebel, B.; Reed, B.; Rocco, D.; Rojas, P.; Ryabov, V.; Sachdev, K.; Sail, P.; Samoylov, O.; Sanchez, M. C.; Schroeter, R.; Sepulveda-Quiroz, J.; Shanahan, P.; Sheshukov, A.; Singh, J.; Singh, J.; Singh, P.; Singh, V.; Smolik, J.; Solomey, N.; Song, E.; Sousa, A.; Soustruznik, K.; Strait, M.; Suter, L.; Talaga, R. L.; Tas, P.; Thayyullathil, R. B.; Thomas, J.; Tian, X.; Tognini, S. C.; Tripathi, J.; Tsaris, A.; Urheim, J.; Vahle, P.; Vasel, J.; Vinton, L.; Vold, A.; Vrba, T.; Wang, B.; Wetstein, M.; Whittington, D.; Wojcicki, S. G.; Wolcott, J.; Yadav, N.; Yang, S.; Zalesak, J.; Zamorano, B.; Zwaska, R.; NOvA Collaboration

2017-10-01

We report results from the first search for sterile neutrinos mixing with active neutrinos through a reduction in the rate of neutral-current interactions over a baseline of 810 km between the NOvA detectors. Analyzing a 14-kton detector equivalent exposure of 6.05 ×1020 protons-on-target in the NuMI beam at Fermilab, we observe 95 neutral-current candidates at the Far Detector compared with 83.5 ±9.7 (stat ) ±9.4 (syst ) events predicted assuming mixing only occurs between active neutrino species. No evidence for νμ→νs transitions is found. Interpreting these results within a 3 +1 model, we place constraints on the mixing angles θ24<20.8 ° and θ34<31.2 ° at the 90% C.L. for 0.05 eV2≤Δ m412≤0.5 eV2 , the range of mass splittings that produce no significant oscillations over the Near Detector baseline.

Can neutrino-electron scattering tell us whether neutrinos are Dirac or Majorana particles?

International Nuclear Information System (INIS)

Kayser, B.

1988-04-01

There has recently been interest in the possibility that neutrino-electron scattering experiments could determine whether neutrinos are Dirac or Majorana particles by providing information on their electromagnetic structure. We try to explain why studies of neutrino electromagnetic structure actually cannot distinguish between Dirac and Majorana neutrinos. 9 refs

Majorana physics through the Cabibbo Haze

Energy Technology Data Exchange (ETDEWEB)

Kile, Jennifer; Pérez, M. Jay; Ramond, Pierre; Zhang, Jue [Institute for Fundamental Theory, Department of Physics, University of Florida,Gainesville, FL 32611 (United States)

2014-02-07

We present a model in which the Supersymmetric Standard Model is augmented by the family symmetry Z{sub 7}⋊Z{sub 3}. Motivated by SO(10), where the charge two-thirds and neutral Dirac Yukawa matrices are related, we propose, using family symmetry, a special form for the seesaw Majorana matrix; it contains a squared correlated hierarchy, allowing it to mitigate the severe hierarchy of the quark sector. It is reproduced naturally by the invariant operators of Z{sub 7}⋊Z{sub 3}, with the hierarchy carried by familon fields. In addition to relating the hierarchy of the ΔI{sub w}=1/2 to the ΔI{sub w}=0 sector, it contains a Gatto-Sartori-Tonin like relation, predicts a normal hierarchy for Tri-bimaximal and Golden Ratio mixings, and gives specific values for the light neutrino masses.

Searches for New Physics at MiniBooNE: Sterile Neutrinos and Mixing Freedom

Energy Technology Data Exchange (ETDEWEB)

Karagiorgi, Georgia S. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2010-09-01

data, with and without constraints from other oscillation experiments with similar sensitivities to those models. A general search for new physics scenarios which would lead to effective non-unitarity of the standard 3 x 3 neutrino mixing matrix, or mixing freedom, is also performed using neutrino and antineutrino data available from MiniBooNE.

CP violation and neutrino masses and mixings from quark mass hierarchies

International Nuclear Information System (INIS)

Buchmueller, W.; Covi, L.; Emmanuel-Costa, D.; Wiesenfeldt, S.

2007-10-01

We study the connection between quark and lepton mass matrices in a supersymmetric SO(10) GUT model in six dimensions, compactified on an orbifold. The physical quarks and leptons are mixtures of brane and bulk states. This leads to a characteristic pattern of mass matrices and high-energy CP violating phases. The hierarchy of up and down quark masses determines the CKM matrix and most charged lepton and neutrino masses and mixings. The small hierarchy of neutrino masses is a consequence of the mismatch of the up and down quark mass hierarchies. The effective CP violating phases in the quark sector, neutrino oscillations and leptogenesis are unrelated. In the neutrino sector we can accomodate naturally sin θ 23 ∝1, sin θ 13 1 2 ∝√(Δm 2 sol ) 3 ∝√(Δm 2 atm ). (orig.)

CP violation and neutrino masses and mixings from quark mass hierarchies

International Nuclear Information System (INIS)

Buchmueller, Wilfried; Covi, Laura; Emmanuel-Costa, David; Wiesenfeldt, Soeren

2007-01-01

We study the connection between quark and lepton mass matrices in a supersymmetric SO(10) GUT model in six dimensions, compactified on an orbifold. The physical quarks and leptons are mixtures of brane and bulk states. This leads to a characteristic pattern of mass matrices and high-energy CP violating phases. The hierarchy of up and down quark masses determines the CKM matrix and most charged lepton and neutrino masses and mixings. The small hierarchy of neutrino masses is a consequence of the mismatch of the up and down quark mass hierarchies. The effective CP violating phases in the quark sector, neutrino oscillations and leptogenesis are unrelated. In the neutrino sector we can accomodate naturally sin θ 23 ∼ 1, sin θ 13 ∼ 1 ∼ 2 ∼ (Δm 2 sol ) 1/2 3 ∼ (Δm 2 atm ) 1/2

Hiding an elephant: heavy sterile neutrino with large mixing angle does not contradict cosmology

Energy Technology Data Exchange (ETDEWEB)

Bezrukov, F. [The University of Manchester, School of Physics and Astronomy, Oxford Road, Manchester M13 9PL (United Kingdom); Chudaykin, A.; Gorbunov, D., E-mail: Fedor.Bezrukov@manchester.ac.uk, E-mail: chudy@ms2.inr.ac.ru, E-mail: gorby@ms2.inr.ac.ru [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect 7a, Moscow 117312 (Russian Federation)

2017-06-01

We study a model of a keV-scale sterile neutrino with a relatively large mixing with the Standard Model sector. Usual considerations predict active generation of such particles in the early Universe, which leads to constraints from the total Dark Matter density and absence of X-ray signal from sterile neutrino decay. These bounds together may deem any attempt of creation of the keV scale sterile neutrino in the laboratory unfeasible. We argue that for models with a hidden sector coupled to the sterile neutrino these bounds can be evaded, opening new perspectives for the direct studies at neutrino experiments such as Troitsk ν-mass and KATRIN. We estimate the generation of sterile neutrinos in scenarios with the hidden sector dynamics keeping the sterile neutrinos either massless or superheavy in the early Universe. In both cases the generation by oscillations from active neutrinos in plasma is suppressed.

Experimental search for muon-neutrino oscillations and analysis of the simultaneous mixing of three neutrino flavors

International Nuclear Information System (INIS)

Bluemer, J.

1985-01-01

In the present thesis the experiment of the CDHS collaboration on the search for inclusive muon-neutrino oscillations is described. The event rates of ν μ reactions via charged currents was simultaneously measured in two detectors which were 130 m and 885 m away from the beam origin. The data contain no hints for oscillation effects. At maximal mixing mass differences of the contributing eigenstates are excluded in a range 0.26 ≤ Δm 2 ≤ 90 eV 2 with 90% confidence. The best sensitivity was reached for Δm 2 =2.5 eV 2 and allows there a maximal mixing parameter sin 2 2 ≤ 0.053. From the CDHS data the hitherto best limits on oscillation parameters resulted. From a common analysis of different oscillation experiments the allowed parameters for the case of simultaneous transitions between electron, muon, and tau neutrinos could be obtained. Regarding systematic uncertainties also here no evidence for oscillations exists. (orig./HSI) [de

Neutrino mass and physics beyond the Standard Model; Masse des Neutrinos et Physique au-dela du Modele Standard

Energy Technology Data Exchange (ETDEWEB)

Hosteins, P

2007-09-15

The purpose of this thesis is to study, in the neutrino sector, the flavour structures at high energy. The work is divided into two main parts. The first part is dedicated to the well known mechanism to produce small neutrino masses: the seesaw mechanism, which implies the existence of massive particles whose decays violate lepton number. Therefore this mechanism can also be used to generate a net baryon number in the early universe and explain the cosmological observation of the asymmetry between matter and antimatter. However, it is often non-trivial to fulfill the constraints coming at the same time from neutrino oscillations and cosmological experiments, at least in frameworks where the couplings can be somehow constrained, like some Grand Unification models. Therefore we devoted the first part to the study of a certain class of seesaw mechanism which can be found in the context of SO(10) theories for example. We introduce a method to extract the mass matrix of the heavy right-handed neutrinos and explore the phenomenological consequences of this quantity, mainly concerning the production of a sufficient baryon asymmetry. When trying to identify the underlying symmetry governing the mixings between the different generations, we see that there is a puzzling difference between the quark and the lepton sectors. However, the quark and lepton parameters have to be compared at the scale of the flavour symmetry breaking, therefore we have to make them run to the appropriate scale. Thus, it is worthwhile investigating models where quantum corrections allow an approximate unification of quark and lepton mixings. This is why the other part of the thesis investigates the running of the effective neutrino mass operator in models with an extra compact dimension, where quantum corrections to the neutrino masses and mixings can be potentially large due to the multiplicity of states.

Majorana mass term, Dirac neutrinos and selective neutrino oscillations

International Nuclear Information System (INIS)

Leung, C.N.

1987-01-01

In a theory of neutrino mixing via a Majorana mass term involving only the left-handed neutrinos there exist selection rules for neutrino oscillations if true Dirac and/or exactly zero mass eigenstates are present. In the case of three neutrino flavours no oscillation is allowed if the mass spectrum contains one Dirac and one nondegenerate Majorana massive neutrino. The origin of these selection rules and their implications are discussed and the number of possible CP-violating phases in the lepton mixing matrix when Dirac and Majorana mass eigenstates coexist is given. (orig.)

Identifying the neutrino mass hierarchy with supernova neutrinos

International Nuclear Information System (INIS)

Tomas, Ricard

2006-01-01

We review how a high-statistics observation of the neutrino signal from a future galactic core-collapse supernova (SN) may be used to discriminate between different neutrino mixing scenarios. We discuss two complementary methods that allow for the positive identification of the mass hierarchy without knowledge of the emitted neutrino fluxes, provided that the 13-mixing angle is large, sin 2 θ 13 -5 . These two approaches are the observation of modulations in the neutrino spectra by Earth matter effects or by the passage of shock waves through the SN envelope. If the value of the 13-mixing angle is unknown, using additionally the information encoded in the prompt neutronization ν e burst-a robust feature found in all modern SN simulations-can be sufficient to fix both the neutrino hierarchy and to decide whether θ 13 is 'small' or 'large'

On Analytic Solution of resonant Mixing for Solar Neutrino Oscillations

OpenAIRE

Masatoshi, ITO; Takao, KANEKO; Masami, NAKAGAWA; Department of Physics, Meijo University; Department of Physics, Meijo University; Department of Physics, Meijo University

1988-01-01

Behavior of resonant mixing in matter-enhancing region for solar neutrino oscillation, the Mikheyev-Smirnov-Wolfenstein mechanism, is reanalyzed by means of an analytic treatment recently proposed. We give solutions in terms of confluent hypergeometric functions, which agree with "exact" solutions of coupled differential equations.

Neutrino mass and the solar neutrino problem

International Nuclear Information System (INIS)

Wolfenstein, L.

1987-01-01

Theoretical ideas about neutrino mass based on grand-unified theories are reviewed. These give the see-saw formula in which neutrino mass is inversely proportional to a large mass scale M. For M between 10/sup 11/ and 10/sup 15/ Gev the study of solar neutrinos appears to be the best probe of neutrino masses and mixings

Measurement of theta13 with reactor neutrinos

International Nuclear Information System (INIS)

Heeger, Karsten M.; Freedman, Stuart J.; Kadel, Richard W.; Luk, Kam-Biu

2004-01-01

Recent experimental results have provided unambiguous evidence that neutrinos have a small but finite mass and mix from one type into another. The phenomenon of neutrino mixing is characterized by the coupling between the neutrino flavor (nu e,mu,tau ) and mass eigenstates (nu 1,2,3 ) and the associated mixing angles. Previous neutrino oscillation experiments have determined two of the three mixing angles in the neutrino mixing matrix, U MNSP . Using multiple neutrino detectors placed at different distances from a nuclear power plant, a future reactor neutrino experiment has the potential to discover and measure the coupling of the electron neutrino flavor to the third mass eigenstate, U e3 , the last undetermined element of the neutrino mixing matrix

Detecting supernova neutrinos in Daya Bay Neutrino Laboratory

International Nuclear Information System (INIS)

Huang Mingyang; Guo Xinheng; Yang Binglin

2011-01-01

While detecting supernova neutrinos in the Daya Bay neutrino laboratory, several supernova neutrino effects need to be considered, including the supernova shock effects, the neutrino collective effects, the Mikheyev-Smirnov-Wolfenstein (MSW) effects, and the Earth matter effects. The phenomena of neutrino oscillation is affected by the above effects. Using some ratios of the event numbers of different supernova neutrinos, we propose some possible methods to identify the mass hierarchy and acquire information about the neutrino mixing angle θ13 and neutrino masses. (authors)

Non-zero θ{sub 13} and leptonic CP phase with A{sub 4} symmetry

Energy Technology Data Exchange (ETDEWEB)

Sruthilaya, M.; Mohanta, R. [University of Hyderabad, School of Physics, Hyderabad (India)

2017-03-15

We consider a model based on A{sub 4} symmetry to explain the phenomenon of neutrino mixing. The spontaneous symmetry breaking of A{sub 4} symmetry leads to a co-bimaximal mixing matrix at leading order. We consider the effect of higher order corrections in neutrino sector and find that the mixing angles thus obtained, come well within the 3σ ranges of their experimental values. We study the implications of this formalism on the other phenomenological observables, such as CP violating phase, Jarlskog invariant and the effective Majorana mass vertical stroke M{sub ee} vertical stroke. We also obtain the branching ratio of the lepton flavour violating decay μ → eγ in the context of this model and find that it can be less than its present experimental upper bound. (orig.)

Reconstructing Neutrino Mass Spectrum

OpenAIRE

Smirnov, A. Yu.

1999-01-01

Reconstruction of the neutrino mass spectrum and lepton mixing is one of the fundamental problems of particle physics. In this connection we consider two central topics: (i) the origin of large lepton mixing, (ii) possible existence of new (sterile) neutrino states. We discuss also possible relation between large mixing and existence of sterile neutrinos.

Physical region for three-neutrino mixing angles

Science.gov (United States)

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

2005-01-01

We derive a set of symmetry relations for the three-neutrino mixing angles, including the Mikheyev-Smirnov-Wolfenstein (MSW) matter effect. Though interesting in their own right, these relations are used to choose the physical region of the mixing angles such that oscillations are parametrized completely and uniquely. We propose that the preferred way of setting the bounds on the mixing angles should be θ12∈[0,π/2], θ13∈[-π/2,π/2], θ23∈[0,π/2], and δ∈[0,π). No CP violation then results simply from setting δ=0. In the presence of the MSW effect, this choice of bounds is a new result. Since the size of the asymmetry about θ13=0 is dependent on the details of the data analysis and is a part of the results of the analysis, we argue that the negative values of θ13 should not be ignored.

Neutrino mass and physics beyond the Standard Model

International Nuclear Information System (INIS)

Hosteins, P.

2007-09-01

The purpose of this thesis is to study, in the neutrino sector, the flavour structures at high energy. The work is divided into two main parts. The first part is dedicated to the well known mechanism to produce small neutrino masses: the seesaw mechanism, which implies the existence of massive particles whose decays violate lepton number. Therefore this mechanism can also be used to generate a net baryon number in the early universe and explain the cosmological observation of the asymmetry between matter and antimatter. However, it is often non-trivial to fulfill the constraints coming at the same time from neutrino oscillations and cosmological experiments, at least in frameworks where the couplings can be somehow constrained, like some Grand Unification models. Therefore we devoted the first part to the study of a certain class of seesaw mechanism which can be found in the context of SO(10) theories for example. We introduce a method to extract the mass matrix of the heavy right-handed neutrinos and explore the phenomenological consequences of this quantity, mainly concerning the production of a sufficient baryon asymmetry. When trying to identify the underlying symmetry governing the mixings between the different generations, we see that there is a puzzling difference between the quark and the lepton sectors. However, the quark and lepton parameters have to be compared at the scale of the flavour symmetry breaking, therefore we have to make them run to the appropriate scale. Thus, it is worthwhile investigating models where quantum corrections allow an approximate unification of quark and lepton mixings. This is why the other part of the thesis investigates the running of the effective neutrino mass operator in models with an extra compact dimension, where quantum corrections to the neutrino masses and mixings can be potentially large due to the multiplicity of states

Higgs mass from neutrino-messenger mixing

International Nuclear Information System (INIS)

Byakti, Pritibhajan; Khosa, Charanjit K.; Mummidi, V.S.; Vempati, Sudhir K.

2017-01-01

The discovery of the Higgs particle at 125 GeV has put strong constraints on minimal messenger models of gauge mediation, pushing the stop masses into the multi-TeV regime. Extensions of these models with matter-messenger mixing terms have been proposed to generate a large trilinear parameter, A t , relaxing these constraints. The detailed survey of these models (DOI: 10.1007/JHEP05(2013)055; 10.1007/JHEP08(2013)093 ) so far considered messenger mixings with only MSSM superfields. In the present work, we extend the survey to MSSM with inverse-seesaw mechanism. The neutrino-sneutrino corrections to the Higgs mass in the inverse seesaw model are not significant in the minimal gauge mediation model, unless one considers messenger-matter interaction terms. We classify all possible models with messenger-matter interactions and perform thorough numerical analysis to find out the promising models. We found that out of the 17 possible models 9 of them can lead to Higgs mass within the observed value without raising the sfermion masses significantly. The successful models have stop masses ∼1.5 TeV with small or negligible mixing and yet a light CP even Higgs at 125 GeV.

Acquiring information about neutrino parameters by detecting supernova neutrinos

Science.gov (United States)

Huang, Ming-Yang; Guo, Xin-Heng; Young, Bing-Lin

2010-08-01

We consider the supernova shock effects, the Mikheyev-Smirnov-Wolfenstein effects, the collective effects, and the Earth matter effects in the detection of type II supernova neutrinos on the Earth. It is found that the event number of supernova neutrinos depends on the neutrino mass hierarchy, the neutrino mixing angle θ13, and neutrino masses. Therefore, we propose possible methods to identify the mass hierarchy and acquire information about θ13 and neutrino masses by detecting supernova neutrinos. We apply these methods to some current neutrino experiments.

Solar neutrino spectrum, sterile neutrinos and additional radiation in the Universe

International Nuclear Information System (INIS)

Holanda, Pedro Cunha de

2011-01-01

Full text: Recent results from the SNO, Super-Kamiokande and Borexino experiments do not show the expected upturn of the energy spectrum of events (the ratio R ≡ N obs /N SSM ) at low energies. At the same time, cosmological observations testify for possible existence of additional relativistic degrees of freedom in the early Universe: ΔN eff = 1 - 2. These facts strengthen the case of very light sterile neutrino, ν s , with Δm 0 1 2 ∼ (0.7 - 2) . 10 -5 e V 2 , which mixes weakly with the active neutrinos. The ν s mixing in the mass eigenstate ν 1 characterized by sin 2 2∝ ∼ 10 -3 can explain an absence of the upturn. The mixing of ν s in the eigenstate ν 3 with sin 2 β ∼ 0.1 leads to production of ν s via oscillations in the Universe and to additional contribution Δ N eff ∼ 0.7 -1 before the big bang nucleosynthesis and later. Such a mixing can be tested in forthcoming experiments with the atmospheric neutrinos as well as in future accelerator long baseline experiments. It has substantial impact on conversion of the supernova neutrinos. We perform a qualitative and quantitative analysis of solar neutrino data including a fourth neutrino with different mixings with the active neutrino sector.(author)

Reactor anti-neutrinos: measurement of the θ13 leptonic mixing angle and search for potential sterile neutrinos

International Nuclear Information System (INIS)

Collin, A.

2014-01-01

The Double Chooz experiment aims to measure the θ 13 mixing angle through the disappearance -induced by the oscillation phenomenon - of anti-neutrinos produced by the Chooz nuclear reactors. In order to reduce systematic uncertainties, the experiment relies on the relative comparison of detected signals in two identical liquid scintillator detectors. The near one, giving the normalization of the emitted flux, is currently being built and will be delivered in spring 2014. The far detector, sensitive to θ 13 , is located at about one kilometer and is taking data since 2011. In this first phase of the experiment, the far detector data are compared to a prediction of the emitted neutrino flux to estimate θ 13 . In this thesis, the Double Chooz experiment and its analysis are presented, especially the background studies and the rejection of parasitic signals due to light emitted by photo-multipliers. Neutron fluxes between the different detector volumes impact the definition of the fiducial volume of neutrino interactions and the efficiency of detection. Detailed studies of these effects are presented. As part of the Double Chooz experiment, studies were performed to improve the prediction of neutrino flux emitted by reactors. This work revealed a deficit of observed neutrino rates in the short baseline experiments of last decades. This deficit could be explained by an oscillation to a sterile state. The Stereo project aims to observe a typical signature of oscillations: the distortion of neutrino spectra both in energy and baseline. This thesis presents the detector concept and simulations as well as sensitivity studies. Background sources and the foreseen shielding are also discussed. (author) [fr

Solar neutrino

Energy Technology Data Exchange (ETDEWEB)

Sugimoto, D [Tokyo Univ. (Japan). Coll. of General Education

1975-01-01

The measurement of solar neutrino was performed by using the reaction /sup 37/cl+..nu..sub(e)..-->../sup 37/Ar+e/sup -/ by Davis et al. The argon gas produced through the above mentioned reaction in a tank containing 610 ton of C/sub 2/Cl/sub 4/ was collected and measured. The rate of production of /sup 37/Ar was 0.13+-0.20/day, and the net production rate by the solar neutrino was 0.06+-0.20/day, being corrected for background. This value corresponds to 0.5+-1.0 SNU. Theoretical calculation with the model of spherically symmetric solar development gave an expected value of 5.6 SNU, which is in contradiction with the experimental value. Reason of this discrepancy was considered. The possibility of decay of neutrino to the other particles with weak interaction is very slight. Various models of the sun were investigated, but the results were still inconsistent with the experiment. The mixing of matters in the sun may cause the reduction of neutrino. If He gas comes to the center of the sun by mixing, the reaction, /sup 3/He+/sup 3/He, progresses excessively at the center, and it produces the expansion of the core of the sun. Then, the temperature drops and the neutrino is reduced. Various models which can explain the neutrino of less than ISNU have been presented. However, other theory says that the reduction of neutrino is not expected even if the mixing is considered. A problem concerning the mixing is whether the thermal instability which causes the mixing exists. (Kato, T.).

Direct and semi-direct approaches to lepton mixing with a massless neutrino

International Nuclear Information System (INIS)

King, Stephen F.; Ludl, Patrick Otto

2016-01-01

We discuss the possibility of enforcing a massless Majorana neutrino in the direct and semi-direct approaches to lepton mixing, in which the PMNS matrix is partly predicted by subgroups of a discrete family symmetry, extending previous group searches up to order 1535. We find a phenomenologically viable scheme for the semi-direct approach based on Q(648) which contains Δ(27) and the quaternion group as subgroups. This leads to novel predictions for the first column of the PMNS matrix corresponding to a normal neutrino mass hierarchy with m_1=0, and sum rules for the mixing angles and phase which are characterised by the solar angle being on the low side θ_1_2∼31"∘ and the Dirac (oscillation) CP phase δ being either about ±45"∘ or ±π.

Acquire information about neutrino parameters by detecting supernova neutrinos

OpenAIRE

Huang, Ming-Yang; Guo, Xin-Heng; Young, Bing-Lin

2010-01-01

We consider the supernova shock effects, the Mikheyev-Smirnov-Wolfenstein (MSW) effects, the collective effects, and the Earth matter effects in the detection of type II supernova neutrinos on the Earth. It is found that the event number of supernova neutrinos depends on the neutrino mass hierarchy, the neutrino mixing angle $\\theta_{13}$, and neutrino masses. Therefore, we propose possible methods to identify the mass hierarchy and acquire information about $\\theta_{13}$ and neutrino masses ...

Neutrino mass matrix

International Nuclear Information System (INIS)

Strobel, E.L.

1985-01-01

Given the many conflicting experimental results, examination is made of the neutrino mass matrix in order to determine possible masses and mixings. It is assumed that the Dirac mass matrix for the electron, muon, and tau neutrinos is similar in form to those of the quarks and charged leptons, and that the smallness of the observed neutrino masses results from the Gell-Mann-Ramond-Slansky mechanism. Analysis of masses and mixings for the neutrinos is performed using general structures for the Majorana mass matrix. It is shown that if certain tentative experimental results concerning the neutrino masses and mixing angles are confirmed, significant limitations may be placed on the Majorana mass matrix. The most satisfactory simple assumption concerning the Majorana mass matrix is that it is approximately proportional to the Dirac mass matrix. A very recent experimental neutrino mass result and its implications are discussed. Some general properties of matrices with structure similar to the Dirac mass matrices are discussed

JUNO. Determination of the neutrino mass hierarchy using reactor neutrinos

Energy Technology Data Exchange (ETDEWEB)

Wonsak, Bjoern [Hamburg University, Inst. Exp. Phys., Hamburg (Germany)

2015-07-01

The Jiangmen Underground Neutrino Observatory (JUNO) is a medium-baseline reactor neutrino experiment located in China. Its aim is to determine the neutrino mass hierarchy at more than 3 sigma significance after six years of data taking by using a 20kt liquid scintillator detector. To achieve this goal, an energy resolution of less than 3%/√(E) is necessary, creating strict requirements on the detector design and the liquid scintillator. Moreover, JUNO will be the only experiment in the near future able to measure the solar mixing parameters with a precision of better than 1%. This is at the same level as our current knowledge on flavour mixing in the quark sector, marking an important milestone of neutrino physics. In addition, supernova neutrinos, geo-neutrinos, sterile neutrinos as well as solar and atmospheric neutrinos can be studied. JUNO was approved in 2013 and the construction of the underground facility started early this year. In this talk the status of the experiment and its prospects is discussed.

Neutrino mass models and CP violation

International Nuclear Information System (INIS)

Joshipura, Anjan S.

2011-01-01

Theoretical ideas on the origin of (a) neutrino masses (b) neutrino mass hierarchies and (c) leptonic mixing angles are reviewed. Topics discussed include (1) symmetries of neutrino mass matrix and their origin (2) ways to understand the observed patterns of leptonic mixing angles and (3)unified description of neutrino masses and mixing angles in grand unified theories.

Renormalization group evolution of neutrino parameters in presence of seesaw threshold effects and Majorana phases

Directory of Open Access Journals (Sweden)

Shivani Gupta

2015-04-01

Full Text Available We examine the renormalization group evolution (RGE for different mixing scenarios in the presence of seesaw threshold effects from high energy scale (GUT to the low electroweak (EW scale in the Standard Model (SM and Minimal Supersymmetric Standard Model (MSSM. We consider four mixing scenarios namely Tri–Bimaximal Mixing, Bimaximal Mixing, Hexagonal Mixing and Golden Ratio Mixing which come from different flavor symmetries at the GUT scale. We find that the Majorana phases play an important role in the RGE running of these mixing patterns along with the seesaw threshold corrections. We present a comparative study of the RGE of all these mixing scenarios both with and without Majorana CP phases when seesaw threshold corrections are taken into consideration. We find that in the absence of these Majorana phases both the RGE running and seesaw effects may lead to θ13<5° at low energies both in the SM and MSSM. However, if the Majorana phases are incorporated into the mixing matrix the running can be enhanced both in the SM and MSSM. Even by incorporating non-zero Majorana CP phases in the SM, we do not get θ13 in its present 3σ range. The current values of the two mass squared differences and mixing angles including θ13 can be produced in the MSSM case with tan⁡β=10 and non-zero Majorana CP phases at low energy. We also calculate the order of effective Majorana mass and Jarlskog Invariant for each scenario under consideration.

Self-induced neutrino flavor conversion without flavor mixing

International Nuclear Information System (INIS)

Chakraborty, S.; Izaguirre, I.; Raffelt, G.G.; Hansen, R. S.

2016-01-01

Neutrino-neutrino refraction in dense media can cause self-induced flavor conversion triggered by collective run-away modes of the interacting flavor oscillators. The growth rates were usually found to be of order a typical vacuum oscillation frequency Δ m 2 /2E. However, even in the simple case of a ν e beam interacting with an opposite-moving ν-bar e beam, and allowing for spatial inhomogeneities, the growth rate of the fastest-growing Fourier mode is of order μ=√2 G F  n ν , a typical ν–ν interaction energy. This growth rate is much larger than the vacuum oscillation frequency and gives rise to flavor conversion on a much shorter time scale. This phenomenon of 'fast flavor conversion' occurs even for vanishing Δ m 2 /2E and thus does not depend on energy, but only on the angle distributions. Moreover, it does not require neutrinos to mix or to have masses, except perhaps for providing seed disturbances. We also construct a simple homogeneous example consisting of intersecting beams and study a schematic supernova model proposed by Ray Sawyer, where ν e and ν-bar e emerge with different zenith-angle distributions, the key ingredient for fast flavor conversion. What happens in realistic astrophysical scenarios remains to be understood

Soft A4 → Z3 symmetry breaking and cobimaximal neutrino mixing

Science.gov (United States)

Ma, Ernest

2016-04-01

I propose a model of radiative charged-lepton and neutrino masses with A4 symmetry. The soft breaking of A4 to Z3 lepton triality is accomplished by dimension-three terms. The breaking of Z3 by dimension-two terms allows cobimaximal neutrino mixing (θ13 ≠ 0, θ23 = π / 4, δCP = ± π / 2) to be realized with only very small finite calculable deviations from the residual Z3 lepton triality. This construction solves a long-standing technical problem inherent in renormalizable A4 models since their inception.

Limits on heavy neutrino mixing from the beta decay of 38mK confined in a magneto-optical trap

International Nuclear Information System (INIS)

Trinczek, M.C.

2001-01-01

This thesis details the search for mixing between electron neutrinos and possible heavy neutrinos using the positron decay of 38m K produced at ISAC, TRIUMF's new radioactive beam facility. Using the novel technique of laser atom trapping to confine 38m K, direct limits on such mixing in β-decay are determined for the mass range of 0.7 MeV/c 2 to 3.8 MeV/c 2 . The results, for part of this mass range, provide the best direct limits for the mixing of heavy neutrinos with the electron neutrino in the literature to date. The Standard Model of electroweak physics has been able to describe a wide range of experimental results, but an unresolved question arises in accounting for lepton masses. The charged leptons (electrons, muons and taus) have masses which vary enormously from one to another (m e = 0.511 MeV/c 2 , m μ = 106 MeV/c 2 , m τ = 1777 MeV/c 2 ), while their accompanying neutrinos appear to have no (or very little) mass. If neutrinos have finite mass, then mixing could occur among the different neutrino species. Thus, evidence of mixing would indicate the existence of non-zero neutrino mass and of the need to modify or extend the Standard Model. Consequently, this is a highly active field of physics. Evidence of possible neutrino mass and oscillation has been recently observed by the detection of energetic neutrinos from the atmosphere. The TRINAT collaboration at TRIUMF has searched for evidence of physics beyond the Standard Model using a radioactive source of 38m K atoms held in a neutral atom trap. The trap provides a source of several thousand atoms confined to a volume of less than a cubic millimeter, suspended in a vacuum vessel, in which the 38m K undergoes radioactive decay with the emission of a positron and a neutrino. This results in the creation of a daughter nucleus, 38 Ar , with momentum equal to the vector sum of the momenta of the positron and the neutrino. The unperturbed nucleus then recoils from the trap and is detected in coincidence

Higgs mass from neutrino-messenger mixing

Energy Technology Data Exchange (ETDEWEB)

Byakti, Pritibhajan [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India); Department of Theoretical Physics, Indian Association for the Cultivation of Science,2A & 2B Raja S.C. Mullick Road, Kolkata 700 032 (India); Khosa, Charanjit K. [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India); Mummidi, V.S. [Harish-Chandra Research Institute,Chhatnag Road, Jhusi, Allahabad 211019 (India); Vempati, Sudhir K. [Center for High Energy Physics, Indian Institute of Science,C.V. Raman Ave, Bangalore 560012 (India)

2017-03-06

The discovery of the Higgs particle at 125 GeV has put strong constraints on minimal messenger models of gauge mediation, pushing the stop masses into the multi-TeV regime. Extensions of these models with matter-messenger mixing terms have been proposed to generate a large trilinear parameter, A{sub t}, relaxing these constraints. The detailed survey of these models (DOI: 10.1007/JHEP05(2013)055; 10.1007/JHEP08(2013)093 ) so far considered messenger mixings with only MSSM superfields. In the present work, we extend the survey to MSSM with inverse-seesaw mechanism. The neutrino-sneutrino corrections to the Higgs mass in the inverse seesaw model are not significant in the minimal gauge mediation model, unless one considers messenger-matter interaction terms. We classify all possible models with messenger-matter interactions and perform thorough numerical analysis to find out the promising models. We found that out of the 17 possible models 9 of them can lead to Higgs mass within the observed value without raising the sfermion masses significantly. The successful models have stop masses ∼1.5 TeV with small or negligible mixing and yet a light CP even Higgs at 125 GeV.

Monochromatic neutrino beams

International Nuclear Information System (INIS)

Bernabeu, Jose; Burguet-Castell, Jordi; Espinoza, Catalina; Lindroos, Mats

2005-01-01

In the last few years spectacular results have been achieved with the demonstration of non vanishing neutrino masses and flavour mixing. The ultimate goal is the understanding of the origin of these properties from new physics. In this road, the last unknown mixing [U e3 ] must be determined. If it is proved to be non-zero, the possibility is open for Charge Conjugation-Parity (CP) violation in the lepton sector. This will require precision experiments with a very intense neutrino source. Here a novel method to create a monochromatic neutrino beam, an old dream for neutrino physics, is proposed based on the recent discovery of nuclei that decay fast through electron capture. Such nuclei will generate a monochromatic directional neutrino beam when decaying at high energy in a storage ring with long straight sections. We also show that the capacity of such a facility to discover new physics is impressive, so that fine tuning of the boosted neutrino energy allows precision measurements of the oscillation parameters even for a [U e3 ] mixing as small as 1 degree. We can thus open a window to the discovery of CP violation in neutrino oscillations

Solar neutrino masses and mixing from bilinear R-parity broken supersymmetry: Analytical versus numerical results

Science.gov (United States)

Díaz, M.; Hirsch, M.; Porod, W.; Romão, J.; Valle, J.

2003-07-01

We give an analytical calculation of solar neutrino masses and mixing at one-loop order within bilinear R-parity breaking supersymmetry, and compare our results to the exact numerical calculation. Our method is based on a systematic perturbative expansion of R-parity violating vertices to leading order. We find in general quite good agreement between the approximate and full numerical calculations, but the approximate expressions are much simpler to implement. Our formalism works especially well for the case of the large mixing angle Mikheyev-Smirnov-Wolfenstein solution, now strongly favored by the recent KamLAND reactor neutrino data.

Neutrino mass and mixing, and non-accelerator experiments

International Nuclear Information System (INIS)

Robertson, R.G.H.

1992-01-01

We review the current status of experimental knowledge about neutrinos derived from kinematic mass measurements, neutrino oscillation searches at reactors and accelerators, solar neutrinos, atmospheric neutrinos, and single and double beta decay. The solar neutrino results yield fairly strong and consistent indication that neutrino oscillations are occurring. Other evidence for new physics is less consistent and convincing

The experimental status of neutrino masses and mixings

International Nuclear Information System (INIS)

Robertson, R.G.H.

1992-01-01

We review the current status of experimental knowledge about neutrinos derived from kinematic mass measurements, neutrino oscillation searches at reactors and accelerators, solar neutrinos, atmospheric neutrinos, and single and double beta decay. The solar neutrino results yield fairly strong and consistent indications that neutrino oscillations are occurring. Other evidence for new physics is less consistent and convincing

Homestake result, sterile neutrinos, and low energy solar neutrino experiments

Science.gov (United States)

de Holanda, P. C.; Smirnov, A. Yu.

2004-06-01

The Homestake result is about ˜2σ lower than the Ar-production rate, QAr, predicted by the large mixing angle (LMA) Mikheyev-Smirnov-Wolfenstein solution of the solar neutrino problem. Also there is no apparent upturn of the energy spectrum (R≡Nobs/NSSM) at low energies in SNO and Super-Kamiokande. Both these facts can be explained if a light, Δm201˜(0.2 2)×10-5 eV2, sterile neutrino exists which mixes very weakly with active neutrinos: sin2 2α˜(10-5 10-3). We perform both the analytical and numerical study of the conversion effects in the system of two active neutrinos with the LMA parameters and one weakly mixed sterile neutrino. The presence of sterile neutrino leads to a dip in the survival probability in the intermediate energy range E=(0.5 5) MeV thus suppressing the Be, or/and pep, CNO, as well as B electron neutrino fluxes. Apart from diminishing QAr it leads to decrease of the Ge-production rate and may lead to the decrease of the BOREXINO signal as well as the CC/NC ratio at SNO. Future studies of the solar neutrinos by SNO, SK, BOREXINO, and KamLAND as well as by the new low energy experiments will allow us to check this possibility.

Neutrino mass?

International Nuclear Information System (INIS)

Kayser, B.

1992-01-01

After arguing that we should be looking for evidence of neutrino mass, we illustrate the possible consequences of neutrino mass and mixing. We then turn to the question of whether neutrinos are their own antiparticles, and to the process which may answer this question: neutrinoless double beta decay. Next, we review the proposed Mikheyev-Smirnov-Wolfenstein solution to the solar neutrino problem, and discuss models which can generate neutrino electromagnetic moments large enough to play a role in the sun. Finally, we consider how the possible 17 keV neutrino, if real, would fit in with everything we know about neutrinos. (orig.)

Understanding neutrino masses and mixings

Indian Academy of Sciences (India)

various possible oscillation solutions to the solar neutrino puzzle. It seems .... A first hint of this new ingredient came from the observation of Weinberg that if ..... Using the discussion of the above paragraph, the Dirac mass of the neutrino as .... that contributes to charged fermion masses, one can write the quark and lepton.

Updated fit to three neutrino mixing: exploring the accelerator-reactor complementarity

International Nuclear Information System (INIS)

Esteban, Ivan; Gonzalez-Garcia, M.C.; Maltoni, Michele; Martinez-Soler, Ivan; Schwetz, Thomas

2017-01-01

We perform a combined fit to global neutrino oscillation data available as of fall 2016 in the scenario of three-neutrino oscillations and present updated allowed ranges of the six oscillation parameters. We discuss the differences arising between the consistent combination of the data samples from accelerator and reactor experiments compared to partial combinations. We quantify the confidence in the determination of the less precisely known parameters θ 23 , δ CP , and the neutrino mass ordering by performing a Monte Carlo study of the long baseline accelerator and reactor data. We find that the sensitivity to the mass ordering and the θ 23 octant is below 1σ. Maximal θ 23 mixing is allowed at slightly more than 90% CL. The best fit for the CP violating phase is around 270 ∘ , CP conservation is allowed at slightly above 1σ, and values of δ CP ≃90 ∘ are disfavored at around 99% CL for normal ordering and higher CL for inverted ordering.

Global Analysis of Neutrino Data

CERN Document Server

González-Garciá, M C

2005-01-01

In this talk I review the present status of neutrino masses and mixing and some of their implications for particle physics phenomenology. I first discuss the minimum extension of the Standard Model of particle physics required to accommodate neutrino masses and introduce the new parameters present in the model and in particular the possibility of leptonic mixing. I then describe the phenomenology of neutrino masses and mixing leading to flavour oscillations and present the existing evidence from solar, reactor, atmospheric and long-baseline neutrinos as well as the results from laboratory searches at short distances. I derive the allowed ranges for the mass and mixing parameters when the bulk of data is consistently analyzed in the framework of mixing between the three active neutrinos and obtain as a result the most up-to-date determination of the leptonic mixing matrix. Then I briefly summarize the status of some proposed phenomenological explanations to accommodate the LSND results: the role of sterile neu...

Neutrino mass spectrum with υμ → υs oscillations of atmospheric neutrinos

International Nuclear Information System (INIS)

Liu, Q.Y.; Smirnov, A.Yu.

1998-02-01

We consider the ''standard'' spectrum of the active neutrinos (characterized by strong mass hierarchy and small mixing) with additional sterile, υ s . The sterile neutrino mixes strongly with the muon neutrino, so that υ μ ↔ υ s oscillations solve the atmospheric neutrino problem. We show that the parametric enhancement of the υ μ ↔ υ s oscillations occurs for the high energy atmospheric neutrinos which cross the core of the Earth. This can be relevant for the anomaly observed by the MACRO experiment. Solar neutrinos are converted both to υ μ and υ s . The heaviest neutrino (approx. υ τ ) may compose the hot dark matter of the Universe. Phenomenology of this scenario is elaborated and crucial experimental signatures are identified. We also discuss properties of the underlying neutrino mass matrix. (author)

The effect of random matter density perturbations on the large mixing angle solution to the solar neutrino problem

Science.gov (United States)

Guzzo, M. M.; Holanda, P. C.; Reggiani, N.

2003-08-01

The neutrino energy spectrum observed in KamLAND is compatible with the predictions based on the Large Mixing Angle realization of the MSW (Mikheyev-Smirnov-Wolfenstein) mechanism, which provides the best solution to the solar neutrino anomaly. From the agreement between solar neutrino data and KamLAND observations, we can obtain the best fit values of the mixing angle and square difference mass. When doing the fitting of the MSW predictions to the solar neutrino data, it is assumed the solar matter do not have any kind of perturbations, that is, it is assumed the the matter density monothonically decays from the center to the surface of the Sun. There are reasons to believe, nevertheless, that the solar matter density fluctuates around the equilibrium profile. In this work, we analysed the effect on the Large Mixing Angle parameters when the density matter randomically fluctuates around the equilibrium profile, solving the evolution equation in this case. We find that, in the presence of these density perturbations, the best fit values of the mixing angle and the square difference mass assume smaller values, compared with the values obtained for the standard Large Mixing Angle Solution without noise. Considering this effect of the random perturbations, the lowest island of allowed region for KamLAND spectral data in the parameter space must be considered and we call it very-low region.

Anti-neutrino imprint in solar neutrino flare

Science.gov (United States)

Fargion, D.

2006-10-01

A future neutrino detector at megaton mass might enlarge the neutrino telescope thresholds revealing cosmic supernova background and largest solar flares (SFs) neutrinos. Indeed the solar energetic (Ep>100 MeV) flare particles (protons, α), while scattering among themselves on solar corona atmosphere must produce prompt charged pions, whose chain decays are source of a solar (electron muon) neutrino 'flare' (at tens or hundreds MeV energy). These brief (minutes) neutrino 'bursts' at largest flare peak may overcome by three to five orders of magnitude the steady atmospheric neutrino noise on the Earth, possibly leading to their detection above detection thresholds (in a full mixed three flavour state). Moreover the birth of anti-neutrinos at a few tens of MeV very clearly flares above a null thermal 'hep' anti-neutrino solar background and also above a tiny supernova relic and atmospheric noise. The largest prompt solar anti-neutrino 'burst' may be well detected in future Super Kamikande (gadolinium implemented) anti-neutrino \\bar\

Neutrino physics present and future

CERN Multimedia

CERN. Geneva

2006-01-01

Our understanding of neutrinos has been revolutionized by the discovery that they have nonzero masses and very large mixing. We will explain the phenomenology of massive neutrinos, including neutrino oscillation in vacuum and in matter, and the physics of neutrinos that are their own antiparticles. We will review the evidence for neutrino masses and mixing, and summarize what has been learned about the neutrinos so far. Identifying the very interesting open questions raised by the discovery of neutrino mass, we will discuss how these questions may be answered through future experiments. Finally, we will consider the possibility that CP violation by neutrinos is the key to understanding the matter-antimatter asymmetry of the universe, and discuss the see-saw theory of why neutrino masses are so tiny.

Neutrino magnetic moments and the solar neutrino problem

Energy Technology Data Exchange (ETDEWEB)

Akhmedov, E.Kh. [Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory]|[Valencia Univ. (Spain). Dept. de Fisica Teorica

1994-08-01

Present status of the neutrino magnetic moment solutions of the solar neutrino problem is reviewed. In particular, we discuss a possibility of reconciling different degrees of suppression and time variation of the signal (or lack of such a variation) observed in different solar neutrino experiments. It is shown that the resonant spin-flavor precession of neutrinos due to the interaction of their transitions magnetic moments with solar magnetic field can account for all the available solar neutrino data. For not too small neutrino mixing angles (sin 2{theta}{sub o} {approx_gt} 0.2 the combined effect of the resonant spin-flavor precession and neutrino oscillations can result in an observable flux of solar {bar {nu}}{sub e}`s.

Neutrino magnetic moments and the solar neutrino problem

International Nuclear Information System (INIS)

Akhmedov, E.Kh.; Valencia Univ.

1994-01-01

Present status of the neutrino magnetic moment solutions of the solar neutrino problem is reviewed. In particular, we discuss a possibility of reconciling different degrees of suppression and time variation of the signal (or lack of such a variation) observed in different solar neutrino experiments. It is shown that the resonant spin-flavor precession of neutrinos due to the interaction of their transitions magnetic moments with solar magnetic field can account for all the available solar neutrino data. For not too small neutrino mixing angles (sin 2θ o approx-gt 0.2 the combined effect of the resonant spin-flavor precession and neutrino oscillations can result in an observable flux of solar bar ν e 's

Results from neutrino experiments

International Nuclear Information System (INIS)

Smirnov, A.Yu.

1993-11-01

Recent (first or/and the best) results from the neutrino experiments are reviewed and their implications for the theory are discussed. The sense of the experiments is the searching for neutrino masses, mixing and interactions beyond the standard model. Present laboratory experiments give upper bounds on the masses and the mixing which are at the level of predictions of the ''electroweak see-saw''. Positive indications of nonzero lepton mixing follow from studies of the solar and atmospheric neutrinos. (author). 95 refs, 11 figs

Neutrino physics

CERN Document Server

Hernandez, P.

2016-01-01

This is the writeup of the lectures on neutrino physics delivered at various schools: TASI and Trieste in 2013 and the CERN-Latin American School in 2015. The topics discussed in this lecture include: general properties of neutrinos in the SM, the theory of neutrino masses and mixings (Dirac and Majorana), neutrino oscillations both in vacuum and in matter, as well as an overview of the experimental evidence for neutrino masses and of the prospects in neutrino oscillation physics. We also briefly review the relevance of neutri- nos in leptogenesis and in beyond-the-Standard-Model physics.

Heavy neutrino mixing in the T2HK, the T2HKK and an extension of the T2HK with a detector at Oki Islands

International Nuclear Information System (INIS)

Abe, Yugo; Asano, Yusuke; Haba, Naoyuki; Yamada, Toshifumi

2017-01-01

We study the discovery potential for the mixing of heavy isospin-singlet neutrinos in extensions of the Tokai-to-Kamioka (T2K) experiment, the Tokai-to-Hyper-Kamiokande (T2HK), the Tokai-to-Hyper-Kamiokande-to-Korea (T2HKK) with a Korea detector with ≅ 1000 km baseline length and 1 circle off-axis angle, and a plan of adding a small detector at Oki Islands to the T2HK. We further pursue the possibility of measuring the neutrino mass hierarchy and the standard CP-violating phase δ CP in the presence of heavy neutrino mixing by fitting data with the standard oscillation parameters only. We show that the sensitivity to heavy neutrino mixing is highly dependent on δ CP and new CP-violating phases in the heavy neutrino mixing matrix, and deteriorates considerably when these phases conspire to suppress interference between the standard oscillation amplitude and an amplitude arising from heavy neutrino mixing, at the first oscillation peak. Although this suppression is avoided by the use of a beam with smaller off-axis angle, the T2HKK and the T2HK+small Oki detector do not show improvement over the T2HK. As for the mass hierarchy measurement, the wrong mass hierarchy is possibly favored in the T2HK because heavy neutrino mixing can mimic matter effects. In contrast, the T2HKK and the T2HK+small Oki detector are capable of correctly measuring the mass hierarchy despite heavy neutrino mixing, as measurements with different baselines resolve degeneracy between heavy neutrino mixing and matter effects. Notably, adding a small detector at Oki to the T2HK drastically ameliorates the sensitivity, which is the central appeal of this paper. As for the δ CP measurement, there can be a sizable discrepancy between the true δ CP and the value obtained by fitting data with the standard oscillation parameters only, which can be comparable to 1σ resolution of the δ CP measurement. Hence, if a hint of heavy neutrino mixing is discovered, it is necessary to incorporate the effects

Heavy neutrino mixing in the T2HK, the T2HKK and an extension of the T2HK with a detector at Oki Islands

Energy Technology Data Exchange (ETDEWEB)

Abe, Yugo [Shimane University, Graduate School of Science and Engineering, Matsue (Japan); Miyakonojo College, National Institute of Technology, Miyakonojo-shi Miyazaki (Japan); Asano, Yusuke; Haba, Naoyuki; Yamada, Toshifumi [Shimane University, Graduate School of Science and Engineering, Matsue (Japan)

2017-12-15

We study the discovery potential for the mixing of heavy isospin-singlet neutrinos in extensions of the Tokai-to-Kamioka (T2K) experiment, the Tokai-to-Hyper-Kamiokande (T2HK), the Tokai-to-Hyper-Kamiokande-to-Korea (T2HKK) with a Korea detector with ≅ 1000 km baseline length and 1 {sup circle} off-axis angle, and a plan of adding a small detector at Oki Islands to the T2HK. We further pursue the possibility of measuring the neutrino mass hierarchy and the standard CP-violating phase δ{sub CP} in the presence of heavy neutrino mixing by fitting data with the standard oscillation parameters only. We show that the sensitivity to heavy neutrino mixing is highly dependent on δ{sub CP} and new CP-violating phases in the heavy neutrino mixing matrix, and deteriorates considerably when these phases conspire to suppress interference between the standard oscillation amplitude and an amplitude arising from heavy neutrino mixing, at the first oscillation peak. Although this suppression is avoided by the use of a beam with smaller off-axis angle, the T2HKK and the T2HK+small Oki detector do not show improvement over the T2HK. As for the mass hierarchy measurement, the wrong mass hierarchy is possibly favored in the T2HK because heavy neutrino mixing can mimic matter effects. In contrast, the T2HKK and the T2HK+small Oki detector are capable of correctly measuring the mass hierarchy despite heavy neutrino mixing, as measurements with different baselines resolve degeneracy between heavy neutrino mixing and matter effects. Notably, adding a small detector at Oki to the T2HK drastically ameliorates the sensitivity, which is the central appeal of this paper. As for the δ{sub CP} measurement, there can be a sizable discrepancy between the true δ{sub CP} and the value obtained by fitting data with the standard oscillation parameters only, which can be comparable to 1σ resolution of the δ{sub CP} measurement. Hence, if a hint of heavy neutrino mixing is discovered, it is

Non-unitary neutrino propagation from neutrino decay

Energy Technology Data Exchange (ETDEWEB)

Berryman, Jeffrey M., E-mail: jeffreyberryman2012@u.northwestern.edu [Northwestern University, Department of Physics & Astronomy, 2145 Sheridan Road, Evanston, IL 60208 (United States); Gouvêa, André de; Hernández, Daniel [Northwestern University, Department of Physics & Astronomy, 2145 Sheridan Road, Evanston, IL 60208 (United States); Oliveira, Roberto L.N. [Northwestern University, Department of Physics & Astronomy, 2145 Sheridan Road, Evanston, IL 60208 (United States); Instituto de Física Gleb Wataghin Universidade Estadual de Campinas, UNICAMP 13083-970, Campinas, São Paulo (Brazil)

2015-03-06

Neutrino propagation in space-time is not constrained to be unitary if very light states – lighter than the active neutrinos – exist into which neutrinos may decay. If this is the case, neutrino flavor-change is governed by a handful of extra mixing and “oscillation” parameters, including new sources of CP-invariance violation. We compute the transition probabilities in the two- and three-flavor scenarios and discuss the different phenomenological consequences of the new physics. These are qualitatively different from other sources of unitarity violation discussed in the literature.

Non-unitary neutrino propagation from neutrino decay

International Nuclear Information System (INIS)

Berryman, Jeffrey M.; Gouvêa, André de; Hernández, Daniel; Oliveira, Roberto L.N.

2015-01-01

Neutrino propagation in space-time is not constrained to be unitary if very light states – lighter than the active neutrinos – exist into which neutrinos may decay. If this is the case, neutrino flavor-change is governed by a handful of extra mixing and “oscillation” parameters, including new sources of CP-invariance violation. We compute the transition probabilities in the two- and three-flavor scenarios and discuss the different phenomenological consequences of the new physics. These are qualitatively different from other sources of unitarity violation discussed in the literature

Updated determination of the solar neutrino fluxes from solar neutrino data

Energy Technology Data Exchange (ETDEWEB)

Bergström, Johannes [Departament d’Estructura i Constituents de la Matèria and Institut de Ciencies del Cosmos,Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Gonzalez-Garcia, M. C. [Departament d’Estructura i Constituents de la Matèria and Institut de Ciencies del Cosmos,Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Institució Catalana de Recerca i Estudis Avançats (ICREA) (Spain); C.N. Yang Institute for Theoretical Physics,State University of New York at Stony Brook, Stony Brook, NY 11794-3840 (United States); Maltoni, Michele [Instituto de Física Teórica UAM/CSIC,Calle de Nicolás Cabrera 13-15, Universidad Autónoma de Madrid,Cantoblanco, E-28049 Madrid (Spain); Peña-Garay, Carlos [Instituto de Física Corpuscular (IFIC), CSIC and Universitat de Valencia,Calle Catedrático José Beltrán, 2, E-46090 Paterna, Valencia (Spain); Serenelli, Aldo M. [Institut de Ciencies de l’Espai (ICE-CSIC/IEEC),Campus UAB, Carrer de Can Magrans s/n, 08193 Cerdanyola del Valls (Spain); Song, Ningqiang [C.N. Yang Institute for Theoretical Physics,State University of New York at Stony Brook, Stony Brook, NY 11794-3840 (United States)

2016-03-18

We present an update of the determination of the solar neutrino fluxes from a global analysis of the solar and terrestrial neutrino data in the framework of three-neutrino mixing. Using a Bayesian analysis we reconstruct the posterior probability distribution function for the eight normalization parameters of the solar neutrino fluxes plus the relevant masses and mixing, with and without imposing the luminosity constraint. We then use these results to compare the description provided by different Standard Solar Models. Our results show that, at present, both models with low and high metallicity can describe the data with equivalent statistical agreement. We also argue that even with the present experimental precision the solar neutrino data have the potential to improve the accuracy of the solar model predictions.

Neutrino-oscillation search with cosmic-ray neutrinos

International Nuclear Information System (INIS)

Ayres, D.S.; Cortez, B.; Gaisser, T.K.; Mann, A.K.; Shrock, R.E.; Sulak, L.R.

1984-01-01

A sensitive search for neutrino oscillations involving ν/sub e/, ν/sub μ/, and ν/sub tau/ may be provided by measurements of the ratio of the total interaction rates of upward- and downward-going cosmic-ray neutrinos within a massive (approx.10 kton) detector. Assuming mixing between all pairs of ν/sub e/, ν/sub μ/, and ν/sub tau/, the experiment is capable of observing time-averaged probabilities /sub t/ and /sub t/ of magnitude set by mixing strengths corresponding to, e.g., the d- to s-quark mixing strength, and of reaching the limit Δm/sub i/j 2 equivalentVertical Barm/sub i/ 2 -m/sub j/ 2 Vertical Barroughly-equal10 -4 eV 2 , where m/sub i/, and m/sub j/ are neutrino mass eigenstates, and P/sub e/tau and P/sub mutau/ are the probabilities for ν/sub e/ and ν/sub μ/, respectively, to oscillate into ν/sub tau/ after traversing a distance Lroughly-equal diameter of the Earth. Possible ambiguities may be resolved through comparison of the ratios N/sub e//N/sub μ/ for the upward- and downward-going neutrinos

Sterile neutrino

International Nuclear Information System (INIS)

Anon.

2007-01-01

Paper deals with the information on the occurrence of the fields of the sterile neutrinos (the righthanded ones) mixed with the normal neutrinos (the lefthanded ones). Both the Max Plank Radioastronomy Institute and the Los Angeles University assumes that the occurrence of the keV mass sterile neutrinos may explain the dark matter nature, the fast rotation of the observed pulsars and the reionization processes. The issues associated with the possibility to record the sterile neutrinos were analyzed in the course of the Sterile Neutrinos in Astrophysics and Cosmology Workshop (Crans Montana, March 2006 [ru

The KASKA project - a Japanese medium-baseline reactor-neutrino oscillation experiment to measure the mixing angle $\\theta_{13}$ -

OpenAIRE

Kuze, Masahiro; Collaboration, for the KASKA

2005-01-01

A new reactor-neutrino oscillation experiment, KASKA, is proposed to measure the unknown neutrino-mixing angle $\\theta_{13}$ using the world's most powerful Kashiwazaki-Kariwa nuclear power station. It will measure a very small deficit of reactor-neutrino flux using three identical detectors, two placed just close to the sources and one at a distance of about 1.8km. Its conceptual design and physics reach are discussed.

Updated fit to three neutrino mixing: exploring the accelerator-reactor complementarity

Energy Technology Data Exchange (ETDEWEB)

Esteban, Ivan [Departament de Fisíca Quàntica i Astrofísica and Institut de Ciencies del Cosmos,Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Gonzalez-Garcia, M.C. [Departament de Fisíca Quàntica i Astrofísica and Institut de Ciencies del Cosmos,Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Institució Catalana de Recerca i Estudis Avançats (ICREA),Pg. Lluis Companys 23, 08010 Barcelona (Spain); C.N. Yang Institute for Theoretical Physics, State University of New York at Stony Brook,Stony Brook, NY 11794-3840 (United States); Maltoni, Michele; Martinez-Soler, Ivan [Instituto de Física Teórica UAM/CSIC, Universidad Autónoma de Madrid,Calle de Nicolás Cabrera 13-15, Cantoblanco, E-28049 Madrid (Spain); Schwetz, Thomas [Institut für Kernphysik, Karlsruher Institut für Technologie (KIT),D-76021 Karlsruhe (Germany)

2017-01-20

We perform a combined fit to global neutrino oscillation data available as of fall 2016 in the scenario of three-neutrino oscillations and present updated allowed ranges of the six oscillation parameters. We discuss the differences arising between the consistent combination of the data samples from accelerator and reactor experiments compared to partial combinations. We quantify the confidence in the determination of the less precisely known parameters θ{sub 23}, δ{sub CP}, and the neutrino mass ordering by performing a Monte Carlo study of the long baseline accelerator and reactor data. We find that the sensitivity to the mass ordering and the θ{sub 23} octant is below 1σ. Maximal θ{sub 23} mixing is allowed at slightly more than 90% CL. The best fit for the CP violating phase is around 270{sup ∘}, CP conservation is allowed at slightly above 1σ, and values of δ{sub CP}≃90{sup ∘} are disfavored at around 99% CL for normal ordering and higher CL for inverted ordering.

The neutrino factory beam and experiments

CERN Document Server

Blondel, A; Campanelli, M; Cervera-Villanueva, Anselmo; Cline, David B; Collot, J; De Jong, M; Donini, Andrea; Dydak, Friedrich; Edgecock, R; Gavela-Legazpi, Maria Belen; Gómez-Cadenas, J J; González-Garciá, M Concepción; Gruber, P M; Harris, D A; Hernández, Pilar; Kuno, Y; Litchfield, P J; McFarland, K; Mena, O; Migliozzi, P; Palladino, Vittorio; Panman, J; Papadopoulos, I M; Para, A; Peña-Garay, C; Pérez, P; Rigolin, Stefano; Romanino, Andrea; Rubbia, André; Strolin, P; Wojcicki, S G

2000-01-01

The discovery of neutrino oscillations marks a major milestone in the history of neutrino physics, and opens a new window to the still mysterious origin of masses and flavour-mixing. Many current and forthcoming experiments will answer open questions; however, a major step forward, up to and possibly including CP violation in the neutrino-mixing matrix, requires the neutrino beams from a \

Neutrino mixing and masses in SO(10) GUTs with hidden sector and flavor symmetries

Energy Technology Data Exchange (ETDEWEB)

Chu, Xiaoyong [International Centre for Theoretical Physics,Strada Costiera 11, I-34100 Trieste (Italy); Smirnov, Alexei Yu. [Max-Planck-Institute for Nuclear Physics,Saupfercheckweg 1, D-69117 Heidelberg (Germany); International Centre for Theoretical Physics,Strada Costiera 11, I-34100 Trieste (Italy)

2016-05-23

We consider the neutrino masses and mixing in the framework of SO(10) GUTs with hidden sector consisting of fermionic and bosonic SO(10) singlets and flavor symmetries. The framework allows to disentangle the CKM physics responsible for the CKM mixing and different mass hierarchies of quarks and leptons and the neutrino new physics which produces smallness of neutrino masses and large lepton mixing. The framework leads naturally to the relation U{sub PMNS}∼V{sub CKM}{sup †}U{sub 0}, where structure of U{sub 0} is determined by the flavor symmetry. The key feature of the framework is that apart from the Dirac mass matrices m{sub D}, the portal mass matrix M{sub D} and the mass matrix of singlets M{sub S} are also involved in generation of the lepton mixing. This opens up new possibilities to realize the flavor symmetries and explain the data. Using A{sub 4}×Z{sub 4} as the flavor group, we systematically explore the flavor structures which can be obtained in this framework depending on field content and symmetry assignments. We formulate additional conditions which lead to U{sub 0}∼U{sub TBM} or U{sub BM}. They include (i) equality (in general, proportionality) of the singlet flavons couplings, (ii) equality of their VEVs; (iii) correlation between VEVs of singlets and triplet, (iv) certain VEV alignment of flavon triplet(s). These features can follow from additional symmetries or be remnants of further unification. Phenomenologically viable schemes with minimal flavon content and minimal number of couplings are constructed.

Neutrino Oscillations Physics

Science.gov (United States)

Fogli, Gianluigi

2005-06-01

We review the status of the neutrino oscillations physics, with a particular emphasis on the present knowledge of the neutrino mass-mixing parameters. We consider first the νμ → ντ flavor transitions of atmospheric neutrinos. It is found that standard oscillations provide the best description of the SK+K2K data, and that the associated mass-mixing parameters are determined at ±1σ (and NDF = 1) as: Δm2 = (2.6 ± 0.4) × 10-3 eV2 and sin 2 2θ = 1.00{ - 0.05}{ + 0.00} . Such indications, presently dominated by SK, could be strengthened by further K2K data. Then we point out that the recent data from the Sudbury Neutrino Observatory, together with other relevant measurements from solar and reactor neutrino experiments, in particular the KamLAND data, convincingly show that the flavor transitions of solar neutrinos are affected by Mikheyev-Smirnov-Wolfenstein (MSW) effects. Finally, we perform an updated analysis of two-family active oscillations of solar and reactor neutrinos in the standard MSW case.

Neutrino bilarge mixing and flavor physics in the flipped SU(5) model

Energy Technology Data Exchange (ETDEWEB)

Huang Chaoshang; Li Tianjun; Liao Wei E-mail: liaow@ictp.trieste.it

2003-11-24

We have constructed a specific supersymmetric flipped SU(5) GUT model in which bilarge neutrino mixing is incorporated. Because the up-type and down-type quarks in the model are flipped in the representations ten and five with respect to the usual SU(5), the radiatively generated flavor mixing in squark mass matrices due to the large neutrino mixing has a pattern different from those in the conventional SU(5) and SO(10) supersymmetric GUTs. This leads to phenomenological consequences quite different from SU(5) or SO(10) supersymmetric GUT models. That is, it has almost no impact on B physics. On the contrary, the model has effects in top and charm physics as well as lepton physics. In particular, it gives promising prediction on the mass difference, {delta}M{sub D}, of the D-D-bar mixing which for some ranges of the parameter space with large tan{beta} can be at the order of 10{sup 9} {Dirac_h} s{sup -1}, one order of magnitude smaller than the experimental upper bound. In some regions of the parameter space {delta}M{sub D} can saturate the present bound. For these ranges of parameter space, t{yields}u,c+h{sup 0} can reach 10{sup -5}-10{sup -6} which would be observed at the LHC and future {gamma}-{gamma} colliders.

Neutrino factories

International Nuclear Information System (INIS)

Dydak, F.

2002-01-01

The discovery of neutrino oscillations marks a major milestone in the history of neutrino physics, and opens a window to what lies beyond the Standard Model. Many current and forthcoming experiments will answer open questions; however, a major step forward, up to and possibly including CP violation in the neutrino mixing matrix, will be offered by the neutrino beams from a neutrino factory. The neutrino factory is a new concept for producing neutrino beams of unprecedented quality in terms of intensity, flavour composition, and precision of the beam parameters. These beams enable the exploration of otherwise inaccessible domains in neutrino oscillation physics by exploiting baselines of planetary dimensions. Suitable detectors pose formidable challenges but seem within reach with only moderate extrapolations from existing technologies. Although the main physics attraction of the neutrino factory is in the area of neutrino oscillations, an interesting spectrum of further opportunities ranging from high-precision, high-rate neutrino scattering to physics with high-intensity stopped muons comes with it

Renormalization group evolution of Dirac neutrino masses

International Nuclear Information System (INIS)

Lindner, Manfred; Ratz, Michael; Schmidt, Michael Andreas

2005-01-01

There are good reasons why neutrinos could be Majorana particles, but there exist also a number of very good reasons why neutrinos could have Dirac masses. The latter option deserves more attention and we derive therefore analytic expressions describing the renormalization group evolution of mixing angles and of the CP phase for Dirac neutrinos. Radiative corrections to leptonic mixings are in this case enhanced compared to the quark mixings because the hierarchy of neutrino masses is milder and because the mixing angles are larger. The renormalization group effects are compared to the precision of current and future neutrino experiments. We find that, in the MSSM framework, radiative corrections of the mixing angles are for large tan β comparable to the precision of future experiments

Flavor composition of the IceCube neutrinos: A quest for sterile neutrinos?

International Nuclear Information System (INIS)

Biondi, R.

2016-01-01

The identification of flavor content in the cosmic high-energy neutrinos recently observed by the IceCube collaboration could spread the light on the origin of these neutrinos. We study the expected fraction of muon tracks for different cases of the neutrino flavor composition at the sources taking into account uncertainties in the neutrino mixing angles and CP-phase. We show that in the frame of the three known neutrinos it is hard to explain the ν_μ fraction observed at IceCube. However if the cosmic component is produced in some hidden sector, in the form of sterile neutrinos which then oscillate into ordinary ones, a better agreement can be obtained. Especially, in a scenario when heavy dark matter with mass of few PeV decay into sterile neutrinos which then oscillate in ordinary neutrinos due to tiny mixing with the latter, it is possible to explain the low fraction of muon tracks in the events observed by IceCube in the energy region from 60TeV to 2PeV

Neutrino mixing and R{sub K} anomaly in U(1){sub X} models: a bottom-up approach

Energy Technology Data Exchange (ETDEWEB)

Bhatia, Disha; Chakraborty, Sabyasachi; Dighe, Amol [Tata Institute of Fundamental Research,Mumbai 400005 (India)

2017-03-22

We identify a class of U(1){sub X} models which can explain the R{sub K} anomaly and the neutrino mixing pattern, by using a bottom-up approach. The different X-charges of lepton generations account for the lepton universality violation required to explain R{sub K}. In addition to the three right-handed neutrinos needed for the Type-I seesaw mechanism, these minimal models only introduce an additional doublet Higgs and a singlet scalar. While the former helps in reproducing the quark mixing structure, the latter gives masses to neutrinos and the new gauge boson Z{sup ′}. Our bottom-up approach determines the X-charges of all particles using theoretical consistency and experimental constraints. We find the parameter space allowed by the constraints from neutral meson mixing, rare b→s decays and direct collider searches for Z{sup ′}. Such a Z{sup ′} may be observable at the ongoing run of the Large Hadron Collider with a few hundred fb{sup −1} of integrated luminosity.

Neutrino Factory Targets and the MICE Beam

International Nuclear Information System (INIS)

Walaron, Kenneth A.

2007-01-01

The future of particle physics in the next 20 years must include detailed study of neutrinos. The first proof of physics beyond the Standard Model of particle physics is evident in results from recent neutrino experiements which imply that neutrinos have mass and flavour mixing. The Neutrino Factory is the leading contender to measure precisely the neutrino mixing parameters to probe beyond the Standard Model physics.

Projection quantum mechanics and neutrino mixing

Energy Technology Data Exchange (ETDEWEB)

Góźdź, A., E-mail: andrzej.gozdz@umcs.lublin.pl; Góźdź, M., E-mail: mgozdz@kft.umcs.lublin.pl [University of Maria Curie–Skłodowska, Faculty of Mathematics, Physics and Computer Science (Poland)

2017-03-15

The theory of neutrino oscillations rests on the assumption, that the interaction basis and the physical (mass) basis of neutrino states are different. Therefore neutrino is produced in a certain welldefined superposition of three mass eigenstates, which propagate separately and may be detected as a different superposition. This is called flavor oscillations. It is, however, not clear why neutrinos behave this way, i.e., what is the underlying mechanism which leads to the production of a superposition of physical states in a single reaction. In this paper we argue, that one of the reasons may be connected with the temporal structure of the process. In order to discuss the role of time in processes on the quantum level, we use a special formulation of the quantum mechanics, which is based on the projection time evolution. We arrive at the conclusion, that for short reaction times the formation of a superposition of states of similar masses is natural.

On the Hierarchy of Neutrino Masses

International Nuclear Information System (INIS)

Jezabek, M.; Urban, P.

2002-01-01

We present a model of neutrino masses combining the seesaw mechanism and strong Dirac mass hierarchy and at the same time exhibiting a significantly reduced hierarchy at the level of active neutrino masses. The heavy Majorana masses are assumed to be degenerate. The suppression of the hierarchy is due to a symmetric and unitary operator R whose role is discussed. The model gives realistic mixing and mass spectrum. The mixing of atmospheric neutrinos is attributed to the charged lepton sector whereas the mixing of solar neutrinos is due to the neutrino sector. Small U e3 is a consequence of the model. The masses of the active neutrinos are given by μ 3 ≅ √(Δm 2 O ) and μ 1 /μ 2 = ≅ tan 2 (θ O ). (author)

Prospects for cosmic neutrino detection in tritium experiments in the case of hierarchical neutrino masses

International Nuclear Information System (INIS)

Blennow, Mattias

2008-01-01

We discuss the effects of neutrino mixing and the neutrino mass hierarchy when considering the capture of the cosmic neutrino background (CNB) on radioactive nuclei. The implications of mixing and hierarchy at future generations of tritium decay experiments are considered. We find that the CNB should be detectable at these experiments provided that the resolution for the kinetic energy of the outgoing electron can be pushed to a few 0.01 eV for the scenario with inverted neutrino mass hierarchy, about an order of magnitude better than that of the upcoming KATRIN experiment. Another order of magnitude improvement is needed in the case of normal neutrino mass hierarchy. We also note that mixing effects generally make the prospects for CNB detection worse due to an increased maximum energy of the normal beta decay background

Beam and experiments summary [neutrino studies

CERN Document Server

Blondel, A; Campanelli, M; Cervera-Villanueva, Anselmo; Cline, David B; Collot, J; De Jong, M; Donini, Andrea; Dydak, Friedrich; Edgecock, R; Gavela-Legazpi, Maria Belen; Gómez-Cadenas, J J; González-Garciá, M Concepción; Gruber, P; Harris, D A; Hernández, Pilar; Kuno, Y; Litchfield, P J; McFarland, K; Mena, O; Migliozzi, P; Palladino, Vittorio; Panman, J; Papadopoulos, I M; Para, A; Peña-Garay, C; Pérez, P; Rigolin, Stefano; Romanino, Andrea; Rubbia, André; Strolin, P; Wojcicki, S G

2000-01-01

The discovery of neutrino oscillations marks a major milestone in the history of neutrino physics, and opens a new window to the still mysterious origin of masses and flavour mixing. Many current and forthcoming experiments will. Answer open questions; however, a major step forward, up to and possibly including CP violation in the neutrino-mixing matrix, requires the neutrino beams from a neutrino factory. The neutrino factory is a new concept for producing neutrino beams of unprecedented quality in terms of intensity, flavour composition, and precision of the beam parameters. Most importantly, the neutrino factory is the only known way to generate a high- intensity beam of electron neutrinos of high energy. The neutrino beam from a neutrino factory, in particular the electron-neutrino beam, enables the exploration of otherwise inaccessible domains in neutrino oscillation physics by exploiting baselines of planetary dimensions. Suitable detectors pose formidable challenges but seem within reach with only mode...

Geometric phase of neutrinos: Differences between Dirac and Majorana neutrinos

Science.gov (United States)

Capolupo, A.; Giampaolo, S. M.; Hiesmayr, B. C.; Vitiello, G.

2018-05-01

We analyze the non-cyclic geometric phase for neutrinos. We find that the geometric phase and the total phase associated to the mixing phenomenon provide a theoretical tool to distinguish between Dirac and Majorana neutrinos. Our results hold for neutrinos propagating in vacuum and through the matter. We feed the values of the experimental parameters in our formulas in order to make contact with experiments. Although it remains an open question how the geometric phase of neutrinos could be detected, our theoretical results may open new scenarios in the investigation of the neutrino nature.

Neutrino oscillations in a predictive SUSY GUT

International Nuclear Information System (INIS)

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

1999-01-01

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)→U(1)→ 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 ν μ -ν τ mixing describing atmospheric neutrino oscillation data and small angle ν e -ν 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 ν 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 ν μ -ν τ 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

Neutrino masses and flavor mixing in the extended double Seesaw model with two texture zeros

International Nuclear Information System (INIS)

Hu, Li-Jun; Dulat, Sayipjamal; Ablat, Abduleziz

2011-01-01

We study the light neutrino mass matrix in the extended double Seesaw model (EDSM), and as a result we get its general form. Also we demonstrate that conventional type-I and double seesaw mechanisms can be regarded as two special cases. We analyze the structure of the 9 x 9 neutrino mass matrix in this scenario, and surprisingly we find that EDSM will degenerate to a conventional type-I seesaw mechanism when M R = M S M μ -1 M S T holds exactly. Considering two simple ansaetze in two texture zeros for its 3 x 3 submatrices, we calculate the neutrino masses and flavor mixing angles, in which the θ 13 is a nonzero large angle. (orig.)

Mikheyev-Smirnov-Wolfenstein effect on neutrino decay

International Nuclear Information System (INIS)

Chou Chihkang; Chou Marty; National Central Univ., Chung-li

2001-01-01

It has early been pointed out by R. S. Raghavan et al. that in solar matter, conversion of the electron neutrino to a ''heaver'' flavor by the MSW effect can catalyze neutrino decay in the small mixing angle MSW solution. Since recent results on solar neutrinos provide hints that the large mixing angle MSW solution could be correct, we present a detailed study of the MSW effect with neutrino decay for both small and large mixing angles. The lower limit for the lifetime of 10 MeV neutrinos is estimated to be τ(10 MeV) >or∼ 10 3 s. (orig.)

Searches for heavy neutrinos from Z decays

International Nuclear Information System (INIS)

Abreu, P.; Adam, W.; Adami, F.

1992-01-01

We have searched for possible fourth family heavy neutrinos, pair produced in Z 0 decays, in a sample of about 112 000 hadronic Z 0 final states collected with the DELPHI detector. For all mixing matrix elements we exclude a new Dirac neutrino light than 44.5 GeV at a 95% confidence level, if the neutrino couples to the electron or muon family, and lighter than 44.0 GeV, if the neutrino couples to the tau family. Depending on the values of the mixing element and to which lepton family the neutrino couples, we obtain mass limits up to 46.2 GeV. For all mixing matrix elements we exclude a new Majorana neutrino lighter than 39.0 GeV, if it couples to the electron or the muon family, and lighter than 38.2 GeV, if it couples to the tau family. Depending on the values of the mixing matrix element and to which lepton family the neutrino couples, we obtain mass limits up to 44.7 GeV. We also exclude stable new Dirac neutrinos lighter than 45.0 GeV and new Majorana neutrinos lighter than 39.5 GeV. (orig.)

New neutrino oscillation results from NOVA

CERN Multimedia

CERN. Geneva

2018-01-01

Neutrinos oscillate among flavors as they travel because a neutrino of a particular flavor is also a superposition of multiple neutrinos with slightly different masses.  The interferometric nature of oscillations allows these tiny mass differences to be measured, along with the parameters of the PMNS matrix which governs the mixing. However, since neutrinos only interact weakly, a powerful neutrino source and massive detectors are required to measure them. In this talk I will show recently updated results from NOvA, a long-baseline neutrino oscillation experiment at Fermilab with two functionally identical scintillator detectors. I will present measurements of muon neutrino disappearance and electron neutrino appearance, and what constraints those measurements put on the remaining open questions in neutrino oscillations: Is the neutrino mass hierarchy "normal" or "inverted?" Do neutrino oscillations violate CP symmetry? Is the mixing in the atmospheric sector maximal? The recent update includes 50%...

Experimental Neutrino Physics: Final Report

Energy Technology Data Exchange (ETDEWEB)

Lane, Charles E.; Maricic, Jelena

2012-09-05

Experimental studies of neutrino properties, with particular emphasis on neutrino oscillation, mass and mixing parameters. This research was pursued by means of underground detectors for reactor anti-neutrinos, measuring the flux and energy spectra of the neutrinos. More recent investigations have been aimed and developing detector technologies for a long-baseline neutrino experiment (LBNE) using a neutrino beam from Fermilab.

Hardron production and neutrino beams

Science.gov (United States)

Guglielmi, A.

2006-11-01

The precise measurements of the neutrino mixing parameters in the oscillation experiments at accelerators require new high-intensity and high-purity neutrino beams. Ancillary hadron-production measurements are then needed as inputs to precise calculation of neutrino beams and of atmospheric neutrino fluxes.

Neutrino oscillations in non-inertial frames and the violation of the equivalence principle neutrino mixing induced by the equivalence principle violation

International Nuclear Information System (INIS)

Lambiase, G.

2001-01-01

Neutrino oscillations are analyzed in an accelerating and rotating reference frame, assuming that the gravitational coupling of neutrinos is flavor dependent, which implies a violation of the equivalence principle. Unlike the usual studies in which a constant gravitational field is considered, such frames could represent a more suitable framework for testing if a breakdown of the equivalence principle occurs, due to the possibility to modulate the (simulated) gravitational field. The violation of the equivalence principle implies, for the case of a maximal gravitational mixing angle, the presence of an off-diagonal term in the mass matrix. The consequences on the evolution of flavor (mass) eigenstates of such a term are analyzed for solar (oscillations in the vacuum) and atmospheric neutrinos. We calculate the flavor oscillation probability in the non-inertial frame, which does depend on its angular velocity and linear acceleration, as well as on the energy of neutrinos, the mass-squared difference between two mass eigenstates, and on the measure of the degree of violation of the equivalence principle (Δγ). In particular, we find that the energy dependence disappears for vanishing mass-squared difference, unlike the result obtained by Gasperini, Halprin, Leung, and other physical mechanisms proposed as a viable explanation of neutrino oscillations. Estimations on the upper values of Δγ are inferred for a rotating observer (with vanishing linear acceleration) comoving with the earth, hence ω∝7.10 -5 rad/sec, and all other alternative mechanisms generating the oscillation phenomena have been neglected. In this case we find that the constraints on Δγ are given by Δγ≤10 2 for solar neutrinos and Δγ≤10 6 for atmospheric neutrinos. (orig.)

Quasi-Dirac neutrino oscillations

Science.gov (United States)

Anamiati, Gaetana; Fonseca, Renato M.; Hirsch, Martin

2018-05-01

Dirac neutrino masses require two distinct neutral Weyl spinors per generation, with a special arrangement of masses and interactions with charged leptons. Once this arrangement is perturbed, lepton number is no longer conserved and neutrinos become Majorana particles. If these lepton number violating perturbations are small compared to the Dirac mass terms, neutrinos are quasi-Dirac particles. Alternatively, this scenario can be characterized by the existence of pairs of neutrinos with almost degenerate masses, and a lepton mixing matrix which has 12 angles and 12 phases. In this work we discuss the phenomenology of quasi-Dirac neutrino oscillations and derive limits on the relevant parameter space from various experiments. In one parameter perturbations of the Dirac limit, very stringent bounds can be derived on the mass splittings between the almost degenerate pairs of neutrinos. However, we also demonstrate that with suitable changes to the lepton mixing matrix, limits on such mass splittings are much weaker, or even completely absent. Finally, we consider the possibility that the mass splittings are too small to be measured and discuss bounds on the new, nonstandard lepton mixing angles from current experiments for this case.

Sudbury Neutrino Observatory

International Nuclear Information System (INIS)

Beier, E.W.

1992-03-01

This document is a technical progress report on work performed at the University of Pennsylvania during the current year on the Sudbury Neutrino Observatory project. The motivation for the experiment is the measurement of neutrinos emitted by the sun. The Sudbury Neutrino Observatory (SNO) is a second generation dedicated solar neutrino experiment which will extend the results of our work with the Kamiokande II detector by measuring three reactions of neutrinos rather than the single reaction measured by the Kamiokande experiment. The collaborative project includes physicists from Canada, the United Kingdom, and the United States. Full funding for the construction of this facility was obtained in January 1990, and its construction is estimated to take five years. The motivation for the SNO experiment is to study the fundamental properties of neutrinos, in particular the mass and mixing parameters, which remain undetermined after decades of experiments in neutrino physics utilizing accelerators and reactors as sources of neutrinos. To continue the study of neutrino properties it is necessary to use the sun as a neutrino source. The long distance to the sun makes the search for neutrino mass sensitive to much smaller mass than can be studied with terrestrial sources. Furthermore, the matter density in the sun is sufficiently large to enhance the effects of small mixing between electron neutrinos and mu or tau neutrinos. This experiment, when combined with the results of the radiochemical 37 Cl and 71 Ga experiments and the Kamiokande II experiment, should extend our knowledge of these fundamental particles, and as a byproduct, improve our understanding of energy generation in the sun

Sterile neutrino search with the Double Chooz experiment

Energy Technology Data Exchange (ETDEWEB)

Hellwig, Denise; Bekman, Ilja; Kampmann, Philipp; Schoppmann, Stefan; Soiron, Michael; Stahl, Achim; Wiebusch, Christopher [III. Physikalisches Institut B, RWTH Aachen (Germany)

2016-07-01

The Double Chooz experiment is a reactor neutrino disappearance experiment located at the Chooz nuclear power plant, France. It measures the electron-antineutrino flux of the two nuclear reactors with two detectors of identical design. A far detector at a distance of about 1 km is operating since 2011; a near detector at a distance of about 400 m is operating since the end of 2014. The combination of the two detectors offers sensitivity to sterile neutrino mixing parameters. Sterile neutrinos are neutrino mass states not taking part in weak interactions, but may mix with known neutrino states. This induces additional mixing angles and mass differences. This talk describes the search for sterile neutrinos and the sensitivity of Double Chooz to the mixing angle θ{sub 14}.

Study of Dynamic Flow and Mixing Performances of Tri-Screw Extruders with Finite Element Method

OpenAIRE

X. Z. Zhu; G. Wang; Y. D. He; Z. F. Cheng

2013-01-01

There is a special circumfluence in the center region of cross-section for a tri-screw extruder. To study the effect of the dynamic center region on the flow and mixing mechanism of the tri-screw extruder, 2D finite element modeling was used to reduce the axial effects. Based on the particle tracking technology, the nonlinear dynamics of a typical particle motions in the center region was carried out and the mixing process in the tri-screw extruder was analyzed with Poincaré maps. Moreover, m...

Neutrino oscillation measurements with reactors

Energy Technology Data Exchange (ETDEWEB)

McKeown, R.D. [W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States)

2010-11-01

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 important information on the neutrino masses and 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.

Neutrino oscillations and the seesaw origin of neutrino mass

Energy Technology Data Exchange (ETDEWEB)

Miranda, O.G., E-mail: omr@fis.cinvestav.mx [Departamento de Física, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740, 07000 Mexico, Distrito Federal (Mexico); Valle, J.W.F. [AHEP Group, Institut de Física Corpuscular – C.S.I.C./Universitat de València, Parc Cientific de Paterna, C/Catedratico José Beltrán, 2, E-46980 Paterna (València) (Spain)

2016-07-15

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.

Impact of hierarchy upon the values of neutrino mixing parameters

International Nuclear Information System (INIS)

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

2010-01-01

A neutrino-oscillation analysis is performed of the more finely binned Super-Kamiokande (Super-K) atmospheric, MINOS, and CHOOZ data to examine the effect of neutrino hierarchy in this data set on the value of θ 13 and the deviation of θ 23 from maximal mixing. Exact oscillation probabilities are used, thus incorporating all powers of θ 13 and ε:=θ 23 -π/4. The extracted oscillation parameters are found to be dependent on the hierarchy, particularly for θ 13 . We find, at a 90% confidence level, that these parameters are Δ 32 =2.44 -0.20 +0.26 and 2.48 -0.22 +0.25 x10 -3 eV 2 , ε=θ 23 -π/4=0.06 -0.16 +0.06 and 0.06 -0.17 +0.08 , and θ 13 =-0.07 -0.11 +0.18 and -0.13 -0.16 +0.23 , for the normal and inverted hierarchies, respectively. The inverted hierarchy is preferred at a statistically insignificant level of 0.3σ.

Investigation of matter enhanced neutrino oscillations relevant to the solar neutrino problem

International Nuclear Information System (INIS)

Losecco, J.M.; Bionta, R.M.; Casper, D.; Claus, R.; Errede, S.; Foster, G.; Park, H.S.; Seidel, S.; Shumard, E.; Sinclair, D.; Stone, J.L.; Sulak, L.; Van der Velde, J.C.; Blewitt, G.; Cortez, B.; Lehmann, E.; Bratton, C.B.; Gajewski, W.; Ganezer, K.S.; Haines, T.J.; Kropp, W.R.; Reines, F.; Schultz, J.; Sobel, H.W.; Wuest, C.; Goldhaber, M.; Jones, T.W.; Kielczewska, D.; Learned, J.G.; Svoboda, R.

1987-01-01

We study the effect of matter enhanced neutrino oscillations on atmospheric neutrinos. A recently proposed solution to the solar neutrino problem with Δm 2 =1.1x10 -4 eV 2 suggests enhanced effects in the range 200 MeV-500 MeV. We find no evidence of this effect for ν μ ??ν e mixing. Limits are set on the magnitude of the mixing angle. Our limit is sin θ V <0.14 at 90% confidence level. The limit is dominated by statistical errors and may be improved. (orig.)

Testing CPT invariance with neutrinos

International Nuclear Information System (INIS)

Ohlsson, Tommy

2003-01-01

We investigate possible tests of CPT invariance on the level of event rates at neutrino factories. We do not assume any specific model, but phenomenological differences in the neutrino-antineutrino masses and mixing angles in a Lorentz invariance preserving context, which could be induced by physics beyond the Standard Model. We especially focus on the muon neutrino and antineutrino disappearance channels in order to obtain constraints on the neutrino-antineutrino mass and mixing angle differences. In a typical neutrino factory setup simulation, we find, for example, that vertical bar m 3 - m-bar 3 vertical bar $1.9 · 10 -4 eV and vertical bar ≡ 23 - ≡-bar 23 vertical bar < or approx. 2 deg

Tribimaximal neutrino mixing from A4 replication

International Nuclear Information System (INIS)

Carone, Christopher D.; Lebed, Richard F.

2011-01-01

Motivated by dimensional deconstruction, we propose a model of tribimaximal neutrino mixing based on A 4 xA 4 symmetry. In this model, the two triplet symmetry-breaking fields of conventional A 4 models are taken to transform under different A 4 group factors, but are not distinguished by any other quantum numbers. An additional bi-triplet flavor field breaks A 4 xA 4 to its diagonal subgroup. If the bi-triplet transforms under an additional Z 3 symmetry, we show that one can construct a general, renormalizable superpotential that yields the desired pattern of symmetry breaking. We identify the features that this model has in common with a deconstructed 5D theory in which A 4 is a subgroup of a continuous gauged flavor symmetry in the bulk.

Neutrinos today

International Nuclear Information System (INIS)

Pontecorvo, B.; Bilen'kij, S.

1987-01-01

After the famous 1983 discovery of intermediate W, Z 0 bosons it may be stated with certainty that W, Z 0 are entirely responsible for the production of neutrinos and for their interactions. Neutrino physics notions are presented from this point of view in the first four introductory, quite elementary, paragraphs of the paper. The following seven paragraphs are more sophisticated. They are devoted to the neutrino mass and neutrino mixing question, which is the most actual problem in today neutrino physics. Vacuum neutrino oscillations, matter neutrino oscillations and netrinoless double-decay are considered. Solar neutrino physics is discussed in some detail from the point of view of vacuum and matter neutrino oscillations. The role played by neutrinos in the Universe is briefly considered. In the last paragraph there discussed the probable observation by different groups of neutrinos connected with the Supernova 1987 A: the first observation of gravitational star collapse (at least the general rehearsal of such observation) opens up a new era in astronomy of today exerimental physics and astrophysics is presented at the end of the paper in the form of a Table

NEUTRINO MASS

OpenAIRE

Kayser, Boris

1988-01-01

This is a review article about the most recent developments on the field of neutrino mass. The first part of the review introduces the idea of neutrino masses and mixing angles, summarizes the most recent experimental data then discusses the experimental prospects and challenges in this area. The second part of the review discusses the implications of these results for particle physics and cosmology, including the origin of neutrino mass, the see-saw mechanism and sequential dominance, and la...

Neutrino mass sum-rule

Science.gov (United States)

Damanik, Asan

2018-03-01

Neutrino mass sum-rele is a very important research subject from theoretical side because neutrino oscillation experiment only gave us two squared-mass differences and three mixing angles. We review neutrino mass sum-rule in literature that have been reported by many authors and discuss its phenomenological implications.

Workshop on low energy neutrino physics

International Nuclear Information System (INIS)

2009-01-01

The main topics of the workshop are: the determination of the neutrino mixing angle theta-13, the experiments concerning the monitoring of reactors based on the measurement of neutrino spectra, solar neutrinos, supernovae neutrinos, geo-neutrinos, neutrino properties, neutrinoless double beta decay and future low energy neutrino detectors. This document gathers together the program of the workshop, the slides of the presentations, some abstracts and some posters

A see-saw mechanism with light sterile neutrinos

International Nuclear Information System (INIS)

McKellar, B.H.J.; Garbutt, M.; Stephenson, G.J.; Goldman, T.

2001-01-01

The usual see-saw mechanism for the generation of light neutrino masses is based on the assumption that all of the flavours of right-handed (more properly, sterile) neutrinos are heavy. If the sterile Majorana mass matrix is singular, one or more of the sterile neutrinos will have zero mass before mixing with the active (left-handed) neutrinos and be light after that mixing is introduced In particular, a rank 1 sterile mass matrix leads naturally to two pseudo-Dirac pairs, one very light active Majorana neutrino and one heavy sterile Majorana neutrino. For any pattern of Dirac masses, there exists a region of parameter space in which the two pseudo-Dirac pairs are nearly degenerate in mass. This, in turn, leads to large amplitude mixing of active states as well as mixing into sterile states

Visible neutrino decay at DUNE

Energy Technology Data Exchange (ETDEWEB)

Coloma, Pilar [Fermilab; Peres, Orlando G. [ICTP, Trieste

2017-05-09

If the heaviest neutrino mass eigenstate is unstable, its decay modes could include lighter neutrino eigenstates. In this case part of the decay products could be visible, as they would interact at neutrino detectors via mixing. At neutrino oscillation experiments, a characteristic signature of such \\emph{visible neutrino decay} would be an apparent excess of events at low energies. We focus on a simple phenomenological model in which the heaviest neutrino decays as $\

Flipped Heavy Neutrinos from the Solar Neutrino Problem to Baryogenesis

CERN Document Server

Ellis, Jonathan Richard; Olive, Keith A

1993-01-01

We discuss baryogenesis using the flipped $SU(5)$ model for lepton mass matrices. We show that the generalized see-saw mechanism in this model can not only provide MSW neutrino mixing suitable for solving the solar neutrino problem, and supply a hot dark matter candidate ($\

Neutrino oscillations in the early universe

International Nuclear Information System (INIS)

Enqvist, K.

1990-01-01

The oscillations of electron neutrinos into inert neutrinos may have resonant behaviour in the heat bath of the early Universe. It is shown that any initial neutrino asymmetry will be washed away by the oscillations. Neutrino oscillations would affect also primordial helium production, which implies stringent limits on the neutrino mixing parameters. (orig.)

Neutrino masses, mixings, and FCNC’s in an S3 flavor symmetric extension of the standard model

International Nuclear Information System (INIS)

Mondragón, A.; Mondragón, M.; Peinado, E.

2011-01-01

By introducing threeHiggs fields that are SU(2) doublets and a flavor permutational symmetry, S 3 , in the theory, we extend the concepts of flavor and generations to the Higgs sector and formulate a Minimal S 3 -Invariant Extension of the Standard Model. The mass matrices of the neutrinos and charged leptons are re-parameterized in terms of their eigenvalues, then the neutrino mixing matrix, V PMNS , is computed and exact, explicit analytical expressions for the neutrino mixing angles as functions of the masses of neutrinos and charged leptons are obtained in excellent agreement with the latest experimental data. We also compute the branching ratios of some selected flavor-changing neutral current (FCNC) processes, as well as the contribution of the exchange of neutral flavor-changing scalars to the anomaly of the magnetic moment of the muon, as functions of the masses of charged leptons and the neutral Higgs bosons. We find that the S 3 × Z 2 flavor symmetry and the strong mass hierarchy of the charged leptons strongly suppress the FCNC processes in the leptonic sector, well below the present experimental bounds by many orders of magnitude. The contribution of FCNC’s to the anomaly of the muon’s magnetic moment is small, but not negligible.

Neutrino masses and large mixings as a indirect signature of grand unified theory

International Nuclear Information System (INIS)

Maekawa, Nobuhiro

2015-01-01

Grand unified theory (GUT) unifies not only three forces (electromagnetic force, strong force and weak force) but also quarks and leptons. As an experimental support for the unification of forces, it is well-known that three gauge couplings meet at a scale (the GUT scale). However, it is not so well-known that there is an experimental support even for the unification of matters (quarks and leptons). We explain the indirect support in this document and show that the important key is what the neutrino experiments have revealed for 20 years. Concretely, for the unification of matters in SU(5) GUT, various observed hierarchies of quark and lepton masses and mixings can be understood only from one assumption that '10 dimensional fields of SU(5) induce stronger hierarchy for the Yukawa couplings than 5-bar fields'. For this explanation, the knowledges on neutrino masses and mixings are critical. In the end, we comment E 6 unification in which the above assumption in the SU(5) GUT can be induced. (author)

Active-sterile neutrino conversion: consequences for the r-process and supernova neutrino detection

Science.gov (United States)

Fetter, J.; McLaughlin, G. C.; Balantekin, A. B.; Fuller, G. M.

2003-02-01

We examine active-sterile neutrino conversion in the late time post-core-bounce supernova environment. By including the effect of feedback on the Mikheyev-Smirnov-Wolfenstein (MSW) conversion potential, we obtain a large range of neutrino mixing parameters which produce a favorable environment for the r-process. We look at the signature of this effect in the current generation of neutrino detectors now coming on line. We also investigate the impact of the neutrino-neutrino forward-scattering-induced potential on the MSW conversion.

Neutrino mass textures with maximal CP violation

International Nuclear Information System (INIS)

Aizawa, Ichiro; Kitabayashi, Teruyuki; Yasue, Masaki

2005-01-01

We show three types of neutrino mass textures, which give maximal CP violation as well as maximal atmospheric neutrino mixing. These textures are described by six real mass parameters: one specified by two complex flavor neutrino masses and two constrained ones and the others specified by three complex flavor neutrino masses. In each texture, we calculate mixing angles and masses, which are consistent with observed data, as well as Majorana CP phases

Neutrino Oscillations at Reactors: What Next?

OpenAIRE

Mikaelyan, L. A.; Sinev, V. V.

1999-01-01

We shortly review past and future experiments at reactors aimed at searches for neutrino masses and mixing. We also consider new idea to search at Krasnoyarsk for small mixing angle oscillations in the atmosheric neutrino mass parameter region.

Highlights on experimental neutrino physics

International Nuclear Information System (INIS)

Kemp, Ernesto

2013-01-01

Full text: In the last years a remarkable progress was achieved in a deeper understanding of neutrino sector. Nowadays we know all mixing angles and mass splits which govern the neutrino oscillation phenomena. The parameters of neutrino mixing were measured by combining results of different experimental approaches including accelerator beams, nuclear reactors, radiative decays and astrophysical neutrinos. Nevertheless, there are open questions which can be viewed as key points to consolidate our knowledge on the intrinsic properties of neutrinos such as mass hierarchy and the existence of a CP violation in leptonic sector. To answer these questions and also to improve the precision of the already known mixing parameters, a series of huge experimental efforts are being set up, even in a world-wide scale in some cases. In this presentation I will review the current knowledge of the fundamental properties of neutrinos and the experimental scenario in which we expect, in a time frame of a decade, to find missing pieces in the leptonic sector. The findings can strengthen the foundations of the Standard Model as well as open very interesting paths for new physics. (author)

The Intermediate Neutrino Program

CERN Document Server

Adams, C.; Ankowski, A.M.; Asaadi, J.A.; Ashenfelter, J.; Axani, S.N.; Babu, K.; Backhouse, C.; Band, H.R.; Barbeau, P.S.; Barros, N.; Bernstein, A.; Betancourt, M.; Bishai, M.; Blucher, E.; Bouffard, J.; Bowden, N.; Brice, S.; Bryan, C.; Camilleri, L.; Cao, J.; Carlson, J.; Carr, R.E.; Chatterjee, A.; Chen, M.; Chen, S.; Chiu, M.; Church, E.D.; Collar, J.I.; Collin, G.; Conrad, J.M.; Convery, M.R.; Cooper, R.L.; Cowen, D.; Davoudiasl, H.; de Gouvea, A.; Dean, D.J.; Deichert, G.; Descamps, F.; DeYoung, T.; Diwan, M.V.; Djurcic, Z.; Dolinski, M.J.; Dolph, J.; Donnelly, B.; Dwyer, D.A.; Dytman, S.; Efremenko, Y.; Everett, L.L.; Fava, A.; Figueroa-Feliciano, E.; Fleming, B.; Friedland, A.; Fujikawa, B.K.; Gaisser, T.K.; Galeazzi, M.; Galehouse, D.C.; Galindo-Uribarri, A.; Garvey, G.T.; Gautam, S.; Gilje, K.E.; Gonzalez-Garcia, M.; Goodman, M.C.; Gordon, H.; Gramellini, E.; Green, M.P.; Guglielmi, A.; Hackenburg, R.W.; Hackenburg, A.; Halzen, F.; Han, K.; Hans, S.; Harris, D.; Heeger, K.M.; Herman, M.; Hill, R.; Holin, A.; Huber, P.; Jaffe, D.E.; Johnson, R.A.; Joshi, J.; Karagiorgi, G.; Kaufman, L.J.; Kayser, B.; Kettell, S.H.; Kirby, B.J.; Klein, J.R.; Kolomensky, Yu. G.; Kriske, R.M.; Lane, C.E.; Langford, T.J.; Lankford, A.; Lau, K.; Learned, J.G.; Ling, J.; Link, J.M.; Lissauer, D.; Littenberg, L.; Littlejohn, B.R.; Lockwitz, S.; Lokajicek, M.; Louis, W.C.; Luk, K.; Lykken, J.; Marciano, W.J.; Maricic, J.; Markoff, D.M.; Martinez Caicedo, D.A.; Mauger, C.; Mavrokoridis, K.; McCluskey, E.; McKeen, D.; McKeown, R.; Mills, G.; Mocioiu, I.; Monreal, B.; Mooney, M.R.; Morfin, J.G.; Mumm, P.; Napolitano, J.; Neilson, R.; Nelson, J.K.; Nessi, M.; Norcini, D.; Nova, F.; Nygren, D.R.; Orebi Gann, G.D.; Palamara, O.; Parsa, Z.; Patterson, R.; Paul, P.; Pocar, A.; Qian, X.; Raaf, J.L.; Rameika, R.; Ranucci, G.; Ray, H.; Reyna, D.; Rich, G.C.; Rodrigues, P.; Romero, E.Romero; Rosero, R.; Rountree, S.D.; Rybolt, B.; Sanchez, M.C.; Santucci, G.; Schmitz, D.; Scholberg, K.; Seckel, D.; Shaevitz, M.; Shrock, R.; Smy, M.B.; Soderberg, M.; Sonzogni, A.; Sousa, A.B.; Spitz, J.; St. John, J.M.; Stewart, J.; Strait, J.B.; Sullivan, G.; Svoboda, R.; Szelc, A.M.; Tayloe, R.; Thomson, M.A.; Toups, M.; Vacheret, A.; Vagins, M.; Van de Water, R.G.; Vogelaar, R.B.; Weber, M.; Weng, W.; Wetstein, M.; White, C.; White, B.R.; Whitehead, L.; Whittington, D.W.; Wilking, M.J.; Wilson, R.J.; Wilson, P.; Winklehner, D.; Winn, D.R.; Worcester, E.; Yang, L.; Yeh, M.; Yokley, Z.W.; Yoo, J.; Yu, B.; Yu, J.; Zhang, C.

2015-01-01

The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summ...

Right-handed neutrinos at CERN LHC and the mechanism of neutrino mass generation

International Nuclear Information System (INIS)

Kersten, Joern; Smirnov, Alexei Yu.

2007-01-01

We consider the possibility to detect right-handed neutrinos, which are mostly singlets of the standard model gauge group, at future accelerators. Substantial mixing of these neutrinos with the active neutrinos requires a cancellation of different contributions to the light neutrino mass matrix at the level of 10 -8 . We discuss possible symmetries behind this cancellation and argue that for three right-handed neutrinos they always lead to conservation of total lepton number. Light neutrino masses can be generated by small perturbations violating these symmetries. In the most general case, LHC physics and the mechanism of neutrino mass generation are essentially decoupled; with additional assumptions, correlations can appear between collider observables and features of the neutrino mass matrix

Oscillation Physics with a Neutrino Factory

CERN Document Server

Apollonio, M.; Broncano, A.; Bonesini, M.; Bouchez, J.; Bueno, A.; Burguet-Castell, J.; Casper, D.; Catanesi, G.; Cervera, A.; Cooper, S.; Donega, M.; Donini, A.; de Gouvea, A.; de Min, A.; Edgecock, R.; Ellis, J.; Fechner, M.; Fernandez, E.; Ferri, F.; Gavela, B.; Giannini, G.; Gibin, D.; Gilardoni, S.; Gomez-Cadenas, J.J.; Gruber, P.; Guglielmi, A.; Hernandez, P.; Huber, P.; Laveder, M.; Lindner, M.; Meloni, D.; Mena, O.; Menghetti, H.; Mezzetto, M.; Migliozzi, P.; Navas-Concha, S.; Palladino, V.; Papadopoulos, I.; Peach, K.; Radicioni, E.; Ragazzi, S.; Rigolin, S.; Romanino, A.; Rico, J.; Rubbia, A.; Santin, G.; Sartorelli, G.; Selvi, M.; Spiro, M.; Tabarelli, T.; Tonazzo, A.; Velasco, M.; Volkov, G.; Winter, W.; Zucchelli, P.

2004-01-01

A generation of neutrino experiments have established that neutrinos mix and probably have mass. The mixing phenomenon points to processes beyond those of the Standard Model, possibly at the Grand Unification energy scale. A extensive sequence of of experiments will be required to measure precisely all the parameters of the neutrino mixing matrix, culminating with the discovery and study of leptonic CP violation. As a first step, extensions of conventional pion/kaon decay beams, such as off-axis beams or low-energy super-beams, have been considered. These could yield first observations of $\

Neutrino mass and mixing: from theory to experiment

International Nuclear Information System (INIS)

King, Stephen F; Merle, Alexander; Morisi, Stefano; Shimizu, Yusuke; Tanimoto, Morimitsu

2014-01-01

The origin of fermion mass hierarchies and mixings is one of the unresolved and most difficult problems in high-energy physics. One possibility to address the flavour problems is by extending the standard model to include a family symmetry. In the recent years it has become very popular to use non-Abelian discrete flavour symmetries because of their power in the prediction of the large leptonic mixing angles relevant for neutrino oscillation experiments. Here we give an introduction to the flavour problem and to discrete groups that have been used to attempt a solution for it. We review the current status of models in light of the recent measurement of the reactor angle, and we consider different model-building directions taken. The use of the flavons or multi-Higgs scalars in model building is discussed as well as the direct versus indirect approaches. We also focus on the possibility of experimentally distinguishing flavour symmetry models by means of mixing sum rules and mass sum rules. In fact, we illustrate in this review the complete path from mathematics, via model building, to experiments, so that any reader interested in starting work in the field could use this text as a starting point in order to obtain a broad overview of the different subject areas

Neutrino masses in the minimal gauged (B -L ) supersymmetry

Science.gov (United States)

Yan, Yu-Li; Feng, Tai-Fu; Yang, Jin-Lei; Zhang, Hai-Bin; Zhao, Shu-Min; Zhu, Rong-Fei

2018-03-01

We present the radiative corrections to neutrino masses in a minimal supersymmetric extension of the standard model with local U (1 )B -L symmetry. At tree level, three tiny active neutrinos and two nearly massless sterile neutrinos can be obtained through the seesaw mechanism. Considering the one-loop corrections to the neutrino masses, the numerical results indicate that two sterile neutrinos obtain KeV masses and the small active-sterile neutrino mixing angles. The lighter sterile neutrino is a very interesting dark matter candidate in cosmology. Meanwhile, the active neutrinos mixing angles and mass squared differences agree with present experimental data.

Measurement of the neutrino mixing angle θ13 with the Double Chooz experiment

Science.gov (United States)

Ostrovskiy, Igor

2009-10-01

The neutrino mixing angle θ13 is last one which value is still unknown. Measuring the θ13 is important for completing our understanding of three flavor neutrino oscillations. Moreover, leptonic CP violation could only be measured in case the value of θ13 is not zero. The current best limit (^2(2θ13)Ardennes. Described in this talk, is another experiment, Double Chooz, that is being prepared at the same site. The Double Chooz experiment offers several fundamental improvements and is aiming to surpass the current limit by an order of magnitude (^2(2θ13) < 0.03). Details of the detector design, overview of systematic errors and expected sensitivity, as well as current status of the experiment are presented.

Neutrino burst from SN1987A and the solar-neutrino puzzle

International Nuclear Information System (INIS)

Arafune, J.; Fukugita, M.; Yanagida, T.; Yoshimura, M.

1987-01-01

The prompt ν/sub e/ signal from the supernova explosion in the Large Magellanic Cloud presumably detected by Kamiokande II does not necessarily mean that the Mikheyev-Smirnov-Wolfenstein effect on the solar-neutrino flux is not operative. The electron neutrino, once rotated to a different-flavor neutrino in the progenitor star, can come back via the matter-oscillation effect in the Earth, or a residual ν/sub e/ flux from the progenitor can directly hit the detector, saving the Mikheyev-Smirnov-Wolfenstein explanation of the solar-neutrino problem for a range of mixing parameters

Supersymmetric interpretations of the neutrino anomalies

CERN Document Server

Valle, José W F

2002-01-01

Solar and atmospheric neutrino data strongly indicate the need for physics beyond the standard model. The neutrino oscillation interpretation of the atmospheric data is rather unambiguous, with more options still open for the solar data. After a brief summary of the latest global fits of neutrino data, I discuss theoretical neutrino mass models. This is done first from a top-bottom approach inspired by unification ideas involving a see-saw mechanism or high dimension operators. Then I consider bottom-up approaches, with especial emphasis on the idea that the origin of neutrino mass and mixing is intrinsically supersymmetric. Models involve effective bilinear breaking of R-parity. This allows for the possibility of probing the neutrino mixing also in the context of high-energy collider experiments such as the LHC. (41 refs).

The Intermediate Neutrino Program

Energy Technology Data Exchange (ETDEWEB)

Adams, C.; et al.

2015-03-23

The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop.

The Intermediate Neutrino Program

Energy Technology Data Exchange (ETDEWEB)

Adams, C. [Yale Univ., New Haven, CT (United States); Alonso, J. R. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Ankowski, A. M. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Asaadi, J. A. [Syracuse Univ., NY (United States); Ashenfelter, J. [Yale Univ., New Haven, CT (United States); Axani, S. N. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Babu, K [Oklahoma State Univ., Stillwater, OK (United States); Backhouse, C. [California Inst. of Technology (CalTech), Pasadena, CA (United States); Band, H. R. [Yale Univ., New Haven, CT (United States); Barbeau, P. S. [Duke Univ., Durham, NC (United States); Barros, N. [Univ. of Pennsylvania, Philadelphia, PA (United States); Bernstein, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Betancourt, M. [Illinois Inst. of Technology, Chicago, IL (United States); Bishai, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blucher, E. [Univ. of Chicago, IL (United States); Bouffard, J. [State Univ. of New York (SUNY), Albany, NY (United States); Bowden, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brice, S. [Illinois Inst. of Technology, Chicago, IL (United States); Bryan, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Camilleri, L. [Columbia Univ., New York, NY (United States); Cao, J. [Inst. of High Energy Physics, Beijing (China); Carlson, J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carr, R. E. [Columbia Univ., New York, NY (United States); Chatterjee, A. [Univ. of Texas, Arlington, TX (United States); Chen, M. [Univ. of California, Irvine, CA (United States); Chen, S. [Tsinghua Univ., Beijing (China); Chiu, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Church, E. D. [Illinois Inst. of Technology, Chicago, IL (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Collar, J. I. [Univ. of Chicago, IL (United States); Collin, G. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Conrad, J. M. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Convery, M. R. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Cooper, R. L. [Indiana Univ., Bloomington, IN (United States); Cowen, D. [Pennsylvania State Univ., University Park, PA (United States); Davoudiasl, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gouvea, A. D. [Northwestern Univ., Evanston, IL (United States); Dean, D. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deichert, G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Descamps, F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); DeYoung, T. [Michigan State Univ., East Lansing, MI (United States); Diwan, M. V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Djurcic, Z. [Argonne National Lab. (ANL), Argonne, IL (United States); Dolinski, M. J. [Drexel Univ., Philadelphia, PA (United States); Dolph, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Donnelly, B. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Dwyer, D. A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dytman, S. [Univ. of Pittsburgh, PA (United States); Efremenko, Y. [Univ. of Tennessee, Knoxville, TN (United States); Everett, L. L. [Univ. of Wisconsin, Madison, WI (United States); Fava, A. [University of Padua, Padova (Italy); Figueroa-Feliciano, E. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Fleming, B. [Yale Univ., New Haven, CT (United States); Friedland, A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fujikawa, B. K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gaisser, T. K. [Univ. of Delaware, Newark, DE (United States); Galeazzi, M. [Univ. of Miami, FL (United States); Galehouse, DC [Univ. of Akron, OH (United States); Galindo-Uribarri, A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Garvey, G. T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gautam, S. [Tribhuvan Univ., Kirtipur (Nepal); Gilje, K. E. [Illinois Inst. of Technology, Chicago, IL (United States); Gonzalez-Garcia, M. [Stony Brook Univ., NY (United States); Goodman, M. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Gordon, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gramellini, E. [Yale Univ., New Haven, CT (United States); Green, M. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Guglielmi, A. [University of Padua, Padova (Italy); Hackenburg, R. W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hackenburg, A. [Yale Univ., New Haven, CT (United States); Halzen, F. [Univ. of Wisconsin, Madison, WI (United States); Han, K. [Yale Univ., New Haven, CT (United States); Hans, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Harris, D. [Illinois Inst. of Technology, Chicago, IL (United States); Heeger, K. M. [Yale Univ., New Haven, CT (United States); Herman, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hill, R. [Univ. of Chicago, IL (United States); Holin, A. [Univ. College London, Bloomsbury (United Kingdom); Huber, P. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Jaffe, D. E. [Brookhaven National Lab. (BNL), Upton, NY (United States); Johnson, R. A. [Univ. of Cincinnati, OH (United States); Joshi, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Karagiorgi, G. [Univ. of Manchester (United Kingdom); Kaufman, L. J. [Indiana Univ., Bloomington, IN (United States); Kayser, B. [Illinois Inst. of Technology, Chicago, IL (United States); Kettell, S. H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Kirby, B. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Klein, J. R. [Univ. of Texas, Arlington, TX (United States); Kolomensky, Y. G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Kriske, R. M. [Univ. of Minnesota, Minneapolis, MN (United States); Lane, C. E. [Drexel Univ., Philadelphia, PA (United States); Langford, T. J. [Yale Univ., New Haven, CT (United States); Lankford, A. [Univ. of California, Irvine, CA (United States); Lau, K. [Univ. of Houston, TX (United States); Learned, J. G. [Univ. of Hawaii, Honolulu, HI (United States); Ling, J. [Univ. of Illinois, Urbana-Champaign, IL (United States); Link, J. M. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Lissauer, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Littenberg, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Littlejohn, B. R. [Illinois Inst. of Technology, Chicago, IL (United States); Lockwitz, S. [Illinois Inst. of Technology, Chicago, IL (United States); Lokajicek, M. [Inst. of Physics of the Academy of Sciences of Czech Republic, Prague (Czech Republic); Louis, W. C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Luk, K. [Univ. of California, Berkeley, CA (United States); Lykken, J. [Illinois Inst. of Technology, Chicago, IL (United States); Marciano, W. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Maricic, J. [Univ. of Hawaii, Honolulu, HI (United States); Markoff, D. M. [North Carolina Central Univ., Durham, NC (United States); Caicedo, D. A. M. [Illinois Inst. of Technology, Chicago, IL (United States); Mauger, C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mavrokoridis, K. [Univ. of Liverpool (United Kingdom); McCluskey, E. [Illinois Inst. of Technology, Chicago, IL (United States); McKeen, D. [Univ. of Washington, Seattle, WA (United States); McKeown, R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Mills, G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mocioiu, I. [Pennsylvania State Univ., University Park, PA (United States); Monreal, B. [Univ. of California, Santa Barbara, CA (United States); Mooney, M. R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Morfin, J. G. [Illinois Inst. of Technology, Chicago, IL (United States); Mumm, P. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Napolitano, J. [Temple Univ., Philadelphia, PA (United States); Neilson, R. [Drexel Univ., Philadelphia, PA (United States); Nelson, J. K. [College of William and Mary, Williamsburg, VA (United States); Nessi, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Norcini, D. [Yale Univ., New Haven, CT (United States); Nova, F. [Univ. of Texas, Austin, TX (United States); Nygren, D. R. [Univ. of Texas, Arlington, TX (United States); Gann, GDO [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Palamara, O. [Illinois Inst. of Technology, Chicago, IL (United States); Parsa, Z. [Brookhaven National Lab. (BNL), Upton, NY (United States); Patterson, R. [California Inst. of Technology (CalTech), Pasadena, CA (United States); Paul, P. [Stony Brook Univ., NY (United States); Pocar, A. [Univ. of Massachusetts, Amherst, MA (United States); Qian, X. [Brookhaven National Lab. (BNL), Upton, NY (United States); Raaf, J. L. [Illinois Inst. of Technology, Chicago, IL (United States); Rameika, R. [Illinois Inst. of Technology, Chicago, IL (United States); Ranucci, G. [National Inst. of Nuclear Physics, Milano (Italy); Ray, H. [Univ. of Florida, Gainesville, FL (United States); Reyna, D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rich, G. C. [Triangle Universities Nuclear Lab., Durham, NC (United States); Rodrigues, P. [Univ. of Rochester, NY (United States); Romero, E. R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States); Rosero, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rountree, S. D. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Rybolt, B. [Univ. of Tennessee, Knoxville, TN (United States); Sanchez, M. C. [Iowa State Univ., Ames, IA (United States); Santucci, G. [Stony Brook Univ., NY (United States); Schmitz, D. [Univ. of Chicago, IL (United States); Scholberg, K. [Duke Univ., Durham, NC (United States); Seckel, D. [Univ. of Delaware, Newark, DE (United States); Shaevitz, M. [Columbia Univ., New York, NY (United States); Shrock, R. [Stony Brook Univ., NY (United States); Smy, M. B. [Univ. of California, Irvine, CA (United States); Soderberg, M. [Syracuse Univ., NY (United States); Sonzogni, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Sousa, A. B. [Univ. of Cincinnati, OH (United States); Spitz, J. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); John, J. M. S. [Univ. of Cincinnati, OH (United States); Stewart, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Strait, J. B. [Illinois Inst. of Technology, Chicago, IL (United States); Sullivan, G. [Univ. of Maryland, College Park, MD (United States); Svoboda, R. [Univ. of California, Davis, CA (United States); Szelc, A. M. [Yale Univ., New Haven, CT (United States); Tayloe, R. [Indiana Univ., Bloomington, IN (United States); Thomson, M. A. [Univ. of Cambridge (United Kingdom); Toups, M. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Vacheret, A. [Univ. of Oxford (United Kingdom); Vagins, M. [Univ. of California, Irvine, CA (United States); Water, R. G. V. D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vogelaar, R. B. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Weber, M. [Bern (Switzerland); Weng, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wetstein, M. [Univ. of Chicago, IL (United States); White, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); White, B. R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Whitehead, L. [Univ. of Houston, TX (United States); Whittington, D. W. [Indiana Univ., Bloomington, IN (United States); Wilking, M. J. [Stony Brook Univ., NY (United States); Wilson, R. J. [Colorado State Univ., Fort Collins, CO (United States); Wilson, P. [Illinois Inst. of Technology, Chicago, IL (United States); Winklehner, D. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Winn, D. R. [Fairfield Univ., CT (United States); Worcester, E. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yang, L. [Univ. of Illinois, Urbana-Champaign, IL (United States); Yeh, M [Brookhaven National Lab. (BNL), Upton, NY (United States); Yokley, Z. W. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Yoo, J. [Illinois Inst. of Technology, Chicago, IL (United States); Yu, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yu, J. [Univ. of Texas, Arlington, TX (United States); Zhang, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2017-04-03

The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop.

Neutrino Oscillations:. a Phenomenological Approach

Science.gov (United States)

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

We review the status of the neutrino oscillations physics, with a particular emphasis on the present knowledge of the neutrino mass-mixing parameters. We consider first the νμ → ντ flavor transitions of atmospheric neutrinos. It is found that standard oscillations provide the best description of the SK+K2K data, and that the associated mass-mixing parameters are determined at ±1σ (and NDF = 1) as: Δm2 = (2.6 ± 0.4) × 10-3 eV2 and sin 2 2θ = 1.00{ - 0.05}{ + 0.00} . Such indications, presently dominated by SK, could be strengthened by further K2K data. Then we point out that the recent data from the Sudbury Neutrino Observatory, together with other relevant measurements from solar and reactor neutrino experiments, in particular the KamLAND data, convincingly show that the flavor transitions of solar neutrinos are affected by Mikheyev-Smirnov-Wolfenstein (MSW) effects. Finally, we perform an updated analysis of two-family active oscillations of solar and reactor neutrinos in the standard MSW case.

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

Energy Technology Data Exchange (ETDEWEB)

Coleman, Stephen James [College of William and Mary, Williamsburg, VA (United States)

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.

Invariant box-parameterization of neutrino oscillations

International Nuclear Information System (INIS)

Weiler, Thomas J.; Wagner, DJ

1998-01-01

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

Search for sterile neutrinos at a new short-baseline CERN neutrino beam

International Nuclear Information System (INIS)

Mauri, N.

2014-01-01

In the last few years the experimental results on neutrino/anti-neutrino oscillations at Short-Baseline (SBL) showed a tension with several phenomenological models. The recent and carefully recomputed anti-neutrino fluxes from nuclear reactors have further increased this tension drawing a picture not fully compatible with the 3 neutrino oscillation scenario. A sterile neutrino is a neutral lepton which does not couple with W/Z bosons. it is not an exotic particle, its existence being a natural consequence of neutrinos having a non-zero mass. Sterile neutrinos can mix with the active ones through additional mass eigenstates, with no necessary mass scale. We will present an experimental search for sterile neutrinos with a new CERN-SPS neutrino beam using muon spectrometers and large LAr detectors. To definitely clarify the physics issue, the proposed experiment will study oscillations in a muon neutrino / antineutrino beam both in appearance and disappearance modes, exploring the Δm 2 ∼ 1 eV 2 range

Identifying the neutrino mass spectrum from a supernova neutrino burst

International Nuclear Information System (INIS)

Dighe, A.S.; Smirnov, A.Yu.

1999-12-01

We study the role that the future detection of the neutrino burst from a galactic supernova can play in the reconstruction of the neutrino mass spectrum. We consider all possible 3ν mass and flavor spectra which describe the solar and atmospheric neutrino data. For each of these spectra we find the observable effects of the supernova neutrino conversions both in the matter of the star and the earth. We show that studies of the electron neutrino and antineutrino spectra as well as observations of the neutral current effects from supernova will allow us (i) to identify the solar neutrino solution, (ii) to determine the type of mass hierarchy (normal or inverted) and (iii) to probe the mixing vertical bar U e3 vertical bar 2 to values as low as 10 -4 - 10 -3 . (author)

Measurement of the Neutrino Mixing Angle θ23 in NOvA

Science.gov (United States)

Adamson, P.; Aliaga, L.; Ambrose, D.; Anfimov, N.; Antoshkin, A.; Arrieta-Diaz, E.; Augsten, K.; Aurisano, A.; Backhouse, C.; Baird, M.; Bambah, B. A.; Bays, K.; Behera, B.; Bending, S.; Bernstein, R.; Bhatnagar, V.; Bhuyan, B.; Bian, J.; Blackburn, T.; Bolshakova, A.; Bromberg, C.; Brown, J.; Brunetti, G.; Buchanan, N.; Butkevich, A.; Bychkov, V.; Campbell, M.; Catano-Mur, E.; Childress, S.; Choudhary, B. C.; Chowdhury, B.; Coan, T. E.; Coelho, J. A. B.; Colo, M.; Cooper, J.; Corwin, L.; Cremonesi, L.; Cronin-Hennessy, D.; Davies, G. S.; Davies, J. P.; Derwent, P. F.; Desai, S.; Dharmapalan, R.; Ding, P.; Djurcic, Z.; Dukes, E. C.; Duyang, H.; Edayath, S.; Ehrlich, R.; Feldman, G. J.; Frank, M. J.; Gabrielyan, M.; Gallagher, H. R.; Germani, S.; Ghosh, T.; Giri, A.; Gomes, R. A.; Goodman, M. C.; Grichine, V.; Group, R.; Grover, D.; Guo, B.; Habig, A.; Hartnell, J.; Hatcher, R.; Hatzikoutelis, A.; Heller, K.; Himmel, A.; Holin, A.; Hylen, J.; Jediny, F.; Judah, M.; Kafka, G. K.; Kalra, D.; Kasahara, S. M. S.; Kasetti, S.; Keloth, R.; Kolupaeva, L.; Kotelnikov, S.; Kourbanis, I.; Kreymer, A.; Kumar, A.; Kurbanov, S.; Lang, K.; Lee, W. M.; Lin, S.; Liu, J.; Lokajicek, M.; Lozier, J.; Luchuk, S.; Maan, K.; Magill, S.; Mann, W. A.; Marshak, M. L.; Matera, K.; Matveev, V.; Méndez, D. P.; Messier, M. D.; Meyer, H.; Miao, T.; Miller, W. H.; Mishra, S. R.; Mohanta, R.; Moren, A.; Mualem, L.; Muether, M.; Mufson, S.; Murphy, R.; Musser, J.; Nelson, J. K.; Nichol, R.; Niner, E.; Norman, A.; Nosek, T.; Oksuzian, Y.; Olshevskiy, A.; Olson, T.; Paley, J.; Pandey, P.; Patterson, R. B.; Pawloski, G.; Pershey, D.; Petrova, O.; Petti, R.; Phan-Budd, S.; Plunkett, R. K.; Poling, R.; Potukuchi, B.; Principato, C.; Psihas, F.; Radovic, A.; Rameika, R. A.; Rebel, B.; Reed, B.; Rocco, D.; Rojas, P.; Ryabov, V.; Sachdev, K.; Sail, P.; Samoylov, O.; Sanchez, M. C.; Schroeter, R.; Sepulveda-Quiroz, J.; Shanahan, P.; Sheshukov, A.; Singh, J.; Singh, J.; Singh, P.; Singh, V.; Smolik, J.; Solomey, N.; Song, E.; Sousa, A.; Soustruznik, K.; Strait, M.; Suter, L.; Talaga, R. L.; Tamsett, M. C.; Tas, P.; Thayyullathil, R. B.; Thomas, J.; Tian, X.; Tognini, S. C.; Tripathi, J.; Tsaris, A.; Urheim, J.; Vahle, P.; Vasel, J.; Vinton, L.; Vold, A.; Vrba, T.; Wang, B.; Wetstein, M.; Whittington, D.; Wojcicki, S. G.; Wolcott, J.; Yadav, N.; Yang, S.; Zalesak, J.; Zamorano, B.; Zwaska, R.; NOvA Collaboration

2017-04-01

This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure of 6.05 ×1 020 protons on target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal θ23 mixing (θ23=π /4 ). Assuming the normal mass hierarchy, we find Δ m322 =(2.67 ±0.11 )×10-3 eV2 and sin2θ23 at the two statistically degenerate values 0.40 4-0.022+0.030 and 0.62 4-0.030+0.022, both at the 68% confidence level. Our data disfavor the maximal mixing scenario with 2.6 σ significance.

Establishing atmospheric neutrino oscillations with Super-Kamiokande

International Nuclear Information System (INIS)

Kajita, T.; Kearns, E.; Shiozawa, M.

2016-01-01

In this article we review the discovery of atmospheric neutrino oscillation by the Super-Kamiokande experiment. This review outlines the sequence of observations and their associated publications that solved the atmospheric neutrino anomaly and established the existence of neutrino oscillations with nearly maximal mixing of muon neutrinos and tau neutrinos. We also discuss subsequent and ongoing studies that use atmospheric neutrinos to continue to reveal the nature of the neutrino.

Non-Unitarity, sterile neutrinos, and Non-Standard neutrino Interactions

CERN Document Server

Blennow, Mattias; Fernandez-Martinez, Enrique; Hernandez-Garcia, Josu; Lopez-Pavon, Jacobo

2017-04-27

The simplest Standard Model extension to explain neutrino masses involves the addition of right-handed neutrinos. At some level, this extension will impact neutrino oscillation searches. In this work we explore the differences and similarities between the case in which these neutrinos are kinematically accessible (sterile neutrinos) or not (mixing matrix non-unitarity). We clarify apparent inconsistencies in the present literature when using different parametrizations to describe these effects and recast both limits in the popular neutrino non-standard interaction (NSI) formal- ism. We find that, in the limit in which sterile oscillations are averaged out at the near detector, their effects at the far detector coincide with non-unitarity at leading order, even in presence of a matter potential. We also summarize the present bounds existing in both limits and compare them with the expected sensitivities of near-future facilities taking the DUNE proposal as a bench- mark. We conclude that non-unitarity effects ...

Mikheyev-Smirnov-Wolfenstein effect with flavor-changing neutrino interactions

International Nuclear Information System (INIS)

Roulet, E.

1991-01-01

We consider the effect that flavor-nondiagonal neutrino interactions with matter have on the resonant ν oscillations. It is shown that, even in the absence of ν mixing in a vacuum, an efficient conversion of the electron neutrinos from the Sun to another ν flavor can result if the strength of this interaction is ∼10 -2 G F . We show how this can be implemented in the minimal supersymmetric standard model with R-parity breaking. Here, the L-violating couplings induce neutrino masses, mixings, and the flavor-nondiagonal neutrino interactions that can provide a Mikheyev-Smirnov-Wolfenstein-like solution to the solar-neutrino problem even for negligible vacuum mixings

Neutrino oscillations: The rise of the PMNS paradigm

Science.gov (United States)

Giganti, C.; Lavignac, S.; Zito, M.

2018-01-01

Since the discovery of neutrino oscillations, the experimental progress in the last two decades has been very fast, with the precision measurements of the neutrino squared-mass differences and of the mixing angles, including the last unknown mixing angle θ13. Today a very large set of oscillation results obtained with a variety of experimental configurations and techniques can be interpreted in the framework of three active massive neutrinos, whose mass and flavour eigenstates are related by a 3 × 3 unitary mixing matrix, the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix, parametrized by three mixing angles θ12, θ23, θ13 and a CP-violating phase δCP. The additional parameters governing neutrino oscillations are the squared-mass differences Δ mji2 = mj2 - mi2, where mi is the mass of the ith neutrino mass eigenstate. This review covers the rise of the PMNS three-neutrino mixing paradigm and the current status of the experimental determination of its parameters. The next years will continue to see a rich program of experimental endeavour coming to fruition and addressing the three missing pieces of the puzzle, namely the determination of the octant and precise value of the mixing angle θ23, the unveiling of the neutrino mass ordering (whether m1

Non-unitarity, sterile neutrinos, and non-standard neutrino interactions

Energy Technology Data Exchange (ETDEWEB)

Blennow, Mattias [Department of Theoretical Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Albanova University Center, 106 91 Stockholm (Sweden); Coloma, Pilar [Theoretical Physics Department, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Fernandez-Martinez, Enrique; Hernandez-Garcia, Josu [Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco E-28049 Madrid (Spain); Instituto de Física Teórica UAM/CSIC, Calle Nicolás Cabrera 13-15, Cantoblanco E-28049 Madrid (Spain); Lopez-Pavon, Jacobo [INFN, Sezione di Genova, via Dodecaneso 33, 16146 Genova (Italy); CERN, Theoretical Physics Department, Geneva (Switzerland)

2017-04-27

The simplest Standard Model extension to explain neutrino masses involves the addition of right-handed neutrinos. At some level, this extension will impact neutrino oscillation searches. In this work we explore the differences and similarities between the case in which these neutrinos are kinematically accessible (sterile neutrinos) or not (mixing matrix non-unitarity). We clarify apparent inconsistencies in the present literature when using different parametrizations to describe these effects and recast both limits in the popular neutrino non-standard interaction (NSI) formalism. We find that, in the limit in which sterile oscillations are averaged out at the near detector, their effects at the far detector coincide with non-unitarity at leading order, even in presence of a matter potential. We also summarize the present bounds existing in both limits and compare them with the expected sensitivities of near-future facilities taking the DUNE proposal as a benchmark. We conclude that non-unitarity effects are too constrained to impact present or near future neutrino oscillation facilities but that sterile neutrinos can play an important role at long baseline experiments. The role of the near detector is also discussed in detail.

Expections for future neutrino searches at accelerators

International Nuclear Information System (INIS)

Reay, N.W.

1995-01-01

Anomalies in the flux of solar and atmosphere neutrinos have motivated a renaissance in the study of neutrino oscillations. Among many new experiments proposed, approved or commencing to run are several which rely on neutrino beams created at accelerators. These latter can be divided into short-baseline efforts searching at ultra-small mixing for neutrino masses in the cosmologically interesting mass range, and long-baseline efforts searching at larger mixing for oscillations in the mass range suggested by the atmosphere anomaly. A brief summary of these searches will be presented

Invariant box parameterization of neutrino oscillations

International Nuclear Information System (INIS)

Weiler, T.J.; Wagner, D.

1998-01-01

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. copyright 1998 American Institute of Physics

Search for sterile neutrinos with IceCube DeepCore

Energy Technology Data Exchange (ETDEWEB)

Terliuk, Andrii [DESY, Platanenallee 6, 15738 Zeuthen (Germany); Collaboration: IceCube-Collaboration

2016-07-01

The DeepCore detector is a sub-array of the IceCube Neutrino Observatory that lowers the energy threshold for neutrino detection down to approximately 10 GeV. DeepCore is used for a variety of studies including atmospheric neutrino oscillations. The standard three-neutrino oscillation paradigm is tested using the DeepCore detector by searching for an additional light, sterile neutrino with a mass on the order of 1 eV. Sterile neutrinos do not interact with the ordinary matter, however they can be mixed with the three active neutrino states. Such mixture changes the picture of standard neutrino oscillations for atmospheric neutrinos with energies below 100 GeV. The capabilities of DeepCore detector to measure such sterile neutrino mixing will be presented in this talk.

Decoherence effect in neutrinos produced in microquasar jets

Science.gov (United States)

Mosquera, M. E.; Civitarese, O.

2018-04-01

We study the effect of decoherence upon the neutrino spectra produced in microquasar jets. In order to analyse the precession of the polarization vector of neutrinos we have calculated its time evolution by solving the corresponding equations of motion, and by assuming two different scenarios, namely: (i) the mixing between two active neutrinos, and (ii) the mixing between one active and one sterile neutrino. The results of the calculations corresponding to these scenarios show that the onset of decoherence does not depends on the activation of neutrino-neutrino interactions when realistic values of the coupling are used in the calculations. We discuss also the case of neutrinos produced in windy microquasars and compare the results which those obtained with more conventional models of microquasars.

Entanglement in neutrino oscillations

Energy Technology Data Exchange (ETDEWEB)

Blasone, M.; Dell' Anno, F.; De Siena, S.; Illuminati, F. [Universita degli Studi di Salerno Via Ponte don Melillon, Dipt. di Matematica e Informatica, Fisciano SA (Italy); INFN Sezione di Napoli, Gruppo collegato di Salerno - Baronissi SA (Italy); Dell' Anno, F.; De Siena, S.; Illuminati, F. [CNR-INFM Coherentia - Napoli (Italy); Blasone, M. [ISI Foundation for Scientific Interchange, Torino (Italy)

2009-03-15

Flavor oscillations in elementary particle physics are related to multimode entanglement of single-particle states. We show that mode entanglement can be expressed in terms of flavor transition probabilities, and therefore that single-particle entangled states acquire a precise operational characterization in the context of particle mixing. We treat in detail the physically relevant cases of two- and three-flavor neutrino oscillations, including the effective measure of CP violation. We discuss experimental schemes for the transfer of the quantum information encoded in single-neutrino states to spatially delocalized two-flavor charged-lepton states, thus showing, at least in principle, that single-particle entangled states of neutrino mixing are legitimate physical resources for quantum information tasks. (authors)

Entanglement in neutrino oscillations

International Nuclear Information System (INIS)

Blasone, M.; Dell'Anno, F.; De Siena, S.; Illuminati, F.; Dell'Anno, F.; De Siena, S.; Illuminati, F.; Blasone, M.

2009-01-01

Flavor oscillations in elementary particle physics are related to multimode entanglement of single-particle states. We show that mode entanglement can be expressed in terms of flavor transition probabilities, and therefore that single-particle entangled states acquire a precise operational characterization in the context of particle mixing. We treat in detail the physically relevant cases of two- and three-flavor neutrino oscillations, including the effective measure of CP violation. We discuss experimental schemes for the transfer of the quantum information encoded in single-neutrino states to spatially delocalized two-flavor charged-lepton states, thus showing, at least in principle, that single-particle entangled states of neutrino mixing are legitimate physical resources for quantum information tasks. (authors)

An Experimentalist's Overview of Solar Neutrinos

Science.gov (United States)

Oser, Scott M.

2012-02-01

Four decades of solar neutrino research have demonstrated that solar models do a remarkable job of predicting the neutrino fluxes from the Sun, to the extent that solar neutrinos can now serve as a calibrated neutrino source for experiments to understand neutrino oscillations and mixing. In this review article I will highlight the most significant experimental results, with emphasis on the latest model-independent measurements from the Sudbury Neutrino Observatory. The solar neutrino fluxes are seen to be generally well-determined experimentally, with no indications of time variability, while future experiments will elucidate the lower energy part of the neutrino spectrum, especially pep and CNO neutrinos.

An Experimentalist's Overview of Solar Neutrinos

International Nuclear Information System (INIS)

Oser, Scott M

2012-01-01

Four decades of solar neutrino research have demonstrated that solar models do a remarkable job of predicting the neutrino fluxes from the Sun, to the extent that solar neutrinos can now serve as a calibrated neutrino source for experiments to understand neutrino oscillations and mixing. In this review article I will highlight the most significant experimental results, with emphasis on the latest model-independent measurements from the Sudbury Neutrino Observatory. The solar neutrino fluxes are seen to be generally well-determined experimentally, with no indications of time variability, while future experiments will elucidate the lower energy part of the neutrino spectrum, especially pep and CNO neutrinos.

Daya bay reactor neutrino experiment

International Nuclear Information System (INIS)

Cao Jun

2010-01-01

Daya Bay Reactor Neutrino Experiment is a large international collaboration experiment under construction. The experiment aims to precisely determine the neutrino mixing angle θ 13 by detecting the neutrinos produced by the Daya Bay Nuclear Power Plant. θ 13 is one of two unknown fundamental parameters in neutrino mixing. Its magnitude is a roadmap of the future neutrino physics, and very likely related to the puzzle of missing antimatter in our universe. The precise measurement has very important physics significance. The detectors of Daya Bay is under construction now. The full operation is expected in 2011. Three years' data taking will reach the designed the precision, to determine sin 2 2θ 13 to better than 0.01. Daya Bay neutrino detector is an underground large nuclear detector of low background, low energy, and high precision. In this paper, the layout of the experiment, the design and fabrication progress of the detectors, and some highlighted nuclear detecting techniques developed in the detector R and D are introduced. (author)

Looking for Cosmic Neutrino Background

Directory of Open Access Journals (Sweden)

Chiaki eYanagisawa

2014-06-01

Full Text Available Since the discovery of neutrino oscillation in atmospheric neutrinos by the Super-Kamiokande experiment in 1998, study of neutrinos has been one of exciting fields in high-energy physics. All the mixing angles were measured. Quests for 1 measurements of the remaining parameters, the lightest neutrino mass, the CP violating phase(s, and the sign of mass splitting between the mass eigenstates m3 and m1, and 2 better measurements to determine whether the mixing angle theta23 is less than pi/4, are in progress in a well-controlled manner. Determining the nature of neutrinos, whether they are Dirac or Majorana particles is also in progress with continuous improvement. On the other hand, although the ideas of detecting cosmic neutrino background have been discussed since 1960s, there has not been a serious concerted effort to achieve this goal. One of the reasons is that it is extremely difficult to detect such low energy neutrinos from the Big Bang. While there has been tremendous accumulation of information on Cosmic Microwave Background since its discovery in 1965, there is no direct evidence for Cosmic Neutrino Background. The importance of detecting Cosmic Neutrino Background is that, although detailed studies of Big Bang Nucleosynthesis and Cosmic Microwave Background give information of the early Universe at ~a few minutes old and ~300 k years old, respectively, observation of Cosmic Neutrino Background allows us to study the early Universe at $sim$ 1 sec old. This article reviews progress made in the past 50 years on detection methods of Cosmic Neutrino Background.

Neutrino-Flavoured Sneutrino Dark Matter

CERN Document Server

March-Russell, John; McCullough, Matthew

2010-01-01

A simple theory of supersymmetric dark matter (DM) naturally linked to neutrino flavour physics is studied. The DM sector comprises a spectrum of mixed lhd-rhd sneutrino states where both the sneutrino flavour structure and mass splittings are determined by the associated neutrino masses and mixings. Prospects for indirect detection from solar capture are good due to a large sneutrino-nucleon cross-section afforded by the inelastic splitting (solar capture limits exclude an explanation of DAMA/LIBRA). We find parameter regions where all heavier states will have decayed, leaving only one flavour mixture of sneutrino as the candidate DM. Such regions have a unique `smoking gun' signature--sneutrino annihilation in the Sun produces a pair of neutrino mass eigenstates free from vacuum oscillations, with the potential for detection at neutrino telescopes through the observation of a hard spectrum of nu_mu and nu_tau (for a normal neutrino hierarchy). Next generation direct detection experiments can explore much of...

A search for oscillations of muon-neutrinos to electron-neutrinos

CERN Document Server

Procario, Michael

1986-01-01

The author has searched in the heavy liquid bubble chamber BEBC for electron neutrino charge current events which could arise from oscillation of the muon neutrinos (average energy ∼1.5 GeV) obtained with a low energy proton beam at the CERN PS targeted 825 m upstream from BEBC. The appearance of electron neutrino CC interactions provides a sensitive indication of nu/sub μ/ → nu/sub e/ oscillation. The author observed 460 muon neutrino CC events and 4 electron neutrino CC events with an estimated background of 3.5 electron neutrino CC events. Using the likelihood ratio method to test the oscillation hypothesis, the author finds no evidence for nu/sub μ/ → nu/sub e/ oscillation and set the limits δm2 ≤ 0.13 eV2 (maximal mixing) and sin22theta ≤ 0.018 for δm2 = 3 eV2 at 90% confidence level

Tests of CPT invariance at neutrino factories

International Nuclear Information System (INIS)

Bilenky, Samoil M.; Freund, Martin; Lindner, Manfred; Ohlsson, Tommy; Winter, Walter

2002-01-01

We investigate possible tests of CPT invariance on the level of event rates at neutrino factories. We do not assume any specific model but phenomenological differences in the neutrino-antineutrino masses and mixing angles in a Lorentz invariance preserving context, such as could be induced by physics beyond the standard model. We especially focus on the muon neutrino and antineutrino disappearance channels in order to obtain constraints on the neutrino-antineutrino mass and mixing angle differences; we found, for example, that the sensitivity |m 3 -m(bar sign) 3 |(less-or-similar sign)1.9x10 -4 eV could be achieved

The MSW Effect and Matter Effects in Neutrino Oscillations

Science.gov (United States)

Smirnov, A. Yu.

2006-03-01

The MSW (Mikheyev-Smirnov-Wolfenstein) effect is the adiabatic or partially adiabatic neutrino flavor conversion in media with varying density. The main notions related to the effect, its dynamics and physical picture are reviewed. The large mixing MSW effect is realized inside the Sun providing a solution of the solar neutrino problem. The small mixing MSW effect driven by the 1-3 mixing can be realized for the supernova (SN) neutrinos. Inside collapsing stars new elements of the MSW dynamics may show up: non-oscillatory transition, non-adiabatic conversion, time dependent adiabaticity violation induced by shock waves. Effects of the resonance enhancement and the parametric enhancement of oscillations can be realized for atmospheric and accelerator neutrinos in the Earth. Precise results for neutrino oscillations in low density media with arbitrary density profile are presented and the attenuation effect is described. The area of applications is the solar and SN neutrinos inside the Earth, and the results are crucial for the neutrino oscillation tomography.

Measurement of the Neutrino Mixing Angle θ.sub.23./sub. in NOvA

Czech Academy of Sciences Publication Activity Database

Adamson, P.; Aliaga, L.; Ambrose, D.; Lokajíček, Miloš; Zálešák, Jaroslav

2017-01-01

Roč. 118, č. 15 (2017), s. 1-7, č. článku 151802. ISSN 0031-9007 R&D Projects: GA MŠk LM2015068; GA MŠk(CZ) LG15047 Institutional support: RVO:68378271 Keywords : muon tau * symmetry * mass * hierarchy * neutrino * mixing * NOvA * experimental results Sub ject RIV: BF - Elementary Particles and High Energy Physics OBOR OECD: Particles and field physics Impact factor: 8.462, year: 2016

Status of non-standard neutrino interactions

International Nuclear Information System (INIS)

Ohlsson, Tommy

2013-01-01

The phenomenon of neutrino oscillations has been established as the leading mechanism behind neutrino flavor transitions, providing solid experimental evidence that neutrinos are massive and lepton flavors are mixed. Here we review sub-leading effects in neutrino flavor transitions known as non-standard neutrino interactions (NSIs), which is currently the most explored description for effects beyond the standard paradigm of neutrino oscillations. In particular, we report on the phenomenology of NSIs and their experimental and phenomenological bounds as well as an outlook for future sensitivity and discovery reach. (review article)

Implication of the solar neutrino experiments

International Nuclear Information System (INIS)

Dar, A.; Nussinov, S.

1992-01-01

The recent results from the KAMIOKANDE II and BAKSAN solar neutrino experiments, if correct, imply that lepton flavour is not conserved. The Mikheyev-Smirnov-Wolfenstein (MSW) solution to the solar neutrino problem, which was first exposed by the HOMESTAKE Cl experiment, fully explains also these results if the electron neutrino is mixed with the muon neutrino or the tau neutrino with mixing parameters Δm 2 ≅ 10 -6 eV 2 2 and sin 2 Θ ≅ 4 x 10 -2 . This MSW solution can be tested with the new generation of solar neutrino experiments which will be able to detect both the predicted distortion of the spectrum of 8 B solar νe's and the 'missing' ν e 's that appear as ν μ 's or ν τ 's. Further evidence may be obtained from the day-night effect and from the flavour content of the neutronization burst from the birth of a neutron star in a nearby supernova. Moreover, the MSW solution combined with the seesaw mechanism for generating neutrino masses further suggests m νe ≅ 10 -8 eV, m νμ ≅ 10 -3 cV, m ντ ≅ 10eV, and sin 2 2Θ ≅ 4x10 -2 for ν μ ν τ mixing. These predictions can be tested by previously proposed neutrino oscillation experiments at accelerators and by detecting neutrinos from a nearby supernova explosion. A tau neutrino with m ντ ≅ 10 eV can account for most of the dark matter in the Universe and is a viable candidate for the hot dark matter scenario of the formation of large scale structure in the Universe. (orig.)

Neutrino sunshine

International Nuclear Information System (INIS)

Anon.

1993-01-01

deficit is taken very seriously, and has led to ideas of neutrino oscillations, and oscillation resonances. If the different neutrino varieties - electron, muon and tau - have a mass, then they can oscillate between themselves. A neutrino beam starting off as pure muon-type, for example, would change its composition as it went along. Setting limits on this behaviour is an important objective in neutrino experiments, with 'long baseline' studies - beams covering a long distance between source and detector, playing a vital role. Lincoln Wolfenstein, one of the architects of the new neutrino oscillation scenarios, says 'it is still not clear whether neutrinos have masses or not'. Laboratory experiments try to measure these masses, but so far only upper Unfits have been established. These studies are beginning to reach the limit of their sensitivity and are unlikely to improve drastically. 'But there is indirect evidence,' says Wolfenstein, 'that neutrinos are much lighter.' The solar neutrino problem is really to solar neutrino opportunity,' he continues. Future experiments with gallium and other new neutrino detection techniques, coupled with new high energy neutrino studies, will answer the question

Physics of the neutrino mass

International Nuclear Information System (INIS)

Mohapatra, R N

2004-01-01

Recent neutrino oscillation experiments have yielded valuable information on the nature of neutrino masses and mixings and qualify as the first evidence for physics beyond the standard model. Even though we are far from a complete understanding of the new physics implied by them, there are many useful hints. As the next precision era in neutrino physics is about to be launched, we review the physics of neutrino mass: what we have learned and what we are going to learn

Magnus approximation in neutrino oscillations

International Nuclear Information System (INIS)

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

2011-01-01

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.

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

Energy Technology Data Exchange (ETDEWEB)

Yang, Tingjun [Stanford Univ., CA (United States)

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 (Δm_atm² and Δm_sol²), three mixing angles (θ₁₂, θ₂₃, and θ₁₃) and one CP violating phase (δ_CP). 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. δ_CP 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 Δm_atm² 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

Search for active-sterile neutrino mixing using neutral-current interactions in NOvA

Czech Academy of Sciences Publication Activity Database

Adamson, P.; Aliaga, L.; Ambrose, D.; Lokajíček, Miloš; Zálešák, Jaroslav

2017-01-01

Roč. 96, č. 7 (2017), s. 1-9, č. článku 072006. ISSN 2470-0010 R&D Projects: GA MŠk LM2015068; GA MŠk(CZ) LG15047 Institutional support: RVO:68378271 Keywords : NOvA * Fermilab * mass difference * near detector * far detector * mixing angle * neutrino * oscillation * experimental results Subject RIV: BF - Elementary Particles and High Energy Physics OBOR OECD: Particles and field physics Impact factor: 4.568, year: 2016

Total cross section measurement of muon neutrinos on isoscalar target. Exact determination of the electroweak mixing parameter

International Nuclear Information System (INIS)

Pain, R.

1987-09-01

The work presented in this thesis is concerned with high energy muon-neutrino nucleon interactions. The experiment was performed at CERN in 1984 using the CHARM marble target-calorimeter exposed to the 160 GeV narrow band beam. The experimental analysis is based on an event-by-event classification of neutral currents (NC) and charged currents (CC) interactions and on precise measurements of neutrinos and antineutrinos fluxes. This leads to precise measurements of CC total cross-sections of neutrinos and antineutrinos between 10 and 160 GeV and of NC to CC ratios of total cross-sections of events with hadron energy greater than 4 GeV: R n eutrino and R a ntineutrino. From the measurements of R n eutrino and of the ratio of CC total cross-sections of antineutrinos and neutrinos, we obtain a high precision value of the electroweak mixing angle. Comparison of this result with those obtained in proton-antiproton collisions make it possible to derive a measurement of electroweak radiative corrections and a precise determination of ρ [fr

Neutrino oscillations. Theory and experiment

International Nuclear Information System (INIS)

Beshtoev, Kh.M.

2001-01-01

Theoretical schemes on neutrino oscillations are considered. The experimental data on neutrino oscillations obtained in the Super-Kamiokande (Japan) and SNO (Canada) experiments are given. Comparison of these data with the predictions obtained in the theoretical schemes is done. Conclusion is made that the experimental data confirm only the scheme with transitions (oscillations) between aromatic ν e -, ν μ -, ν τ - neutrinos with maximal angle mixings. (author)

Pulsar kicks from a dark-matter sterile neutrino

International Nuclear Information System (INIS)

Fuller, George M.; Kusenko, Alexander; Mocioiu, Irina; Pascoli, Silvia

2003-01-01

We show that a sterile neutrino with a mass in the 1-20 keV range and a small mixing with the electron neutrino can simultaneously explain the origin of the pulsar motions and the dark matter in the Universe. An asymmetric neutrino emission from a hot nascent neutron star can be the explanation of the observed pulsar velocities. In addition to the pulsar kick mechanism based on resonant neutrino transitions, we point out a new possibility: an asymmetric off-resonant emission of sterile neutrinos. The two cases correspond to different values of the masses and mixing angles. In both cases we identify the ranges of parameters consistent with the pulsar kick, as well as cosmological constraints

Addendum to "Compact Perturbative Expressions for Neutrino Oscillations in Matter"

Energy Technology Data Exchange (ETDEWEB)

Denton, Peter B. [Bohr Inst.; Minakata, Hisakazu [CSIC, Madrid; Parke, Stephen J. [Fermilab

2018-01-19

In this paper we rewrite the neutrino mixing angles and mass squared differences in matter given, in our original paper, in a notation that is more conventional for the reader. Replacing the usual neutrino mixing angles and mass squared differences in the expressions for the vacuum oscillation probabilities with these matter mixing angles and mass squared differences gives an excellent approximation to the oscillation probabilities in matter. Comparisons for T2K, NOvA, T2HKK and DUNE are also given for neutrinos and anti-neutrinos, disappearance and appearance channels, normal ordering and inverted ordering.

Minimalistic Neutrino Mass Model

CERN Document Server

De Gouvêa, A; Gouvea, Andre de

2001-01-01

We consider the simplest model which solves the solar and atmospheric neutrino puzzles, in the sense that it contains the smallest amount of beyond the Standard Model ingredients. The solar neutrino data is accounted for by Planck-mass effects while the atmospheric neutrino anomaly is due to the existence of a single right-handed neutrino at an intermediate mass scale between 10^9 GeV and 10^14 GeV. Even though the neutrino mixing angles are not exactly predicted, they can be naturally large, which agrees well with the current experimental situation. Furthermore, the amount of lepton asymmetry produced in the early universe by the decay of the right-handed neutrino is very predictive and may be enough to explain the current baryon-to-photon ratio if the right-handed neutrinos are produced out of thermal equilibrium. One definitive test for the model is the search for anomalous seasonal effects at Borexino.

Solar Neutrino Day-Night Effect

International Nuclear Information System (INIS)

Blennow, Mattias; Ohlsson, Tommy; Snellman, Hakan

2005-01-01

We summarize the results of Ref. [M. Blennow, T. Ohlsson and H. Snellman, Phys. Rev. D 69 (2004) 073006, hep-ph/0311098] in which we determine the effects of three flavor mixing on the day-night asymmetry in the flux of solar neutrinos. Analytic methods are used to determine the difference in the day and night solar electron neutrino survival probabilities and numerical methods are used to determine the effect of three flavor mixing at detectors

Question of neutrino mass

International Nuclear Information System (INIS)

Branco, G.C.; Senjanovic, G.

1978-01-01

We investigate the question of neutrino mass in theories in which neutrinos are four-component Dirac particles. Our analysis is done in the framework of left-right--symmetric theories. The requirement of calculability and natural smallness of neutrino mass leads to the following constraints: (i) left and right charged weak currents must be ''orthogonal'' to each other, and (ii) there should be no W/sub L/-W/sub R/ mixing at the three level. Finally, we exhibit a model in which, due to the existence of an unbroken symmetry of the total Lagrangian, the electron and muon neutrinos remain massless to all orders in perturbation theory

Search for sterile neutrinos in MINOS and MINOS+ using a two-detector fit

Energy Technology Data Exchange (ETDEWEB)

Adamson, P.; et al.

2017-10-17

A search for mixing between active neutrinos and light sterile neutrinos has been performed by looking for muon neutrino disappearance in two detectors at baselines of 1.04 km and 735 km, using a combined MINOS and MINOS+ exposure of $16.36\\times10^{20}$ protons-on-target. A simultaneous fit to the charged-current muon neutrino and neutral-current neutrino energy spectra in the two detectors yields no evidence for sterile neutrino mixing using a 3+1 model. The most stringent limit to date is set on the mixing parameter $\\sin^2\\theta_{24}$ for most values of the sterile neutrino mass-splitting $\\Delta m^2_{41} > 10^{-4}$ eV$^2$.

Parametrization of Seesaw Models and Light Sterile Neutrinos

CERN Document Server

Blennow, Mattias

2011-01-01

The recent recomputation of the neutrino fluxes from nuclear reactors relaxes the tension between the LSND and MiniBooNE anomalies and disappearance data when interpreted in terms of sterile neutrino oscillations. The simplest extension of the Standard Model with such fermion singlets is the addition of right-handed sterile neutrinos with small Majorana masses. Even when introducing three right-handed neutrinos, this scenario has less free parameters than the 3+2 scenarios studied in the literature. This begs the question whether the best fit regions obtained can be reproduced by this simplest extension of the Standard Model. In order to address this question, we devise an exact parametrization of Standard Model extensions with right-handed neutrinos. Apart from the usual 3x3 neutrino mixing matrix and the 3 masses of the lightest neutrinos, the extra degrees of freedom are encoded in another 3x3 unitary matrix and 3 additional mixing angles. The parametrization includes all the correlations among masses and ...

Majorana neutrinos in a warped 5D standard model

International Nuclear Information System (INIS)

Huber, S.J.; Shafi, Q.

2002-05-01

We consider neutrino oscillations and neutrinoless double beta decay in a five dimensional standard model with warped geometry. Although the see-saw mechanism in its simplest form cannot be implemented because of the warped geometry, the bulk standard model neutrinos can acquire the desired (Majorana) masses from dimension five interactions. We discuss how large mixings can arise, why the large mixing angle MSW solution for solar neutrinos is favored, and provide estimates for the mixing angle U e3 . Implications for neutrinoless double beta decay are also discussed. (orig.)

Flavor origin of dark matter and its relation with leptonic nonzero θ{sub 13} and Dirac CP phase δ

Energy Technology Data Exchange (ETDEWEB)

Bhattacharya, Subhaditya; Karmakar, Biswajit [Department of Physics, Indian Institute of Technology Guwahati,781039 Assam (India); Sahu, Narendra [Department of Physics, Indian Institute of Technology,Hyderabad, Kandi, Sangareddy 502285, Medak, Telengana (India); Sil, Arunansu [Department of Physics, Indian Institute of Technology Guwahati,781039 Assam (India)

2017-05-12

We propose a minimal extension of the standard model by including a U(1) flavor symmetry to establish a correlation between the relic abundance of dark matter, measured by WMAP and PLANCK satellite experiments and non-zero value of sin θ{sub 13} observed at DOUBLE CHOOZ, Daya Bay, RENO and T2K. The flavour symmetry is allowed to be broken at a high scale to a remnant Z{sub 2} symmetry, which not only ensures the stability to the dark matter, but also gives rise to a modification to the existing A{sub 4}-based tri-bimaximal neutrino mixing. This deviation in turn suggests the required non-zero value of sin θ{sub 13}. We assume the dark matter to be neutral under the existing A{sub 4} symmetry while charged under the U(1) flavor symmetry. Hence in this set-up, the non-zero value of sin θ{sub 13} predicts the dark matter charge under U(1), which can be tested at various ongoing and future direct and collider dark matter search experiments. We also point out the involvement of nonzero leptonic CP phase δ, which plays an important role in the analysis.

Constraints on three flavor neutrino mixing

Indian Academy of Sciences (India)

expression for electron neutrino survival probability, integrated over the time of .... the numerator and the theoretical uncertainty in the denominator, added in quadrature. .... There are detailed Monte Carlo predictions for these fluxes, and they.

Exploring new features of neutrino oscillations with very low energy monoenergetic neutrinos

CERN Document Server

Vergados, J D

2010-01-01

In the present work we propose to study neutrino oscillations employing sources of monoenergetic neutrinos following electron capture by the nucleus. Since the neutrino energy is very low the smaller of the two oscillation lengths, L23, appearing in this electronic neutrino disappearance experiment can be so small that the full oscillation can take place inside the detector and one may determine very accurately the neutrino oscillation parameters. Since in this case the oscillation probability is proportional to theta13, one can measure or set a better limit on the unknown parameter theta13. This is quite important, since, if this mixing angle vanishes, there is not going to be CP violation in the leptonic sector. The best way to detect it is by measuring electron recoils in neutrino-electron scattering. One, however, has to pay the price that the expected counting rates are very small. Thus one needs a very intensive neutrino source and a large detector with as low as possible energy threshold and high energ...

Direct cosmic ray muons and atmospheric neutrinos

International Nuclear Information System (INIS)

Ryazhskaya, O.G.; Volkova, L.V.; Zatsepin, G.T.

2005-01-01

A possible contribution of very short living particles (particles with life-time much shorter than that of charmed particles), for example, resonances, into cosmic ray muon and atmospheric neutrino fluxes (direct muons and neutrinos) is estimated. This contribution could become of the same order of magnitude as that from pions and kaons (conventional) already at energies of hundreds TeV and tens TeV for muons and muon neutrinos coming to the sea level in the vertical direction correspondingly. Of course, the estimation has quite a qualitative character and even it is quite arbitrary but it is necessary to keep this contribution in mind when studying EAS, cosmic ray muon component or trying to interpret data of experiments on cosmic neutrino searching at high energies

The status of the solar neutrino problem and the Russian-American gallium experiment (SAGE)

International Nuclear Information System (INIS)

Bowles, T.J.

1994-01-01

Perhaps the most outstanding discrepancy between prediction and measurements in current particle physics comes from the solar neutrino problem, in which a large deficit of high-energy solar neutrinos is observed. Many Nonstandard Solar Models have been invoked to try to reduce the predicted flux, but all have run into problems in trying to reproduce other measured parameters (e.g., the luminosity) of the Sun. Other explanations involving new physics such as neutrino decay and neutrino oscillations, etc. have also been proffered. Again, most of these explanations have been ruled out by either laboratory or astrophysical measurements. It appears that perhaps the most likely particle physics solution is that of matter enhanced neutrino oscillation, the Mikheyev-Smirnov-Wolfenstein (MSW) oscillations. Two new radiochemical gallium experiments, which have a low enough threshold to be sensitive to the dominant flux of low-energy p-p neutrinos, now also report a deficit and also favor a particle physics solution

A three-parameter neutrino mass matrix with maximal CP violation

International Nuclear Information System (INIS)

Grimus, W.; Lavoura, L.

2009-01-01

Using the seesaw mechanism, we construct a model for the light-neutrino Majorana mass matrix which yields trimaximal lepton mixing together with maximal CP violation and maximal atmospheric-neutrino mixing. We demonstrate that, in our model, the light-neutrino mass matrix retains its form under the one-loop renormalization-group evolution. With our neutrino mass matrix, the absolute neutrino mass scale is a function of |U e3 | and of the atmospheric mass-squared difference. We study the effective mass in neutrinoless ββ decay as a function of |U e3 |, showing that it contains a fourfold ambiguity

Zooming in on neutrino oscillations with DUNE

Science.gov (United States)

Srivastava, Rahul; Ternes, Christoph A.; Tórtola, Mariam; Valle, José W. F.

2018-05-01

We examine the capabilities of the DUNE experiment as a probe of the neutrino mixing paradigm. Taking the current status of neutrino oscillations and the design specifications of DUNE, we determine the experiment's potential to probe the structure of neutrino mixing and C P violation. We focus on the poorly determined parameters θ23 and δC P and consider both two and seven years of run. We take various benchmarks as our true values, such as the current preferred values of θ23 and δC P, as well as several theory-motivated choices. We determine quantitatively DUNE's potential to perform a precision measurement of θ23, as well as to test the C P violation hypothesis in a model-independent way. We find that, after running for seven years, DUNE will make a substantial step in the precise determination of these parameters, bringing to quantitative test the predictions of various theories of neutrino mixing.

Present status and future prospects of the atmospheric neutrino experiments

International Nuclear Information System (INIS)

Kajita, Takaaki

2003-01-01

During the last several years, the understanding of the neutrino masses and mixings has been improved significantly. In this paper, we discuss neutrino oscillation studies in atmospheric neutrino experiments. Prospects of future atmospheric neutrino experiments are also discussed

Sterile neutrinos and indirect dark matter searches in IceCube

Science.gov (United States)

Argüelles, Carlos A.; Kopp, Joachim

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.

Neutrino Oscillation Results from NOvA

CERN Multimedia

CERN. Geneva

2016-01-01

NOvA is an accelerator long-baseline neutrino oscillation experiment optimised to measure electron neutrino appearance in a high-purity beam of muon neutrinos from Fermilab. The exciting discovery of the theta13 neutrino mixing angle in 2012 has opened a door to making multiple new measurements of neutrinos. These include leptonic CP violation, the neutrino mass ordering and the octant of theta23. NOvA with its 810km baseline and higher energy beam has about triple the matter effect of T2K which opens a new window on the neutrino mass ordering. With about 20% of our design beam exposure and significant analysis improvements we have recently released updated results. I will present both our disappearance and appearance measurements.

Simulating nonlinear neutrino flavor evolution

Energy Technology Data Exchange (ETDEWEB)

Duan, H [Institute for Nuclear Theory, University of Washington, Seattle, WA 98195 (United States); Fuller, G M [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States); Carlson, J [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)], E-mail: hduan@phys.washington.edu, E-mail: gfuller@ucsd.edu, E-mail: carlson@lanl.gov

2008-10-01

We discuss a new kind of astrophysical transport problem: the coherent evolution of neutrino flavor in core collapse supernovae. Solution of this problem requires a numerical approach which can simulate accurately the quantum mechanical coupling of intersecting neutrino trajectories and the associated nonlinearity which characterizes neutrino flavor conversion. We describe here the two codes developed to attack this problem. We also describe the surprising phenomena revealed by these numerical calculations. Chief among these is that the nonlinearities in the problem can engineer neutrino flavor transformation which is dramatically different to that in standard Mikheyev-Smirnov-Wolfenstein treatments. This happens even though the neutrino mass-squared differences are measured to be small, and even when neutrino self-coupling is sub-dominant. Our numerical work has revealed potential signatures which, if detected in the neutrino burst from a Galactic core collapse event, could reveal heretofore unmeasurable properties of the neutrinos, such as the mass hierarchy and vacuum mixing angle {theta}{sub 13}.

Simulating nonlinear neutrino flavor evolution

Science.gov (United States)

Duan, H.; Fuller, G. M.; Carlson, J.

2008-10-01

We discuss a new kind of astrophysical transport problem: the coherent evolution of neutrino flavor in core collapse supernovae. Solution of this problem requires a numerical approach which can simulate accurately the quantum mechanical coupling of intersecting neutrino trajectories and the associated nonlinearity which characterizes neutrino flavor conversion. We describe here the two codes developed to attack this problem. We also describe the surprising phenomena revealed by these numerical calculations. Chief among these is that the nonlinearities in the problem can engineer neutrino flavor transformation which is dramatically different to that in standard Mikheyev Smirnov Wolfenstein treatments. This happens even though the neutrino mass-squared differences are measured to be small, and even when neutrino self-coupling is sub-dominant. Our numerical work has revealed potential signatures which, if detected in the neutrino burst from a Galactic core collapse event, could reveal heretofore unmeasurable properties of the neutrinos, such as the mass hierarchy and vacuum mixing angle θ13.

Neutrino oscillations at proton accelerators

International Nuclear Information System (INIS)

Michael, Douglas

2002-01-01

Data from many different experiments have started to build a first glimpse of the phenomenology associated with neutrino oscillations. Results on atmospheric and solar neutrinos are particularly clear while a third result from LSND suggests a possibly very complex oscillation phenomenology. As impressive as the results from current experiments are, it is clear that we are just getting started on a long-term experimental program to understand neutrino masses, mixings and the physics which produce them. A number of exciting fundamental physics possibilities exist, including that neutrino oscillations could demonstrate CP or CPT violation and could be tied to exotic high-energy phenomena including strings and extra dimensions. A complete exploration of oscillation phenomena demands many experiments, including those possible using neutrino beams produced at high energy proton accelerators. Most existing neutrino experiments are statistics limited even though they use gigantic detectors. High intensity proton beams are essential for producing the intense neutrino beams which we need for next generation neutrino oscillation experiments

Neutrino Oscillations at Proton Accelerators

Science.gov (United States)

Michael, Douglas

2002-12-01

Data from many different experiments have started to build a first glimpse of the phenomenology associated with neutrino oscillations. Results on atmospheric and solar neutrinos are particularly clear while a third result from LSND suggests a possibly very complex oscillation phenomenology. As impressive as the results from current experiments are, it is clear that we are just getting started on a long-term experimental program to understand neutrino masses, mixings and the physics which produce them. A number of exciting fundamental physics possibilities exist, including that neutrino oscillations could demonstrate CP or CPT violation and could be tied to exotic high-energy phenomena including strings and extra dimensions. A complete exploration of oscillation phenomena demands many experiments, including those possible using neutrino beams produced at high energy proton accelerators. Most existing neutrino experiments are statistics limited even though they use gigantic detectors. High intensity proton beams are essential for producing the intense neutrino beams which we need for next generation neutrino oscillation experiments.

Highlights from e-EPS: Neutrino Oscillation / DPG President / Outreach Database

CERN Multimedia

2012-01-01

e-EPS News is a monthly addition to the CERN Bulletin line-up, showcasing articles from e-EPS – the European Physical Society newsletter – as part of a collaboration between the two publications.   Asian experiments unlock neutrino oscillation mystery Two reactor experiments, China’s Daya Bay and Korea’s RENO, have made the best measurement of the neutrino mixing angle, θ13, an essential property for neutrino research. The discovery of a non-zero θ13 at approximately 9˚ – which was published in March and April this year – completes our picture of neutrino mixing. This quite large value for the mixing angle will make it easier to conduct future long baseline neutrino experiments. This, in turn, may lead to a better understanding of the matter-antimatter asymmetry seen in the Universe. Neutrino oscillations – the change in flavour&a...

Muon neutrino disappearance at MINOS

International Nuclear Information System (INIS)

Armstrong, R.

2009-01-01

A strong case has been made by several experiments that neutrinos oscillate, although important questions remain as to the mechanisms and precise values of the parameters. In the standard picture, two parameters describe the nature of how the neutrinos oscillate: the mass-squared difference between states and the mixing angle. The purpose of this thesis is to use data from the MINOS experiment to precisely measure the parameters associated with oscillations first observed in studies of atmospheric neutrinos. MINOS utilizes two similar detectors to observe the oscillatory nature of neutrinos. The Near Detector, located 1 km from the source, observes the unoscillated energy spectrum while the Far Detector, located 735 km away, is positioned to see the oscillation signal. Using the data in the Near Detector, a prediction of the expected neutrino spectrum at the Far Detector assuming no oscillations is made. By comparing this prediction with the MINOS data, the atmospheric mixing parameters are measured to be Δm 32 2 = 2.45 +0.12 -0.12 x 10 -3 eV 2 and sin 2 (2θ 32 ) = 1.00 -0.04 +0.00 (> 0.90 at 90% confidence level).

Neutrino mass hierarchy and three-flavor spectral splits of supernova neutrinos

International Nuclear Information System (INIS)

Dasgupta, Basudeb; Mirizzi, Alessandro; Tomas, Ricard; Tamborra, Irene

2010-01-01

It was recently realized that three-flavor effects could peculiarly modify the development of spectral splits induced by collective oscillations, for supernova neutrinos emitted during the cooling phase of a protoneutron star. We systematically explore this case, explaining how the impact of these three-flavor effects depends on the ordering of the neutrino masses. In inverted mass hierarchy, the solar mass splitting gives rise to instabilities in regions of the (anti)neutrino energy spectra that were otherwise stable under the leading two-flavor evolution governed by the atmospheric mass splitting and by the 1-3 mixing angle. As a consequence, the high-energy spectral splits found in the electron (anti)neutrino spectra disappear, and are transferred to other flavors. Imperfect adiabaticity leads to smearing of spectral swap features. In normal mass hierarchy, the three-flavor and the two-flavor instabilities act in the same region of the neutrino energy spectrum, leading to only minor departures from the two-flavor treatment.

Sterile neutrinos beyond LSND at the neutrino factory

International Nuclear Information System (INIS)

Meloni, Davide; Tang Jian; Winter, Walter

2010-01-01

We discuss the effects of one additional sterile neutrino at the Neutrino Factory. Compared to earlier analyses, which have been motivated by Liquid Scintillator Neutrino Detector (LSND) results, we do not impose any constraint on the additional mass squared splitting. This means that the additional mass eigenstate could, with small mixings, be located among the known ones, as it is suggested by the recent analysis of cosmological data. We use a self-consistent framework at the Neutrino Factory without any constraints on the new parameters. We demonstrate for a combined short and long baseline setup that near detectors can provide the expected sensitivity at the LSND-motivated Δm 41 2 -range, while some sensitivity can also be obtained in the region of the atmospheric mass splitting from the long baselines. We point out that limits on such very light sterile neutrinos may also be obtained from a reanalysis of atmospheric and solar neutrino oscillation data, as well as from supernova neutrino observations. In the second part of the analysis, we compare our sensitivity with the existing literature using additional assumptions, such as |Δm 41 2 |>>|Δm 31 2 |, leading to averaging of the fast oscillations in the far detectors. We demonstrate that while the Neutrino Factory has excellent sensitivity compared to existing studies using similar assumptions, one has to be very careful interpreting these results for a combined short and long baseline setup where oscillations could occur in the near detectors. We also test the impact of additional ν τ detectors at the short and long baselines, and we do not find a substantial improvement of the sensitivities.

Reconstructing neutrino properties from collider experiments in a Higgs triplet neutrino mass model

International Nuclear Information System (INIS)

Aristizabal Sierra, D.; Hirsch, M.; Valle, J. W. F.; Villanova del Moral, A.

2003-01-01

We extend the minimal supersymmetric standard model with bilinear R-parity violation to include a pair of Higgs triplet superfields. The neutral components of the Higgs triplets develop small vacuum expectation values (VEVs) quadratic in the bilinear R-parity breaking parameters. In this scheme the atmospheric neutrino mass scale arises from bilinear R-parity breaking while for reasonable values of parameters the solar neutrino mass scale is generated from the small Higgs triplet VEVs. We calculate neutrino masses and mixing angles in this model and show how the model can be tested at future colliders. The branching ratios of the doubly charged triplet decays are related to the solar neutrino angle via a simple formula

Neutrino mass hierarchy determination via atmospheric neutrinos with future detectors

International Nuclear Information System (INIS)

Gandhi, Raj; Ghoshal, Pomita; Goswami, Srubabati; Mehta, Poonam; Sankar, S Uma; Shalgar, Shashank

2008-01-01

The issue of determining the neutrino mass hierarchy is one of the outstanding questions in neutrino physics. We consider the potential of hierarchy determination using atmospheric neutrinos as the source in three different proposed future detectors: A large Iron Calorimeter detector, a megaton Water Cerenkov detector and a large-mass Liquid Argon detector. If the mixing angle θ 13 is about 10 deg. (close to CHOOZ upper bound), the hierarchy sensitivity is essentially determined by resonant matter effects. To maximize the potential of these effects in atmospheric neutrinos, charge discrimination capability in the detector is desirable. Hence, detectors with this capability have an advantage in hierarchy determination. We compare and contrast the performance of the above three detectors in this respect. We perform a realistic analysis of the above future detectors for atmospheric neutrinos and show that it is possible to achieve a significant hierarchy sensitivity if the detector characteristics are favourable. Note: The abstract has been modified from its original form to incorporate suggestions received during the conference. The poster is being submitted in its original form.

Experimental Neutrino Physics

Energy Technology Data Exchange (ETDEWEB)

Wilkes, Richard Jeffrey [Univ. of Washington, Seattle, WA (United States)

2017-11-15

The University of Washington (UW) HEP neutrino group performed experimental research on the physics of neutrinos, using the capabilities offered by the T2K Experiment and the Super-Kamiokande Neutrino Observatory. The UW group included senior investigator R. J. Wilkes, two PhD students, four MS degree students, and a research engineer, all of whom are members of the international scientific collaborations for T2K and Super-Kamiokande. During the period of support, within T2K we pursued new precision studies sensitive to new physics, going beyond the limits of current measurements of the fundamental neutrino oscillation parameters (mass differences and mixing angles). We began efforts to measure (or significantly determine the absence of) 1 the CP-violating phase parameter δCP and determine the neutrino mass hierarchy. Using the Super-Kamiokande (SK) detector we pursued newly increased precision in measurement of neutrino oscillation parameters with atmospheric neutrinos, and extended the current reach in searches for proton decay, in addition to running the most sensitive supernova watch instrument [Scholberg 2012], performing other astrophysical neutrino studies, and analyzing beam-induced events from T2K. Overall, the research addressed central questions in the field of particle physics. It included the training of graduate students (both PhD and professional MS degree students), and postdoctoral researchers. Undergraduate students also participated as laboratory assistants.

Neutrino oscillations in Gallium and reactor experiments and cosmological effects of a light sterile neutrino

International Nuclear Information System (INIS)

Acero-Ortega, Mario Andres

2009-01-01

Neutrino oscillations is a very well studied phenomenon and the observations from Solar, very-long-baseline Reactor, Atmospheric and Accelerator neutrino oscillation experiments give very robust evidence of three-neutrino mixing. On the other hand, some experimental data have shown anomalies that could be interpreted as indication of exotic neutrino physics beyond three-neutrino mixing. Furthermore, from a cosmological point of view, the possibility of extra light species contributing as a subdominant hot (or warm) component of the Universe is still interesting. In the first part of this Thesis, we focused on the anomaly observed in the Gallium radioactive source experiments. These experiments were done to test the Gallium solar neutrino detectors GALLEX and SAGE, by measuring the electron neutrino flux produced by intense artificial radioactive sources placed inside the detectors. The measured number of events was smaller than the expected one. We interpreted this anomaly as a possible indication of the disappearance of electron neutrinos and, in the effective framework of two-neutrino mixing, we obtained sin 2 2θ ≥ 0.03 and Δm 2 ≥ 0.1 eV 2 . We also studied the compatibility of this result with the data of the Bugey and Chooz reactor antineutrino disappearance experiments. We found that the Bugey data present a hint of neutrino oscillations with 0.02 ≤ sin 2 2θ ≤ 0.07 and Δm 2 ≅ 1.95 eV 2 , which is compatible with the Gallium allowed region of the mixing parameters. Then, combining the data of Bugey and Chooz, the data of Gallium and Bugey, and the data of Gallium, Bugey and Chooz, we found that this hint persists, with an acceptable compatibility of the experimental data. Furthermore, we analyzed the experimental data of the I.L.L., S.R.S, and Gosgen nuclear Reactor experiments. We obtained a good fit of the I.L.L. data, showing 1 and 2σ allowed regions in the oscillation parameters space. However, the combination of I.L.L. data with the Bugey

Mirror model for sterile neutrinos

International Nuclear Information System (INIS)

Berezinsky, Veniamin; Narayan, Mohan; Vissani, Francesco

2003-01-01

Sterile neutrinos are studied as subdominant contribution to solar neutrino physics. The mirror-matter neutrinos are considered as sterile neutrinos. We use the symmetric mirror model with gravitational communication between mirror and visible sectors. This communication term provides mixing between visible and mirror neutrinos with the basic scale μ=v EW 2 /M Pl =2.5x10 -6 eV, where v EW =174 GeV is the vacuum expectation value of the standard electroweak group and M Pl is the Planckian mass. It is demonstrated that each mass eigenstate of active neutrinos splits into two states separated by small Δm 2 . Unsuppressed oscillations between active and sterile neutrinos (ν a ↔ν s ) occur only in transitions between each of these close pairs ('windows'). These oscillations are characterized by very small Δm 2 and can suppress the flux and distort spectrum of pp-neutrinos in detectable way. The other observable effect is anomalous seasonal variation of neutrino flux, which appears in LMA solution. The considered subdominant neutrino oscillations ν a ↔ν s can reveal itself as big effects in observations of supernova neutrinos and high-energy (HE) neutrinos. In the case of HE neutrinos they can provide a very large diffuse flux of active neutrinos unconstrained by the e-m cascade upper limit

Deep Secrets of the Neutrino: Physics Underground

Energy Technology Data Exchange (ETDEWEB)

Rowson, P.C.

2010-03-23

Among the many beautiful, unexpected and sometimes revolutionary discoveries to emerge from subatomic physics, probably none is more bizarre than an elementary particle known as the 'neutrino'. More than a trillion of these microscopic phantoms pass unnoticed through our bodies every second, and indeed, through the entire Earth - but their properties remain poorly understood. In recent years, exquisitely sensitive experiments, often conducted deep below ground, have brought neutrino physics to the forefront. In this talk, we will explore the neutrino - what we know, what we want to know, and how one experiment in a New Mexico mine is trying to get there.

Radiative stability of neutrino-mass textures

Indian Academy of Sciences (India)

physics pp. 647-650. Radiative stability of neutrino-mass textures. M K PARIDA ... A major challenge to particle physics at present is the theoretical understanding of ... A possible origin of two large neutrino mixings for /e -/μ and /μ -/г but small.

First measurement of muon-neutrino disappearance in NOvA

Czech Academy of Sciences Publication Activity Database

Adamson, P.; Ader, C.; Andrews, M.; Lokajíček, Miloš; Zálešák, Jaroslav

2016-01-01

Roč. 93, č. 5 (2016), 1-8, č. článku 051104. ISSN 2470-0010 R&D Projects: GA MŠk(CZ) LG15047; GA MŠk LM2015068 Institutional support: RVO:68378271 Keywords : neutrino: oscillation * neutrino/mu: beam * neutrino * mixing angle * neutrino: mass difference * neutrino * mass: hierarchy * NOvA Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.568, year: 2016

Simulation of coherent nonlinear neutrino flavor transformation in the supernova environment: Correlated neutrino trajectories

Science.gov (United States)

Duan, Huaiyu; Fuller, George M.; Carlson, J.; Qian, Yong-Zhong

2006-11-01

We present results of large-scale numerical simulations of the evolution of neutrino and antineutrino flavors in the region above the late-time post-supernova-explosion proto-neutron star. Our calculations are the first to allow explicit flavor evolution histories on different neutrino trajectories and to self-consistently couple flavor development on these trajectories through forward scattering-induced quantum coupling. Employing the atmospheric-scale neutrino mass-squared difference (|δm2|≃3×10-3eV2) and values of θ13 allowed by current bounds, we find transformation of neutrino and antineutrino flavors over broad ranges of energy and luminosity in roughly the “bi-polar” collective mode. We find that this large-scale flavor conversion, largely driven by the flavor off-diagonal neutrino-neutrino forward scattering potential, sets in much closer to the proto-neutron star than simple estimates based on flavor-diagonal potentials and Mikheyev-Smirnov-Wolfenstein evolution would indicate. In turn, this suggests that models of r-process nucleosynthesis sited in the neutrino-driven wind could be affected substantially by active-active neutrino flavor mixing, even with the small measured neutrino mass-squared differences.

The NESSiE Concept for Sterile Neutrinos

CERN Document Server

Stanco, L; Bagulya, A; Benettoni, M; Bernardini, P; Bertolin, A; Brugnera, R; Calabrese, M; Cecchetti, A; Cecchini, S; Chernyavskiy, M; Collazuol, G; Creti, P; Corso, F Dal; Dalkarov, O; Del Prete, A; De Mitri, I; De Robertis, G; De Serio, M; Esposti, L Degli; Di Ferdinando, D; Dore, U; Dusini, S; Dzhatdoev, T; Fanin, C; Fini, R A; Fiore, G; Galati, G; Garfagnini, A; Giacomelli, G; Giacomelli, R; Golovanov, S; Guandalin, C; Guerzoni, M; Klicek, B; Kose, U; Jakovcic, K; Laurenti, G; Laveder, M; Lippi, I; Loddo, F; Longhin, A; Loverre, P; Malenica, M; Mancarella, G; Mandrioli, G; Margiotta, A; Marsella, G; Mauri, N; Medinaceli, E; Mengucci, A; Mezzetto, M; Michinelli, R; Mingazheva, R; Morgunova, O; Muciaccia, M T; Orecchini, D; Paoloni, A; Papadia, G; Paparella, L; Pastore, A; Patrizii, L; Polukhina, N; Pozzato, M; Roda, M; Roganova, T; Rosa, G; Sahnoun, Z; Simone, S; Sioli, M; Sirignano, C; Sirri, G; Spurio, M; Starkov, N; Stipcevic, M; Surdo, A; Tenti, M; Togo, V; Ventura, M; Vladymyrov, M; Zago, M

2013-01-01

Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing problem of new physics beyond the Standard Model. The recent measurement of the third mixing angle theta13 in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, several puzzling measurements exist, which deserve an exhaustive evaluation. The NESSiE Collaboration has been setup to undertake a definitive experiment to clarify the muon disappearance measurements at small L/E, which will be able to put severe constraints to any model with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. Within the context of the current CERN project, aimed to revitalize the neutrino field in Europe, we will illustrate the achievements that can be obtained by a double muon-spectrometer system, with emphasis on the search ...

The Deep Underground Neutrino Experiment: The precision era of neutrino physics

Energy Technology Data Exchange (ETDEWEB)

Kemp, E. [Gleb Wataghin Institute of Physics, Universidade de Campinas - UNICAMP, Campinas Brazil

2017-12-01

The last decade was remarkable for neutrino physics. In particular, the phenomenon of neutrino flavor oscillations has been firmly established by a series of independent measurements. All parameters of the neutrino mixing are now known, and we have the elements to plan a judicious exploration of new scenarios that are opened by these recent advances. With precise measurements, we can test the three-neutrino paradigm, neutrino mass hierarchy, and charge conjugation parity (CP) asymmetry in the lepton sector. The future long-baseline experiments are considered to be a fundamental tool to deepen our knowledge of electroweak interactions. The Deep Underground Neutrino Experiment (DUNE) will detect a broadband neutrino beam from Fermilab in an underground massive liquid argon time-projection chamber at an L/E of about 103 km GeV-1 to reach good sensitivity for CP-phase measurements and the determination of the mass hierarchy. The dimensions and the depth of the far detector also create an excellent opportunity to look for rare signals like proton decay to study violation of the baryonic number, as well as supernova neutrino bursts, broadening the scope of the experiment to astrophysics and associated impacts in cosmology. In this paper, we discuss the physics motivations and the main experimental features of the DUNE project required to reach its scientific goals.

Neutrino masses and beyond from supersymmetry

International Nuclear Information System (INIS)

Kong, O.C.W.

2004-01-01

A generic form of the supersymmetric SM naturally gives rise to the lepton number violating neutrino masses and mixings, without the need for extra superfields beyond the minimal spectrum. Hence, SUSY can be considered the origin of beyond SM properties of neutrinos. We have developed a formulation under which one can efficiently analyze the model. Various sources of neutrino masses are discussed. Such mass contributions come from lepton number and flavor violating couplings that also give rise to a rich phenomenology of the neutrinos and other leptons, also to be discussed. (author)

A liquid scintillator detector for the solar neutrino

Energy Technology Data Exchange (ETDEWEB)

Ranucci, G [Lab. Nazionali del Gran Sasso, Assergi (Italy) Massachusetts Inst. of Technology, Cambridge, MA (United States) Joint Inst. for Nuclear Research, Dubna (USSR) Technical Univ. of Munich, Garching (Germany) Physics Dept., Univ. Genova (Italy) INFN, Genova (Italy) Univ. Hawaii, Honolulu, HI (United States) CCR Euratom, Ispra (Italy) Physics Dept., Univ. Milano (Italy) INFN, Milano (Italy) AT and T Bell Lab., Murray Hill, NJ (United States) Physics Dept., Univ. Pavia (Italy) INFN, Pavia (Italy) Physics Dept., Univ. Perugia (Italy) INFN, Perugia (Italy) Drexel Univ., Philadelphia, PA (United States) Charles Univ., Prague (Czechoslovakia) Czech Technical Univ., Prague (Czechoslovakia); Borex Collaboration

1992-05-01

Results of the three solar neutrino experiments presently running strongly suggest new neutrino physics scenarios to explain the discrepancy between the expected and measured neutrino flux. New experiments are needed to decide among the several theoretical explanations for this that has become known as the solar neutrino problem. This paper describes the unique features of the proposed low energy solar neutrino detector Borexino, that fully exploiting the powerful handless of liquid scintillation spectroscopy on large scale, will probe emerging suggestions on scenarios invoking neutrino mass mixing and magnetic moment. (orig.).

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

Energy Technology Data Exchange (ETDEWEB)

Cooper, N.G. [ed.

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.

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

International Nuclear Information System (INIS)

Cooper, N.G.

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

Do high-energy neutrinos travel faster than photons in a discrete space-time?

Energy Technology Data Exchange (ETDEWEB)

Xue Shesheng, E-mail: xue@icra.it [ICRANeT, Piazzale della Repubblica, 10-65122, Pescara, Physics Department, University of Rome ' ' La Sapienza' ' , Rome (Italy)

2011-12-06

The recent OPERA measurement of high-energy neutrino velocity, once independently verified, implies new physics in the neutrino sector. We revisit the theoretical inconsistency of the fundamental high-energy cutoff attributing to quantum gravity with the parity-violating gauge symmetry of local quantum field theory describing neutrinos. This inconsistency suggests high-dimension operators of neutrino interactions. Based on these studies, we try to view the OPERA result, high-energy neutrino oscillations and indicate to observe the restoration of parity conservation by measuring the asymmetry of high-energy neutrinos colliding with left- and right-handed polarized electrons.

Scientific Opportunities with the Long-Baseline Neutrino Experiment

Energy Technology Data Exchange (ETDEWEB)

Adams, C.; et al.

2013-07-28

In this document, we describe the wealth of science opportunities and capabilities of LBNE, the Long-Baseline Neutrino Experiment. LBNE has been developed to provide a unique and compelling program for the exploration of key questions at the forefront of particle physics. Chief among the discovery opportunities are observation of CP symmetry violation in neutrino mixing, resolution of the neutrino mass hierarchy, determination of maximal or near-maximal mixing in neutrinos, searches for nucleon decay signatures, and detailed studies of neutrino bursts from galactic supernovae. To fulfill these and other goals as a world-class facility, LBNE is conceived around four central components: (1) a new, intense wide-band neutrino source at Fermilab, (2) a fine-grained `near' neutrino detector just downstream of the source, (3) the Sanford Underground Research Facility (SURF) in Lead, South Dakota at an optimal distance (~1300 km) from the neutrino source, and (4) a massive liquid argon time-projection chamber (LArTPC) deployed there as a 'far' detector. The facilities envisioned are expected to enable many other science opportunities due to the high event rates and excellent detector resolution from beam neutrinos in the near detector and atmospheric neutrinos in the far detector. This is a mature, well developed, world class experiment whose relevance, importance, and probability of unearthing critical and exciting physics has increased with time.

Relativistic N-body simulations with massive neutrinos

Science.gov (United States)

Adamek, Julian; Durrer, Ruth; Kunz, Martin

2017-11-01

Some of the dark matter in the Universe is made up of massive neutrinos. Their impact on the formation of large scale structure can be used to determine their absolute mass scale from cosmology, but to this end accurate numerical simulations have to be developed. Due to their relativistic nature, neutrinos pose additional challenges when one tries to include them in N-body simulations that are traditionally based on Newtonian physics. Here we present the first numerical study of massive neutrinos that uses a fully relativistic approach. Our N-body code, gevolution, is based on a weak-field formulation of general relativity that naturally provides a self-consistent framework for relativistic particle species. This allows us to model neutrinos from first principles, without invoking any ad-hoc recipes. Our simulation suite comprises some of the largest neutrino simulations performed to date. We study the effect of massive neutrinos on the nonlinear power spectra and the halo mass function, focusing on the interesting mass range between 0.06 eV and 0.3 eV and including a case for an inverted mass hierarchy.

Large or small angle MSW from single right-handed neutrino dominance

International Nuclear Information System (INIS)

King, S.F

2000-01-01

In this talk we discuss a natural explanation of both neutrino mass hierarchies and large neutrino mixing angles, as required by the atmospheric neutrino data, in terms of a single right-handed neutrino giving the dominant contribution to the 23 block of the light effective neutrino matrix, and illustrate this mechanism in the framework of models with U(1) family symmetries. Sub-dominant contributions from other right-handed neutrinos are required to give small mass splittings appropriate to the MSW solution to the solar neutrino problem. We present three explicit examples for achieving the small angle MSW solution in the framework of U(1) family symmetry models containing three right-handed neutrinos, which can naturally describe all quark and lepton masses and mixing angles. In this talk we also extend the analysis to the large angle MSW solution

Physics Reach with a Monochromatic Neutrino Beam from Electron Capture

CERN Document Server

Bernabeu, J.; Espinoza, C.; Lindroos, M.

2005-01-01

Neutrino oscillation experiments from different sources have demonstrated non-vanishing neutrino masses and flavour mixings. The next experiments have to address the determination of the connecting mixing U(e3) and the existence of the CP violating phase. Whereas U(e3) measures the strength of the oscillation probability in appearance experiments, the CP phase acts as a phase-shift in the interference pattern. Here we propose to separate these two parameters by energy dependence, using the novel idea of a monochromatic neutrino beam facility based on the acceleration of ions that decay fast through electron capture. Fine tuning of the boosted neutrino energy allows precision measurements able to open a window for the discovery of CP violation, even for a mixing as small as 1 degree

Fermion masses and mixings in the 3-3-1 model with right-handed neutrinos based on the S{sub 3} flavor symmetry

Energy Technology Data Exchange (ETDEWEB)

Hernandez, A.E.C. [Universidad Tecnica Federico Santa Maria, Valparaiso (Chile); Martinez, R.; Ochoa, F. [Universidad Nacional de Colombia, Departamento de Fisica, Bogota (Colombia)

2016-11-15

We propose a 3-3-1 model where the SU(3){sub C} x SU(3){sub L} x U(1){sub X} symmetry is extended by S{sub 3} x Z{sub 3} x Z{sub 3}{sup '} x Z{sub 8} x Z{sub 16} and the scalar spectrum is enlarged by extra SU(3){sub L} singlet scalar fields. The model successfully describes the observed SM fermion mass and mixing pattern. In this framework, the light active neutrino masses arise via an inverse seesaw mechanism and the observed charged fermion mass and quark mixing hierarchy is a consequence of the Z{sub 3} x Z{sub 3}{sup '} x Z{sub 8} x Z{sub 16} symmetry breaking at very high energy. The obtained physical observables for both quark and lepton sectors are compatible with their experimental values. The model predicts the effective Majorana neutrino mass parameter of neutrinoless double beta decay to be m{sub ββ} = 4 and 48 meV for the normal and the inverted neutrino spectra, respectively. Furthermore, we found a leptonic Dirac CP-violating phase close to (π)/(2) and a Jarlskog invariant close to about 3 x 10{sup -2} for both normal and inverted neutrino mass hierarchy. (orig.)

Absolute values of neutrino masses: status and prospects

International Nuclear Information System (INIS)

Bilenky, S.M.; Giunti, C.; Grifols, J.A.; Masso, E.

2003-01-01

Compelling evidences in favor of neutrino masses and mixing obtained in the last years in Super-Kamiokande, SNO, KamLAND and other neutrino experiments made the physics of massive and mixed neutrinos a frontier field of research in particle physics and astrophysics. There are many open problems in this new field. In this review we consider the problem of the absolute values of neutrino masses, which apparently is the most difficult one from the experimental point of view. We discuss the present limits and the future prospects of β-decay neutrino mass measurements and neutrinoless double-β decay. We consider the important problem of the calculation of nuclear matrix elements of neutrinoless double-β decay and discuss the possibility to check the results of different model calculations of the nuclear matrix elements through their comparison with the experimental data. We discuss the upper bound of the total mass of neutrinos that was obtained recently from the data of the 2dF Galaxy Redshift Survey and other cosmological data and we discuss future prospects of the cosmological measurements of the total mass of neutrinos. We discuss also the possibility to obtain information on neutrino masses from the observation of the ultra high-energy cosmic rays (beyond the GZK cutoff). Finally, we review the main aspects of the physics of core-collapse supernovae, the limits on the absolute values of neutrino masses from the observation of SN1987A neutrinos and the future prospects of supernova neutrino detection

Neutrino oscillations in strong magnetic fields

International Nuclear Information System (INIS)

Likhachev, G.G.; Studenikin, A.I.

1994-07-01

Neutrino conversion processes between two neutrino species and the corresponding oscillations induced by strong magnetic fields are considered. The value of the critical strength of magnetic field B cr as a function of characteristics of neutrinos in vacuum (Δm 2 ν , mixing angle θ), effective particle density of matter n eff , neutrino (transition) magnetic moment μ-tilde and energy E is introduced. It is shown that the neutrino conversion and oscillations effects induced by magnetic fields B ≥ B cr are important and may result in the depletion of the initial type of ν's in the bunch. A possible increase of these effects in the case when neutrinos pass through a sudden decrease of density of matter (''cross-boundary effect'') and applications to neutrinos from neutron stars and supernova are discussed. (author). 25 refs

Phenomenology of neutrino oscillations at the neutrino factory

International Nuclear Information System (INIS)

Tang, Jian

2011-01-01

We consider the prospects for a neutrino factory measuring mixing angles, the CP violating phase and mass-squared differences by detecting wrong-charge muons arising from the chain μ + → ν e → ν μ → μ - and the right-charge muons coming from the chain μ + → anti ν μ → anti ν μ → μ - (similar to μ - chains), where ν e → ν μ and anti ν μ → anti ν μ are neutrino oscillation channels through a long baseline. First, we study physics with near detectors and consider the treatment of systematic errors including cross section errors, flux errors, and background uncertainties. We illustrate for which measurements near detectors are required, discuss how many are needed, and what the role of the flux monitoring is. We demonstrate that near detectors are mandatory for the leading atmospheric parameter measurements if the neutrino factory has only one baseline, whereas systematic errors partially cancel if the neutrino factory complex includes the magic baseline. Second, we perform the baseline and energy optimization of the neutrino factory including the latest simulation results from the magnetized iron neutrino detector (MIND). We also consider the impact of τ decays, generated by appearance channels ν μ → ν τ and ν e → ν τ , on the discovery reaches of the mass orderings, the leptonic CP violation, and the non-zero θ 13 , which we find to be negligible for the considered detector. Third, we make a comparison of a high energy neutrino factory to a low energy neutrino factory and find that they are just two versions of the same experiment optimized for different regions of the parameter space. In addition, we briefly comment on whether it is useful to build the bi-magic baseline at the low energy neutrino factory. Finally, the effects of one additional massive sterile neutrino are discussed in the context of a combined short and long baseline setup. It is found that near detectors can provide the required sensitivity at the

Neutrino mass hierarchy and matter effects

OpenAIRE

Smirnov, Alexei Yu.

2013-01-01

Matter effects modify the mixing and the effective masses of neutrinos in a way which depends on the neutrino mass hierarchy. Consequently, for normal and inverted hierarchies the oscillations and flavor conversion results are different. Sensitivity to the mass hierarchy appears whenever the matter effects on the 1-3 mixing and mass splitting become substantial. This happens in supernovae in wide energy range and in the matter of the Earth. The Earth density profile is a multi-layer medium wh...

Atmospheric neutrino-induced muons in the MACRO detector

CERN Document Server

Ronga, F

1999-01-01

A measurement of the flux of neutrino-induced muons using the MACRO detector is presented. Different event topologies, corresponding to different neutrino parent energies can be detected. The upward throughgoing muon sample is the larger event sample. The observed upward-throughgoing muons are 26% fewer than expected and the zenith angle distribution does not fit with the expected one. Assuming neutrino oscillations, both measurements suggest maximum mixing and Dm2 of a few times 10-3 eV2. The other samples are due to the internally produced events and to upward-going stopping muons. These data show a regular deficit of observed events in each angular bin, as expected assuming neutrino oscillations with maximum mixing, in agreement with the analysis of the upward-throughgoing muon sample.

The high mass frontier: limits on heavy neutrinos

International Nuclear Information System (INIS)

Gronau, M.

1984-01-01

The theoretical motivation for a search for heavy neutrinos is discussed followed by the presentation of typical model dependent expectations for the mixing of the latter with ordinary neutrinos. Present mass and mixing limits on such heavy neutral leptons are based on search for secondary peaks in π and K leptonic decays and on the absence of neutrino decay signatures in neutrino beams from conventional sources and beam dumps. While these limits are quite poor for masses above 1 GeV, we describe methods to extend the limits to masses in the many GeV region. Such limits may be derived from search in b decays, high statistics neutrino experiments, search in ep colliders, W and Z decays and finally - decays of very heavy gauge bosons (if such exist in the TeV region) when produced in multi-TeV pp and antipp colliders

Neutrino physics with JUNO

Science.gov (United States)

An, Fengpeng; An, Guangpeng; An, Qi; Antonelli, Vito; Baussan, Eric; Beacom, John; Bezrukov, Leonid; Blyth, Simon; Brugnera, Riccardo; Buizza Avanzini, Margherita; Busto, Jose; Cabrera, Anatael; Cai, Hao; Cai, Xiao; Cammi, Antonio; Cao, Guofu; Cao, Jun; Chang, Yun; Chen, Shaomin; Chen, Shenjian; Chen, Yixue; Chiesa, Davide; Clemenza, Massimiliano; Clerbaux, Barbara; Conrad, Janet; D'Angelo, Davide; De Kerret, Hervé; Deng, Zhi; Deng, Ziyan; Ding, Yayun; Djurcic, Zelimir; Dornic, Damien; Dracos, Marcos; Drapier, Olivier; Dusini, Stefano; Dye, Stephen; Enqvist, Timo; Fan, Donghua; Fang, Jian; Favart, Laurent; Ford, Richard; Göger-Neff, Marianne; Gan, Haonan; Garfagnini, Alberto; Giammarchi, Marco; Gonchar, Maxim; Gong, Guanghua; Gong, Hui; Gonin, Michel; Grassi, Marco; Grewing, Christian; Guan, Mengyun; Guarino, Vic; Guo, Gang; Guo, Wanlei; Guo, Xin-Heng; Hagner, Caren; Han, Ran; He, Miao; Heng, Yuekun; Hsiung, Yee; Hu, Jun; Hu, Shouyang; Hu, Tao; Huang, Hanxiong; Huang, Xingtao; Huo, Lei; Ioannisian, Ara; Jeitler, Manfred; Ji, Xiangdong; Jiang, Xiaoshan; Jollet, Cécile; Kang, Li; Karagounis, Michael; Kazarian, Narine; Krumshteyn, Zinovy; Kruth, Andre; Kuusiniemi, Pasi; Lachenmaier, Tobias; Leitner, Rupert; Li, Chao; Li, Jiaxing; Li, Weidong; Li, Weiguo; Li, Xiaomei; Li, Xiaonan; Li, Yi; Li, Yufeng; Li, Zhi-Bing; Liang, Hao; Lin, Guey-Lin; Lin, Tao; Lin, Yen-Hsun; Ling, Jiajie; Lippi, Ivano; Liu, Dawei; Liu, Hongbang; Liu, Hu; Liu, Jianglai; Liu, Jianli; Liu, Jinchang; Liu, Qian; Liu, Shubin; Liu, Shulin; Lombardi, Paolo; Long, Yongbing; Lu, Haoqi; Lu, Jiashu; Lu, Jingbin; Lu, Junguang; Lubsandorzhiev, Bayarto; Ludhova, Livia; Luo, Shu; Lyashuk, Vladimir; Möllenberg, Randolph; Ma, Xubo; Mantovani, Fabio; Mao, Yajun; Mari, Stefano M.; McDonough, William F.; Meng, Guang; Meregaglia, Anselmo; Meroni, Emanuela; Mezzetto, Mauro; Miramonti, Lino; Mueller, Thomas; Naumov, Dmitry; Oberauer, Lothar; Ochoa-Ricoux, Juan Pedro; Olshevskiy, Alexander; Ortica, Fausto; Paoloni, Alessandro; Peng, Haiping; Peng, Jen-Chieh; Previtali, Ezio; Qi, Ming; Qian, Sen; Qian, Xin; Qian, Yongzhong; Qin, Zhonghua; Raffelt, Georg; Ranucci, Gioacchino; Ricci, Barbara; Robens, Markus; Romani, Aldo; Ruan, Xiangdong; Ruan, Xichao; Salamanna, Giuseppe; Shaevitz, Mike; Sinev, Valery; Sirignano, Chiara; Sisti, Monica; Smirnov, Oleg; Soiron, Michael; Stahl, Achim; Stanco, Luca; Steinmann, Jochen; Sun, Xilei; Sun, Yongjie; Taichenachev, Dmitriy; Tang, Jian; Tkachev, Igor; Trzaska, Wladyslaw; van Waasen, Stefan; Volpe, Cristina; Vorobel, Vit; Votano, Lucia; Wang, Chung-Hsiang; Wang, Guoli; Wang, Hao; Wang, Meng; Wang, Ruiguang; Wang, Siguang; Wang, Wei; Wang, Yi; Wang, Yi; Wang, Yifang; Wang, Zhe; Wang, Zheng; Wang, Zhigang; Wang, Zhimin; Wei, Wei; Wen, Liangjian; Wiebusch, Christopher; Wonsak, Björn; Wu, Qun; Wulz, Claudia-Elisabeth; Wurm, Michael; Xi, Yufei; Xia, Dongmei; Xie, Yuguang; Xing, Zhi-zhong; Xu, Jilei; Yan, Baojun; Yang, Changgen; Yang, Chaowen; Yang, Guang; Yang, Lei; Yang, Yifan; Yao, Yu; Yegin, Ugur; Yermia, Frédéric; You, Zhengyun; Yu, Boxiang; Yu, Chunxu; Yu, Zeyuan; Zavatarelli, Sandra; Zhan, Liang; Zhang, Chao; Zhang, Hong-Hao; Zhang, Jiawen; Zhang, Jingbo; Zhang, Qingmin; Zhang, Yu-Mei; Zhang, Zhenyu; Zhao, Zhenghua; Zheng, Yangheng; Zhong, Weili; Zhou, Guorong; Zhou, Jing; Zhou, Li; Zhou, Rong; Zhou, Shun; Zhou, Wenxiong; Zhou, Xiang; Zhou, Yeling; Zhou, Yufeng; Zou, Jiaheng

2016-03-01

. Detection of neutrinos from all past core-collapse supernova explosions in the visible universe with JUNO would further provide valuable information on the cosmic star-formation rate and the average core-collapse neutrino energy spectrum. Antineutrinos originating from the radioactive decay of uranium and thorium in the Earth can be detected in JUNO with a rate of ˜400 events per year, significantly improving the statistics of existing geoneutrino event samples. Atmospheric neutrino events collected in JUNO can provide independent inputs for determining the MH and the octant of the {θ }23 mixing angle. Detection of the 7Be and 8B solar neutrino events at JUNO would shed new light on the solar metallicity problem and examine the transition region between the vacuum and matter dominated neutrino oscillations. Regarding light sterile neutrino topics, sterile neutrinos with {10}-5 {{{eV}}}2\\lt {{Δ }}{m}412\\lt {10}-2 {{{eV}}}2 and a sufficiently large mixing angle {θ }14 could be identified through a precise measurement of the reactor antineutrino energy spectrum. Meanwhile, JUNO can also provide us excellent opportunities to test the eV-scale sterile neutrino hypothesis, using either the radioactive neutrino sources or a cyclotron-produced neutrino beam. The JUNO detector is also sensitive to several other beyondthe-standard-model physics. Examples include the search for proton decay via the p\\to {K}++\\bar{ν } decay channel, search for neutrinos resulting from dark-matter annihilation in the Sun, search for violation of Lorentz invariance via the sidereal modulation of the reactor neutrino event rate, and search for the effects of non-standard interactions. The proposed construction of the JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics in a timely and cost-effective fashion. It holds the great potential for further advancing our quest to understanding the fundamental properties of neutrinos, one

nuPRISM: An experimental method to remove neutrino interaction uncertainties from oscillation experiments

CERN Multimedia

CERN. Geneva

2014-01-01

Future experiments propose to make precision measurements of parameters in the neutrino mixing matrix, including the possibly maximal mixing angle theta23, and an unknown CP violating phase, dCP, by comparing the event rate of neutrinos and antineutrinos observed close to, and far from the source. Such "near to far" extrapolation methods must achieve percent level understanding of neutrino and antineutrino interactions; the interaction determines the relationship between experimental observables and the oscillation probability which depends on the neutrino energy. However, recent developments over the last 5 years demonstrate that our understanding of neutrino interactions is insufficient. In particular, the interaction of neutrinos on correlated pairs of nucleons has only recently been added to neutrino interaction simulations. The identification of these processes as interactions on a single nucleon results in a significant bias to the measured mixing parameters, even when near detector i...

A multi-signature approach to low-scale sterile neutrino phenomenology

CERN Document Server

Ross-Lonergan, Mark

2017-01-01

Since the discovery of non-zero neutrino masses, through the observation of neutrino flavour oscillations, we had a plethora of successful experiments which have made increasingly precise measurements of the mixing angles and mass-differences that drive the phenomena. In this thesis we highlight the fact that there is still significant room for new physics, however, when one removes the assumption of unitarity of the 3x3 neutrino mixing matrix, an assumption inherent in the 3ν paradigm. We refit all global data to show just how much non-unitarity is currently allowed. The canonical way that such a non-unitarity is introduced to the 3x3 neutrino mixing matrix is by the addition of additional neutral fermions, singlets under the Standard Model gauge group. These “Sterile Neutrinos” have a wide range of the- oretical and phenomenological implications. Alongside the sensitivity non-unitarity measurements have to sterile neutrinos, in this thesis we will study in detail two additional signatures of low-scale ...

Neutrino physics at LAMPF

International Nuclear Information System (INIS)

Garvey, G.T.

1989-01-01

There are three neutrino experiments at LAMPF in various stages of completion or development. E225, the study of electron-neutrino electron scattering, which completed data taking in December 1986 and has just about completed all its analysis. E645, a search for /bar /nu///sub μ/ → /bar /nu///sub e/ oscillation, is in its third and final year of data taking. The Large Cerenkov Detector (LCD), associated with E1015, has undergone extensive scientific and technical review and we are presently trying to obtain the necessary funds to build the detector, beam line, and target. In the following, each of these experiments will be briefly discussed. Before doing so, it is useful to show the characteristics of the neutrino spectrum resulting from the decay of π + at rest. It is also useful to realize that, on average, an 800-MeV proton from LAMPF produces about 0.1 π + decaying at rest. 16 refs., 5 figs., 4 tabs

Search for sterile neutrinos in muon neutrino disappearance mode at FNAL

International Nuclear Information System (INIS)

Anokhina, A.; Dzhatdoev, T.; Morgunova, O.; Roganova, T.; Bagulya, A.; Chernyavskiy, M.; Dalkarov, O.; Mingazheva, R.; Shchedrina, T.; Starkov, N.; Vladymyrov, M.; Benettoni, M.; Dal Corso, F.; Dusini, S.; Lippi, I.; Longhin, A.; Bernardini, P.; Mancarella, G.; Marsella, G.; Brugnera, R.; Garfagnini, A.; Medinaceli, E.; Roda, M.; Sirignano, C.; Calabrese, M.; Fiore, G.; Surdo, A.; Cecchetti, A.; Orecchini, D.; Paoloni, A.; Cecchini, S.; Di Ferdinando, D.; Guerzoni, M.; Laurenti, G.; Mandrioli, G.; Mauri, N.; Patrizii, L.; Pozzato, M.; Sahnoun, Z.; Sirri, G.; Togo, V.; Del Prete, A.; Papadia, G.; De Robertis, G.; Fini, R.A.; Loddo, F.; Pastore, A.; De Serio, M.; Paparella, L.; Simone, S.; Klicek, B.; Jakovcic, K.; Malenica, M.; Stipcevic, M.; Kose, U.; Nessi, M.; Margiotta, A.; Pasqualini, L.; Spurio, M.; Muciaccia, M.T.; Polukhina, N.; Rosa, G.; Stanco, L.; Tenti, M.

2017-01-01

The NESSiE Collaboration has been setup to undertake a conclusive experiment to clarify the muon-neutrino disappearance measurements at short baselines in order to put severe constraints to models with more than the three-standard neutrinos. To this aim the current FNAL-Booster neutrino beam for a Short-Baseline experiment was carefully evaluated by considering the use of magnetic spectrometers at two sites, near and far ones. The detector locations were studied, together with the achievable performances of two OPERA-like spectrometers. The study was constrained by the availability of existing hardware and a time-schedule compatible with the undergoing project of multi-site Liquid-Argon detectors at FNAL. The settled physics case and the kind of proposed experiment on the Booster neutrino beam would definitively clarify the existing tension between the ν μ disappearance and the ν e appearance/disappearance at the eV mass scale. In the context of neutrino oscillations the measurement of ν μ disappearance is a robust and fast approach to either reject or discover new neutrino states at the eV mass scale. We discuss an experimental program able to extend by more than one order of magnitude (for neutrino disappearance) and by almost one order of magnitude (for antineutrino disappearance) the present range of sensitivity for the mixing angle between standard and sterile neutrinos. These extensions are larger than those achieved in any other proposal presented so far. (orig.)

Search for sterile neutrinos in muon neutrino disappearance mode at FNAL

Science.gov (United States)

Anokhina, A.; Bagulya, A.; Benettoni, M.; Bernardini, P.; Brugnera, R.; Calabrese, M.; Cecchetti, A.; Cecchini, S.; Chernyavskiy, M.; Dal Corso, F.; Dalkarov, O.; Del Prete, A.; De Robertis, G.; De Serio, M.; Di Ferdinando, D.; Dusini, S.; Dzhatdoev, T.; Fini, R. A.; Fiore, G.; Garfagnini, A.; Guerzoni, M.; Klicek, B.; Kose, U.; Jakovcic, K.; Laurenti, G.; Lippi, I.; Loddo, F.; Longhin, A.; Malenica, M.; Mancarella, G.; Mandrioli, G.; Margiotta, A.; Marsella, G.; Mauri, N.; Medinaceli, E.; Mingazheva, R.; Morgunova, O.; Muciaccia, M. T.; Nessi, M.; Orecchini, D.; Paoloni, A.; Papadia, G.; Paparella, L.; Pasqualini, L.; Pastore, A.; Patrizii, L.; Polukhina, N.; Pozzato, M.; Roda, M.; Roganova, T.; Rosa, G.; Sahnoun, Z.; Shchedrina, T.; Simone, S.; Sirignano, C.; Sirri, G.; Spurio, M.; Stanco, L.; Starkov, N.; Stipcevic, M.; Surdo, A.; Tenti, M.; Togo, V.; Vladymyrov, M.

2017-01-01

The NESSiE Collaboration has been setup to undertake a conclusive experiment to clarify the muon-neutrino disappearance measurements at short baselines in order to put severe constraints to models with more than the three-standard neutrinos. To this aim the current FNAL-Booster neutrino beam for a Short-Baseline experiment was carefully evaluated by considering the use of magnetic spectrometers at two sites, near and far ones. The detector locations were studied, together with the achievable performances of two OPERA-like spectrometers. The study was constrained by the availability of existing hardware and a time-schedule compatible with the undergoing project of multi-site Liquid-Argon detectors at FNAL. The settled physics case and the kind of proposed experiment on the Booster neutrino beam would definitively clarify the existing tension between the ν _{μ } disappearance and the ν e appearance/disappearance at the eV mass scale. In the context of neutrino oscillations the measurement of ν _{μ } disappearance is a robust and fast approach to either reject or discover new neutrino states at the eV mass scale. We discuss an experimental program able to extend by more than one order of magnitude (for neutrino disappearance) and by almost one order of magnitude (for antineutrino disappearance) the present range of sensitivity for the mixing angle between standard and sterile neutrinos. These extensions are larger than those achieved in any other proposal presented so far.

Search for sterile neutrinos in muon neutrino disappearance mode at FNAL

Energy Technology Data Exchange (ETDEWEB)

Anokhina, A.; Dzhatdoev, T.; Morgunova, O.; Roganova, T. [Lomonosov Moscow State University (MSU SINP), Moscow (Russian Federation); Bagulya, A.; Chernyavskiy, M.; Dalkarov, O.; Mingazheva, R.; Shchedrina, T.; Starkov, N.; Vladymyrov, M. [Lebedev Physical Institute of Russian Academy of Sciences, Moscow (Russian Federation); Benettoni, M.; Dal Corso, F.; Dusini, S.; Lippi, I.; Longhin, A. [INFN, Sezione di Padova, Padua (Italy); Bernardini, P.; Mancarella, G.; Marsella, G. [Universita del Salento, Dipartimento di Matematica e Fisica, Lecce (Italy); INFN, Sezione di Lecce, Lecce (Italy); Brugnera, R.; Garfagnini, A.; Medinaceli, E.; Roda, M.; Sirignano, C. [INFN, Sezione di Padova, Padua (Italy); Universita di Padova, Dipartimento di Fisica e Astronomia, Padua (Italy); Calabrese, M.; Fiore, G.; Surdo, A. [INFN, Sezione di Lecce, Lecce (Italy); Cecchetti, A.; Orecchini, D.; Paoloni, A. [INFN, Laboratori Nazionali di Frascati, Frascati, RM (Italy); Cecchini, S.; Di Ferdinando, D.; Guerzoni, M.; Laurenti, G.; Mandrioli, G.; Mauri, N.; Patrizii, L.; Pozzato, M.; Sahnoun, Z.; Sirri, G.; Togo, V. [INFN, Sezione di Bologna, Bologna (Italy); Del Prete, A.; Papadia, G. [INFN, Sezione di Lecce, Lecce (Italy); Universita del Salento, Dipartimento di Ingegneria dell' Innovazione, Lecce (Italy); De Robertis, G.; Fini, R.A.; Loddo, F.; Pastore, A. [INFN, Sezione di Bari, Bari (Italy); De Serio, M.; Paparella, L.; Simone, S. [INFN, Sezione di Bari, Bari (Italy); Universita di Bari, Dipartimento di Fisica, Bari (Italy); Klicek, B.; Jakovcic, K.; Malenica, M.; Stipcevic, M. [Rudjer Boskovic Institute, Zagreb (Croatia); Kose, U.; Nessi, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Margiotta, A.; Pasqualini, L.; Spurio, M. [INFN, Sezione di Bologna, Bologna (Italy); Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); Muciaccia, M.T. [Universita di Bari, Dipartimento di Fisica, Bari (Italy); Polukhina, N. [Lebedev Physical Institute of Russian Academy of Sciences, Moscow (Russian Federation); National Research Nuclear University MEPhI, Moscow (Russian Federation); Rosa, G. [INFN, Sezione di Roma, Rome (Italy); Stanco, L. [INFN, Sezione di Padova, Padua (Italy); Tenti, M. [Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); NFN-CNAF, Bologna (Italy)

2017-01-15

The NESSiE Collaboration has been setup to undertake a conclusive experiment to clarify the muon-neutrino disappearance measurements at short baselines in order to put severe constraints to models with more than the three-standard neutrinos. To this aim the current FNAL-Booster neutrino beam for a Short-Baseline experiment was carefully evaluated by considering the use of magnetic spectrometers at two sites, near and far ones. The detector locations were studied, together with the achievable performances of two OPERA-like spectrometers. The study was constrained by the availability of existing hardware and a time-schedule compatible with the undergoing project of multi-site Liquid-Argon detectors at FNAL. The settled physics case and the kind of proposed experiment on the Booster neutrino beam would definitively clarify the existing tension between the ν{sub μ} disappearance and the ν{sub e} appearance/disappearance at the eV mass scale. In the context of neutrino oscillations the measurement of ν{sub μ} disappearance is a robust and fast approach to either reject or discover new neutrino states at the eV mass scale. We discuss an experimental program able to extend by more than one order of magnitude (for neutrino disappearance) and by almost one order of magnitude (for antineutrino disappearance) the present range of sensitivity for the mixing angle between standard and sterile neutrinos. These extensions are larger than those achieved in any other proposal presented so far. (orig.)

From the measurement of the θ13 mixing angle to the search for geo-neutrinos: studying νe-bare with Double Chooz and Borexino

International Nuclear Information System (INIS)

Roncin, Romain

2014-01-01

Double Chooz is a reactor neutrino oscillation experiment which aims at measuring the θ 13 mixing angle thanks to two identical detectors located at different distances from the two reactors of the Chooz nuclear power plant, in the French Ardennes. While the near detector will start taking data in fall 2014 to normalize the flux of the neutrinos emitted by the nuclear reactors, the far detector is running since April 2011 and allows to observe the neutrinos disappearance through the neutrino oscillation phenomenon. This thesis is also dedicated to the Borexino experiment which was designed to observe solar neutrinos. Due to its low background level as well as its position in a nuclear free country, Italy, Borexino is also sensitive to geo-neutrinos. This thesis presents both the Double Chooz and Borexino experiments, from the description of the detectors to the main results, with a special attention to the background and its rejection. Studies on the neutrino directionality with these two experiments are also detailed. In the case of Double Chooz, since the neutrinos are coming from the two nuclear reactors, the precision of the analysis method can be assessed. This thesis presents also for the first time the possibility to retrieve the initial direction of the neutrinos when the neutrons created in the inverse beta decay reactions are captured on hydrogen. In the case of Borexino, neutrino directionality information could facilitate the discrimination between geo-neutrinos and neutrinos from nuclear reactors. (author) [fr

Possible explanation of the solar-neutrino puzzle

Science.gov (United States)

Bethe, H. A.

1986-01-01

A new derivation of the Mikheyev and Smirnov (1985) mechanism for the conversion of electron neutrinos into mu neutrinos when traversing the sun is presented, and various hypotheses set forth. It is assumed that this process is responsible for the detection of fewer solar neutrinos than expected, with neutrinos below a minimum energy, E(m), being undetectable. E(m) is found to be about 6 MeV, and the difference of the squares of the respective neutrino masses is calculated to be 6 X 10 to the - 5th sq eV. A restriction on the neutrino mixing angle is assumed such that the change of density near the crossing point is adiabatic. It is predicted that no resonance conversion of neutrinos will occur in the dense core of supernovae, but conversion of electron neutrinos to mu neutrinos will occur as they escape outward through a density region around 100.

Apparent CPT violation in neutrino oscillation experiments

International Nuclear Information System (INIS)

Engelhardt, Netta; Nelson, Ann E.; Walsh, Jonathan R.

2010-01-01

We consider searching for light sterile fermions and new forces by using long baseline oscillations of neutrinos and antineutrinos. A new light sterile state and/or a new force can lead to apparent CPT violation in muon neutrino and antineutrino oscillations. As an example, we present an economical model of neutrino masses containing a sterile neutrino. The potential from the standard model weak neutral current gives rise to a difference between the disappearance probabilities of neutrinos and antineutrinos, when mixing with a light sterile neutrino is considered. The addition of a B-L interaction adds coherently to the neutrino current potential and increases the difference between neutrino and antineutrino disappearance. We find that this model can improve the fit to the results of MINOS for both neutrinos and antineutrinos, without any CPT violation, and that the regions of parameter space which improve the fit are within experimental constraints.

Golden Jubilee photos: Elusive Neutrinos

CERN Multimedia

2004-01-01

Catching neutrinos isn't easy. They interact only rarely with matter, so they have a good chance of passing straight through the Earth without stopping. However, when they do interact it is possible to see what effect they have on other particles. CERN had been doing this type of research for more than a decade by the time the detector in the picture was finished in 1977. The picture shows Klaus Winter, who worked on the 100 tonne CHARM experiment. CHARM is seen here in the West Area where it was set up with the 1250 tonne CDHS experiment. Researchers used these machines to help develop the Standard Model of particle physics and further our understanding of the structure of the atomic nucleus. The research also helped expand physics into a new field aimed at understanding the peculiar behaviour of neutrinos. There are three 'flavours' of neutrino - the electron, muon, and the tau neutrino. Over a long enough distance, they oscillate from one flavour to another. In 2006, CERN will try to make more progress on...

Neutrino masses from U(1) symmetries and the Super-Kamiokande data

CERN Document Server

Lola, S; Lola, Smaragda; Ross, Graham G.

1999-01-01

Motivated by the Super-Kamiokande data, we revisit models with U(1) symmetries and discuss the origin of neutrino masses and mixings in such theories. We show that, in models with just three light neutrinos and a hierarchy of neutrino masses, large (2-3) mixing fixes the lepton doublet U(1) charges and is thus related to the structure of the charged lepton mass matrix. We discuss the fermion mass structure that follows from the abelian family symmetry with an extended gauge group. Requiring that the quark and lepton masses be ordered by the family symmetry, we identify the most promising scheme. This requires large, but not necessarily maximal, mixing in the mu tau sector and gives e mu mixing in the range that is required for the small angle solution of the solar neutrino deficit.

Phenomenological analysis of properties of the right-handed Majorana neutrino in the seesaw mechanism

International Nuclear Information System (INIS)

Pan Haijun; Cheng, G.

2002-01-01

As an extension of our previous work in the seesaw mechanism, we analyze the influence of nonzero U e3 on the properties (masses and mixing) of the right-handed Majorana neutrinos in three flavors. The quasidegenerate light neutrinos case is also considered. Assuming the hierarchical Dirac neutrino masses, we find the heavy Majorana neutrino mass spectrum is either hierarchical or partially degenerate if θ 23 ν is large. We show that degenerate right-handed (RH) Majorana masses correspond to a maximal RH mixing angle while hierarchical ones correspond to the RH mixing angles which scale linearly with the mass ratios of the Dirac neutrino masses. An interesting analogue to the behavior of the matter-enhanced neutrino conversion and their difference is presented

Neutrino coherent forward scattering and its index of refraction

International Nuclear Information System (INIS)

Liu, J.

1992-01-01

It is pointed out that, if neutrinos are to maintain coherence over the required distance for the Mikheyev-Smirnov-Wolfenstein solutions to the solar-neutrino problem, effects arising from neutrino multiple scattering must be considered. We give a simple derivation for the neutrino index of refraction that takes into account this effect. The same method is also shown to be useful for situations with varying matter densities and neutrino mixing. We also examine the question whether the coherence of propagating neutrinos in matter will be affected by switching on an external magnetic field, assuming neutrinos have a large magnetic moment

Quasi-degenerate neutrinos from an abelian family symmetry

International Nuclear Information System (INIS)

Binetruy, P.; Lavignac, S.; Petcov, S.; Ist. Nazionale di Fisica Nucleare, Trieste; Ramond, P.

1996-01-01

The authors show that models with an abelian family symmetry which accounts for the observed hierarchies of masses and mixings in the quark sector may also accommodate quasi-degeneracies in the neutrino mass spectrum. Such approximate degeneracies are, in this context, associated with large mixing angles. The parameters of this class of models are constrained. The authors discuss their phenomenological implications for present and foreseen neutrino experiments

Production of heavy sterile neutrinos from vector boson decay at electroweak temperatures

Science.gov (United States)

Lello, Louis; Boyanovsky, Daniel; Pisarski, Robert D.

2017-02-01

In the standard model extended with a seesaw mass matrix, we study the production of sterile neutrinos from the decay of vector bosons at temperatures near the masses of the electroweak bosons. We derive a general quantum kinetic equation for the production of sterile neutrinos and their effective mixing angles, which is applicable over a wide range of temperature, to all orders in interactions of the standard model and to leading order in a small mixing angle for the neutrinos. We emphasize the relation between the production rate and Landau damping at one-loop order and show that production rates and effective mixing angles depend sensitively upon the neutrino's helicity. Sterile neutrinos with positive helicity interact more weakly with the medium than those with negative helicity, and their effective mixing angle is not modified significantly. Negative helicity states couple more strongly to the vector bosons, but their mixing angle is strongly suppressed by the medium. Consequently, if the mass of the sterile neutrino is ≲8.35 MeV , there are fewer states with negative helicity produced than those with positive helicity. There is an Mikheyev-Smirnov-Wolfenstein-type resonance in the absence of lepton asymmetry, but due to screening by the damping rate, the production rate is not enhanced. Sterile neutrinos with negative helicity freeze out at Tf-≃5 GeV , whereas positive helicity neutrinos freeze out at Tf+≃8 GeV , with both distributions far from thermal. As the temperature decreases, due to competition between a decreasing production rate and an increasing mixing angle, the distribution function for states with negative helicity is broader in momentum and hotter than that for those with positive helicity. Sterile neutrinos produced via vector boson decay do not satisfy the abundance, lifetime, and cosmological constraints to be the sole dark matter component in the Universe. Massive sterile neutrinos produced via vector boson decay might solve the 7Li

Neutrino oscillations and antiνsub(e)-e scattering

International Nuclear Information System (INIS)

Halls, B.; McKellar, B.H.J.

1980-01-01

Electron antineutrino-electron scattering is modified in the presence of neutrino mixing and neutrino oscillation. In the Weinberg-Salam model the results for reactor antineutrinos are insensitive to the degree of mixing, to the extent that the experiment of Reines, Gurr and Sobel cannot differentiate between no oscillation and complete disappearance of the electron antineutrinos from the beam

MASSIVE NEUTRINOS IN A GROUNDS-UP APPROACH

International Nuclear Information System (INIS)

BAR-SHALOM, S.; ATWOOD, D.; SONI, A.

2005-01-01

We examine neutrino oscillations in a two Higgs doublet model (2HDM) in which the second doublet couples only to the third generation right-handed up-fermions, i.e., to t R and N 3 which is the heaviest right-handed Majorana neutrino. The inherently large tan β of this model can naturally account for the large top-quark mass and, based on a quark-lepton similarity ansatz, when embedded into a seesaw mechanism it can also account for the observed neutrino masses and mixing angles giving a very small θ 13 : -0.96 0 ∼ 13 ∼ 0 at 99% CL, and a very restrictive prediction for the atmospheric mixing angle: 42.9 0 ∼ atm ∼ 0 at 99% CL. The large value of tan β also sets the mass scale of the heaviest right-handed Majorana neutrino N 3 and triggers successful leptogenesis

Subpanel on accelerator-based neutrino oscillation experiments

International Nuclear Information System (INIS)

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

New experimental limits on heavy neutrino mixing in 8B decay obtained with the BOREXINO counting test facility

International Nuclear Information System (INIS)

Back, H.O.; Hagner, C.; Vogelaar, R.B.

2003-01-01

If heavy neutrinos with mass m νH ≥2m e are emitted in the decays of 8 B in the Sun, then decays ν H →ν L +e + +e - should be observed. The results of background measurements with the BOREXINO Counting Test Facility have been used to obtain bounds on the number of these decays. As a result, new limits on the coupling |U eH | 2 of a massive neutrino in the range of 1.1 to 12 MeV have been derived (|U eH | 2 ≤10 -3 -10 -5 ). The obtained limits on the mixing parameter are stronger than those obtained in the previous experiments using nuclear reactors and accelerators

Comments on reconstruction and origins of the neutrino mass spectrum

International Nuclear Information System (INIS)

Smirnov, A.Yu.

2000-01-01

There are two main issues in the present day neutrino physics: (i) Reconstruction of the neutrino mass (and flavor) spectrum and (ii) Identification of origin of the neutrino mass and mixing, or in other terms, implications of the neutrino data for the fundamental theory. Present status and perspectives of the reconstruction are summarized. We comment on the see-saw and the 'bulk-brane' mechanisms of neutrino mass generation

Constraints on a general 3-generation neutrino mass matrix from neutrino data application to the MSSM with R-parity violation

CERN Document Server

Abada, A

2000-01-01

We consider a general symmetric $(3\\times 3)$ mass matrix for three generations of neutrinos. Imposing the constraints, from the atmospheric neutrino and solar neutrino anomalies as well as from the CHOOZ experiment, on the mass squared differences and on the mixing angles, we identify the ranges of allowed inputs for the 6 matrix elements. We apply our results to Majorana left-handed neutrino masses generated at tree level and through The present experimental results on neutrinos from laboratories, cosmology and astrophysics are implemented to either put bounds on trilinear ($\\lambda_{ijk}, or constrain combinations of products of these couplings.

Status of the MSW-solution of the solar neutrino problem

International Nuclear Information System (INIS)

Smirnov, A.Yu.

1992-12-01

Status of the resonant flavor conversion is formulated in view of latest solar neutrino data. We discuss different methods of determination of neutrino parameters. The effects of third neutrino admixture as well as possible nonvacuum mixing are considered. (author). 24 refs, 5 figs

Simpson's neutrino and the singular see-saw

International Nuclear Information System (INIS)

Allen, T.J.; Johnson, R.; Ranfone, S.; Schechter, J.; Walle, J.W.F.

1991-01-01

The authors of this paper derive explicit forms for the neutrino and lepton mixing-matrices which describe the generic singular see-saw model. The dependence on the hierarchy parameter is contrasted with the non-singular case. Application is made to Simpson's 17 keV neutrino

The neutrino mass hierarchy measurement with a neutrino telescope in the Mediterranean Sea: A feasibility study

Energy Technology Data Exchange (ETDEWEB)

Tsirigotis, A. G. [Physics Laboratory, Hellenic Open University (Greece); Collaboration: KM3NeT Collaboration

2014-11-18

With the measurement of a non zero value of the θ{sub 13} neutrino mixing parameter, interest in neutrinos as source of the baryon asymmetry of the universe has increased. Among the measurements of a rich and varied program in near future neutrino physics is the determination of the mass hierarchy. We present the status of a study of the feasibility of using a densely instrumented undersea neutrino detector to determine the mass hierarchy, utilizing the Mikheyev-Smirnov-Wolfenstein (MSW) effect on atmospheric neutrino oscillations. The detector will use technology developed for KM3NeT. We present the systematic studies of the optimization of a detector in the required 5–10 GeV energy regime. These studies include new tracking and interaction identification algorithms as well as geometrical optimizations of the detector.

Phenomenology of neutrino oscillations at the neutrino factory

Energy Technology Data Exchange (ETDEWEB)

Tang, Jian

2011-12-19

We consider the prospects for a neutrino factory measuring mixing angles, the CP violating phase and mass-squared differences by detecting wrong-charge muons arising from the chain {mu}{sup +} {yields} {nu}{sub e} {yields} {nu}{sub {mu}} {yields} {mu}{sup -} and the right-charge muons coming from the chain {mu}{sup +} {yields} anti {nu}{sub {mu}} {yields} anti {nu}{sub {mu}} {yields} {mu}{sup -} (similar to {mu}{sup -} chains), where {nu}{sub e} {yields} {nu}{sub {mu}} and anti {nu}{sub {mu}} {yields} anti {nu}{sub {mu}} are neutrino oscillation channels through a long baseline. First, we study physics with near detectors and consider the treatment of systematic errors including cross section errors, flux errors, and background uncertainties. We illustrate for which measurements near detectors are required, discuss how many are needed, and what the role of the flux monitoring is. We demonstrate that near detectors are mandatory for the leading atmospheric parameter measurements if the neutrino factory has only one baseline, whereas systematic errors partially cancel if the neutrino factory complex includes the magic baseline. Second, we perform the baseline and energy optimization of the neutrino factory including the latest simulation results from the magnetized iron neutrino detector (MIND). We also consider the impact of {tau} decays, generated by appearance channels {nu}{sub {mu}} {yields} {nu}{sub {tau}} and {nu}{sub e} {yields} {nu}{sub {tau}}, on the discovery reaches of the mass orderings, the leptonic CP violation, and the non-zero {theta}{sub 13}, which we find to be negligible for the considered detector. Third, we make a comparison of a high energy neutrino factory to a low energy neutrino factory and find that they are just two versions of the same experiment optimized for different regions of the parameter space. In addition, we briefly comment on whether it is useful to build the bi-magic baseline at the low energy neutrino factory. Finally, the

Gravity wave and neutrino bursts from stellar collapse: A sensitive test of neutrino masses

International Nuclear Information System (INIS)

Arnaud, N.; Barsuglia, M.; Bizouard, M.A.; Cavalier, F.; Davier, M.; Hello, P.; Pradier, T.

2002-01-01

New methods are proposed with the goal to determine absolute neutrino masses from the simultaneous observation of the bursts of neutrinos and gravitational waves emitted during a stellar collapse. It is shown that the neutronization electron neutrino flash and the maximum amplitude of the gravitational wave signal are tightly synchronized with the bounce occurring at the end of the core collapse on a time scale better than 1 ms. The existing underground neutrino detectors (SuperKamiokande, SNO,...) and the gravity wave antennas soon to operate (LIGO, VIRGO,...) are well matched in their performance for detecting galactic supernovae and for making use of the proposed approach. Several methods are described, which apply to the different scenarios depending on neutrino mixing. Given the present knowledge on neutrino oscillations, the methods proposed are sensitive to a mass range where neutrinos would essentially be mass degenerate. The 95% C.L. upper limit which can be achieved varies from 0.75 eV/c 2 for large ν e survival probabilities to 1.1 eV/c 2 when in practice all ν e 's convert into ν μ 's or ν τ 's. The sensitivity is nearly independent of the supernova distance

Search for sterile neutrinos at RENO

Science.gov (United States)

Yeo, In Sung; RENO Collaboration

2017-09-01

The RENO experiment was designed to measure a neutrino mixing angle, θ13, by detecting electron antineutrinos emitted from the Hanbit nuclear reactors in Korea, and succeeded to measure θ13 from the disappearance mode in three neutrino frame. We investigate the possibility of sterile neutrinos existence at RENO experiment and compare data with Monte Carlo generated in four neutrino frame. In this talk, we present some recent results using chi-square analysis method. The probability deficit curve as a function of an effective baseline and the excluded contour plot in sin2(2 θ14) - Δ(m41)2 space will be shown.

Multipartite entanglement in neutrino oscillations

International Nuclear Information System (INIS)

Blasone, Massimo; Dell'Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio

2009-01-01

Particle mixing is related to multi-mode entanglement of single-particle states The occupation number of both flavor eigenstates and mass eigenstates can be used to define a multiqubit space. In such a framework, flavor neutrino states can be interpreted as multipartite mode-entangled states. By using two different entanglement measures, we analyze the behavior of multipartite entanglement in the phenomenon of neutrino oscillations.

Multipartite entanglement in neutrino oscillations

Energy Technology Data Exchange (ETDEWEB)

Blasone, Massimo; Dell' Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio, E-mail: blasone@sa.infn.i [Dipartimento di Matematica e Informatica, Universita degli Studi di Salerno, Via Ponte don Melillo, I-84084 Fisciano (Italy)

2009-06-01

Particle mixing is related to multi-mode entanglement of single-particle states The occupation number of both flavor eigenstates and mass eigenstates can be used to define a multiqubit space. In such a framework, flavor neutrino states can be interpreted as multipartite mode-entangled states. By using two different entanglement measures, we analyze the behavior of multipartite entanglement in the phenomenon of neutrino oscillations.

Anarchy and neutrino physics

Energy Technology Data Exchange (ETDEWEB)

Fortin, Jean-François; Giasson, Nicolas; Marleau, Luc [Département de Physique, de Génie Physique et d’Optique,Université Laval, Québec, QC G1V 0A6 (Canada)

2017-04-21

The neutrino sector of a seesaw-extended Standard Model is investigated under the anarchy hypothesis. The previously derived probability density functions for neutrino masses and mixings, which characterize the type I-III seesaw ensemble of N×N complex random matrices, are used to extract information on the relevant physical parameters. For N=2 and N=3, the distributions of the light neutrino masses, as well as the mixing angles and phases, are obtained using numerical integration methods. A systematic comparison with the much simpler type II seesaw ensemble is also performed to point out the fundamental differences between the two ensembles. It is found that the type I-III seesaw ensemble is better suited to accommodate experimental data. Moreover, the results indicate a strong preference for the mass splitting associated to normal hierarchy. However, since all permutations of the singular values are found to be equally probable for a particular mass splitting, predictions regarding the hierarchy of the mass spectrum remains out of reach in the framework of anarchy.

Phenomenology of maximal and near-maximal lepton mixing

International Nuclear Information System (INIS)

Gonzalez-Garcia, M. C.; Pena-Garay, Carlos; Nir, Yosef; Smirnov, Alexei Yu.

2001-01-01

The possible existence of maximal or near-maximal lepton mixing constitutes an intriguing challenge for fundamental theories of flavor. We study the phenomenological consequences of maximal and near-maximal mixing of the electron neutrino with other (x=tau and/or muon) neutrinos. We describe the deviations from maximal mixing in terms of a parameter ε(equivalent to)1-2sin 2 θ ex and quantify the present experimental status for |ε| e mixing comes from solar neutrino experiments. We find that the global analysis of solar neutrino data allows maximal mixing with confidence level better than 99% for 10 -8 eV 2 ∼ 2 ∼ -7 eV 2 . In the mass ranges Δm 2 ∼>1.5x10 -5 eV 2 and 4x10 -10 eV 2 ∼ 2 ∼ -7 eV 2 the full interval |ε| e mixing in atmospheric neutrinos, supernova neutrinos, and neutrinoless double beta decay

PINGU sensitivity to neutrino mass hierarchy

International Nuclear Information System (INIS)

Groß, Andreas

2014-01-01

Determination of the neutrino mass hierarchy (NMH) is among the most fundamental questions in particle physics. Recent measurements of 1) a large mixing angle between the first and the third neutrino mass eigenstates and 2) the first observation of atmospheric neutrino oscillations at tens of GeV with neutrino telescopes, open the intriguing new possibility to exploit matter effects in neutrino oscillation to determine the neutrino mass hierarchy. A further extension of IceCube/DeepCore called PINGU (Precision IceCube Next Generation Upgrade) has been recently envisioned with the ultimate goal to measure neutrino mass hierarchy. PINGU would consist of additional IceCube-like strings of detectors deployed in the deepest and cleanest ice in the center of IceCube. More densely deployed instrumentation would provide a threshold substantially below 10 GeV and enhance the sensitivity to the mass hierarchy signal in atmospheric neutrinos. Here we discuss an estimate of the PINGU sensitivity to the mass hierarchy determined using an approximation with an Asimov dataset and an oscillation parameter fit

Noncommutative spectral geometry, Bogoliubov transformations and neutrino oscillations

International Nuclear Information System (INIS)

Gargiulo, Maria Vittoria; Vitiello, Giuseppe; Sakellariadou, Mairi

2015-01-01

In this report we show that neutrino mixing is intrinsically contained in Connes’ noncommutatives pectral geometry construction, thanks to the introduction of the doubling of algebra, which is connected to the Bogoliubov transformation. It is known indeed that these transformations are responsible for the mixing, turning the mass vacuum state into the flavor vacuum state, in such a way that mass and flavor vacuum states are not unitary equivalent. There is thus a red thread that binds the doubling of algebra of Connes’ model to the neutrino mixing. (paper)

A 4-neutrino model with a Higgs triplet

International Nuclear Information System (INIS)

Grimus, W.; Pfeiffer, R.; Schwetz, T.

2000-01-01

We take as a starting point the Gelmini-Roncadelli model enlarged by a term with explicit lepton number violation in the Higgs potential and add a neutrino singlet field that is coupled via a scalar doublet to the usual leptons. This scenario allows us to take into account all three present indications in favor of neutrino oscillations provided by the solar, atmospheric, and LSND neutrino oscillation experiments. Furthermore, it suggests a model which reproduces naturally one of the two 4-neutrino mass spectra favored by the data. In this model, the solar neutrino problem is solved by large mixing MSW ν e →ν τ transitions, and the atmospheric neutrino problem by transitions of ν μ into a sterile neutrino. (orig.)

New initiatives on lepton flavor violation and neutrino oscillation with high intense muon and neutrino sources

CERN Document Server

Kuno, Yoshitaka; Pakvasa, Sandip

2002-01-01

The area of physics involving muons and neutrinos has become exciting in particle physics. Using their high intensity sources, physicists undertake, in various ways, extensive searches for new physics beyond the Standard Model, such as tests of supersymmetric grand unification (SUSY-GUT) and precision measurements of the muon and neutrino properties, which will in future extend to ambitious studies such as determination of the three-generation neutrino mixing matrix elements and CP violation in the lepton sector. The physics of this field is advancing, with potential improvements of the source

The singular seesaw mechanism with hierarchical Dirac neutrino mass

International Nuclear Information System (INIS)

Chikira, Y.; Mimura, Y.

2000-01-01

The singular seesaw mechanism can naturally explain the atmospheric neutrino deficit by maximal oscillations between ν μ L and ν μ R . This mechanism can also induce three different scales of the neutrino mass squared differences, which can explain the neutrino deficits of three independent experiments (solar, atmospheric, and LSND) by neutrino oscillations. In this paper we show that realistic mixing angles among the neutrinos can be obtained by introducing a hierarchy in the Dirac neutrino mass. In the case where the Majorana neutrino mass matrix has rank 2, the solar neutrino deficit is explained by vacuum oscillations between ν e and ν τ . We also consider the case where the Majorana neutrino mass matrix has rank 1. In this case, the matter enhanced Mikheyev-Smirnov-Wolfenstein solar neutrino solution is preferred as the solution of the solar neutrino deficit. (orig.)

Neutrino mass and mixing – status

Indian Academy of Sciences (India)

be specific, a Majorana mass term for neutrinos, together with the mass term for charged leptons: LM = −. 1 .... hierarchy, respectively (see refs [5,6] for details and references). Parameter ... In figure 3 we show the region in the sin2 θ13–δ plane indicated by T2K ..... and 40 m and the precise rate measurement from Bugey4.

Investigation of Neutrino Properties with Bolometric Detectors

Energy Technology Data Exchange (ETDEWEB)

Heeger, Karsten M [University of Wisconsin & Yale University

2014-11-01

Neutrino mass and mixing are amongst the major discoveries of the past decade. The particle nature of neutrinos and the hierarchy of mass eigenstates, however, are unknown. Neutrinoless double beta-decay (0νββ) is the only known mechanism to test whether neutrinos are their own antiparticles. The observation of 0νββ would imply lepton number violation and show that neutrinos have Majorana mass. This report describes research activities performed at the University of Wisconsin in 2011-2014 aimed at the search for 0νββ with CUORE-0 and CUORE with the goal of exploring the inverted mass hierarchy region and probing an effective neutrino mass of ~40- 120 meV.

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

Science.gov (United States)

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.

Sterile neutrinos, lepton asymmetries, primordial elements: How much of each?

International Nuclear Information System (INIS)

Chu Yizen; Cirelli, Marco

2006-01-01

We investigate quantitatively the extent to which having a primordial leptonic asymmetry (n ν ≠n ν ) relaxes the bounds on light sterile neutrinos imposed by BBN and LSS. We adopt a few assumptions that allow us to solve the neutrino evolution equations over a broad range of mixing parameters and asymmetries. For the general cases of sterile mixing with the electron or muon neutrino, we identify the regions that can be reopened. For the particular case of a LSND-like sterile neutrino, soon to be rejected or confirmed by MiniBooNE, we find that an asymmetry of the order of 10 -4 is needed to lift the conflicts with cosmology

Reactor Neutrino Oscillations: KamLAND and KASKA

International Nuclear Information System (INIS)

Suekane, F.

2006-01-01

Nuclear reactors generate a huge number of low energy ν-bar e 's. The reactor neutrinos have been used to study properties of neutrinos since its discovery a half century ago. Recently, KamLAND group finally discovered reactor neutrino oscillation with average baseline 180 km. According to the 3 flavor scheme of standard theory and measured oscillation parameters so far, the reactor neutrino is expected to perform another type of small oscillation at a baseline 1.8 km. KASKA experiment is a project to detect this small oscillation and to measure the last neutrino mixing angle θ 13 by using the world most powerful reactor complex, Kashiwazaki-Kariwa nuclear power station. In this proceedings, phenomena of neutrino oscillation and the two reactor oscillation experiments, KamLAND and KASKA, are introduced

Mixed Inert scalar triplet dark matter, radiative neutrino masses and leptogenesis

Directory of Open Access Journals (Sweden)

Wen-Bin Lu

2017-11-01

Full Text Available The neutral component of an inert scalar multiplet with hypercharge can provide a stable dark matter particle when its real and imaginary parts have a splitting mass spectrum. Otherwise, a tree-level dark-matter-nucleon scattering mediated by the Z boson will be much above the experimental limit. In this paper we focus on a mixed inert scalar triplet dark matter scenario where a complex scalar triplet with hypercharge can mix with another real scalar triplet without hypercharge through their renormalizable coupling to the standard model Higgs doublet. We consider three specified cases that carry most of the relevant features of the full parameter space: (i the neutral component of the real triplet dominates the dark matter particle, (ii the neutral component of the complex triplet dominates the dark matter particle; and (iii the neutral components of the real and complex triplets equally constitute the dark matter particle. Subject to the dark matter relic abundance and direct detection constraint, we perform a systematic study on the allowed parameter space with particular emphasis on the interplay among triplet-doublet terms and gauge interactions. In the presence of these mixed inert scalar triplets, some heavy Dirac fermions composed of inert fermion doublets can be utilized to generate a tiny Majorana neutrino mass term at one-loop level and realize a successful leptogenesis for explaining the cosmic baryon asymmetry.

John Adams Lecture | Accelerator-Based Neutrino Physics: Past, Present and Future by Kenneth Long | 8 December

CERN Multimedia

2014-01-01

John Adams Lecture: Accelerator-Based Neutrino Physics: Past, Present and Future by Dr. Kenneth Long (Imperial College London & STFC).   Monday, 8 December 2014 from 2 p.m. to 4 p.m. at CERN ( 503-1-001 - Council Chamber ) Abstract: The study of the neutrino is the study of physics beyond the Standard Model. We now know that the neutrinos have mass and that neutrino mixing occurs causing neutrino flavour to oscillate as neutrinos propagate through space and time. Further, some measurements can be interpreted as hints for new particles known as sterile neutrinos. The measured values of the mixing parameters make it possible that the matter-antimatter (CP) symmetry may be violated through the mixing process. The consequences of observing CP-invariance violation in neutrinos would be profound. To discover CP-invariance violation will require measurements of exquisite precision. Accelerator-based neutrino sources are central to the future programme and advances in technique are required ...

Three-generation neutrino oscillations in curved spacetime

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yu-Hao, E-mail: yhzhang1994@gmail.com; Li, Xue-Qian, E-mail: lixq@nankai.edu.cn

2016-10-15

Three-generation MSW effect in curved spacetime is studied and a brief discussion on the gravitational correction to the neutrino self-energy is given. The modified mixing parameters and corresponding conversion probabilities of neutrinos after traveling through celestial objects of constant densities are obtained. The method to distinguish between the normal hierarchy and inverted hierarchy is discussed in this framework. Due to the gravitational redshift of energy, in some extreme situations, the resonance energy of neutrinos might be shifted noticeably and the gravitational effect on the self-energy of neutrino becomes significant at the vicinities of spacetime singularities.

μ→3e and μ→eγ decays in the model with neutrino and heavy neutral leptons mixing

International Nuclear Information System (INIS)

Ovchinnikova, A.A.

1978-01-01

Muon number nonconservation is discussed within the framework of the renormalizable model of Decker and Pestieau. To renormalize this model four heavy leptons are added. Then the gauge group SU(2)xU(1) is considered. Besides standard left doublets, the right ones in which mixing of neutrino and neutral heavy leptons takes place are introduced. In such a scheme the neutral current of charged leptons is a pure vector. Then the branching ratios of μ→3e and μ→eγ decays are evaluated. It has been shown that these quantities greatly depend upon neutrino masses. If neutrino has a mass about 0.65 MeV, the μ→eγ decay probability may well be close to its experimentally determined upper limit. It this model the μ→3e decay rate is a/π times less than the μ→eγ decay rate

The solar neutrino day/night effect in Super-Kamiokande

International Nuclear Information System (INIS)

Smy, Michael B.

2005-01-01

The time variation of the elastic scattering rate of solar neutrinos with electrons in Super-Kamiokande-I was fit to the day/night variations expected from active two-neutrino oscillations in the Large Mixing Angle region. Combining Super-Kamiokande measurements with other solar and reactor neutrino data, the mixing angle is determined as sin 2 θ=0.276 -0.026 +0.033 and the mass squared difference between the two neutrino mass eigenstates as Δm 2 =7.1 -0.5 +0.6 x10 -5 eV 2 . For the best fit parameters, a day/night asymmetry of -1.7+/-1.6(stat) -1.2 +1.3 (syst)% determined from the Super-Kamiokande data, which has improved statistical precision over previous measurements and is in excellent agreement with the expected value of -1.6%

Hadronic EDMs in SUSY SU(5) GUTs with right-handed neutrinos

International Nuclear Information System (INIS)

Hisano, Junji; Kakizaki, Mitsuru; Nagai, Minoru; Shimizu, Yasuhiro

2004-01-01

We discuss hadronic EDM constraints on the neutrino sector in the SUSY SU(5) GUT with the right-handed neutrinos. The hadronic EDMs are sensitive to the right-handed down-type squark mixings, especially between the second and third generations and between the first and third ones, compared with the other low-energy hadronic observables, and the flavor mixings are induced by the neutrino Yukawa interaction. The current experimental bound of the neutron EDM may imply that the right-handed tau neutrino mass is smaller than about 10 14 GeV in the minimal supergravity scenario, and it may be improved furthermore in future experiments, such as the deuteron EDM measurement

Study on the Neutrino Oscillation with a Next Generation Medium-Baseline Reactor Experiment

International Nuclear Information System (INIS)

Joo, Kyung Kwang; Shin, Chang Dong

2014-01-01

For over fifty years, reactor experiments have played an important role in neutrino physics, in both discoveries and precision measurements. One of the methods to verify the existence of neutrino is the observation of neutrino oscillation phenomena. Electron antineutrinos emitted from a reactor provide the measurement of the small mixing angle θ 13 , providing rich programs of neutrino properties, detector development, nuclear monitoring, and application. Using reactor neutrinos, future reactor neutrino experiments, more precise measurements of θ 12 ,Δm 12 2 , and mass hierarchy will be explored. The precise measurement of θ 13 would be crucial for measuring the CP violation parameters at accelerators. Therefore, reactor neutrino physics will assist in the complete understanding of the fundamental nature and implications of neutrino masses and mixing. In this paper, we investigated several characteristics of RENO-50, which is a future medium-baseline reactor neutrino oscillation experiment, by using the GloBES simulation package

Sterile neutrinos in light of recent cosmological and oscillation data: a multi-flavor scheme approach

International Nuclear Information System (INIS)

Melchiorri, Alessandro; Mena, Olga; Sorel, Michel; Palomares-Ruiz, Sergio; Pascoli, Silvia; Slosar, Anze

2009-01-01

Light sterile neutrinos might mix with the active ones and be copiously produced in the early Universe. In the present paper, a detailed multi-flavor analysis of sterile neutrino production is performed. Making some justified approximations allows us to consider not only neutrino interactions with the primeval medium and neutrino coherence breaking effects, but also oscillation effects arising from the presence of three light (mostly-active) neutrino states mixed with two heavier (mostly-sterile) states. First, we emphasize the underlying physics via an analytical description of sterile neutrino abundances that is valid for cases with small mixing between active and sterile neutrinos. Then, we study in detail the phenomenology of (3+2) sterile neutrino models in light of short-baseline oscillation data, including the LSND and MiniBooNE results. Finally, by using the information provided by this analysis, we obtain the expected sterile neutrino cosmological abundances and then contrast them with the most recent available data from Cosmic Microwave Background and Large Scale Structure observations. We conclude that (3+2) models are significantly more disfavored by the internal inconsistencies between sterile neutrino interpretations of appearance and disappearance short-baseline data themselves, rather than by the used cosmological data

The MSW conversion of solar neutrinos and random matter density perturbations

International Nuclear Information System (INIS)

Nunokawa, H.; Rossi, A.; Valle, J.W.F.

1997-01-01

A generalization of the resonant neutrino conversion in matter, including a random component in the matter density profile is presented. The study is focused on the effect of such matter perturbations upon both large and small mixing angle MSW solutions to the solar neutrino problem. This is carried out both for the active-active ν e → ν μ , τ as well as active-sterile ν e → conversion channels. The small mixing MSW solution is much more stable than the large mixing solution has been found. Future solar neutrino experiments, such as Borexino, could probe solar matter density noise at the few percent level

Masses, flavor mix and CP violation

International Nuclear Information System (INIS)

Chaussard, L.

2004-06-01

The author describes the relationships between masses, mixing of flavors and CP violation. This document is divided into 4 chapters: 1) fermions' masses, 2) mixing of flavors and CP violation, 3) beauty physics and 4) neutrino physics. In chapter 1 an attempt is made to explain what is behind the concepts of lepton mass and quark mass. As for neutrinos, the only neutral fermion, Dirac's and Majorana's views are exposed as well as their consequences. Fermion flavors are mixed in the process of mass generation and this mix is responsible for the breaking of CP and T symmetries. In chapter 2 the author shows how the analysis of particle oscillations from neutral mesons (K 0 , D 0 , B d 0 and B s 0 ) and from neutrinos can shed light on CP violation. Chapter 3 is dedicated to the contribution of beauty physics to the determination of the unitary triangle, through the oscillations of beauty mesons. In chapter 4 the author reviews the experimental results obtained recently concerning neutrino mass and neutrino oscillations and draws some perspectives on future neutrino experiments. (A.C.)

Sterile Neutrino Search with the Double Chooz Experiment

Science.gov (United States)

Hellwig, D.; Matsubara, T.; Double Chooz Collaboration

2017-09-01

Double Chooz is a reactor antineutrino disappearance experiment located in Chooz, France. A far detector at a distance of about 1 km from reactor cores is operating since 2011; a near detector of identical design at a distance of about 400 m is operating since begin 2015. Beyond the precise measurement of θ 13, Double Chooz has a strong sensitivity to so called light sterile neutrinos. Sterile neutrinos are neutrino mass states not taking part in weak interactions, but may mix with known neutrino states. In this paper, we present an analysis method to search for sterile neutrinos and the expected sensitivity with the baselines of our detectors.

Non-standard interaction effects at reactor neutrino experiments

International Nuclear Information System (INIS)

Ohlsson, Tommy; Zhang, He

2009-01-01

We study non-standard interactions (NSIs) at reactor neutrino experiments, and in particular, the mimicking effects on θ 13 . We present generic formulas for oscillation probabilities including NSIs from sources and detectors. Instructive mappings between the fundamental leptonic mixing parameters and the effective leptonic mixing parameters are established. In addition, NSI corrections to the mixing angles θ 13 and θ 12 are discussed in detailed. Finally, we show that, even for a vanishing θ 13 , an oscillation phenomenon may still be observed in future short baseline reactor neutrino experiments, such as Double Chooz and Daya Bay, due to the existences of NSIs

Unified fit of solar and atmospheric neutrinos: towards the MNSP matrix; Ajustements globaux des resultats des experiences de neutrinos solaires et atmospheriques: vers la determination de la matrice de melange des neutrinos (dite MNSP)

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-01-01

Present solar and atmospheric neutrino give a strong indication that neutrinos oscillate between the three active species. This is the first step towards the determination of their mass. But we have also to determine the 3 x 3 neutrino mixing matrix (3 angles and one or several phases linked to CP violation), called MNSP (Maki-Nakagawa-Suzuki-Pontecorvo) and similar to the quark mixing matrix, called CKM (Cabibbo-Kobayashi-Maskawa). The purpose of the colloquium (one day) is to give an overview of the present situation and what progresses are expected in the forthcoming years. 3 guidelines: pedagogical approach, critical review of the experimental situation and of the different analyses, lookout to the future. (author)

LENS spectroscopy of low energy solar neutrinos

CERN Document Server

Schönert, S

2001-01-01

The LENS experiments will measure energy resolved sub-MeV solar electron-neutrinos ( nu /sub e/) in real time via inverse beta - transition populating an isomeric state in the daughter nuclei. The subsequent de-excitation provides a delayed coincidence tag which discriminates against background. A liquid scintillation detector loaded with 20 t of Yb would yield an event rate of 190 pp- and 175 /sup 7/Be neutrinos per year. Essential information on neutrino mixing and masses can be derived.

Sterile Neutrinos in Cold Climates

International Nuclear Information System (INIS)

Jones, Benjamin J.P.

2015-01-01

Measurements of neutrino oscillations at short baselines contain an intriguing set of experimental anomalies that may be suggestive of new physics such as the existence of sterile neutrinos. This three-part thesis presents research directed towards understanding these anomalies and searching for sterile neutrino oscillations. Part I contains a theoretical discussion of neutrino coherence properties. The open-quantum-system picture of neutrino beams, which allows a rigorous prediction of coherence distances for accelerator neutrinos, is presented. Validity of the standard treatment of active and sterile neutrino oscillations at short baselines is verified, and non-standard coherence loss effects at longer baselines are predicted. Part II concerns liquid argon detector development for the MicroBooNE experiment, which will search for short-baseline oscillations in the Booster Neutrino Beam at Fermilab. Topics include characterization and installation of the MicroBooNE optical system; test-stand measurements of liquid argon optical properties with dissolved impurities; optimization of wavelength-shifting coatings for liquid argon scintillation light detection; testing and deployment of high-voltage surge arrestors to protect TPC field cages; and software development for optical and TPC simulation and reconstruction. Part III presents a search for sterile neutrinos using the IceCube neutrino telescope, which has collected a large sample of atmospheric-neutrino-induced events in the 1-10 TeV energy range. Sterile neutrinos would modify the detected neutrino flux shape via MSW-resonant oscillations. Following a careful treatment of systematic uncertainties in the sample, no evidence for MSW-resonant oscillations is observed, and exclusion limits on 3+1 model parameter space are derived. Under the mixing assumptions made, the 90% confidence level exclusion limit extends to sin 2 2θ 24 ≤ 0.02 at m 2 ~ 0.3 eV 2 , and the LSND and MiniBooNE allowed regions are excluded at

The Neutrino: A Better Understanding Through Astrophysics: Final Report

Energy Technology Data Exchange (ETDEWEB)

Kneller, James P. [North Carolina State Univ., Raleigh, NC (United States)

2016-10-12

The final report for the award "The Neutrino: A Better Understanding Through Astrophysics" is given. The goals of the work were the following: to construct new theoretical approaches to the problem of neutrino propagation in media including where neutrino-neutrino interactions are important; to pioneer the use of new approaches, including super-scattering operators, for the evolution of neutrino thermal and statistical ensembles; to implement these new approaches in computer codes to study neutrino evolution in supernovae and other hot, dense environments; to increase the realism of simulated signals of a Galactic supernovae neutrino burst in current and future neutrino detectors; to study the simulated signals to determine the ability to extract information on the missing neutrino mixing parameters and the dynamics of the supernova explosion; and to study sterile neutrinos and non-standard interactions of neutrinos in supernovae and their effect upon the signal. Accomplishments made in these areas are described.

The Neutrino: A Better Understanding Through Astrophysics: Final Report

International Nuclear Information System (INIS)

Kneller, James P.

2016-01-01

The final report for the award 'The Neutrino: A Better Understanding Through Astrophysics' is given. The goals of the work were the following: to construct new theoretical approaches to the problem of neutrino propagation in media including where neutrino-neutrino interactions are important; to pioneer the use of new approaches, including super-scattering operators, for the evolution of neutrino thermal and statistical ensembles; to implement these new approaches in computer codes to study neutrino evolution in supernovae and other hot, dense environments; to increase the realism of simulated signals of a Galactic supernovae neutrino burst in current and future neutrino detectors; to study the simulated signals to determine the ability to extract information on the missing neutrino mixing parameters and the dynamics of the supernova explosion; and to study sterile neutrinos and non-standard interactions of neutrinos in supernovae and their effect upon the signal. Accomplishments made in these areas are described.

Neutrino oscillations - the Double Chooz experiment

Energy Technology Data Exchange (ETDEWEB)

Lasserre, Th. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules de Physique Nucleaire et de l' Instrumentation Associee (DSM/DAPNIA/SPP/APC), 91- Gif sur Yvette (France)

2007-07-01

{theta}{sub 13} is the mixing angle that couples the field of the neutrino number 3 (the heaviest) to the electron field. The Double Chooz experiment will use 2 identical detectors, near the Chooz nuclear reactor cores to measure the last undetermined mixing angle {theta}{sub 13}. The basic principle of the multi-detector concept is the cancellation of the reactor-induced systematic errors. The first detector will be installed in the existing underground laboratory (1050 meters away from the plant station) that was used in the first Chooz experiment in the nineties. The second detector will be constructed from 2009 in a new neutrino laboratory, located down a 45 m well that will be excavated 300 m away from the reactors. An average visible neutrino rate of 55 (550) events per day is expected to be detected inside the far (near) detector, taking into account the various inefficiencies, if no oscillations. The near detector will perform a measurement of the anti-neutrino flux and its energy spectrum with an unprecedented accuracy and for a long period (3 years). These huge statistics will also be exploited to monitor changes in the relative amounts of U{sup 235} and Pu{sup 239} in the core, paving the way to use neutrino detection for safeguards applications. (A.C.)

Cosmological lepton asymmetry, primordial nucleosynthesis and sterile neutrinos

Science.gov (United States)

Abazajian, Kevork; Bell, Nicole F.; Fuller, George M.; Wong, Yvonne Y. Y.

2005-09-01

We study post weak decoupling coherent active-sterile and active-active matter-enhanced neutrino flavor transformation in the early Universe. We show that flavor conversion efficiency at Mikheyev-Smirnov-Wolfenstein resonances is likely to be high (adiabatic evolution) for relevant neutrino parameters and energies. However, we point out that these resonances cannot sweep smoothly and continuously with the expansion of the Universe. We show how neutrino flavor conversion in this way can leave both the active and sterile neutrinos with nonthermal energy spectra, and how, in turn, these distorted energy spectra can affect the neutron-to-proton ratio, primordial nucleosynthesis, and cosmological mass/closure constraints on sterile neutrinos. We demonstrate that the existence of a light sterile neutrino which mixes with active neutrinos can change fundamentally the relationship between the cosmological lepton numbers and the primordial nucleosynthesis He4 yield.

Nontrivial correlation between the CKM and MNS matrices

International Nuclear Information System (INIS)

Xing Zhizhong

2005-01-01

We point out that the Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix V CKM and the Maki-Nakagawa-Sakata (MNS) lepton mixing matrix V MNS can naturally be correlated in a class of seesaw models if the Dirac neutrino mass matrix and the up-type quark mass matrix are symmetric and identical, but the texture of their correlation matrix F ν is rather nontrivial. The bimaximal mixing pattern of F ν is disfavored by current data, and other special forms of F ν may suffer from fine-tuning of the free phase parameters in fitting the so-called quark-lepton complementarity relation. A straightforward calculation of F ν in terms of V CKM and V MNS reveals a striking feature of F ν : its (1,3) element cannot be zero or too small, no matter whether the (1,3) elements of V CKM and V MNS are vanishing or not. We also add some brief comments on possible radiative corrections to V CKM and V MNS

Predicting {theta}{sub 13} and the neutrino mass scale from quark lepton mass hierarchies

Energy Technology Data Exchange (ETDEWEB)

Buchmueller, W.; Domcke, V.; Schmitz, K.

2011-11-15

Flavour symmetries of Froggatt-Nielsen type can naturally reconcile the large quark and charged lepton mass hierarchies and the small quark mixing angles with the observed small neutrino mass hierarchies and their large mixing angles. We point out that such a flavour structure, together with the measured neutrino mass squared differences and mixing angles, strongly constrains yet undetermined parameters of the neutrino sector. Treating unknown O(1) parameters as random variables, we obtain surprisingly accurate predictions for the smallest mixing angle, sin{sup 2}2{theta}{sub 13}=0.07{sup +0.11}{sub -0.05}, the smallest neutrino mass, m{sub 1}=2.5{sup +1.7}{sub -1.6} x 10{sup -3} eV, and one Majorana phase, {alpha}{sub 21}/{pi}=1.0{sup +0.2}{sub -0.2}. (orig.)

Observing Muon Neutrino to Electron Neutrino Oscillations in the NOνA Experiment

Energy Technology Data Exchange (ETDEWEB)

Xin, Tian [Iowa State U.

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.

The NESSiE way to searches for sterile neutrinos at FNAL

CERN Document Server

Stanco, L.; Benettoni, M.; Bernardini, P.; Brugnera, R.; Calabrese, M.; Cecchetti, A.; Cecchini, S.; Chernyavskiy, M.; Creti, P.; Dal Corso, F.; Dalkarov, O.; Del Prete, A.; De Robertis, G.; De Serio, M.; Esposti, L.Degli; Di Ferdinando, D.; Dusini, S.; Dzhatdoev, T.; Fanin, C.; Fini, R.A.; Fiore, G.; Garfagnini, A.; Golovanov, S.; Guerzoni, M.; Klicek, B.; Jakovcic, K.; Laurenti, G.; Lippi, I.; Loddo, F.; Longhin, A.; Malenica, M.; Mancarella, G.; Mandrioli, G.; Margiotta, A.; Marsella, G.; Mauri, N.; Medinaceli, E.; Mengucci, A.; Mingazheva, R.; Morgunova, O.; Muciaccia, M.T.; Orecchini, D.; Paoloni, A.; Papadia, G.; Paparella, L.; Pasqualini, L.; Pastore, A.; Patrizii, L.; Polukhina, N.; Pozzato, M.; Roda, M.; Roganova, T.; Rosa, G.; Sahnoun, Z.; Simone, S.; Sirignano, C.; Sirri, G.; Spurio, M.; Stanko, L.; Starkov, N.; Stipcevic, M.; Surdo, A.; Tenti, M.; Togo, V.; Ventura, M.; Vladymyrov, M.; Kose, U.; Nessi, M.

2016-01-01

Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing problem of new physics beyond the Standard Model. The recent measurement of the mixing angle $\\theta_{13}$ in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE Collaboration has been setup to undertake conclusive experiments to clarify the muon-neutrino disappearance measurements at small $L/E$, which will be able to put severe constraints to models with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. To this aim the use of the current FNAL-Booster neutrino beam for a Short-Baseline experiment has been carefully evaluated. Its recent proposal refers to the use of magnetic spectrometers at two different sites, Near and Far...

Axion-assisted production of sterile neutrino dark matter

Energy Technology Data Exchange (ETDEWEB)

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. 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.

Neutrino masses in RPV models with two pairs of Higgs doublets

Energy Technology Data Exchange (ETDEWEB)

Grossman, Yuval [Laboratory for Elementary-Particle Physics, Cornell University,Ithaca, N.Y. (United States); Peset, Clara [Institut de Fisica d’Altes Energies (IFAE), Universitat Autònoma de Barcelona,08193 Bellaterra, Barcelona (Spain)

2014-04-07

We study the generation of neutrino masses and mixing in supersymmetric R-parity violating models containing two pairs of Higgs doublets. In these models, new RPV terms H^{sub D{sub 1}}H^{sub D{sub 2}}E^ arise in the superpotential, as well as new soft terms. Such terms give new contributions to neutrino masses. We identify the different parameters and suppression/enhancement factors that control each of these contributions. At tree level, just like in the MSSM, only one neutrino acquires a mass due to neutrino-neutralino mixing. There are no new one loop effects. We study the two loop contributions and find the conditions under which they can be important.

Accelerator-based neutrino oscillation searches

International Nuclear Information System (INIS)

Whitehouse, D.A.; Rameika, R.; Stanton, N.

1993-01-01

This paper attempts to summarize the neutrino oscillation section of the Workshop on Future Directions in Particle and Nuclear Physics at Multi-GeV Hadron Beam Facilities. There were very lively discussions about the merits of the different oscillation channels, experiments, and facilities, but we believe a substantial consensus emerged. First, the next decade is one of great potential for discovery in neutrino physics, but it is also one of great peril. The possibility that neutrino oscillations explain the solar neutrino and atmospheric neutrino experiments, and the indirect evidence that Hot Dark Matter (HDM) in the form of light neutrinos might make up 30% of the mass of the universe, point to areas where accelerator-based experiments could play a crucial role in piecing together the puzzle. At the same time, the field faces a very uncertain future. The LSND experiment at LAMPF is the only funded neutrino oscillation experiment in the United States and it is threatened by the abrupt shutdown of LAMPF proposed for fiscal 1994. The future of neutrino physics at the Brookhaven National Laboratory AGS depends the continuation of High Energy Physics (HEP) funding after the RHIC startup. Most proposed neutrino oscillation searches at Fermilab depend on the completion of the Main Injector project and on the construction of a new neutrino beamline, which is uncertain at this point. The proposed KAON facility at TRIUMF would provide a neutrino beam similar to that at the AGS but with a much increase intensity. The future of KAON is also uncertain. Despite the difficult obstacles present, there is a real possibility that we are on the verge of understanding the masses and mixings of the neutrinos. The physics importance of such a discovery can not be overstated. The current experimental status and future possibilities are discussed below