Neutrino mass matrix

Top PDF Neutrino mass matrix:

Reactor mixing angle from hybrid neutrino masses

Reactor mixing angle from hybrid neutrino masses

Since the NLO approach is not particularly favored by data, it is important to con- sider alternative possibilities. In Ref. [7], it was argued that the TBM-form plus small deviations structure, can be interpreted as a hint that different mechanisms participate in the generation of neutrino masses, so-called “hybrid neutrino masses”. The idea is that of starting with a Lagrangian invariant under G, in which after G and electroweak symmetry breaking one mechanism accounts for the TBM-form while the deviations are provided by the other mechanism (rather than by NLO corrections), with both contributions to the neutrino mass matrix entering at the same order, generically LO. This type of scenario was investigated before in the context of bi-maximal mixing [15] and also in the case of TBM [16]. In [17] it was explored in models with extra dimensions. More recently in [18, 19, 20], type-I seesaw [21] was assumed to be responsible for the leading TBM-form and type-II seesaw [22] contributions introduced the deviations to TBM.
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Eigenvector-based approach to neutrino mixing

Eigenvector-based approach to neutrino mixing

∗ daristizabal@ulg.ac.be † ivo.de@udo.edu ‡ eric.houet@student.ulg.ac.be Majorana neutrino masses can be incorporated in the standard model Lagrangian through the dimension five effective operator O 5 ∼ LLHH [9], the type-I seesaw [10] being the most popular and simplest realization of this operator. Other realizations have been considered as pathways to neutrino masses but often the resulting neutrino mass matrix is solely sourced by a single set of lepton number violating parameters, e.g. in type-I see- saw the right-handed neutrino masses. However, given the multiple realizations of O 5 a conceivable possibility is that in which the neutrino mass matrix involves several independent sets of lepton number breaking parameters, a situation we refer to generically as “hybrid neutrino masses”, as would be the case e.g. in a scheme involving interplay between type-I and type-II seesaw [18]. Al- ready with two contributions sourcing the neutrino mass matrix several scenarios for neutrino mixing arising from interplay between them can be envisaged.
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Radiative Origin of Majorana Neutrino Masses

Radiative Origin of Majorana Neutrino Masses

The diagrammatic approach follows a simple strategy which can be summarized as follows. As soon as the order at which the analysis is going to be done is fixed: (i) find the topologies that can potentially lead to “genuine” diagrams, (ii) from those topologies draw the different diagrams paying special attention to those that can “genuinely” determine the mass matrix, (iii) fix the EW quantum numbers of the BSM fields, (iv) calculate the loop integrals. The list of models resulting from such classification provide a catalog of “genuine” neutrino mass models. With genuine here we refer to diagrams for which the absence of leading-order diagrams can be guaranteed. Only in those cases it can be entirely assured that the neutrino mass matrix originates at the same order that the corresponding diagram.
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Neutrino mass textures and partial mu-tau symmetry

Neutrino mass textures and partial mu-tau symmetry

As to the origin of the perturbations, there are a few strategies to follow. First, one can add terms explicitly violating the μ–τ symmetry in the Lagrangian, as was done in [26] . Second, one may assume exact symmetry, leading to θ z ¼ 0, at the high scale. Then renormalization group (RG) running of the neutrino mass matrix elements creates a term that breaks the μ–τ symmetry at the electroweak scale. However, many studies showed that the RG effects are negligible. In [27] , this process of symmetry breaking via RG running within a multiple Higgs doublets model was only valid, for a sizable θ z , in a quasidegenrate spectrum. In [28] , the same conclusion, about the inability of radiative breaking to generate a relatively large θ z , was reached in minimal supersymmetric standard model (MSSM) schemes. Thus, we shall not consider RG effects, but impose approximate μ–τ symmetry at the high scale (the seesaw scale, say) which would remain valid at the measurable electroweak scale. Third, as was done in [29] , the μ–τ symmetry is replaced by another symmetry including the former as a subgroup. In this spirit and in line with [23,25] , we address in detail the question of the perturbations ’ root and present some concrete examples at the Lagrangian level for the minimal texture form which has only one breaking parameter by means of adding extra Higgs fields and symmetries, in both types I and II of seesaw mechanisms. In type II seesaw, we achieve the desired perturbed form by adding a new Z 2 symmetry to the one characterizing the μ-τ symmetry (which we denote henceforth by S) and three Higgs triplets responsible for giving masses to the left-handed (LH) neutrinos and by substituting three Higgs doublets for the SM Higgs field for the charged lepton masses. On the other hand, we achieve the desired form in type I seesaw by considering a flavor
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Rapid characterization of aquatic hyphomycetes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Rapid characterization of aquatic hyphomycetes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

In addition to taxonomic studies, analysis of protein mass fingerprints using MALDI-TOF MS may be a powerful tool to investigate and quantify genetic and phenotypic correlations, because the method can detect most dominant proteins simultaneously. Phenotypic variability in response to environmental conditions is probably reflected by protein expression, which can potentially be quantified by MALDI-TOF MS, assuming the development of additional quantita- tive protocols (Pan et al. 2009 ) and annotated genome sequences of study organisms. Providing an example for such applications, Howard and Boyer ( 2007 ) devel- oped protocols to quantify cyanobacteria microcystins from environmental samples using MALDI-TOF MS with internal standards. In aquatic hyphomycete ecology, elucidating the role of intraspecific diversity, phenotypic variability, and the organisms’ responses to environmental conditions may advance the mechanistic understanding not only of functional differences but also of interactions among strains and species with consequences for ecosystem functions (Ferreira et al.
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Configuring the Long-Baseline Neutrino Experiment

Configuring the Long-Baseline Neutrino Experiment

The sensitivities to the mass hierarchy, octant, and CP violation are shown in Figs. 1 , 2 , and 3 . From these figures, it is clear that, as expected, the best sensitivities are obtained from a combination of beam and atmospheric neutrino data collected by an FD in conjunction with an ND (solid green lines in Figs. 1 –3 ). However, this optimal configuration is not expected for the first phase of LBNE. As is evident from Fig. 1 , for a range of δ CP values, the determination of the mass hierarchy benefits more from having an underground FD than from having an ND with an FD on the surface (compare the dashed green lines with the solid magenta lines). Specifically, the underground detector provides significantly better results for the mass hierarchy resolution where the sensitivity to δ CP is gen- erally poor (δ CP ∈ ½0.25π; 0.75π for the normal hierarchy and δ CP ∈ ½−0.75π; −0.25π for the inverted hierarchy).
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Combined analysis of all three phases of solar neutrino data from the Sudbury Neutrino Observatory

Combined analysis of all three phases of solar neutrino data from the Sudbury Neutrino Observatory

7 Be reactions (not shown) are almost identical in the region of those measurements. The blue shaded band is the result of the measurement the 8 B neutrino ν e survival probability reported here. The red point is the result of the Borexino measurement [ 42 ] of the survival probability for ν e s produced by 7 Be + e − → 7 Li + ν e reactions in the Sun. The blue point is the result of various measurements [ 40 ] of the survival probability for ν e s produced by p + p → 2 H + e + + ν e reactions in the Sun; note that these measurements did not exclusively measure this reaction, so the contribution from other reactions were removed assuming the best fit LMA solution, and so actually depends on all solar neutrino results. The uncertainty in absolute flux of the subtracted reactions was included in the calculation of the total uncertainty of this point, but the uncertainty due to the neutrino oscillation probability of these reactions was not. The uncertainty due to the normalization of the two points by the expected flux was included. For clarity, this plot illustrates the LMA solution relative to only a subset of the solar neutrino experimental results.
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Phenomenology of supersymmetric neutrino mass models

Phenomenology of supersymmetric neutrino mass models

always been observed to be left-handed in all performed experiments. This popular framework, widely studied and extended in several directions, is one of the most common ways to generate neutrino masses and it can be used with or without supersymmetry. As we will see below, there are other types of Seesaw mechanism. They all share the common feature of the suppression of neutrino masses by the existence of a high energy scale. If this scale is very high, like in the numerical example given above, direct tests of the model become impossible. The energies reached at colliders do not allow to produce such heavy particles, and thus only indirect tests are at best available. As discussed in chapter 8, the supersymmetric version of the seesaw mechanism, in each of its variations, offers some experimental chances due to the existence of the superparticles. In particular, the sleptons carry some information on the high energy regime, which allows to test some scenarios. The non-SUSY case, however, does not provide this possibility, and thus the model cannot be put to experimental test.
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Radiative origin of neutrino masses

Radiative origin of neutrino masses

Once a particular neutrino mass generating framework is fixed, the ori- gin of neutrino mixing can be addressed in several ways. The “standard” approach, however, relies on the idea that the UV completion involves, in addition to the new dof, extra symmetries which enforce the observed mix- ing pattern, see e.g. [ 19 , 20 ]. Another approach, pointed out in the context of the tribimaximal (TBM) pattern, consists of “hybrid” neutrino masses, where the TBM structure is sourced by one mechanism, while the experi- mentally required deviations by another one, see Refs. [ 21 ] for more details.
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Récents progrès dans la physique du neutrino massif

Récents progrès dans la physique du neutrino massif

14 CHAPITRE 1. INTRODUCTION GÉNÉRALE par le mécanisme dit de la balançoire (see-saw) et qui sera décrit au chapitre 2. Toutes ces questions sur les propriétés des neutrinos et leurs conséquences ont poussé les physiciens à élargir les investigations et explorer toutes les pistes. Ainsi, plusieurs sources de neutrinos sont exploitées : les neutrinos produits par la radioactivité naturelle des élé- ments, par les réacteurs nucléaires et par les accélérateurs à hautes énergies. On se sert aussi des neutrinos venant de l’espace en mettant au point de détecteurs de plus en plus efficaces profondément enterrés (afin de ne pas les confondre avec les neutrinos terrestres). Ces neutrinos sont trés intéressants car n’interagissant que très faiblement, et voyageant avec une vitesse proche de celle de la lumière, partant de régions inaccessibles de l’espace (galaxies lointaines) et du temps (origine de l’Univers), ils peuvent atteindre nos détec- teurs, contrairement aux photons, les messagers traditionnels de l’astronomie qui eux se font piègér par la matière (le seul inconvéniant des neutrinos par rapport aux photons est que leur section efficace d’interaction est très petite ce qui nécessite des détecteurs à grand volume). Par exemple, en comparant les durées de voyage jusqu’à la Terre d’un photon et d’un neutrino, tous deux issus du coeur du soleil, on remarque que le photon met un million d’années pour arriver tandis que le neutrino ne met que six minutes. Inversement, appor- tant de riches informations sur leurs origines, ces neutrinos peuvent nous servir à sonder l’intérieur des étoiles et à examiner directement les processus énergétiques physiques qui ont lieu dans les noyaux stellaires.
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An algorithm for the reconstruction of neutrino-induced showers in the ANTARES neutrino telescope

An algorithm for the reconstruction of neutrino-induced showers in the ANTARES neutrino telescope

A likelihood function is defined to describe the probability P (q i ) that a hypothetical neutrino ν with energy E ν , direction ~p ν and creating a shower at position ~r shower causes hits with a total measured charge q i on a PMT i. The measured charge is compared to the expectation value of the number of photons on this PMT for such a shower. This expectation value depends on the neutrino energy E ν , the distance d i of the OM to the nominal shower position, the photon emission angle φ i from the neutrino direction and its incident angle α i on the PMT photocathode 1 . A schematic overview of the geometric variables that enter this signal part of the likelihood function is given in figure 1. The likelihood also takes into consideration that the hit could be caused by ambient background and evaluates the probability that a background event causes a charge as observed on the PMT (P bg (q i )). The PMTs that did not record any hits which passed the hit selection are also taken into account (P (q i = 0)).
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AMADEUS - The Acoustic Neutrino Detection Test System of the Deep-Sea ANTARES Neutrino Telescope

AMADEUS - The Acoustic Neutrino Detection Test System of the Deep-Sea ANTARES Neutrino Telescope

ah ITEP - Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117218 Moscow, Russia Abstract The AMADEUS system described in this article is integrated into the ANTARES neu- trino telescope in the Mediterranean Sea and aims at the investigation of techniques for acoustic detection of neutrinos in the deep sea. Installed at water depths between 2000 and 2400 m, its acoustic sensors employ piezo-electric elements for the broad-band record- ing of signals with frequencies ranging up to 125 kHz with typical sensitivities around −145 dB re. 1V/µPa (including preamplifier). Completed in May 2008, AMADEUS con- sists of six “acoustic clusters”, each comprising six acoustic sensors that are arranged at distances of roughly 1 m from each other. Three acoustic clusters each are installed along two vertical mechanical structures (so-called lines) of the ANTARES detector at a horizon- tal distance of 240 m. Vertical spacings within a line range from 15 m to 125 m. Each cluster contains custom-designed electronics boards to amplify and digitise the acoustic data from the sensors. The data transmission to shore is done via optical fibres, using the TCP/IP pro- tocol. An on-shore computer cluster, currently consisting of four dedicated servers, is used to process, filter and store the selected data. The daily volume of recorded data is about 10 – 20 GByte. The system is operating continuously and automatically, requiring only little human intervention. AMADEUS allows for extensive studies of both transient signals and ambient noise in the deep sea as well as signal correlations on several length scales and localisation of acoustic point sources. Thus the system is excellently suited to assess the background conditions that affect the measurement of bipolar pulses expected to originate from neutrino interactions. This in turn allows for feasibility studies of a future large-scale acoustic neutrino telescope in the Mediterranean Sea.
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Lepton flavour violation and neutrino masses

Lepton flavour violation and neutrino masses

Although cLFV need not arise from the underlying NP model responsible for neutrino mass generation, models in which this is indeed the case - such as the different seesaw realisations - are particularly appealing frameworks. While theoretically appealing, realisations of the see- saw at very large scale (high-scale seesaws) have little impact on the cLFV observables here discussed: despite the associated large “natural” values for the neutrino Yukawa couplings, the contributions to the rates are heavily suppressed due to the very large mass of the mediators. Low-scale seesaw realisations, in which the comparatively light new states (with masses be- tween the MeV and the TeV) have non-negligible mixings with the active states and hence do not decouple, offer very rich prospects for both cLFV and LNV observables. This is illustrated on the left panel of Fig. 4 , which displays the predictions to several cLFV muon channels as a function of the mass of the mediators, for a low-scale realisation of a type I seesaw [ 36 ].
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Neutrino and antineutrino quasielastic interactions with nuclei

Neutrino and antineutrino quasielastic interactions with nuclei

We have treated these responses in the ring approxi- mation of the RPA so as to account for collective effects. A limitation of our description is that it does not incor- porate final state interactions such as for instance the possibility for a real pion produced by the neutrino to be reabsorbed in the nucleus leading to multinucleon ejec- tion. This fraction of the produced pions would thus be counted in the “quasielastic” events. These events have been subtracted in the MiniBooNE analysis through their Monte Carlo evaluation. Hence our theory can be con- fronted to their corrected experimental results.
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Measurement of the top quark mass in the lepton+jets final state with the matrix element method

Measurement of the top quark mass in the lepton+jets final state with the matrix element method

information, the events selected are analyzed with the Matrix Element method. This method was developed by D0 for the Run I measurement of the top quark mass [5] and led to the single most precise measurement during Run I. For each event, a probability is calculated as a function of the top quark mass that this event has arisen from t¯ t production. A similar probability is computed for the main background process, which is the production of a leptonically decaying W boson produced in association with jets. The detector resolution is taken into account in the calculation of these probabilities. The top quark mass is then extracted from the joint probability calculated for all selected events. To reduce the sensitivity to the energy scale of the jets measured in the calorimeter, the Matrix Element method has been extended so this scale can be determined simultaneously with the top quark mass from the same event sample [4, 6].
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Recherche d'un neutrino lourd avec le détecteur ATLAS au LHC

Recherche d'un neutrino lourd avec le détecteur ATLAS au LHC

4.2 Modes de désintégration Suite à la collision des deux protons au LHC, un lepton lourd peut être produit en association avec un lepton de la première génération par la fusion d’un quark et d’un antiquark, par échange d’un W ou Z dans le canal s. Ces leptons lourds se désintègrent ensuite en un boson et un autre lepton de la première génération. L’état final qu’on cherche à étudier contient au moins trois leptons associés à un neutrino. Donc, en tenant compte de la conserva- tion du nombre leptonique et de la charge, il existe quatre types de modes de désintégration pour cet état final. À l’aide d’une interaction faisant intervenir un courant neutre, le lepton lourd chargé (E), qui est couplé au lepton chargé de la première génération, l’électron (e), se désintègre via le boson Z pour produire à l’état final quatre leptons, soit quatre électrons ou deux électrons et deux muons (voir Fig 4.2).
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Models of neutrino masses: anarchy versus hierarchy

Models of neutrino masses: anarchy versus hierarchy

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignemen[r]

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Time Calibration of the ANTARES Neutrino Telescope

Time Calibration of the ANTARES Neutrino Telescope

Accepted Manuscript Time Calibration of the ANTARES Neutrino Telescope J.A. Aguilar, I. Al Samarai, A. Albert, M. André, M. Anghinolfi, G. Anton, S. Anvar, M. Ardid, A.C. Assis Jesus, T. Astraatmadja, J.J. Aubert, R. Auer, B. Baret, S. Basa, M. Bazzotti, V. Bertin, S. Biagi, C. Bigongiari, M. Bou-Cabo, M.C. Bouwhuis, A.M. Brown, J. Brunner, J. Busto, F. Camarena, A. Capone, C. Cârloganu, G. Carminati, J. Carr, S. Cecchini, Ph. Charvis, T. Chiarusi, M. Circella, H. Costantini, N. Cottini, P. Coyle, C. Curtil, M.P. Decowski, I. Dekeyser, A. Deschamps, C. Distefano, C. Donzaud, D. Dornic, D. Drouhin, T. Eberl, U. Emanuele, J.P. Ernenwein, S. Escoffier, F. Fehr, V. Flaminio, U. Fritsch, J.L. Fuda, S. Galata, P. Gay, G. Giacomelli, J.P. Gómez-González, K. Graf, G. Guillard, G. Halladjian, G. Hallewell, H. van Haren, A.J. Heijboer, Y. Hello, J.J. Hernández-Rey, B. Herold, J. Hö ßl, C.C. Hsu, M. de Jong, M. Kadler, N. Kalantar-Nayestanaki, O. Kalekin, A. Kappes, U. Katz, P. Kooijman, C. Kopper, A. Kouchner, V. Kulikovskiy, R. Lahmann, P. Lamare, G. Larosa, D. Lefèvre, G. Lim, D. Lo Presti, H. Loehner, S. Loucatos, F. Lucarelli, S. Mangano, M. Marcelin, A. Margiotta, J.A. Martinez-Mora, A. Mazure, T. Montaruli, M. Morganti, L. Moscoso, H. Motz, C. Naumann, M. Neff, D. Palioselitis, G.E. Păvălaş, P. Payre, J. Petrovic, P. Piattelli, N. Picot-Clemente, C. Picq, V. Popa, T. Pradier, E. Presani, C. Racca, C. Reed, G. Riccobene, C. Richardt, M. Rujoiu, G.V. Russo, F. Salesa, P. Sapienza, F. Schöck, J.P. Schuller, R. Shanidze, F. Simeone, A. Spies, M. Spurio, J.J.M. Steijger, Th. Stolarczyk, M. Taiuti, C. Tamburini, L. Tasca, S. Toscano, B. Vallage, V. Van Elewyck, G. Vannoni, M. Vecchi, P. Vernin, G. Wijnker, E. de Wolf, H. Yepes,
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SoLid: a short baseline reactor neutrino experiment

SoLid: a short baseline reactor neutrino experiment

8 Conclusion The Solid collaboration constructed a 1.6 ton highly segmented neutrino detector based on an affordable dual scintillator technology in the years 2016-2017. The use of PVT for calorimetry is cost-effective and provides a linear energy response with an adequate energy resolution of 12% at 1 MeV, allowing for a very fine spatial segmentation of the fiducial volume. The 3D segmentation is an intrinsic feature of our detector with the potential to reduce intrinsic radioactivity backgrounds, accidentals and multiple recoils induced by fast neutrons. It will eventually also allow us to tag the annihilation gammas from positron interactions, which is a distinct feature of IBD events, provided that the energy reconstruction thresholds can address the low energy deposits per cell of 511 keV gammas. The detector is capable of operating at very close proximity to a compact research reactor with practically no overburden. Its design is simple and very modular and some of its parameters were improved after a measurement campaign with a single module prototype in 2015. As of the spring of 2018 the full size SoLid detector is in continuous operation at the BR2 research reactor of the SCK ⋅ CEN in Belgium. The BR2 reactor is operated with highly enriched 235 U fuel arranged in a very compact geometry, which reduces the uncertainties in the calculation of the incoming electron antineutrino flux and its energy spectrum. The detector has proven to run very stably over long periods of time and can be routinely calibrated with dedicated gamma and neutron sources with an in-situ system. The statistical energy resolution, the energy scale precision and the level of inter-channel response calibration all adhere to or surpass the initial SoLid design specifications. A detailed geometry description and detector response simulation have been developed, allowing for a future validation and understanding of the physical and instrumental backgrounds and an optimisation of the neutrino detection and oscillation measurements.
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Boosted dark matter at neutrino experiments

Boosted dark matter at neutrino experiments

The largest constraints affecting the parameter space studied in this work are from our analysis of published Super-K data, where Super-K has not detected any excess of electron events over muon events above statistical fluctuations. Such limits are set without any angular information, and thus can be extended by the Super-K, Hyper-K and DUNE collaborations through a similar analysis to the one described in this work. Other limits, although not discussed above, are model specific and need to be taken into consideration when building a BDM model. These limits include direct detection bounds on any thermal component of a particle interacting with electrons and/or quarks: Direct detection limits on electron scattering are set by the same process that enables the B particle detection at neutrino experiments, but affect the thermal B component instead of the relativistic one [67] . Direct detection limits from proton scattering would affect B particles with masses larger than Oð1Þ GeV, making the ability of the DUNE experiment to lower the energy detection threshold of utmost importance [16,68,69] . Other possible limits include cosmic microwave back- ground (CMB) constraints on the power injected by the thermal B component into SM particles at early redshifts
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