Suchergebnisse

We study the electromagnetic contribution to elastic neutrino-nucleon scattering processes. The neutrino
electromagnetic charge, magnetic, electric, and anapole form factors of both diagonal and transition types in
the mass basis are taken into account in the present formalism. When treating the nucleon electromagnetic
vertex, we take into account not only the charge and magnetic form factors of a nucleon, but also its electric and
anapole form factors. We examine the effects of the neutrino magnetic moment on elastic neutrino-nucleon
scattering and how they can be disentangled from those of the strange form factors contributions to the
nucleon's weak neutral current.

10 páginas, 8 figuras.-- El PDF es la versión pre-print (arXiv:0911.3103v1).-- Trabajo presentado al SUSY09: 7th International Conference on Supersymmetry and the Unification of Fundamental Interactions. ; After summarizing neutrino oscillation results I discuss high and low-scale seesaw mechanisms, with or without supersymmetry, as well as recent attempts to understand the pattern of neutrino mixing from flavor symmetries. I also mention the possibility of intrinsic supersymmetric neutrino masses in the context of broken R parity models, showing how this leads to clear tests at the LHC. ; This work is supported by the Spanish grants FPA2008-00319/FPA and PROMETEO/ 2009/091 and by European Union network UNILHC (PITN-GA-2009-237920). ; Peer reviewed

The T2K Collaboration reports evidence for electron neutrino appearance at the atmospheric mass splitting, vertical bar Delta m(32)(2)vertical bar approximate to 2.4 X 10(-3) eV(2). An excess of electron neutrino interactions over background is observed from a muon neutrino beam with a peak energy of 0.6 GeV at the Super-Kamiokande (SK) detector 295 km from the beam's origin. Signal and background predictions are constrained by data from near detectors located 280 m from the neutrino production target. We observe 11 electron neutrino candidate events at the SK detector when a background of 3.3 +/- 0.4(syst) events is expected. The background-only hypothesis is rejected with a p value of 0.0009 (3.1 sigma), and a fit assuming nu(mu) -> nu(e) oscillations with sin (2)2 theta(23) = 1, delta(CP) = 0 and vertical bar Delta m(32)(2)vertical bar = 2.4 X 10(-3) eV(2) yields sin (2)2 theta(13) = 0.088(-0.039)(+0.049)(stat + syst). ; We thank the J-PARC accelerator team for the superb accelerator performance and CERN NA61 colleagues for providing essential particle production data and for their fruitful collaboration. We acknowledge the support of MEXT, Japan; NSERC, NRC and CFI, Canada; CEA and CNRS/IN2P3, France; DFG, Germany; INFN, Italy; Ministry of Science and Higher Education, Poland; RAS, RFBR and the Ministry of Education and Science of the Russian Federation; MEST and NRF, South Korea; MICINN and CPAN, Spain; SNSF and SER, Switzerland; STFC, U.K.; NSF and DOE, USA We also thank CERN for their donation of the UA1/NOMAD magnet and DESY for the HERA-B magnet mover system. In addition, participation of individual researchers and institutions in T2K has been further supported by funds from ERC (FP7), EU; JSPS, Japan; Royal Society, UK; DOE Early Career program, and the A. P. Sloan Foundation, USA Computations were performed on the supercomputers at the SciNet [115] HPC Consortium. SciNet is funded by the Canada Foundation for Innovation under the auspices of Compute Canada; the Government of Ontario; Ontario Research Fund - Research Excellence; and the University of Toronto. ; Peer reviewed

35th International Conference of High Energy Physics - ICHEP2010, July 22-28, 2010, Paris (France). PoS(ICHEP 2010) 296. ; We update present bounds on the helicity of the neutrinos produced in muon decay, including e+e− ! f f LEP 2 data. These significantly reduce the limits derived from all the other electroweak precision data. In Standard Model extensions designed to maximize the RH neutrino production in such a decay the neutrino deficit eventually observable in a near detector at a neutrino factory can be of the order of 5 %. Motivated by the current LHC run at 7 TeV, we also update previous work providing discovery limits on see-saw mediators at this centre of mass energy. Lepton triplets with 200 GeV could be discovered with luminosities of 1 - 1.5 fb−1. Scalar triplets of the same mass might be seen with 0.75 - 3 fb−1. What makes their search also attractive in the first LHC analyses. ; This work has been partially supported by MICINN (FPA2006-05294), Junta de Andalucía (FQM 101, FQM 03048) and the European Union (MRTN-CT-2006-035505).

We explore the possibility that dark matter interactions with Standard Model particles are dominated by interactions with neutrinos. We examine whether it is possible to construct such a scenario in a gauge invariant manner. We first study the coupling of dark matter to the full lepton doublet and confirm that this generally leads to the dark matter phenomenology being dominated by interactions with charged leptons. We then explore two different implementations of the neutrino portal in which neutrinos mix with a Standard Model singlet fermion that interacts directly with dark matter through either a scalar or vector mediator. In the latter cases we find that the neutrino interactions can dominate the dark matter phenomenology. Present neutrino detectors can probe dark matter annihilations into neutrinos and already set the strongest constraints on these realisations. Future experiments such as Hyper-Kamiokande, MEMPHYS, DUNE, or DARWIN could allow to probe dark matter-neutrino cross sections down to the value required to obtain the correct thermal relic abundance ; This work is supported in part by the European Union's Horizon 2020 research and innovation programme under the Marie SklodowskaCurie Grant agreements 674896-Elusives, 690575-InvisiblesPlus, and 777419-ESSnuSB, as well as by the COST Action CA15139 EuroNuNet. MB, EFM, and SR acknowledge support from the "Spanish Agencia Estatal de Investigación" (AEI) and the EU "Fondo Europeo de Desarrollo Regional" (FEDER) through the project FPA2016-78645-P; and the Spanish MINECO through the "Ramón y Cajal" programme and through the Centro de Excelencia Severo Ochoa Program under Grant SEV-2016-0597. MB also acknowledges support from the Göran Gustafsson foundation. SP and AOD are also (partially) supported by the European Research Council under ERC Grant "NuMass" (FP7- IDEAS-ERC ERC-CG 617143). SP would like to acknowledge partial support from the Wolfson Foundation and the Royal Society.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant ; European Research Council under ERC Grant NuMass ; Wolfson Foundation ; Royal Society ; European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant: 690575 ; European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant: 674896 ; European Research Council under ERC Grant NuMass: FP7-IDEAS-ERC ERC-CG 617143 ; Neutrino trident scattering is a rare Standard Model process where a charged-lepton pair is produced in neutrino-nucleus scattering. To date, only the dimuon final-state has been observed, with around 100 total events, while the other channels are as yet unexplored. In this work, we compute the trident production cross section by performing a complete four-body phase space calculation for different hadronic targets. This provides a correct estimate both of the coherent and the diffractive contributions to these cross sections, but also allows us to address certain inconsistencies in the literature related to the use of the Equivalent Photon Approximation in this context. We show that this approximation can give a reasonable estimate only for the production of dimuon final-states in coherent scattering, being inadmissible for all other cases considered. We provide estimates of the number and distribution of trident events at several current and future near detector facilities subjected to intense neutrino beams from accelerators: five liquid-argon detectors (SBND, BooNE, ICARUS, DUNE and STORM), the iron detector of T2K (INGRID) and three detectors made of composite material (MINOS, NOA and MINERA). We find that for many experiments, trident measurements are an attainable goal and a valuable addition to their near detector physics programme.

In this paper acoustic transmitters that were developed for use in underwater neutrino telescopes are presented. Firstly, an acoustic transceiver has been developed as part of the acoustic positioning system of neutrino telescopes. These infrastructures are not completely rigid and require a positioning system in order to monitor the position of the optical sensors which move due to sea currents. To guarantee a reliable and versatile system, the transceiver has the requirements of reduced cost, low power consumption, high pressure withstanding (up to 500 bars), high intensity for emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring and processing received signals. Secondly, a compact acoustic transmitter array has been developed for the calibration of acoustic neutrino detection systems. The array is able to mimic the signature of ultra-high-energy neutrino interaction in emission directivity and signal shape. The technique of parametric acoustic sources has been used to achieve the proposed aim. The developed compact array has practical features such as easy manageability and operation. The prototype designs and the results of different tests are described. The techniques applied for these two acoustic systems are so powerful and versatile that may be of interest in other marine applications using acoustic transmitters. © 2012 by the authors; licensee MDPI, Basel, Switzerland. ; This work has been supported by the Ministerio de Ciencia e Innovacion (Spanish Government), project references FPA2009-13983-C02-02, ACI2009-1067, AIC10-D-00583, Consolider-Ingenio Multidark (CSD2009-00064). Authors Manuel Bou-Cabo and Silvia Adrian-Martinez thank Multidark for the fellowships. The work has also been funded by Generalitat Valenciana, Prometeo/2009/26, and the European 7th Framework Programme, Grant No. 212525. ; Ardid Ramírez, M.; Martínez Mora, JA.; Bou Cabo, M.; Larosa ., G.; Adrián Martínez, S.; Llorens Alvarez, CD. (2012). Acoustic Transmitters for Underwater Neutrino ...

PACS numbers: 14.60.St, 13.15.+g, 13.35.Hb, 13.66.Hk ; We discuss the phenomenology of the most general effective Lagrangian, up to operators of dimension five, built with standard model fields and interactions including right-handed neutrinos. In particular, we find there is a dimension five electroweak moment operator of right-handed neutrinos, not discussed previously in the literature, which could have interesting phenomenological consequences. ; This work has been supported in part by the Ministry of Science and Innovation (MICINN) Spain, under Grant No. FPA2008-03373, by the European Union within the Marie Curie Research & Training Networks, MRTN-CT- 2006-035482 (FLAVIAnet), and by the U.S. Department of Energy Grant No. DE-FG03-94ER40837. A.A. is supported by the MICINN under the FPU program. A.A and A. S. thank Sacha Davidson and Jordi Vidal for interesting discussions in the early stages of this work, Vicente Vento for his advice on some of the calculations presented here, and Carmen Garcia for her help with the experimental data on neutral heavy leptons. J.W. gratefully acknowledges Ernest Ma's help and comments. ; Peer reviewed

11th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2009). Rome, ITALY, JUL 01-05, 2009 ; I briefly summarize neutrino oscillation results and discuss their robustness. I mention recent attempts to understand the pattern of neutrino mixing within various seesaw mechanisms, with or without supersymmetry and/or flavor symmetries. I also mention the possibility of intrinsic supersymmetric neutrino masses in the context of broken R parity models, showing how this leads to clear tests at the LHC. ; Work supported by Spanish grants FPA2008-00319/FPA and PROMETEO/2009/091 and by European Union network UNILHC (PITN-GA-2009-237920).

We compute the one-loop running of the dimension-six CP-even Higgs operators in the Standard Model e ective eld theory involving the right-handed component of the would-be Dirac neutrinos. Then, on the basis of naturalness arguments, for some operators we obtain bounds that surpass direct constraints by orders of magnitude. We also discuss the implications of a large Dirac neutrino magnetic dipole moment. In particular, we demonstrate that a neutrino magnetic moment explaining the recent XENON1T excess induces Higgs and Z invisible decays with branching ratios in the range [10(-18); 10(-12)]. These numbers are unfortunately beyond the reach of current and near future facilities. ; Spanish MINECO under the Juan de la Cierva programme ; Spanish Government FPA2016-78220-C3-3-P ; Junta de Andalucía FQM 101 A-FQM-211-UGR18

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; European Union ; European Research Council ; Wolfson Foundation ; Royal Society ; U.S. Department of Energy ; European Union: 690575 ; European Union: 674896 ; European Research Council: FP7-IDEAS-ERC ERC-CG 617143 ; U.S. Department of Energy: DE-AC02-07CH11359 ; Novel leptophilic neutral currents can be tested at upcoming neutrino oscillation experiments using two complementary processes, neutrino trident production and neutrino-electron (nu - e) elastic scattering. Considering generic anomaly-free U(1) extensions of the Standard Model, we discuss the characteristics of nu - e scattering as well as e(+)e(-) and mu(+)mu(-) trident production at the DUNE near detector in the presence of such beyond the Standard Model scenarios. We then determine the sensitivity of DUNE in constraining the well-known L-e - L-mu and L-mu - L-tau models. We conclude that DUNE will be able to probe these leptophilic models with unprecedented sensitivity, covering unproved explanations of the (g-2)(mu) discrepancy.

Artículo escrito por muchos autores, sólo se referencian el primero, los autores que firman como Universidad Autónoma de Madrid y el grupo de colaboración en el caso de que aparezca en el artículo ; Hyper-Kamiokande will be a next-generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of CP asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this paper, the physics potential of a long-baseline neutrino experiment using the Hyper- Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis uses the framework and systematic uncertainties derived from the ongoing T2K experiment. With a total exposure of 7.5 MW ×107 s integrated proton beam power (corresponding to 1.56 × 1022 protons on target with a 30 GeV proton beam) to a 2.5° off-axis neutrino beam, it is expected that the leptonic CP phase δCP can be determined to better than 19 degrees for all possible values of δCP, and CP violation can be established with a statistical significance of more than 3 σ (5 σ) for 76% (58%) of the δCP parameter space. Using both νeappearance and νμ disappearance data, the expected 1 σ uncertainty of sin2 Θ23 is 0.015(0.006) for sin2 Θ23= 0.5(0.45) ; This work was supported by a MEXT Grant-in-Aid for Scientific Research on Innovative Areas Number 25105004, titled "Unification and Development of the Neutrino Science Frontier." In addition, the participation of individual researchers has been further supported by funds from JSPS, Japan; the European Union ERC-207282, H2020 RISE-GA644294-JENNIFER, and H2020 RISE-GA641540-SKPLUS; RSF, RFBR, and MES, Russia; and JSPS and RFBR under the Japan–Russia Research Cooperative Program

16 pages, 12 figures.-- PACS nrs.: 14.60.Pq; 97.60.Bw.-- ISI Article Identifier: 000251987300100.-- ArXiv pre-print available at: http://arxiv.org/abs/0706.2498 ; In the dense-neutrino region at 50-400 km above the neutrino sphere in a supernova, neutrino-neutrino interactions cause large flavor transformations. We study when the multiangle nature of the neutrino trajectories leads to flavor decoherence between different angular modes. We consider a two-flavor mixing scenario between nu(e) and another flavor nu(x) and assume the usual hierarchy F-nu e > F-[overline nu][sub e] > F-nu x = F-[overline nu][sub x] for the number fluxes. We define epsilon = (F-nu e - F-[overline nu][sub e])/(F-[overline nu][sub e] - F-[overline nu][sub x]) as a measure for the deleptonization flux which is the one crucial parameter. The transition between the quasi-single-angle behavior and multiangle decoherence is abrupt as a function of epsilon. For typical choices of other parameters, multiangle decoherence is suppressed for epsilon greater than or similar to 0.3, but a much smaller asymmetry suffices if the neutrino mass hierarchy is normal and the mixing angle small. The critical epsilon depends logarithmically on the neutrino luminosity. In a realistic supernova scenario, the deleptonization flux is probably enough to suppress multiangle decoherence. ; This work was partly supported by the Deutsche Forschungsgemeinschaft under the Grant No. TR-27 "Neutrinos and Beyond", by The Cluster of Excellence for Fundamental Physics "Origin and Structure of the Universe" (Garching and Munich), by the European Union under the ILIAS project (Contract No. RII3-CT-2004-506222) and an RT Network (Contract No. MRTNCT-2004-503369), and by the Spanish grants FPA2005-01269 (MEC) and ACOMP07-270 (Generalitat Valenciana). A. E. has been supported by a FPU grant from the Spanish Government. S. P. and R. T. were supported by MEC contracts (Ramón y Cajal and Juan de la Cierva, respectively). ; Peer reviewed