5,943 research outputs found

    Clone flow analysis for a theory inspired Neutrino Experiment planning

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    The presence of several clone solutions in the simultaneous measurement of (θ13,δ\theta_{13},\delta) has been widely discussed in literature. In this letter we write the analytical formulae of the clones location in the (θ13,δ\theta_{13},\delta) plane as a function of the physical input pair (θˉ13,δˉ\bar\theta_{13},\bar\delta). We show how the clones move with changing θˉ13\bar\theta_{13}. The "clone flow" can be significantly different if computed (naively) from the oscillation probabilities or (exactly) from the probabilities integrated over the neutrino flux and cross-section. Using our complete computation we compare the clone flow of a set of possible future neutrino experiments: the CERN SuperBeam, BetaBeam and Neutrino Factory proposals. We show that the combination of these specific BetaBeam and SuperBeam does not help in solving the degeneracies. On the contrary, the combination of one of them with the Neutrino Factory Golden and Silver channel can be used, from a theoretical point of view, to solve completely the eightfold degeneracy.Comment: 23 pages, using epsfi

    Golden measurements at a neutrino factory

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    The precision and discovery potential of a neutrino factory based on muon storage rings is studied. For three-family neutrino oscillations, we analyse how to measure or severely constraint the angle θ13\theta_{13}, CP violation, MSW effects and the sign of the atmospheric mass difference Δm232\Delta m^2_{23}. We present a simple analytical formula for the oscillation probabilities in matter, with all neutrino mass differences non-vanishing, which clarifies the subtleties involved in disentangling the unknown parameters. The appearance of ``wrong-sign muons'' at three reference baselines is considered: 732 km, 3500 km, and 7332 km. We exploit the dependence of the signal on the neutrino energy, and include as well realistic background estimations and detection efficiencies. The optimal baseline turns out to be O(3000{\cal O}(3000 km). Analyses combining the information from different baselines are also presented.Comment: 45 pages, Latex2e, 24 figures using epsfig.sty. An incorrect statement and a few misprints have been corrected. Results and conclusions are unchange

    Summary of Golden Measurements at a ν\nu-Factory

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    The precision and discovery potential of a neutrino factory based on muon storage rings is summarized. For three-family neutrino oscillations, we analyze how to measure or severely constraint the angle θ13\theta_{13}, CP violation, MSW effects and the sign of the atmospheric mass difference Δm232\Delta m^2_{23}. The appearance of ``wrong-sign muons'' at three reference baselines is considered: 732 km, 3500 km and 7332 km. We exploit the dependence of the signal on the neutrino energy, and include as well realistic background estimations and detection efficiencies. The optimal baseline turns out to be OO(3000 km).Comment: 7 pages, Latex2e, 5 eps figures, use package espfi

    Lattice QCD Calculation of the Kaon B-parameter with the Wilson Quark Action

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    The kaon B parameter is calculated in quenched lattice QCD with the Wilson quark action. The mixing problem of the \Delta s=2 four-quark operators is solved non-perturbatively with full use of chiral Ward identities, and this method enables us to construct the weak four-quark operators exhibiting good chiral behavior. We find B_K(NDR, 2GeV)=0.562(64) in the continuum limit, which agrees with the value obtained with the Kogut-Susskind quark action.Comment: 11 pages, latex source-file, 4 figures as ps-fil

    A Beta Beam complex based on the machine upgrades for the LHC

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    The Beta Beam CERN design is based on the present LHC injection complex and its physics reach is mainly limited by the maximum rigidity of the SPS. In fact, some of the scenarios for the machine upgrades of the LHC, particularly the construction of a fast cycling 1 TeV injector (``Super-SPS''), are very synergic with the construction of a higher γ\gamma Beta Beam. At the energies that can be reached by this machine, we demonstrate that dense calorimeters can already be used for the detection of ν\nu at the far location. Even at moderate masses (40 kton) as the ones imposed by the use of existing underground halls at Gran Sasso, the CP reach is very large for any value of θ13\theta_{13} that would provide evidence of νe\nu_e appearance at T2K or NOν\nuA (θ133\theta_{13}\geq 3^\circ). Exploitation of matter effects at the CERN to Gran Sasso distance provides sensitivity to the neutrino mass hierarchy in significant areas of the θ13δ\theta_{13}-\delta plane

    θ13\theta_{13}, δ\delta and the neutrino mass hierarchy at a γ=350\gamma=350 double baseline Li/B β\beta-Beam

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    We consider a β\beta-Beam facility where 8^8Li and 8^8B ions are accelerated at γ=350\gamma = 350, accumulated in a 10 Km storage ring and let decay, so as to produce intense νˉe\bar \nu_e and νe\nu_e beams. These beams illuminate two iron detectors located at L2000L \simeq 2000 Km and L7000L \simeq 7000 Km, respectively. The physics potential of this setup is analysed in full detail as a function of the flux. We find that, for the highest flux (10×101810 \times 10^{18} ion decays per year per baseline), the sensitivity to θ13\theta_{13} reaches sin22θ132×104\sin^2 2 \theta_{13} \geq 2 \times10^{-4}; the sign of the atmospheric mass difference can be identified, regardless of the true hierarchy, for sin22θ134×104\sin^2 2 \theta_{13} \geq 4\times10^{-4}; and, CP-violation can be discovered in 70% of the δ\delta-parameter space for sin22θ13103\sin^2 2 \theta_{13} \geq 10^{-3}, having some sensitivity to CP-violation down to sin22θ13104\sin^2 2 \theta_{13} \geq 10^{-4} for δ90|\delta| \sim 90^\circ.Comment: 35 pages, 20 figures. Minor changes, matches the published versio

    A minimal Beta Beam with high-Q ions to address CP violation in the leptonic sector

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    In this paper we consider a Beta Beam setup that tries to leverage at most existing European facilities: i.e. a setup that takes advantage of facilities at CERN to boost high-Q ions (8Li and 8B) aiming at a far detector located at L = 732 Km in the Gran Sasso Underground Laboratory. The average neutrino energy for 8Li and 8B ions boosted at \gamma ~ 100 is in the range E_\nu = [1,2] GeV, high enough to use a large iron detector of the MINOS type at the far site. We perform, then, a study of the neutrino and antineutrino fluxes needed to measure a CP-violating phase delta in a significant part of the parameter space. In particular, for theta_13 > 3 deg, if an antineutrino flux of 3 10^19 useful 8Li decays per year is achievable, we find that delta can be measured in 60% of the parameter space with 6 10^18 useful 8B decays per year.Comment: 19 pages, 10 figures, added references and corrected typo

    Exact and Approximate Formulas for Neutrino Mixing and Oscillations with Non-Standard Interactions

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    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 \eta \equiv \Delta m^2_{21}/\Delta m^2_{31}, the vacuum leptonic mixing parameter s_{13} \equiv \sin\theta_{13}, and the NSI parameters \epsilon_{\alpha\beta}. A detailed numerical analysis about how the NSIs affect the smallest leptonic mixing angle \theta_{13}, the deviation of the leptonic mixing angle \theta_{23} from its maximal mixing value, and the transition probabilities useful for future experiments are performed using our analytical results.Comment: 29 pages, 8 figures, final version published in J. High Energy Phy

    U(1)' Symmetry Breaking in Supersymmetric E6 Models

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    We study the electroweak and U(1)U(1)^{'} symmetry breaking patterns in models with the particle content of supersymmetric E6E_{6}, including standard model singlets SS and exotic quarks D, DˉD,~\bar{D}. Motivated by free fermionic string models, we do not require E6E_{6}-type relations between Yukawa couplings. In particular, we assume that baryon and lepton numbers are conserved, so that the exotic quarks can be light. Gauge invariance allows Yukawa interactions between SS and Higgs doublets, and between SS and the exotic quarks, allowing radiative U(1)U(1)^{'} symmetry breaking and the generation of an effective μ\mu parameter at the electroweak scale. For both the E6E_{6} ψ\psi and η\eta models, universal soft supersymmetry breaking parameters and Yukawa universality at the high (string) scale do not yield acceptable low energy phenomenology. Relaxing universality, we find solutions with phenomenologically acceptable values of MZM_{Z^{'}} and the ZZZ-Z^{'} mixing angle. In addition, by varying the U(1)U(1)^{'} charge assignments due to the mixing of U(1)χU(1)_{\chi} and U(1)ψU(1)_{\psi} of E6E_{6}, it is possible to have acceptable low energy phenomenology with universal boundary conditions.Comment: 24 pages, 6 figures, 4 tables, LaTex; minor revision of the numerical results, typos corrected, reference adde
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