231 research outputs found

    Minimal Neutrino Beta Beam for Large theta_13

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    We discuss the minimum requirements for a neutrino beta beam if theta_13 is discovered by an upcoming reactor experiment, such as Double Chooz or Daya Bay. We require that both neutrino mass hierarchy and leptonic CP violation can be measured to competitive precisions with a single-baseline experiment in the entire remaining theta_13 range. We find that for very high isotope production rates, such as they might be possible using a production ring, a (B,Li) beta beam with a gamma as low as 60 could already be sufficient to perform all of these measurements. If only the often used nominal source luminosities can be achieved, for example, a (Ne,He) beta beam from Fermilab to a possibly existing water Cherenkov detector at Homestake with gamma \sim 190-350 (depending on the Double Chooz best-fit) could outperform practically any other beam technology including wide-band beam and neutrino factory.Comment: 11 pages, 2 figures, 1 tabl

    Neutrino Mixings and Leptonic CP Violation from CKM Matrix and Majorana Phases

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    The high scale mixing unification hypothesis recently proposed by three of us (R. N. M., M. K. P. and G. R.) states that if at the seesaw scale, the quark and lepton mixing matrices are equal then for quasi-degenerate neutrinos, radiative corrections can lead to large solar and atmospheric mixings and small reactor angle at the weak scale in agreement with data. Evidence for quasi-degenerate neutrinos could, within this framework, be interpreted as a sign of quark-lepton unification at high scale. In the current work, we extend this model to show that the hypothesis works quite successfully in the presence of CP violating phases (which were set to zero in the first paper). In the case where the PMNS matrix is identical to the CKM matrix at the seesaw scale, with a Dirac phase but no Majorana phase, the low energy Dirac phase is predicted to be (0.3\simeq 0.3^{\circ}) and leptonic CP-violation parameter JCP(48)×105J_{CP} \simeq (4 - 8)\times 10^{-5} and θ13=3.5\theta_{13} = 3.5^{\circ}. If on the other hand, the PMNS matrix is assumed to also have Majorana phases initially, the resulting theory damps radiative magnification phenomenon for a large range of parameters but nevertheless has enough parameter space to give the two necessary large neutrino mixing angles. In this case, one has θ13=3.510\theta_{13} = 3.5^{\circ} - 10^{\circ} and JCP|J_{CP}| as large as 0.020.040.02-0.04 which are accessible to long baseline neutrino oscillation experiments.Comment: 15 pages and 10 figures, typo correcte

    Precision on leptonic mixing parameters at future neutrino oscillation experiments

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    We perform a comparison of the different future neutrino oscillation experiments based on the achievable precision in the determination of the fundamental parameters theta_{13} and the CP phase, delta, assuming that theta_{13} is in the range indicated by the recent Daya Bay measurement. We study the non-trivial dependence of the error on delta on its true value. When matter effects are small, the largest error is found at the points where CP violation is maximal, and the smallest at the CP conserving points. The situation is different when matter effects are sizable. As a result of this effect, the comparison of the physics reach of different experiments on the basis of the CP discovery potential, as usually done, can be misleading. We have compared various proposed super-beam, beta-beam and neutrino factory setups on the basis of the relative precision of theta_{13} and the error on delta. Neutrino factories, both high-energy or low-energy, outperform alternative beam technologies. An ultimate precision on theta_{13} below 3% and an error on delta of < 7^{\circ} at 1 sigma (1 d.o.f.) can be obtained at a neutrino factory.Comment: Minor changes, matches version accepted in JHEP. 30 pages, 9 figure

    Probing the Neutrino Mass Hierarchy with Super-Kamiokande

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    We show that for recently discovered large values of theta(13), a superbeam with an average neutrino energy of ~ 5 GeV, such as those being proposed at CERN, if pointing to Super-Kamiokande (L = 8770 km), could reveal the neutrino mass hierarchy at 5 sigma in less than two years irrespective of the true hierarchy and CP phase. The measurement relies on the near resonant matter effect in the numu to nue oscillation channel, and can be done counting the total number of appearance events with just a neutrino beam.Comment: 16 pages, 7 pdf figures, 2 tables. Format changed and text extended. Four new pdf figures added. Dependency of the result on 1-3 mixing angle discussed. Conclusions unchanged. Accepted in JHE

    Information Content of Implicit Spot Prices Embedded in Single Stock Future Prices: Evidence from Indian Market

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    This study examines the information content of pricing error, measured by the difference between the implied price computed using the cost of carry model and the spot price of Single Stock Futures (SSFs), traded on National Stock Exchange (NSE), India. The returns of portfolios, based on ranking of such pricing errors, are investigated. The consistency of results is verified by controlling for established risk factors, that is, market, size, value and momentum premium, and idiosyncratic factors such as firm’s liquidity and size. Our study reveals that the pricing error is a priced risk factor that contains incremental information about stock returns of day t, and not beyond. We conclude that implied spot prices from stock futures market are useful for traders to profit in the spot market

    Potential of optimized NOvA for large theta(13) & combined performance with a LArTPC & T2K

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    NOvA experiment has reoptimized its event selection criteria in light of the recently measured moderately large value of theta(13). We study the improvement in the sensitivity to the neutrino mass hierarchy and to leptonic CP violation due to these new features. For favourable values of deltacp, NOvA sensitivity to mass hierarchy and leptonic CP violation is increased by 20%. Addition of 5 years of neutrino data from T2K to NOvA more than doubles the range of deltacp for which the leptonic CP violation can be discovered, compared to stand alone NOvA. But for unfavourable values of deltacp, the combination of NOvA and T2K are not enough to provide even a 90% C.L. hint of hierarchy discovery. Therefore, we further explore the improvement in the hierarchy and CP violation sensitivities due to the addition of a 10 kt liquid argon detector placed close to NOvA site. The capabilities of such a detector are equivalent to those of NOvA in all respects. We find that combined data from 10 kt liquid argon detector (3 years of nu + 3 years of nubar run), NOvA (6 years of nu + 6 years of nubar run) and T2K (5 years of nu run) can give a close to 2 sigma hint of hierarchy discovery for all values of deltacp. With this combined data, we can achieve CP violation discovery at 95% C.L. for roughly 60% values of deltacp.Comment: 22 pages, 24 pdf figures, 5 tables. In the appendix, new results are presented with conservative choices of central values of oscillation parameters. New references are added. Accepted in JHE

    MiniBooNE Oscillation Results 2011

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    The MiniBooNE neutrino oscillation search experiment at Fermilab has recently updated results from a search for νˉμνˉe\bar\nu_\mu \rightarrow \bar\nu_e oscillations, using a data sample corresponding to 8.58×10208.58 \times 10^{20} protons on target in anti-neutrino mode. This high statistics result represent an increase in statistics of 52% compared to result published in 2010. An excess of 57.7 ±\pm 28.5 events is observed in the energy range 200 MeV <Eν<< E_\nu < 3000 MeV. The data favor LSND-like νˉμνˉe\bar\nu_\mu \rightarrow \bar\nu_e oscillations over a background only hypothesis at 91.1% confidence level in the energy range 475 <Eν<< E_\nu< 3000 MeV.Comment: 4 pages, 6 figures, talk given at NuFact 2011, XIIIth InternationalWorkshop on Neutrino Factories, Super beams and Beta beams, CERN/UNIGE, Geneva, Switzerland, August 1-6, 201

    Phonon Hall effect in ionic crystals in the presence of static magnetic field

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    We study phonon Hall effect (PHE) for ionic crystals in the presence of static magnetic field. Using Green-Kubo formula, we present an exact calculation of thermal conductivity tensor by considering both positive and negative frequency phonons. Numerical results are shown for some lattices such as hexagonal lattices, triangular lattices, and square lattices. We find that the PHE occurs on the nonmagnetic ionic crystal NaCl, although the magnitude is very small which is due to the tiny charge-to-mass ratio of the ions. The off-diagonal thermal conductivity is finite for nonzero magnetic field and changes sign for high value of magnetic field at high temperature. We also found that the off-diagonal thermal conductivity diverges as ±1/T\pm{1/T} at low temperature
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