The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform

D.c. Cox - One of the best experts on this subject based on the ideXlab platform.

  • Test of Lorentz and CPT violation with short baseline neutrino oscillation excesses
    Physics Letters B, 2013
    Co-Authors: A.a. Aguilar-arevalo, C.e. Anderson, A.o. Bazarko, S.j. Brice, B.c. Brown, L. Bugel, J. Cao, L. Coney, J.m. Conrad, D.c. Cox
    Abstract:

    The Sidereal Time dependence of MiniBooNE nu(e) and (nu) over bar (e) appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov-Smirnov (K-S) test shows both the nu(e) and (nu) over bar (e) appearance data are compatible with the null Sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the nu(e) appearance data prefer a Sidereal Time-independent solution, and the (nu) over bar (e) appearance data slightly prefer a Sidereal Time-dependent solution. Limits of order 10(-20) GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for nu(mu) -> nu(e) and (nu) over bar (mu) -> (nu) over bar (e) oscillations. The fit values and limits of combinations of SME coefficients are provided.Peer reviewe

  • Test of Lorentz and CPT violation with Short Baseline Neutrino Oscillation Excesses
    Physics Letters B, 2011
    Co-Authors: A.a. Aguilar-arevalo, C.e. Anderson, A.o. Bazarko, S.j. Brice, B.c. Brown, L. Bugel, J. Cao, L. Coney, Janet Conrad, D.c. Cox
    Abstract:

    Abstract The Sidereal Time dependence of MiniBooNE ν e and ν ¯ e appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov–Smirnov (K–S) test shows both the ν e and ν ¯ e appearance data are compatible with the null Sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the ν e appearance data prefer a Sidereal Time-independent solution, and the ν ¯ e appearance data slightly prefer a Sidereal Time-dependent solution. Limits of order 10 − 20 GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for ν μ → ν e and ν ¯ μ → ν ¯ e oscillations. The fit values and limits of combinations of SME coefficients are provided.

Yu. Baryshev - One of the best experts on this subject based on the ideXlab platform.

  • Prediction of the Sidereal Time Distribution of Gravitational Wave Events for Different Detectors
    The Astrophysical Journal, 2003
    Co-Authors: G. Paturel, Yu. Baryshev
    Abstract:

    NAUTILUS-EXPLORER coincidences of gravitational wave (GW) events observed during 1998 and 2001 independently reveal the possible excess of events around 4 and 14 hr of Sidereal Time, exactly where it was predicted for tensor GW sources localized in the Galactic center. The statistical significance of the observed excess is small and needs confirmation. Nevertheless, if one accepts this result, one can predict the distribution of GW events that should be observed by other existing detectors. This gives us a way to confirm or reject the interpretation of these observations as being due to real GW signal. Then, we discuss the methods of analysis in order to facilitate the interpretation. First, we emphasize that the detectors used for coincidence analysis must be compatible, otherwise some coincident events may be lost. Then, we emphasize two important points resulting from the natural modulation of the signal provided by the Earth's rotation: (1) the Sidereal Time analysis can work with one detector only, without necessarily considering coincidences between two detectors, and (2) a very low signal-to-noise ratio (≈0.5) can be used.

  • Sidereal Time analysis as a tool for the study of the space distribution of sources of gravitational waves
    Astronomy & Astrophysics, 2003
    Co-Authors: G. Paturel, Yu. Baryshev
    Abstract:

    Gravitational wave (GW) detectors operating on a long Time range can be used for the study of space distribution of sources of GW bursts or to put strong upper limits on the GW signal of a wide class of source candidates. For this purpose we propose here a Sidereal Time analysis to analyze the output signal of GW detectors. Using the characteristics of some existing detectors, we demonstrate the capability of the Sidereal Time analysis to give a clear signature of different localizations of GW sources: the Galactic Center, the Galactic Plane, the Supergalactic plane, the Great Attractor. On the contrary, a homogeneous 3D-distribution of GW sources gives a signal without features. In this paper we consider tensor gravitational waves with randomly oriented polarization. We consider GW detectors at fixed positions on the Earth, and afixed orientation of the antenna.

T. I. Tulupova - One of the best experts on this subject based on the ideXlab platform.

  • Reconstruction of the Direction of True Anisotropy of Cosmic Rays at Energy of about 100 TeV
    2011
    Co-Authors: V. A. Kozyarivsky, A. S. Lidvansky, T. I. Tulupova
    Abstract:

    Based on experimental data of the Baksan Air Shower Array (BASA) for the period 1994 - 2006 we have derived the true declination of cosmic ray anisotropy with effective energy about 100 TeV. The method used for this is a modification of the method suggested by us in 2005 and based on the analysis of zero harmonic of intensity in the Sidereal Time. The CR anisotropy declination turned out to be about 60 degrees. Thus, our previously published data, according to which the anisotropy vector lies in the galactic plane, is confirmed. In this case the correction of the am- plitude of the first harmonic in Sidereal Time reduced to the equator by the cosine of the true declination gives for the total amplitude of the anisotropy vector a value of 0.16%.

  • Reconstruction of the Direction of the True Anisotropy of Galactic Cosmic Rays
    Astronomy Letters, 2010
    Co-Authors: D. D. Dzhappuev, V. A. Kozyarivsky, A. S. Lidvansky, A. U. Kudzhaev, T. I. Tulupova
    Abstract:

    A method of reconstructing the declination of galactic cosmic ray anisotropy is described, and its results are presented. The method is based on analysis of delay distributions in symmetrically arranged detectors of an air shower array, and it represents a modification of the crossed telescopes method. It is shown that the declination of the true anisotropy vector is close to 60° (i.e., this vector lies approximately within the galactic plane). Because of this, the true degree of anisotropy of galactic cosmic rays is severalfold higher than the first harmonic of intensity in the Sidereal Time (the quantity measured directly), and it equals about 0.2%.

G. Paturel - One of the best experts on this subject based on the ideXlab platform.

  • Prediction of the Sidereal Time Distribution of Gravitational Wave Events for Different Detectors
    The Astrophysical Journal, 2003
    Co-Authors: G. Paturel, Yu. Baryshev
    Abstract:

    NAUTILUS-EXPLORER coincidences of gravitational wave (GW) events observed during 1998 and 2001 independently reveal the possible excess of events around 4 and 14 hr of Sidereal Time, exactly where it was predicted for tensor GW sources localized in the Galactic center. The statistical significance of the observed excess is small and needs confirmation. Nevertheless, if one accepts this result, one can predict the distribution of GW events that should be observed by other existing detectors. This gives us a way to confirm or reject the interpretation of these observations as being due to real GW signal. Then, we discuss the methods of analysis in order to facilitate the interpretation. First, we emphasize that the detectors used for coincidence analysis must be compatible, otherwise some coincident events may be lost. Then, we emphasize two important points resulting from the natural modulation of the signal provided by the Earth's rotation: (1) the Sidereal Time analysis can work with one detector only, without necessarily considering coincidences between two detectors, and (2) a very low signal-to-noise ratio (≈0.5) can be used.

  • Sidereal Time analysis as a tool for the study of the space distribution of sources of gravitational waves
    Astronomy & Astrophysics, 2003
    Co-Authors: G. Paturel, Yu. Baryshev
    Abstract:

    Gravitational wave (GW) detectors operating on a long Time range can be used for the study of space distribution of sources of GW bursts or to put strong upper limits on the GW signal of a wide class of source candidates. For this purpose we propose here a Sidereal Time analysis to analyze the output signal of GW detectors. Using the characteristics of some existing detectors, we demonstrate the capability of the Sidereal Time analysis to give a clear signature of different localizations of GW sources: the Galactic Center, the Galactic Plane, the Supergalactic plane, the Great Attractor. On the contrary, a homogeneous 3D-distribution of GW sources gives a signal without features. In this paper we consider tensor gravitational waves with randomly oriented polarization. We consider GW detectors at fixed positions on the Earth, and afixed orientation of the antenna.

  • Statistics of the detection rates for tensor and scalar gravitational waves from the local galaxy universe
    Astronomy & Astrophysics, 2001
    Co-Authors: Yu. V. Baryshev, G. Paturel
    Abstract:

    We use data on the local 3-dimensional galaxy distribution for studying the statistics of the detection rates of gravitational waves (GW) coming from supernova explosions. We consider both tensor and scalar gravitational waves which are possible in a wide range of relativistic and quantum gravity theories. We show that statistics of GW events as a function of Sidereal Time can be used for distinction between scalar and tensor gravitational waves because of the anisotropy of spatial galaxy distribution. For calculation of the expected amplitudes of GW signals we use the values of the released GW energy, frequency and duration of GW pulse which are consistent with existing scenarios of SN core collapse. The amplitudes of the signals produced by Virgo and the Great Attractor clusters of galaxies is expressed as a function of the Sidereal Time for resonant bar detectors operating now (IGEC) and for forthcoming laser interferometric detectors (VIRGO).Then, we calculate the expected number of GW events as a function of Sidereal Time produced by all the galaxies within 100 Mpc. In the case of axisymmetric rotational core collapse which radiates a GW energy of $10^{-9}M_{\odot}c^2$, only the closest explosions can be detected. However, in the case of nonaxisymmetric supernova explosion, due to such phenomena as centrifugal hangup, bar and lump formation, the GW radiation could be as strong as that from a coalescing neutron-star binary. For radiated GW energy higher than $10^{-6}M_{\odot}c^2$ and sensitivity of detectors at the level $h \approx 10^{-23}$ it is possible to detect Virgo cluster and Great Attractor, and hence to use the statistics of GW events for testing gravity theories.

A.a. Aguilar-arevalo - One of the best experts on this subject based on the ideXlab platform.

  • Test of Lorentz and CPT violation with short baseline neutrino oscillation excesses
    Physics Letters B, 2013
    Co-Authors: A.a. Aguilar-arevalo, C.e. Anderson, A.o. Bazarko, S.j. Brice, B.c. Brown, L. Bugel, J. Cao, L. Coney, J.m. Conrad, D.c. Cox
    Abstract:

    The Sidereal Time dependence of MiniBooNE nu(e) and (nu) over bar (e) appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov-Smirnov (K-S) test shows both the nu(e) and (nu) over bar (e) appearance data are compatible with the null Sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the nu(e) appearance data prefer a Sidereal Time-independent solution, and the (nu) over bar (e) appearance data slightly prefer a Sidereal Time-dependent solution. Limits of order 10(-20) GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for nu(mu) -> nu(e) and (nu) over bar (mu) -> (nu) over bar (e) oscillations. The fit values and limits of combinations of SME coefficients are provided.Peer reviewe

  • Test of Lorentz and CPT violation with Short Baseline Neutrino Oscillation Excesses
    Physics Letters B, 2011
    Co-Authors: A.a. Aguilar-arevalo, C.e. Anderson, A.o. Bazarko, S.j. Brice, B.c. Brown, L. Bugel, J. Cao, L. Coney, Janet Conrad, D.c. Cox
    Abstract:

    Abstract The Sidereal Time dependence of MiniBooNE ν e and ν ¯ e appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov–Smirnov (K–S) test shows both the ν e and ν ¯ e appearance data are compatible with the null Sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the ν e appearance data prefer a Sidereal Time-independent solution, and the ν ¯ e appearance data slightly prefer a Sidereal Time-dependent solution. Limits of order 10 − 20 GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for ν μ → ν e and ν ¯ μ → ν ¯ e oscillations. The fit values and limits of combinations of SME coefficients are provided.