11,571 research outputs found

    Neutrino telescope modelling of Lorentz invariance violation in oscillations of atmospheric neutrinos

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    One possible feature of quantum gravity may be the violation of Lorentz invariance. In this paper, we consider one particular manifestation of the violation of Lorentz invariance, namely modified dispersion relations for massive neutrinos. We show how such modified dispersion relations may affect atmospheric neutrino oscillations. We then consider how neutrino telescopes, such as ANTARES, may be able to place bounds on the magnitude of this type of Lorentz invariance violation

    Time resolution below 100 ps for the SciTil detector of PANDA employing SiPM

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    The barrel time-of-flight (TOF) detector for the PANDA experiment at FAIR in Darmstadt is planned as a scintillator tile hodoscope (SciTil) using 8000 small scintillator tiles. It will provide fast event timing for a software trigger in the otherwise trigger-less data acquisition scheme of PANDA, relative timing in a multiple track event topology as well as additional particle identification in the low momentum region. The goal is to achieve a time resolution of sigma ~ 100 ps. We have conducted measurements using organic scintillators coupled to Silicon Photomultipliers (SiPM). The results are encouraging such that we are confident to reach the required time resolution.Comment: 10 pages, 7 figure

    Higher-Order Angular Galaxy Correlations in the SDSS: Redshift and Color Dependence of non-Linear Bias

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    We present estimates of the N-point galaxy, area-averaged, angular correlation functions ωˉN\bar{\omega}_{N}(θ\theta) for NN = 2,...,7 for galaxies from the fifth data release of the Sloan Digital Sky Survey. Our parent sample is selected from galaxies with 18≤r<2118 \leq r < 21, and is the largest ever used to study higher-order correlations. We subdivide this parent sample into two volume limited samples using photometric redshifts, and these two samples are further subdivided by magnitude, redshift, and color (producing early- and late-type galaxy samples) to determine the dependence of ωˉN\bar{\omega}_{N}(θ\theta) on luminosity, redshift, and galaxy-type. We measure ωˉN\bar{\omega}_{N}(θ\theta) using oversampling techniques and use them to calculate the projected, sNs_{N}. Using models derived from theoretical power-spectra and perturbation theory, we measure the bias parameters b1b_1 and c2c_2, finding that the large differences in both bias parameters (b1b_1 and c2c_2) between early- and late-type galaxies are robust against changes in redshift, luminosity, and σ8\sigma_8, and that both terms are consistently smaller for late-type galaxies. By directly comparing their higher-order correlation measurements, we find large differences in the clustering of late-type galaxies at redshifts lower than 0.3 and those at redshifts higher than 0.3, both at large scales (c2c_2 is larger by ∼0.5\sim0.5 at z>0.3z > 0.3) and small scales (large amplitudes are measured at small scales only for z>0.3z > 0.3, suggesting much more merger driven star formation at z>0.3z > 0.3). Finally, our measurements of c2c_2 suggest both that σ8<0.8\sigma_8 < 0.8 and c2c_2 is negative.Comment: 46 pages, 19 figures, Accepted to Ap

    Permutation branes and linear matrix factorisations

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    All the known rational boundary states for Gepner models can be regarded as permutation branes. On general grounds, one expects that topological branes in Gepner models can be encoded as matrix factorisations of the corresponding Landau-Ginzburg potentials. In this paper we identify the matrix factorisations associated to arbitrary B-type permutation branes.Comment: 43 pages. v2: References adde
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