11,914 research outputs found
Neutrino telescope modelling of Lorentz invariance violation in oscillations of atmospheric neutrinos
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
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
We present estimates of the N-point galaxy, area-averaged, angular
correlation functions () for = 2,...,7 for
galaxies from the fifth data release of the Sloan Digital Sky Survey. Our
parent sample is selected from galaxies with , 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
() on luminosity, redshift, and galaxy-type. We
measure () using oversampling techniques and use them
to calculate the projected, . Using models derived from theoretical
power-spectra and perturbation theory, we measure the bias parameters and
, finding that the large differences in both bias parameters ( and
) between early- and late-type galaxies are robust against changes in
redshift, luminosity, and , 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 ( is larger by at ) and
small scales (large amplitudes are measured at small scales only for ,
suggesting much more merger driven star formation at ). Finally, our
measurements of suggest both that and is negative.Comment: 46 pages, 19 figures, Accepted to Ap
Permutation branes and linear matrix factorisations
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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