43 research outputs found
Handedness asymmetry of spiral galaxies with z<0.3 shows cosmic parity violation and a dipole axis
A dataset of 126,501 spiral galaxies taken from Sloan Digital Sky Survey was
used to analyze the large-scale galaxy handedness in different regions of the
local universe. The analysis was automated by using a transformation of the
galaxy images to their radial intensity plots, which allows automatic analysis
of the galaxy spin and can therefore be used to analyze a large galaxy dataset.
The results show that the local universe (z<0.3) is not isotropic in terms of
galaxy spin, with probability P<5.8*10^-6 of such asymmetry to occur by chance.
The handedness asymmetries exhibit an approximate cosine dependence, and the
most likely dipole axis was found at RA=132, DEC=32 with 1 sigma error range of
107 to 179 degrees for the RA. The probability of such axis to occur by chance
is P<1.95*10^-5 . The amplitude of the handedness asymmetry reported in this
paper is generally in agreement with Longo, but the statistical significance is
improved by a factor of 40, and the direction of the axis disagrees somewhat.Comment: 8 pages, 6 figures. Accepted for publication in Physics Letters
ILC Beam Energy Measurement by means of Laser Compton Backscattering
A novel, non-invasive method of measuring the beam energy at the
International Linear Collider is proposed. Laser light collides head-on with
beam particles and either the energy of the Compton scattered electrons near
the kinematic end-point is measured or the positions of the Compton
backscattered -rays, the edge electrons and the unscattered beam
particles are recorded. A compact layout for the Compton spectrometer is
suggested. It consists of a bending magnet and position sensitive detectors
operating in a large radiation environment. Several options for high spatial
resolution detectors are discussed. Simulation studies support the use of an
infrared or green laser and quartz fiber detectors to monitor the backscattered
photons and edge electrons. Employing a cavity monitor, the beam particle
position downstream of the magnet can be recorded with submicrometer precision.
Such a scheme provides a feasible and promising method to access the incident
beam energy with precisions of or better on a bunch-to-bunch basis
while the electron and positron beams are in collision.Comment: 47 pages, 26 figures, version as accepted by Nucl. Instr. Meth. A
after improvement
A method for detection of muon induced electromagnetic showers with the ANTARES detector
The primary aim of ANTARES is neutrino astronomy with upward going muons
created in charged current muon neutrino interactions in the detector and its
surroundings. Downward going muons are background for neutrino searches. These
muons are the decay products of cosmic-ray collisions in the Earth's atmosphere
far above the detector. This paper presents a method to identify and count
electromagnetic showers induced along atmospheric muon tracks with the ANTARES
detector. The method is applied to both cosmic muon data and simulations and
its applicability to the reconstruction of muon event energies is demonstrated.Comment: 20 pages, 7 figure
Producción de materia seca y su distribución en prados de las regiones de Checoslovaquia con estación seca
Se hace un estudio de comparación y distribución estacional de los rendimientos de distintas especies pratenses en la región más árida de Checoslovaquia. Igualmente se compara la productividad de pastos naturales y artificiales a diferentes niveles de fertilización nitrogenada. (Sección 3ª. Presidente: Dr. L. Miró-Granada