4,967 research outputs found
Precision Measurement of the Position-space Wave Functions of Gravitationally Bound Ultracold Neutrons
Gravity is the most familiar force at our natural length scale. However, it
is still exotic from the view point of particle physics. The first experimental
study of quantum effects under gravity was performed using a cold neutron beam
in 1975. Following this, an investigation of gravitationally bound quantum
states using ultracold neutrons was started in 2002. This quantum bound system
is now well understood, and one can use it as a tunable tool to probe gravity.
In this paper, we review a recent measurement of position-space wave functions
of such gravitationally bound states, and discuss issues related to this
analysis, such as neutron loss models in a thin neutron guide, the formulation
of phase space quantum mechanics, and UCN position sensitive detectors. The
quantum modulation of neutron bound states measured in this experiment shows
good agreement with the prediction from quantum mechanics.Comment: 13 pages, 5 figure
The Nagoya cosmic-ray muon spectrometer 3, part 2: Track detector
The twelve wide gap spark chambers were utilized as the track detectors of the Nagoya cosmic-ray muon spectrometer not only to obtain the precise locations of particles, but also to get some information about the correspondences between segments of trajectories. The area of each chamber is 150 x 70 sq cm and the width of a gap is 5 cm. The gas used is He at the atmospheric pressure. Each three pairs of them are placed on both sides of the deflection magnet. All images of sparks for each event are projected through the mirror system and recorded by two cameras stereoscopically. The mean detection efficiency of each chamber is 95 + or - 2% and the spacial resolution (jitter and drift) obtained from the prototype-experiment is 0.12 mm. Maximum detectable momentum of the spectrometer is estimated at about 10 TeV/c taking into account these characteristics together with the effects of the energy loss and multiple Coulomb scattering of muons in the iron magnet
Triple Products and Yang-Baxter Equation (I): Octonionic and Quaternionic Triple Systems
We can recast the Yang-Baxter equation as a triple product equation. Assuming
the triple product to satisfy some algebraic relations, we can find new
solutions of the Yang-Baxter equation. This program has been completed here for
the simplest triple systems which we call octonionic and quaternionic. The
solutions are of rational type.Comment: 29 page
Angular and Abundance Distribution of High-energy Gamma Rays and Neutrons Simulated by GEANT4 Code for Solar Flares
In the solar flare observed on June 3, 2012, high energy gamma-rays and
neutrons were observed. The event includes a remarkable feature of a high
neutron/gamma-ratio in the secondary particles. We have examined whether this
high n/-ratio can be explained by simulation. As a result of
simulations using the GEANT4 program, the high n/-ratio may be
reproduced for the case that helium and other heavy ions were dominantly
accelerated in the flare.Comment: submitted to the Proceeding of The 20th International Symposium on
Very High Energy Cosmic Ray Interaction (ISVHECRI 2018, Nagoya, Japan),
Europian Physics Journa
Discrete subgroups of PU(2,1) with screw parabolic elements
We give a version of Shimizu's lemma for groups of complex hyperbolic isometries one of whose generators is a parabolic screw motion. Suppose that G is a discrete group containing a parabolic screw motion A and let B be any element of G not fixing the fixed point of A. Our result gives a bound on the radius of the isometric spheres of B and B−1 in terms of the translation lengths of A at their centres. We use this result to give a sub-horospherical region precisely invariant under the stabiliser of the fixed point of A in G
Monolithic Ge:Ga Detector Development for SAFARI
We describe the current status and the prospect for the development of
monolithic Ge:Ga array detector for SAFARI. Our goal is to develop a 64x64
array for the 45 -- 110 um band, on the basis of existing technologies to make
3x20 monolithic arrays for the AKARI satellite. For the AKARI detector we have
achieved a responsivity of 10 A/W and a read-out noise limited NEP (noise
equivalent power) of 10^-17 W/rHz. We plan to develop the detector for SAFARI
with technical improvements; significantly reduced read-out noise with newly
developed cold read-out electronics, mitigated spectral fringes as well as
optical cross-talks with a multi-layer antireflection coat. Since most of the
elemental technologies to fabricate the detector are flight-proven, high
technical readiness levels (TRLs) should be achieved for fabricating the
detector with the above mentioned technical demonstrations. We demonstrate some
of these elemental technologies showing results of measurements for test
coatings and prototype arrays.Comment: To appear in Proc. Workshop "The Space Infrared Telescope for
Cosmology & Astrophysics: Revealing the Origins of Planets and Galaxies".
Eds. A.M. Heras, B. Swinyard, K. Isaak, and J.R. Goicoeche
Summary of Payload Integration Plan (PIP) for Starlab-1 flight experiment, enclosure 3
The objectives of the Autogenic Feedback Training (AFT) are to: determine if preflight AFT is an effective treatment for space adaptation syndrome (SAS); determine if preflight improvements in motion sickness tolerance can be used to predict crewmembers' success in controlling symptoms in flight; and identify differences and similarities between the physiological data from preflight motion sickness tests and data collected during symptom episodes in space. The goal is to test the AFT on 8 trained and 8 control subjects. At present 2 trained and 2 contol subjects were tested. The testing will continue until the experimental goal of testing 16 individual is reached
Josephson junction in cobalt-doped BaFe2As2 epitaxial thin films on (La, Sr)(Al, Ta)O3 bicrystal substrates
Josephson junctions were fabricated in epitaxial films of cobalt-doped
BaFe2As2 on [001]-tilt (La,Sr)(Al,Ta)O3 bicrystal substrates. 10m-wide
microbridges spanning a 30-degrees-tilted bicrystal grain boundary (BGB bridge)
exhibited resistively-shunted-junction (RSJ)-like current-voltage
characteristics up to 17 K, and the critical current was suppressed remarkably
by a magnetic field. Microbridges without a BGB did not show the RSJ-like
behavior, and their critical current densities were 20 times larger than those
of BGB bridges, confirming BGB bridges display a Josephson effect originating
from weakly-linked BGB
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