200 research outputs found
Study of the (d,2-He) Reaction at E_d = 99 MeV
This work was supported by the National Science Foundation Grants NSF PHY 78-22774 A03, NSF PHY 81-14339, and by Indiana Universit
Bremsstrahlung in Alpha-Decay
We present the first fully quantum mechanical calculation of photon radiation
accompanying charged particle decay from a barrier resonance. The soft-photon
limit agrees with the classical results, but differences appear at
next-to-leading-order. Under the conditions of alpha-decay of heavy nuclei, the
main contribution to the photon emission stems from Coulomb acceleration and
may be computed analytically. We find only a small contribution from the
tunneling wave function under the barrier.Comment: 12 pages, 2 Postscript figure
Deep Hole States in Medium Mass Nuclei
Supported by the National Science Foundation and Indiana Universit
Comparative Analysis of the Mechanisms of Fast Light Particle Formation in Nucleus-Nucleus Collisions at Low and Intermediate Energies
The dynamics and the mechanisms of preequilibrium-light-particle formation in
nucleus-nucleus collisions at low and intermediate energies are studied on the
basis of a classical four-body model. The angular and energy distributions of
light particles from such processes are calculated. It is found that, at
energies below 50 MeV per nucleon, the hardest section of the energy spectrum
is formed owing to the acceleration of light particles from the target by the
mean field of the projectile nucleus. Good agreement with available
experimental data is obtained.Comment: 23 pages, 10 figures, LaTeX, published in Physics of Atomic Nuclei
v.65, No. 8, 2002, pp. 1459 - 1473 translated from Yadernaya Fizika v. 65,
No. 8, 2002, pp. 1494 - 150
Quantum M\"{u}nchhausen effect in tunneling
It is demonstrated that radiative corrections increase tunneling probability
of a charged particle
Anomalous enhancements of low-energy fusion rates in plasmas: the role of ion momentum distributions and inhomogeneous screening
Non-resonant fusion cross-sections significantly higher than corresponding
theoretical predictions are observed in low-energy experiments with deuterated
matrix target. Models based on thermal effects, electron screening, or
quantum-effect dispersion relations have been proposed to explain these
anomalous results: none of them appears to satisfactory reproduce the
experiments. Velocity distributions are fundamental for the reaction rates and
deviations from the Maxwellian limit could play a central role in explaining
the enhancement. We examine two effects: an increase of the tail of the target
Deuteron momentum distribution due to the Galitskii-Yakimets quantum
uncertainty effect, which broadens the energy-momentum relation; and spatial
fluctuations of the Debye-H\"{u}ckel radius leading to an effective increase of
electron screening. Either effect leads to larger reaction rates especially
large at energies below a few keV, reducing the discrepancy between
observations and theoretical expectations.Comment: 6 pages, 3 figure
Precise measurement on the binding energy of hypertriton from the nuclear emulsion data using analysis with machine learning
6 pags., 3 figs.A machine learning model has been developed to search for events of production and decay of a hypertriton in nuclear emulsion data, which
is used for measuring the binding energy of the hypertriton at the best precision. The developed model employs an established technique
for object detection and is trained with surrogate images generated by Monte Carlo simulations and image transfer techniques. The first
hypertriton event has already been detected with the developed method only with 10−4 of the total emulsion data. It implies that a sufficient
number of hypertriton events will soon be detected for the precise measurement of the hypertriton binding energy
Radiation exposure and circulatory disease risk: Hiroshima and Nagasaki atomic bomb survivor data, 1950-2003
Objective To investigate the degree to which ionising radiation confers risk of mortality from heart disease and stroke
Multipolar model of bremsstrahlung accompanying proton-decay of nuclei
Emission of bremsstrahlung photons accompanying proton decay of nuclei is
studied. The new improved multipolar model describing such a process is
presented. The angular formalism of calculations of the matrix elements is
stated in details. The bremsstrahlung probabilities for the ,
, and nuclei decaying from
the state, the and nuclei decaying from the state, the and nuclei decaying from the
state are predicted. Such spectra have orders of values similar to the
experimental data for the bremsstrahlung photons emitted during the
-decay. This indicates on real possibility to study bremsstrahlung
photons during proton decay experimentally and perform further measurements.Comment: 14 pages, 6 figure
Hypernuclear event detection in the nuclear emulsion with Monte Carlo simulation and machine learning
This study developed a novel method for detecting hypernuclear events
recorded in nuclear emulsion sheets using machine learning techniques. The
artificial neural network-based object detection model was trained on surrogate
images created through Monte Carlo simulations and image-style transformations
using generative adversarial networks. The performance of the proposed model
was evaluated using -decay events obtained from the J-PARC E07 emulsion
data. The model achieved approximately twice the detection efficiency of
conventional image processing and reduced the time spent on manual visual
inspection by approximately 1/17. The established method was successfully
applied to the detection of hypernuclear events. This approach is a
state-of-the-art tool for discovering rare events recorded in nuclear emulsion
sheets without any real data for training.Comment: 32 pages, 13 figure
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