scholarly journals Forbidden transitions in nuclear weak processes relevant to neutrino detection, nucleosynthesis and evolution of stars

2019 ◽  
Vol 223 ◽  
pp. 01063
Author(s):  
Toshio Suzuki ◽  
Satoshi Chiba ◽  
Takashi Yoshida ◽  
Koh Takahashi ◽  
Hideyuki Umeda ◽  
...  
Keyword(s):  
Shell Model ◽  
Cross Sections ◽  
Neutral Current ◽  
Expansion Method ◽  
Multipole Expansion ◽  
Reaction Cross ◽  
Model Calculations ◽  
Multipole Expansion Method ◽  
Supernova Explosions ◽  
Model Hamiltonians

The distribution of the spin-dipole strengths in 16O and neutrino-induced reactions on 16O areinvestigated by shell-model calculations with new shell-model Hamiltonians. Chargedcurrent and neutral-current reactioncross sections are valuated in various particle and γ emission channels as well as the total ones at neutrinoenergies up to Eν≈ 100 MeV. Effects of multiparticle emission channels, especially the αp emission channels, on nucleosynthesis of 11B and 11C in core-collapse supernova explosions are investigated. The MSW neutrino oscillation effects oncharged-current reaction cross sections are investigated for future supernova burst. Electron capture rates for a forbidden transition 20Ne(Og.s.+) → 20F(2g.s.+) in stellar environments are evaluated by the multipole expansion method with the use of shell model Hamiltonians, and compared with those obtained by a prescription that treats the transition as an allowed GamowTeller (GT) transition. Different electron energy dependence of the transition strengths between the two methods is found to lead to sizable differences in the weak rates of the two methods.

Electromagnetic scattering by an arbitrary configuration of dielectric spheres

1990 ◽  
Vol 68 (12) ◽  
pp. 1419-1428 ◽  
Author(s):  
A-K. Hamid ◽  
I. R. Ciric ◽  
M. Hamid
Keyword(s):  
Cross Sections ◽  
Electromagnetic Scattering ◽  
Plane Electromagnetic Wave ◽  
Linear Equations ◽  
Spherical Wave ◽  
Expansion Method ◽  
Multipole Expansion ◽  
Arbitrary Configuration ◽  
Multipole Expansion Method ◽  
Dielectric Spheres

An analytic solution is obtained for the problem of plane electromagnetic-wave scattering by an arbitrary configuration of N dielectric spheres. The multipole expansion method is employed, and the boundary condition is imposed using the translational addition theorem for vector spherical wave functions. A system of simultaneous linear equations is given in matrix form for the scattering coefficients. An approximate solution, which has been developed and employed by the authors for the scattering by N conducting spheres, is extended to the dielectric spheres case. Plots for the normalized backscattering, bistatic, and forward-scattering cross sections are presented over wide ranges of permittivity, size, and electrical separations between the neighbouring spheres. The results show a reduction in the normalized backscattering and bistatic cross sections for certain choices of permittivity relative to conducting arrays of spheres of the same dimensions and separations.

scholarly journals On the Convergence of the Multipole Expansion Method

2021 ◽  
Vol 59 (5) ◽  
pp. 2473-2499
Author(s):  
Brian Fitzpatrick ◽  
Enzo De Sena ◽  
Toon van Waterschoot
Keyword(s):  
Expansion Method ◽  
Multipole Expansion ◽  
Multipole Expansion Method

scholarly journals Statistical model calculations of 72,73Ge(n,p) and 72,74Ge(n,α) reactions on natural Ge

2020 ◽  
Vol 15 ◽  
pp. 104
Author(s):  
S. Galanopoulos ◽  
R. Vlastou ◽  
P. Demetriou ◽  
M. Kokkoris ◽  
C. T. Papadopoulos ◽  
...  
Keyword(s):  
Statistical Model ◽  
Energy Range ◽  
Neutron Energy ◽  
Cross Sections ◽  
Reaction Cross ◽  
Model Calculations ◽  
Monoenergetic Neutron ◽  
Theoretical Investigations ◽  
Equilibrium Emission ◽  
Reaction Cross Sections

Systematic experimental and theoretical investigations of the 72,73Ge(n,p)72,73 Ga and 72,74Ge(n,α)69,71Znm reaction cross sections are presented in the energy range from thresh- old to about 17 MeV neutron energy. The above reaction cross sections were measured from 8.8 to 11.4 MeV by using the activation method, relative to the 27Al(n,α)24Na refer- ence reaction. The quasi-monoenergetic neutron beams were produced via the 2H(d,n)3He reaction at the 5 MV VdG Tandem T11/25 accelerator of NCSR “Demokritos”. Statisti- cal model calculations using the code EMPIRE-II (version 2.19) taking into consideration pre-equilibrium emission were performed on the data measured in this work as well as on data reported in literature.

scholarly journals Cross section calculations for neutrino-nucleus reactions at low and intermediate energies.

2020 ◽  
Vol 15 ◽  
pp. 249
Author(s):  
V. Ch. Chasioti ◽  
T. S. Kosmas ◽  
P. Divari
Keyword(s):  
Cross Sections ◽  
Neutral Current ◽  
Axial Vector ◽  
Random Phase ◽  
Neutrino Energy ◽  
Reaction Cross ◽  
Neutrino Experiment ◽  
Final State ◽  
Quasi Particle ◽  
Intermediate Energies

Inelastic neutrino-nucleus reaction cross sections are studied focusing on the neutral current processes. Particularly, we investigate the angular and initial neutrino-energy dependence of the differential and integrated cross sections for low and intermediate energies of the incoming neutrino (or antineutrino). Contributions coming from both, the vector and axial-vector components of the corresponding hadronic currents have been included. The initial and final state nuclear wave-functions have been calculated in the context of the Quasi-particle Random Phase Approximation (QRPA) tested on the reproducibility of the low-lying energy spectrum (up to about 5 MeV) of the studied nuclei. The results presented here refer to the nuclear isotopes 16O and 98Mo. As it is well known, O plays a significant role in supernova evolution phenomena and Mo is used as a target in the MOON neutrino experiment at Japan.

scholarly journals Bonding modes of some labile Si compounds studied by charge density analysis

2014 ◽  
Vol 70 (a1) ◽  
pp. C1698-C1698
Author(s):  
Daisuke Hashizume
Keyword(s):  
Organic Molecules ◽  
Expansion Method ◽  
Multipole Expansion ◽  
Bond Critical Point ◽  
X Ray Diffraction ◽  
Density Distributions ◽  
Density Maps ◽  
Multipole Expansion Method ◽  
Density Analysis ◽  
Electron Donation

Some organic molecules containing Si atom(s) are very labile, even if the corresponding carbon analogs are very stable. To gain information on bonding modes of such compounds, we analyzed valence density distribution, which play critical roles in chemistry of molecule, by applying multipole expansion method. Very recently, an imine coordinated silacyclopropan-1-one, 1, has synthesized by Baceiredo, Kato and co-workers.[1] To clarify the bonding mode of 1, the electron density distributions of 1 and its precursor have analyzed by a multiple expansion method using single crystal X-ray diffraction data. As shown in static model density maps, bonding electrons of Si-C bonds distribute on the outside of the silacyclopropane ring (Si1-C1-C2 ring) (Fig. 1a) with largely extent, in compared with that of the precursor, indicating an in-plane pi-interaction on the Si1-C1 and Si1-C2 bonds. On the other hand, the C1-C2 bonding electrons distribute on the bond, and the bond critical point (BCP) is located on the inside of the three membered ring. In addition, the C1-C2 bonding electrons elongates inside the ring toward the Si1 atom, indicating electron donation from sigma(C1-C2)-bond to the Si1 (Fig. 1b). Consequently, these maps propose greater contribution of canonical structures in Fig. 1c.

ANALYTIC FIRST-ORDER EIKONAL MODEL FOR HEAVY-ION ELASTIC SCATTERINGS

2010 ◽  
Vol 19 (10) ◽  
pp. 1947-1960
Author(s):  
YONG JOO KIM ◽  
JONG-KWAN WOO ◽  
MOON HOE CHA
Keyword(s):  
Phase Shift ◽  
Cross Sections ◽  
Theoretical Method ◽  
Heavy Ion ◽  
Reaction Cross ◽  
Order Correction ◽  
Model Calculations ◽  
First Order ◽  
Eikonal Model ◽  
First Order Correction

We present analytic expressions for the zero-order eikonal phase shift and its first-order correction by approximating a distance between two colliding nuclei. This formalism has been applied to elastic scatterings of the 12 C + 40 Ca and the 12 C + 90 Zr systems at E lab = 420 MeV , and the 16 O + 40 Ca and the 16 O + 90 Zr ones at E lab = 1503 MeV . The calculated angular distributions, taking into account up to the analytic first-order eikonal phase shift, are found to be in fairly good agreement with the observed data. The reaction cross-sections obtained from the present model produce very excellent agreements with ones of exact first-order eikonal model calculations. We have found that analytic eikonal phase shift including the first-order correction is one theoretical method to the analysis of heavy-ion elastic scattering.

scholarly journals Trapped modes around a row of circular cylinders in a channel

1999 ◽  
Vol 386 ◽  
pp. 259-279 ◽  
Author(s):  
T. UTSUNOMIYA ◽  
R. EATOCK TAYLOR
Keyword(s):  
Expansion Method ◽  
Wave Theory ◽  
Multipole Expansion ◽  
Circular Cylinders ◽  
Large Radius ◽  
Trapped Modes ◽  
Resonant Phenomenon ◽  
Trapped Mode ◽  
Linear Water Wave Theory ◽  
Multipole Expansion Method

Trapped modes around a row of bottom-mounted vertical circular cylinders in a channel are examined. The cylinders are identical, and their axes equally spaced in a plane perpendicular to the channel walls. The analysis has been made by employing the multipole expansion method under the assumption of linear water wave theory. At least the same number of trapped modes is shown to exist as the number of cylinders for both Neumann and Dirichlet trapped modes, with the exception that for cylinders having large radius the mode corresponding to the Dirichlet trapped mode for one cylinder will disappear. Close similarities between the Dirichlet trapped modes around a row of cylinders in a channel and the near-resonant phenomenon in the wave diffraction around a long array of cylinders in the open sea are discussed. An analogy with a mass–spring oscillating system is also presented.

Sign in / Sign up

Export Citation Format

Share Document