NUCLEAR ALTERNATING-PARITY BANDS AND TRANSITION RATES IN A MODEL OF COHERENT QUADRUPOLE–OCTUPOLE MOTION

2012 ◽  
Vol 21 (05) ◽  
pp. 1250021 ◽  
Author(s):  
N. MINKOV ◽  
S. DRENSKA ◽  
M. STRECKER ◽  
W. SCHEID
Keyword(s):  
Complex Shape ◽  
Transition Probabilities ◽  
Negative Parity ◽  
Transition Rates ◽  
Angular Momenta ◽  
State Band ◽  
Electric Transition ◽  
Reduced Transition Probabilities ◽  
Transition Operators ◽  
Shape Characteristics

A further extension of a model of coherent quadrupole–octupole vibrations and rotations and its application to alternating-parity spectra in heavy even–even nuclei is presented. Within the model the yrast alternating-parity sequence includes the ground state band and the lowest negative parity levels with odd angular momenta, while the non-yrast sequences include excited β-bands and higher negative-parity levels. Electric transition operators reflecting the complex shape characteristics associated with the quadrupole–octupole vibration modes are introduced. By using them B(E1), B(E2) and B(E3) reduced transition probabilities within and between the different energy sequences are calculated. It is shown that the model successfully reproduces yrast and non-yrast alternating-parity bands together with the attendant B(E1)–B(E3) transition rates in the nuclei 154 Sm , 156 Gd and 100 Mo .

Band structure of odd-mass lanthanum nuclei

2014 ◽  
Vol 23 (04) ◽  
pp. 1450020
Author(s):  
Deepti Sharma ◽  
Preeti Verma ◽  
Suram Singh ◽  
Arun Bharti ◽  
S. K. Khosa
Keyword(s):  
Band Structure ◽  
Shell Model ◽  
Nuclear Structure ◽  
Transition Probabilities ◽  
Theoretical Data ◽  
Negative Parity ◽  
Projected Shell Model ◽  
Experimental Feature ◽  
Reduced Transition Probabilities ◽  
Structure Properties

Negative parity energy states in 121–131 La have been studied using Projected Shell Model (PSM). Some nuclear structure properties like yrast spectra, back-bending in moment of inertia, reduced transition probabilities and band diagrams have been described. The experimental feature of the co-existence of prolate–oblate shapes in 125–131 La isotopes has been satisfactorily explained by PSM results. Comparison of the theoretical data with their experimental counterparts has also been made. From the calculations, it is found that the yrast states arise because of multi-quasiparticle states.

Coulomb excitation of low-energy levels in 45Sc

1979 ◽  
Vol 57 (8) ◽  
pp. 1196-1203 ◽  
Author(s):  
V. U. Patil ◽  
R. G. Kulkarni
Keyword(s):  
Gamma Ray ◽  
Transition Probabilities ◽  
Coulomb Excitation ◽  
Energy Levels ◽  
Negative Parity ◽  
Core Excitation ◽  
Mixing Ratios ◽  
Reduced Transition Probabilities ◽  
Excitation Model ◽  
First Time

Low-lying negative parity levels in 45Sc were Coulomb excited with 2.5 to 3.5 MeV protons and 4 to 5 MeV 4He ions to test the weak coupling core-excitation model. A Ge(Li) detector was used to measure the gamma-ray yields. The 543, 976, 1408, and 1662 keV levels in 45Sc were Coulomb excited for the first time. Gamma-ray angular distributions were measured at 3.0 MeV proton energy in deducing multipole mixing ratios and spin values. Energy level measurements (in units of kiloelectronvolts) and spin values obtained are as follows: 976, 5/2, 7/2 and 1408, 7/2. The E2 and M1 reduced transition probabilities were determined for the six states. The 376, 720, 1237, 1408, and 1662 keV levels have properties consistent with the interpretation of coupling a 1f7/2 proton to the first 2+ core state.

TRIAXIAL REFLECTION ASYMMETRIC SHELL MODEL

2008 ◽  
Vol 17 (supp01) ◽  
pp. 146-158 ◽  
Author(s):  
Y. S. CHEN ◽  
Z. C. GAO
Keyword(s):  
Shell Model ◽  
Transition Probabilities ◽  
Mean Field ◽  
Negative Parity ◽  
Laboratory Frame ◽  
Superheavy Nuclei ◽  
Tetrahedral Symmetry ◽  
State Band ◽  
Natural Way ◽  
Good Agreement

The spontaneously broken reflection and axial symmetries in the nuclear mean field and their necessary restorations in the laboratory frame are described in a natural way in the triaxial Reflection Asymmetric Shell Model. This recently developed theoretical model has been applied to explore the possibility that some superheavy nuclei may have an exotic shape, tetrahedral-like. The ground state band and the partner low-lying negative parity bands are calculated for the Cf isotopes and the results are in a good agreement with the available experimental data. The tetrahedral symmetry, realized at the first order with the nonaxial octupole Y 32 deformation, plays an important role for understanding the low-lying band structures in transfermium and superheavy nuclei, but it is significantly obscured by the competing quadrupole deformation as well as the axial octupole component. The calculated reduced E3 transition probabilities between the low lying 2–-band states and the ground band states show a large enhancement of the nonaxial octupole collectivity.

Study of odd mass 115−125Sb isotopes with the projected shell model calculations

2017 ◽  
Vol 26 (06) ◽  
pp. 1750041 ◽  
Author(s):  
Dhanvir Singh ◽  
Arun Bharti ◽  
Amit Kumar ◽  
Suram Singh ◽  
G. H. Bhat ◽  
...  
Keyword(s):  
Shell Model ◽  
Transition Probabilities ◽  
Negative Parity ◽  
Yrast Band ◽  
Spin States ◽  
Projected Shell Model ◽  
Model Calculations ◽  
High Spin States ◽  
Reduced Transition Probabilities ◽  
First Time

The projected shell model (PSM) with the deformed single-particle states, generated by the standard Nilsson potential, is applied to study the negative-parity high spin states of [Formula: see text] nuclei. The nuclear structure quantities like band structure and back-bending in moment of inertia have been calculated with PSM method and are compared with the available experimental data. In addition, the reduced transition probabilities, i.e., B[Formula: see text] and B[Formula: see text], are also obtained for the yrast band of these isotopes for the first time by using PSM wave function. A multi-quasiparticle structure has been predicted for [Formula: see text] isotopes by the present PSM calculations.

Level structure studies of 182W from the decay of 182Ta

1992 ◽  
Vol 70 (4) ◽  
pp. 242-251 ◽  
Author(s):  
Bakhshish Chand ◽  
J. Goswamy ◽  
Devinder Mehta ◽  
Nirmal Singh ◽  
P. N. Trehan
Keyword(s):  
Transition Probabilities ◽  
Level Structure ◽  
Correlation Coefficients ◽  
Negative Parity ◽  
X Rays ◽  
Internal Conversion Coefficients ◽  
Symmetric Rotor ◽  
Conversion Coefficients ◽  
Reduced Transition Probabilities ◽  
First Time

The relative intensities of X rays and γ rays from the decay of 182Ta were measured precisely using Si(Li) and HPGe detectors. The intensities of the different components of K and L X rays were measured for the first time. The conversion electron intensities for the transitions with energy above 800 keV from the 182Ta decay were measured using a mini-orange electron spectrometer and the internal conversion coefficients for various transitions in 182W deduced. The (M + N)-conversion coefficients for the 1001.7, 1189.1, 1231.0, 1257.2, 1289.2, and 1342.7 keV transitions in 182W were measured for the first time. Also, γ–γ coincidence and correlation measurements were carried out using a HPGe–HPGe coincidence setup (2τ = 7 ns). The directional correlation coefficients for the 928–229, 960–229, 1002–229, 1044–229, 1158–229, 1223–229, and 1002–222 keV cascades in 182W are determined for the first time. The multipole mixing ratio for the 152, 156, 179, 222, 928, 1002, 1113, 1158, 1223, and 1231 keV transitions are deduced from the present directional correlation and conversion coefficient measurements. Experimental ratios of reduced transition probabilities for the transitions in 182W from positive and negative parity states are deduced and compared with the values predicted by the symmetric rotor model. From this comparison a unique K assignment of Kπ = 1+ and Kπ = 1− is made to the bands built on the 1257 and 1553 keV levels, respectively.

Spectroscopy and reduced transition probabilities of negative parity bands up to band termination in 45 Ti

2009 ◽  
Vol 33 (S1) ◽  
pp. 67-69 ◽  
Author(s):  
Ma Hai-Liang ◽  
Yan Yu-Liang ◽  
Zhang Xi-Zhen ◽  
Zhou Dong-Mei ◽  
Dong Bao-Guo
Keyword(s):  
Transition Probabilities ◽  
Negative Parity ◽  
Reduced Transition Probabilities ◽  
Band Termination

Study of negative parity levels in 63Cu

1980 ◽  
Vol 58 (4) ◽  
pp. 472-480 ◽  
Author(s):  
R.G. Kulkarni ◽  
D. P. Navalkele
Keyword(s):  
Gamma Ray ◽  
Transition Probabilities ◽  
Negative Parity ◽  
Angular Distributions ◽  
Core Excitation ◽  
Model Calculations ◽  
Mixing Ratios ◽  
Reduced Transition Probabilities ◽  
Excitation Model ◽  
First Time

Low-lying negative parity levels in 63Cu were Coulomb excited with 3.25 to 4.25 MeV protons to test the weak coupling core-excitation model. A Ge(Li) detector was used to measure the gamma-ray yields. The 1412, 1547, and 1861 keV levels in 63Cu were Coulomb excited for the first time. Gamma-ray angular distributions were measured at 4.25 MeV proton energy in deducing multipole mixing ratios and spin values. The E2 and M1 reduced transition probabilities were determined for the six states. The 669.6, 962, 1327, and 1547 keV levels have properties consistent with the interpretation of coupling a 2p3/2 proton to the first 2+core state. The present results were compared with the available particle–core and particle–phonon model calculations.

CHARACTERISTICS OF TWO-QUASIPARTICLE CHIRAL BANDS

2011 ◽  
Vol 20 (02) ◽  
pp. 358-363
Author(s):  
OBED SHIRINDA ◽  
ELENA LAWRIE
Keyword(s):  
Transition Probabilities ◽  
Broken Symmetry ◽  
Angular Momenta ◽  
Collective Rotation ◽  
Reduced Transition Probabilities ◽  
Rotor Model

The two-quasiparticle-plus-triaxial-rotor model was applied to study chiral configurations in the 100, 130 and 190 mass regions. It was shown that in order for a degeneracy in the two-quasiparticle partner bands to occur, one needs mutually orthogonal angular momenta of the odd proton, odd neutron and the collective rotation. The staggering in the B(M1) reduced transition probabilities as an indication of strongly broken symmetry was studied too.

A review of multistate modelling approaches in monitoring disease progression: Bayesian estimation using the Kolmogorov-Chapman forward equations

2021 ◽  
pp. 096228022199750
Author(s):  
Zvifadzo Matsena Zingoni ◽  
Tobias F Chirwa ◽  
Jim Todd ◽  
Eustasius Musenge
Keyword(s):  
Bayesian Estimation ◽  
Transition Probabilities ◽  
Markov Property ◽  
Likelihood Estimation ◽  
Single Individual ◽  
Transition Rates ◽  
Multistate Models ◽  
Time To Event ◽  
Modeling Framework ◽  
Forward Equations

There are numerous fields of science in which multistate models are used, including biomedical research and health economics. In biomedical studies, these stochastic continuous-time models are used to describe the time-to-event life history of an individual through a flexible framework for longitudinal data. The multistate framework can describe more than one possible time-to-event outcome for a single individual. The standard estimation quantities in multistate models are transition probabilities and transition rates which can be mapped through the Kolmogorov-Chapman forward equations from the Bayesian estimation perspective. Most multistate models assume the Markov property and time homogeneity; however, if these assumptions are violated, an extension to non-Markovian and time-varying transition rates is possible. This manuscript extends reviews in various types of multistate models, assumptions, methods of estimation and data features compatible with fitting multistate models. We highlight the contrast between the frequentist (maximum likelihood estimation) and the Bayesian estimation approaches in the multistate modeling framework and point out where the latter is advantageous. A partially observed and aggregated dataset from the Zimbabwe national ART program was used to illustrate the use of Kolmogorov-Chapman forward equations. The transition rates from a three-stage reversible multistate model based on viral load measurements in WinBUGS were reported.

scholarly journals Stability Analysis for Markovian Jump Neutral Systems with Mixed Delays and Partially Known Transition Rates

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
Lianglin Xiong ◽  
Xiaobing Zhou ◽  
Jie Qiu ◽  
Jing Lei
Keyword(s):  
Partial Information ◽  
Transition Probabilities ◽  
Mixed Delays ◽  
Transition Rates ◽  
Neutral Systems ◽  
Markovian Jump ◽  
Markovian Jump System ◽  
Analysis Technique ◽  
Transition Rate Matrix ◽  
Delay Dependent

The delay-dependent stability problem is studied for Markovian jump neutral systems with partial information on transition probabilities, and the considered delays are mixed and model dependent. By constructing the new stochastic Lyapunov-Krasovskii functional, which combined the introduced free matrices with the analysis technique of matrix inequalities, a sufficient condition for the systems with fully known transition rates is firstly established. Then, making full use of the transition rate matrix, the results are obtained for the other case, and the uncertain neutral Markovian jump system with incomplete transition rates is also considered. Finally, to show the validity of the obtained results, three numerical examples are provided.

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