Spectra and electromagnetic transitions of ^(98–104)Zr in the interacting boson model

The low-lying energy levels and electromagnetic transitions of even-even nuclei ^98Zr, ^100Zr, ^102Zr,^104Zr are studied within the framework of the interacting boson model. The Hamiltonian matrix elements and some of their states have been respectively analyzed and determined with respect to the current nuclear experimental data. The B（E2） of electromagnetic transitions have also been calculated and the wave function structures also analyzed. The results show good agreement with the available experimental data. The present study shows that these series of nuclei are in the transition from U（5） to SU（3）, namely from vibration to rotation.

Decay rates and electromagnetic transitions of heavy quarkonia

The electromagnetic radiative transition widths for heavy quarkonia, as well as digamma and digluon decay widths, are computed in the framework of the extended harmonic confinement model （ERHM） and Coulomb plus power potential （CPP,） with varying potential index v. The outcome is compared with the values obtained from other theoretical models and experimental results. While the mass spectra, digamma and digluon widths from ERHM as well as CPP v=1 are in good agreement with experimental data, the electromagnetic transition widths span over a wide range for the potential models considered here making it difficult to prefer a particular model over the others because of the lack of experimental data for most transition widths.

Electromagnetic transitions in multiple chiral doublet bands

Multiple chiral doublet bands （MχD） in the 80, 130 and 190 mass regions are studied by the model of γ=90°triaxial rotor coupled with identical symmetric proton-neutron configurations. By selecting a suitable basis, the calculated wave functions are explicitly exhibited to be symmetric under the operator A, which is defined as rotation by 90° about the 3-axis with the exchange of valance proton and neutron. We found that both M1 and E2 transitions are allowed between levels with different values of A, while they are forbidden between levels with same values of A. Such a selection rule holds true for MχD in different mass regions.

Spectra and electromagnetic transitions of ^(72-84)Kr in the interacting boson model-1

Within the framework of the interacting boson model- 1, the energy levels and electromagnetic transitions in 72-84Kr isotopes are calculated. The structures of the eigenstate and Hamiltonian matrix for some low-lying states are also calculated. The calculated results are compared with available experimental data, and the results are generally in good agreement. The present study shows that the 72,74,76,80,82,84Kr isotopes are in the transition from U（5）→ SU（3）, and 7SKr is in the transition from U（5）→ O（6）.

RETRACTED: Nuclear Structure Study of Odd-Odd Yttrium Nuclei within Interacting-Boson Fermi-Fermion Model (IBFFM)

Short Retraction NoticeThe paper does not meet the standards of "Journal of Applied Mathematics and Physics". This article has been retracted to straighten the academic record. In making this decision the Editorial Board follows COPE's Retraction Guidelines. The aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused.Editor guiding this retraction: Prof. Wen-Xiu Ma (EiC of JAMP)The full retraction notice in PDF is preceding the original paper, which is marked "RETRACTED".

Isospin and Symmetry Structure in ^(36)Ar

The interacting boson model-3(IBM-3) has been used to study the isospin excitation states and electromag-netic transitions for ^(36)Ar nucleus.The mixed symmetry states and superdeformed band at low spin are also analyzed.The theoretical calculations are in agreement with experimental data,and the ^(36)Ar is superdeformed rotational nucleusclose to the SU(3) limit.The present calcula,tions indicate that the 2_4^+ state is the lowest mixed symmetry state and thelowest isospin T=1 excitation state and at about 6.2 MeV,and the bandhead of superdeformed band is 0_2^+ state.

Test of Chirality in Nucleus ^(130)Cs

The level lifetimes in partner bands of 130Cs have been measured using the Doppler Shift Attenuation method （DSAM）. The high-spin states of 130Cs were populated via fusion evap- oration reaction 124Sn（11B; 5n）130Cs at a beam energy of 65 MeV. The absolute M1 and E2 transition probabilities have been deduced. The results indicate that the partner bands of 130Cs indeed manifest chiral properties.

Microscopic Cluster Study of the 10Be Nucleus

Using a microscopic four-body cluster model,we investigate the spectral properties and structural configurations of the ioBe nucleus.We calculate physical quantities such as the root-mean-squared(r.m.s.)radii and electromagnetic transition strengths.The theoretical results for the energies and certain electromagnetic transition strengths of the low-lying states show good agreement with experimental data.In particular,the enhancement of the r.m.s.radius and isoscalar monopole transition strength of the O,state indicates a well-developed cluster structure.We obtained three 1-states in Ex<15 MeV that show remarkable dipole transition strengths,suggesting that the 1-states may have cluster structure.Using the obtained wave functions,we calculate the reduced-width amplitudes(RWAs)to investigate the SHe+αand'Be+n two-body cluster structures in IOBe.The results suggest that the lowlying states show the two-body 6He+α and 9Be+n configuration,with the 6He+α components of the two-body structure diminishing as the energy increases,which due to the breakup of He and 9Be at higher excitation energies.Moreover,a few states above the α+α+n+n threshold still exhibit significant 9Be+n components.

Mixed symmetry states and electromagnetic transition in the N=Z nucleus ^(28)Si

The interacting boson model with isospin （IBM-3） has been used to study mixed symmetry states and electromagnetic transitions at low-lying states for a ^28Si nucleus. The theoretical calculations show that the 24^＋ state is the lowest mixed symmetry state in ^28Si and the 43＋ state is also a mixed symmetry state.

A new mechanism for the electromagnetic transition γ^＊N→N^＊（1535）

The heiicity amplitude A1/2^P for the electromagnetic transition γ^＊N→N^＊（1535） is investigated. It is found that a new mechanism γ^＊→q^-q plays an important role in order to improve the description of this transition. On one hand, the A1/2^p is decreased to fall in the data range at the photon point Q^2 = 0, while on the other hand, the new mechanism makes the function A1/2^p（Q^2） to decrease more slowly vs increasing Q^2 as required by the data.

Experimental studies for nuclear chirality in China

In the last decade,chiral symmetry in atomic nuclei has attracted significant attention and become one of the hot topics in current nuclear physics frontiers.This paper provides a review of experimental studies for nuclear chirality in China.In particular,the experimental setups,chiral mass regions,lifetime measurements,and simultaneous breaking of chirality and other symmetries are discussed in detail.These studies found a new chiral mass region(A≈80),extended the boundaries of the A≈100 and 130 chiral mass regions,and tested the chiral geometry of^(130)Cs,^(106)Ag,^(80)Br and^(76)Br by lifetime measurements.In addition,simultaneous breaking of chirality and other symmetries have been studied in^(74)As,^(76)Br,^(78)Br,^(80)Br,^(81)Kr and^(131)Ba.

Isospin and mixed symmetry structure in ^(26)Mg

The isospin excitation states and electromagnetic transitions of the 26Mg nucleus are studied with the isospin-dependent interacting boson model （IBM-3）. The mixed symmetry states at low spin and the main components of the wave function for some states are also analyzed. The results show good agreement with the available experimental data. From the IBM-3 Hamiltonian expressed in Casimir operator form, the 26Mg is also proved to be a transition nuclei from U（5） to SU（3）.

Isospin and mixed symmetry structure in ^(24)Mg

The interacting boson model with isospin （IBM-3） has been used to study the isospin excitation states and electromagnetic transitions for 24Mg nucleus. The mixed symmetry states at low spin are also analyzed. The theoretical calculations are in agreement with experimental data. The present calculations indicate that the 3^＋ state is the lowest mixed symmetry state.

Isospin structure in ^(68)Ge

The interacting boson model-3(IBM-3) has been used to study the low-energy level structure and electromagnetic transitions of 68Ge nucleus. The main components of the wave function for some states are also analyzed respectively. The theoretical calculations are in agreement with experimental data, and the 68Ge is in transition from U(5) to SU(3).

Lifetime measurements in chiral nucleus ^(130)Cs

The level lifetimes in partner bands of 130Cs have been measured using the Doppler Shift Attenuation method. The high-spin states of 130Cs were populated via fusion evaporation reaction 124Sn(11B,5n)130Cs at a beam energy of 65 MeV. The absolute M1 and E2 transition probabilities have been deduced. The results indicate that the partner bands of 130Cs manifest the chiral properties.

Chiral doublet bands and energy-level crossing

Different definitions for chiral doublet bands based on excitation energies, B(E2) and B(M1) respectively are discussed in the triaxial particle rotor model. For the ideal chiral geometry, the selection rules of the electromagnetic transitions in different band definitions are illustrated. It is also shown that the energy-level crossings between chiral doublet bands may occur.

Single π0electro-production in the resonance region with CLAS＊

We report the analysis status of single π0electroproduction in the resonance region to study the electromagnetic excitation of the nucleon resonances. The study is aimed at understanding of the internal structure and dynamics of the nucleon. The experiment was performed using an unpolarized cryogenic hydrogen target and 2.0 and 5.8 GeV polarized electron beam during the ele and e1-6 run periods with CLAS at Jefferson Lab. The new measurements will produce a data base with high statistics and large kinematic coverage for the hadronic invariant mass （W） up to 2.0 CeV in the momentum transfer （Q2） range of 0.3--6.0 GeV2. Preliminary results will be presented and compared with the various model calculations.

Low-lying spectra and E2 transition rates in ^(160-170)Er isotopes in the interaction boson model

Spectra and E2 transition rates for the 160-170Er isotopes are studied in the framework of the interaction boson model. A schematic Hamiltonian able to describe their spectra and B(E2) transition is used. It is found that the 160-170Er isotopes are in the transition from the vibrational limit to rotational limit.

πg_(9/2)νh_(11/2) doublet bands in A～100 mass region

Using the model with one particle and one hole coupled with a triaxial rotor, the πg9/2/1/2νh11/2 doublet bands in the A～100 mass region are studied, and compared with the πg9/2/1/2νh11/2 doublet bands. It is found that the calculated results for the configuration of πg9/2/1/2νh11/2 are very similar the results for a pure h11/2 proton particle and a neutron quasiparticle with λn = ε5. After including the pair correlation, the model describes the candidate chiral doublet bands in 106Rh successfully, which supports the interpretation of chirality geometry.

The g-factor measurement as an ultimate test for nuclear chirality

We present results of a series of experiments aimed at finding the most direct fingerprints of a phenomenon of nuclear chirality. These experiments brought a detailed knowledge of the so called partner bands in 132La, 128Cs and 126Cs including absolute values of E2 and M1 transition probabilities obtained through the DSA (Doppler Shift Attenuation) method. Considering the indirect character of observables such as energies and transition rates we proposed measurement of the g-factor of a chosen state as a direct, ultimate test of chirality. Our experiment on the bandhead of partner bands in 128Cs showed feasibility of this approach. Measured value of the g-factor which suggests non-chiral character of this state leads to another puzzle in the chirality studies — how the chirality emerges with increasing spin of levels along a partner band.