稀土区奇奇核πh_(11/2)νi_(13/2)带B(M1)/B(E2)比值增强特性

在稀土区奇奇核πh11/2νi13/2转动带中,系统地观测到随转动频率或角动量增加,B(M1)/B(E2)曲线表现出所谓parabola like形状,即在增加到某一转动频率或自旋后,B(M1)/B(E2)比值快速增强。基于推转模型和粒子转子模型关于奇奇核二准粒子转动带磁偶极约化跃迁几率的描述,对稀土区双奇核的这一行为进行了讨论。指出该现象的发生与νi13/2准中子转动顺排特性密切相关。B(M1)/B(E2)比值在接近第二带交叉(即BC准中子对顺排)的较高频率处的增强效果,可以理解为主要来源于带交叉引起的波函数中混合四准粒子成分的结果。通过对B(M1)/B(E2)比值的增强效果发生在较低频率处的分析,对稀土区奇奇核πh11/2νi13/2带角动量耦合图像有了进一步认识。     

稀土区奇质子Lu和Ta核旋称反转研究

研究了奇质子核Lu和Ta同位素链h11/2质子9／2[514]转动带旋称劈裂的系统规律，并与同一核区奇奇核的πh11/2×vi13/2两准粒子转动带低自旋区旋称劈裂规律进行了比较，指出奇质子Lu和Ta核三准粒子带的旋称反转很可能是来源于h11/2准质子和 i13/2准中子之间的相互作用。The systematic features of signature splitting of the h11/2 9/2 [ 514] rotational band in Lutetium and Tantalum isotope chains have been investigated and compared with that of πh11/2×vi13/2 2-quasiparticle band in oddodd nuclei of the same nuclear region. It is shown that signature inversion of 3-quasiparticle band of some odd- Z Lutetium and Tantalum nuclei most probably caused by the p-n interaction of h11/2 quasiproton and i13/2 quasineutron.     

High Spin States in Odd--Odd 160Tm Nucleus

High-spin states of ^160Tm are studied by the ^146 Nd（^19F, 5n） reaction at a beam energy of 102 MeV. The previously known πh11/2 ＋ vi13/2 yrast band and πh11/2 ＋ vh9/2 side band are confirmed. The level scheme is enriched and more low-lying levels are observed. A new side band is observed and assigned as the favoured signature partner of πd3/2 ＋ vi13/2. The spin of this band is assigned with the energy level systematics. It is pointed out that the B （M1）/B （E2） ratios increase rapidly at the high frequency approaching the second crossing in the π h11/2 ＋ vi13/2 braid, which is closely related to the alignment gain of the aligned i13/2 quasineutron.     

Signature splitting in 129Ce

The high spin states of ¹²⁹Ce have been populated via heavy-ion fusion evaporation reaction ⁹⁶Mo (³⁷Cl, 1p3n) ¹²⁹Ce. The γ-γ coincidence and intensity balance used to measure the B(M1; I→I-1)/B(E2; I→I-2) (the probability ratio of the dipole and quadrupole transition) in ν7/2[523] rotational band of ¹²⁹Ce. And the energy splitting (Δe′) has been got through the experimental Routhians. The lifetimes and quadrupole moments Q_t have been extracted from the lineshape analyses using DSAM. The deformation of the ν7/2[523] rotational band of ¹²⁹Ce was extracted from the Q_t and moment of inertia J_RR.     

双奇核172Re高自旋态实验研究

利用149Sm(27Al,4nγ)172Re反应布居了形变双奇核172Re的高自旋态,用12套带有BGO反康普顿抑制的高纯锗探测器阵列进行了在束γ实验测量,首次建立了172Re由3个转动带构成的高自旋态能级纲图.研究和讨论了3个转动带的结构特征,基于已有的高自旋态核结构知识并通过系统学比较和分析指出它们的准粒子组态分别为πh11/2 νi13/2,πh9/2 νi13/2和 π1/2-[541] ν1/2-[521].发现前两个转动带在自旋小于18时其转动能级呈现反常的旋称劈裂.High-spin states in the odd-odd~(172)Re have been investigated via the~(149)Sm(~(27)Al, 4nγ)~(172)Re reaction through excitation functions, X-γ and γ-γ coincidence measurements. A level scheme consisting of three rotational bands have been identified for the first time extending the high-spin studies of A≈160 odd-odd nuclei to the currently lightest rhenium isotope. The three bands have been assigned to be built on the πh_(11/2) νi_(13/2), πh_(9/2) νi_(13/2 ) and π1/2~-\ν1/2~-\ configurations ...     

Analysis of the excited bottom and bottom-strange states B1（5721）, B2*（5747）,Bs1（5830）, Bs2*（5840）, BJ（5840） and BJ（5970） of the B meson family

In order to make a further confirmation of the assignments of the excited bottom and bottom-strange mesons B1(5721),B2^*(5747),Bs1(5830)and Bs2^*(5840)and identify possible assignments of BJ(5840)and BJ(5970),we study the strong decay of these states with the 3P0 decay model.Our analysis supports the assignments of B1(5721)and B2*(5747)as the 1P'1 and 1^3P2 states,and Bs1(5830)and Bs2^*(5840)as the strange partners of B1(5721)and B2^*(5747).Besides,we tentatively identify the recently observed BJ(5840)and BJ(5970)as the 2^3S1 and 13D3 states.It is noted that these conclusions need further confirmation by measurements of the decay channels BJ(5840)→Bπand BJ(5970)→Bπ.     

Collisional broadening of some 21△g ← B1∏u lines in Na2 molecules by optical-optical double resonance spectroscopy

Using the optical-optical double resonance (OODR) technique, we have studied the collisional broadening of some 21△g ← B1∏u lines in Na2 molecules. A single line Ar+ laser is used to pump the sodium dimers from thermally populated ground state X1∑g+ level to the intermediate B1∏u state. Then, a single-mode diode laser is used to probe the doubly excited 21△g state. The broadening rate coefficient is determined from the slope of the total linewidth versus Ne density curve. We obtain the average value kbr = (1.1 ± 0.5) × 10-s cm3s-1. The collisional excitation transfer between rotational levels of the B1∏u state (I.e., B1∏u(2,83/84) ← B1∏u(2, 82)) is also investigated. The rates can be determined from the relative intensities of the main peak and satellite lines, combined with a rate equation model. The rates of 1.25 × 106 and 1.07 × 106 s-1 are obtained, respectively.     

双奇核174Re中的准粒子形状驱动效应

对双奇核174Re的在束γ谱学实验数据作了仔细分析, 提取出了带间与带内E2 γ跃迁分支比, 并导出了其约化跃迁概率的比值。用带混合理论对约化跃迁概率的比值进行了分析, 得到带间相互作用强度及转动带形变的信息。发现不同组态的转动带其跃迁电四极矩具有明显的差异。与相邻奇A核的结构特征类似,这种跃迁电四极矩的差异很可能是由于1/2-[541]准质子或1/2-[521] 准中子对原子核的形状驱动效应造成的。 By analyzing carefully the in beam γ spectroscopy data of odd-odd 174Re, we have extracted the branching ratios of the interband and intraband E2 γ transitions from the two rotational bands of different configurations in 174Re.The ratios of the reduced transition probabilities B(E2) have been deduced and analyzed using a band mixing theory. Information on the band interaction and deformation have been obtained. Apparent differences of transition quadrupole moments are found in the two configurations. A likely reason for the differences in the transition quadrupole moments is the shape driving effects of 1/2-[541] quasi proton or 1/2-[521] quasi neutron, which has been proposed in the oddA neighbors of 174Re.     

双奇核184Au中πi13/2⊙νi13/2转动带的结构特征研究

利用重离子熔合蒸发反应和在束γ谱学实验方法,研究了双奇核184?Au的高自旋态能级结构.扩展了基于πh9/2ν7/2–[514]和πi13/2νi13/22准粒子组态下的转动带能级纲图,建立了两个转动带之间以及πh9/2ν7/2-[514]带与基态的谱学连接.从而确定了πi13/2νi13/2带能级的自旋和宇称,证实了此转动带在低自旋区出现旋称反转.分析了πi13/2νi13/2带和相邻核转动带的准粒子顺排特征,指出此带的第一回弯以及相邻核转动带在低频观测到的顺排异常可能与h9/2质子顺排有关.     

The rotational anisotropies in the ferromagnetism/antiferromagnetism 1/ antiferromagnetism 2 exchange bias structures

The rotational anisotropies in the exchange bias structures of ferromagnetism/antiferromagnetism 1/antiferromagnetism 2 are studied in this paper. Based on the model, in which the antiferromagnetism is treated with an Ising mean field theory and the rotational anisotropy is assumed to be related to the field created by the moment induced on the antiferromagnetic layer next to the ferromagnetic layer, we can explain why in experiments for ferromagnetism (FM)/antiferromagntism 1 (AFM1)/antiferromagnetism 2 (AFM2) systems the thickness-dependent rotational anisotropy value is non-monotonic, i.e. it reaches a minimum for this system at a specific thickness of the first antiferromagnetic layer and exhibits oscillatory behaviour. In addition, we find that the temperature-dependent rotational anisotropy value is in good agreement with the experimental result.     

Systematic study of the product((E(2_2~+)/E(2_1~+)) * B(E2)↑) through the asymmetric rotor model

A systematic study of the product((E(2_2~+)/E(2_1~+))*B(E2)↑) is carried out in the major shell space Z=50-82,N=82-126 within the framework of the asymmetric rotor model where the asymmetry parameter γ0reflects change in the nuclear structure.A systematic study of the product((E(2+)/E(2+))*B(E2)↑) with neutron number N is also discussed.The product((E(2_2~+)/E(2_1~+))*B(E2)↑) provides a direct correlation with the asymmetry parameter γ0.The effect of subshells is visible in Ba-Gd nuclei with N 82,but not in Hf-Pt nuclei with N 104.We study,for the first time,the dependency of the product((E(2_2~+)/E(2_1~+))*B(E2)↑) on the asymmetry parameterγ0.     

双奇核~(184)Au中πi_(913/2)νi_(13/2)转动带的结构特征研究

利用重离子熔合蒸发反应和在束γ谱学实验方法 ,研究了双奇核184 Au的高自旋态能级结构 .扩展了基于πh9/ 2 ν7/ 2 - [5 14 ]和πi13/ 2 νi13/ 2 2准粒子组态下的转动带能级纲图 ,建立了两个转动带之间以及πh9/ 2 ν7/ 2 - [5 14 ]带与基态的谱学连接 .从而确定了πi13/ 2 νi13/ 2 带能级的自旋和宇称 ,证实了此转动带在低自旋区出现旋称反转 .分析了πi13/ 2 νi13/ 2 带和相邻核转动带的准粒子顺排特征 ,指出此带的第一回弯以及相邻核转动带在低频观测到的顺排异常可能与h9/ 2 质子顺排有关 .     

三轴形变对102Rh旋称反转的影响

将两准粒子加轴对称转子模型扩展到三轴形变, 对奇奇核102Rh的旋称反转进行了研究和分析, 结果表明, 可能的旋称反转机制 (即低K 空间n p相互作用和科氏力的相互竞争), 对于A=100质量区奇奇核也是适用的, 三轴形变可以明显地改进能谱的振荡特性. The model of an axially symmetric rotor plus two quasi particles for the Signature Inversion (SI) in odd odd nuclei is generalized to the triaxial deformation. The calculation of the odd odd nucleus 102Rh shows that the possible SI mechanism (i. e., the competition between the n p interaction and the coriolis force in low K space) is also appropriate for odd odd nuclei in the A=100 region. A triaxial shape can improve the vibration property of the rotational spectra remarkably.     

偶偶No同位素转动性质研究(英文)

通过总Routhian 面计算方法研究了Z = 102 号元素已实验合成的偶偶248-264No同位素的转动性质。计算的基态形变β2,β4 与前人的计算相符。252,245No 两核基态带的转动惯量特征能得到基本再现。偶偶248-264No同位素转动惯量系统上弯的现象可归因于带交叉。研究还表明,推转时质子与中子顺排有强烈竞争,在较轻的No同位素中j_15/2 中子拆对顺排较为优先,而在较重的No 核中i_13/2 质子顺排更加优先。The rotational properties of the synthesized even-even 248-264No isotopes have been investigated by means of total Routhian surface calculations. The calculated ground-state properties (e.g. β2; β4) are in agreement with previous calculations. The behaviors of moment of inertia of 252,254No are well reproduced by our calculations. The systematic upbending in moment of inertia is attributed to band crossing. It is found that the j_15/2 neutron rotation-alignment is preferred for the lighter No isotopes, but the i_13/2 proton alignment is favored in the heavier ones.     

Systematic dependence of SFE*B(E2)↑ and ROTE*B(E2)↑on N_pN_n in the framework of shape fluctuation model

A systematic dependence of shape fluctuation energy product SFE * B(E2)↑ and rotational energy product ROTE * B(E2)↑ on the valence nucleon product Np Nn is carried out in the Z = 50-82,N = 82-126 major shell space.For the shape transitional nuclei,the product SFE*B(E2)↑ drops to zero and becomes negative,indicating direct dependence on N_pN_n.A relative rise,on the other hand,is observed in the product ROTE*B(E2) ↑plotted against N_pN_n for all the nuclei in Z = 50-82 and N = 82-126.In the N 104 region,large positive values of the product SFE * B(E2) ↑ are observed for the Pt nucleus,which indicates sphericity.A systematic study of the product SFE * B(E2)↑ and ROTE * B(E2) ↑ with atomic number Z is also discussed.The products SFE * B(E2) ↑and ROTE * B(E2) ↑ vary sharply with Z for the N = 88 isotones.We discuss here for the first time the correlation between SFE * B(E2) ↑ and ROTE * B(E2) ↑ with valence nucleon product N_pN_n.     

Collisional broadening of some 2~1Δ_g←B~1Π_u lines in Na_2 molecules by optical-optical double resonance spectroscopy

Using the optical-optical double resonance (OODR) technique, we have studied the collisional broadening of some 2~1Δ_g←B~1Π_u lines in Na2 molecules. A single line Ar laser is used to pump the sodium dimers from thermally populated ground state X1∑ 9 level to the intermediate B~1Π_u state. Then, a single-mode diode laser is used to probe the doubly excited 21Δ_g state. The broadening rate coefficient is determined from the slope of the total linewidth versus Ne density curve. We obtain the average value kbr=(1.1±0.5)×10-8 cm3s-1. The collisional excitation transfer between rotational levels of the B~1Π_u state (i.e., B~1Π_u(2, 83/84)←B~1Π_u(2,82)) is also investigated. The rates can be determined from the relative intensities of the main peak and satellite lines, combined with a rate equation model. The rates of 1.25×10~6 and 1.07×10~6 s-1 are obtained, respectively.     

双奇核~(170)Re高自旋转动带分析(英文)

通过重离子熔合蒸发反应142Nd(32S,1p3nγ)170Re布居了缺中子双奇核170Re的高自旋激发态,识别出了该核的一条转动带并建议了其组态为πh1/2 νi13/2。基于对同中子素能级系统性、旋称反转系统性、带内B(M1)/B(E2)、准粒子Routhians、动力学转动惯量和Total Routhian Surface(TRS)等带结构特征的详细分析和讨论,进一步确认了对A=170核区目前最缺中子双奇核高自旋转动带组态、宇称和自旋值的指定。     

A≈100和130核区手征双重带的描述

利用三轴形变的粒子 转子模型讨论了A≈100和A≈130核区手征双重带.基于粒子空穴组态πh11/2 νh-111/2的计算很好地再现了A≈130核区N=75同中子素的手征双重带实验能谱.通过分析基于组态πg9/2 νg-19/2的约化跃迁几率B(E2)和B(M1)研究A≈100核区可能的手征双重带. The Chiral doublets for nuclei in A≈100 and 130 regions have been studied with the particle-rotor model. The experimental spectra of chiral partner bands for four N=75 isotones in A≈region have been well reproduced by the calculation with the configuration πh_(11/2)νh~(-1)_(11/2). The possible chiral doublets in A≈100 region have been predicted by the particle-rotor model (PRM) with the configuration πg_(9/2) νg~(-1)_(9/2) based on the analysis of the B(M1) and B(E2) transition probabilities.     

Microscopic Mechanism of the ω Variation in Moments of Inertia for the Yrast Superdeformed Bands ^194T1（1a,1b）

The variation in moments of inertia(J^(1)and J^(2) with rotational frequency for the superdeformed bands in odd-odd nuclei,194T1(1a,1b),is investigated by using the particle-number conserving method for treating the pairing interaction(monopole and quadrupole),The observed variations ofJ^(1) and J^(2) with ω are reproduced quite well in the calculation and the contributions from each major shell are clearly displayed.     

Lepton-number-violating decays of singly-charged Higgs bosons in the type-(Ⅰ+Ⅱ) seesaw model

The lepton-number-violating decays of singly-charged Higgs bosons H± are investigated in the minimal type-(Ⅰ+Ⅱ) seesaw model with one SU(2)L Higgs triplet Δ and one heavy Majorana neutrino N1 at the TeV scale.We find that the branching ratios B(H+ → lα+ ν)(for α = e,μ,τ) depend not only on the mass and mixing parameters of three light neutrinos νi(for i=1,2,3) but also on those of N1.Assuming that the mass of N1 lies in the range of 200 GeV to 1 TeV,we figure out the generous interference bands for the contributions of νi and N1 to B(H+ →lα+ ν).We illustrate some salient features of such interference effects by considering three typical mass patterns of νi,and show that the relevant Majorana CP-violating phases can affect the magnitudes of B(H+ →l+αν) in this parameter region.