Identification of a 9/2~-[505] isomer in the neutron-rich ~(193)Os nucleus

The neutron rich nucleus ¹⁹³Os was produced in the ¹⁹²Os(⁷Li, ⁶Li)¹⁹³Os reaction. An isomeric state based on the 9/2^-[505] Nilsson orbital was identified in the present work. The half-life of the isomeric state was extracted and discussed in terms of the K quantum number. A level scheme built on the isomeric state was proposed based on the experimental data.     

Experimental Measurements for the QEC-Value of 183Os-Decay

Activities of ¹⁸³Os were produced by 39MeV α particles bombarding on a natural tungsten target.β⁺ spectrum with coincidence gate set on the strongest 382keV γ-rays of ¹⁸³Os decay was measured.The endpoint energy of the β⁺ spectrum was determined and the Q_EC value of ¹⁸³Os decay was extracted to be 2.24±0.10MeV which is in good agreement with the predicted value 2.30±0.10MeV on the basis of mass systematics.     

Mixing between the 23S1 and 13D1 Ds

Mixing between the 2³S₁ and 1³D₁ D_s is studied within the ³P₀ model. If mixing between these two 1^- states exists, D_s1^*(2700)^± and D_sJ^*(2860)^± could be interpreted as the two orthogonal mixed states with mixing angle θ≈ -80° in the case of a special β for each meson. However, in the case of a universal β for all mesons, D_s1^*(2700)^± could be interpreted as the mixed state of 2³S₁ and 1³D₁ with mixing angle 12° < θ < 21° but D_sJ^*(2860)^± seems difficult to interpret as the orthogonal partner of D_s1^*(2700)^±.     

ON THE CONTRACTION AND DEFORMATION OF DEUTERON CLUSTER IN 6Li

The ground state of ⁶Li is investigated by means of the projected variational method for double well-cluster shell model. The results of the variational calculation show that the root-mean-square radius of d-cluster in the ground state of ⁶Li is smaller than that of free deuteron and as the mean distance between the α-cluster and the d-cluster decreases there are two effects on the d-cluster, namely contraction effect in which the d-cluster contracts first and then makes a bit extension and deformation effect in which the d-cluster makes oblation first and then streteches.It is also demonstrated by the calculation that the repulsive component of the odd sytate of N-N force and the pauli exchange of the nucleons between the clusters play an important role not only on the cluster structure in the ground state of ⁶Li but also on the contraction and the deformation of d-cluster in ⁶Li.     

Three-Body Model of 11Li

A new effective interaction between a neutron and the ⁹Li core is introduced, and based on the n+n+⁹Li model, a variational calculation on the neutron rich nucleus ¹¹Li is completed. The one-body density, formfactor and shapedensity are investigated, The RMS radius and the binding energy are also calculated and are in good agreement with the experimental data.     

Single-Proton Pickup Reaction of the Halo Nucleus ^6He on a ^9Be Target at 25 MeV/nucleon

The inclusive differential cross sections of the ^7 Li nucleus in a reaction induced by ^6He on a ^9Be target are measured at an incident energy of 25 MeV/nucleon. Finite-range distorted-wave Born approximation calculations suggest that these ^7 Li particles are formed in a direct single-proton pickup reaction ^9Be（^6He,^7 Li）^8Li. The experimental data can be well reproduced by taking into account of the contributions of both the ground states and the first excited states of ^7Li and ^8Li.     

Measurement of Angular Distribution for the ^8Li（p,d）^7Li Reaction

The ^8Li（p, d）^7 Li reaction plays an important role in the inhomogeneous Big Bang nucleosynthesis and in the seed-nuclide production phase for the r-process. For the first time, its angular distribution at backward angles was measured in inverse kinematics at Ec.m.=4.0 MeV by using an ^8Li secondary beam. The result of measurement includes the contributions of ^8Li（p, d0）^7Li and ^8Li（p, d1）^7Li^＊. The ^8Li（p, d0）^7Li component is estimated to be 40%-58% in the mixture angular distribution by analysing the measured result.     

THE DYNAMIC EFFECT ON NUCLEAR DEFORMATION I.DEFORMATIONS AT HIGH SPINS FOR NUCLEUS 172Os

According to a method of numerical solution of Hill-Wheeler equation proposed by us recently,the dynamic evolution of shapes in the Yrast band of ¹⁷²Os was calculated.Results show better agreement with the recent lifetime measurement than the normal TRS calculation.This means the dynamic effect on the nuclear shape is not negligible at least for the transitional nuclei like ¹⁷²Os.     

Main linac lattice design and optimization for Ecm=1 TeV CLIC

The Compact Linear Collider (CLIC) is a future e⁺e^- linear collider. The CLIC study concentrated on a design of center-of-mass energy of 3 TeV and demonstrated the feasibility of the technology. However, the physics also demands lower energy collision. To satisfy this, CLIC can be built in stages. The actual stages will depend on LHC results. Some specific scenarios of staged constructions have been shown in CLIC Concept Design Report (CDR). In this paper, we concentrate on the main linac lattice design for E_cm=1 TeV CLIC aiming to upgrade from E_cm=500 GeV CLIC and then to E_cm=3 TeV one. This main linac accelerates the electron or positron beam from 9 GeV to 500 GeV. A primary lattice design based on the 3 TeV CLIC main linac design and its optimization based on the beam dynamics study will be presented. As we use the same design principles as 3TeV CLIC main linac, this optimization is basically identical to the 3 TeV one. All the simulations results are obtained using the tracking code PLACET.     

A Three-Body Model of 11Li,14Be and 17B

The nuclei ¹¹Li,¹⁴Be and ¹⁷B are considered as three-body systems composed of the N=2Z core and two outside neutrons.The core-neutron and neutronneutron interactions are assumed to be the attractive exponential potentials.It has been shown that the three-body system can have a bound state although any two constituents of the system cannot have a bound state. The experimental data of the binding energy and extraordinarily large matter root-mean-square radius can be explained in the frame of the three-body model.     

New band structures in 107Ag

High spin states in ¹⁰⁷Ag are studied via the ¹⁰⁰Mo(¹¹B, 4n)¹⁰⁷Ag reaction at an incident beam energy of 60 MeV. Prompt γ-γ coincidence and DCO ratios are measured by the detector arrays in CIAE. The level scheme has been updated and a new negative band belonging to ¹⁰⁷Ag is identified. The new negative side band has been constructed and its configuration is tentatively assigned to πg_9/2 νh_11/2(g_7/2/d_5/2).     

Isotope Ratios of Light Charged Particles and Temperature in the Reactions 30MeV/u40Ar+112,124Sn

Coincidence measurements between residues and light charged particles (LCPs) have been made for the reactions 30MeV/u 40Ar+^112,124Sn. The LCPs were measured by 11 semi-conduct telescopes from very forward angle to backward angle. The times of flight of the residues were measured by PPACs installed concentrically around the beam at forward angle. The excitation energy of the primary hot nuclei was obtained from the velocity of residues in the frame of incomplete fusion model. The single isotope ratios, as function of observing angle and excitation energy have been studied. The ratio of ³He/⁴He and ⁶Li/⁷Li increases with angle while that of ⁶He/⁴He and ⁸Li/⁷Li decreases. The calculation of statistical theory can not reproduce the curve quantitatively, implying the existence of dynamic effect. Isospin effect of the primary hot nuclei on the single isotopic ratios is demonstrated. However, the temperature extracted from double isotope ratios is target independent.     

Nuclear levels in193Os

The previously completely unknown energy levels of¹⁹³Os have been investigated using the reactions¹⁹²Os(d, p)¹⁹³Os and¹⁹²Os(n, γ)¹⁹³Os. The neutron separation energy was measured to be 5583.5±2.0 keV. Most of the states below 500 keV can be qualitatively interpreted in terms of the Nilsson model; however the occurrence of four levels with significantl=1 transfer strength in this energy range is incompatible with that model. The Nilsson orbital systematics of the odd-A Os and W isotopes are compared.     

Angular-correlation study of the level scheme of 193Ir

The decay of ¹⁹³Os to ¹⁹³Ir has been studied by γγ angular correlations. Inconsistencies between previous angular correlations, internal conversion coefficients, and nuclear orientation angular distributions have been satisfactorily resolved by the present results. These data are used to derive a set of $\text{E2}\text{M 1}$ multipole mixing ratios of the transitions between low-lying states. The resulting electromagnetic transition moments are compared with calculations based on the Nilsson model with Coriolis mixing and on the interacting boson-fermion model.     

A NEW TRANSITION BRANCH OF THE 5.2 SEC ISOMER IN 183W

During the bombardment of 14.8MeV neutron on natural wolfram samples a γ-ray with energy 291.7keV and halflife 5.17±0.03 sec is observed. From the experimental facts it is assumed that in addition to the two well known transition branches from the decay of 5.2 sec isomer in ¹³⁸W there exists another 11/2⁺11/2[615]→5/2^－3/2[512] isomeric (E3) transition. The hindrance factor of this new transition is calculated. It is well cosistent with the general empirical rule of k^－ forbidden isomeric transition.     

A New Level Scheme of 127I

Study of in beam γ ray spectroscopy of ¹²⁷I has been performed using ¹²⁴Sn(⁷Li, 4n)¹²⁷I reaction at 32 MeV beam energy. A new level scheme of ¹²⁷I has been established including 25 new levels and 52 new γ transitions. Negative parity levels based on 11/2^－ π h_11/2 particle state have been observed up to (35/2^－) extending our knowledge of decoupled structures to the heavier iodine isotope. Two ΔI=2 yrast positive-parity levels have been proposed to be associated mainly with the πg_7/2 configuration due to observations of several strong inter band transitions. Two weakly populated ΔI=2 positive parity levels and a high-lying ΔI=1 cascade have been newly identified and tentatively assigned as πd_5/2 one-quasiparticle and three quasiparticle bands, respectively.     

Nuclear moment determination by Mössbauer effect detection of low temperature nuclear orientation (No/Me)

Absorption Mössbauer spectra were measured on low temperature (6–21 mK) oriented nuclei. For magnetic orientation this method allows the determination of the sign of the parent state magnetic moment. The method enables the determination of the parent state quadrupole coupling even for a polycrystalline sample. Signs of ground state magnetic moments for¹⁹¹Pt and¹⁹³Os, and electric quadrupole moments for¹²⁵Te^m and¹²⁹Te are determined.     

INFLUENCE OF THE NEUTRON NUMBER OF TARGET NUCLEUS ON CROSS SECTIONS OF PARTICLES EMISSION IN 12C+112,124Sn

The energy spectra and angular distributions of Li, Be, B particles emitted from the ¹²C+¹¹²Sn and ¹²C+¹²⁴Sn reactions at E_L=70.0MeV are measured. The angular distributions of the Li, Be, and B particles are found to be peaked around the grazing angle, without any forward peaked component.
The experimental results also showed that the cross section for emission is larger in ¹²C+¹¹²Sn reaction than that in ¹²C+¹²⁴Sn reaction, in contrast with the cross sections for Li, Be and B emissions. The indicates the effect of the neutron number of the target nucleus on the emission probability.     

Branching ratio and CP asymmetry of Bs→K0*(1430)η(') decays in the PQCD approach

In the two-quark model supposition for K₀^*(1430), which can be viewed as either the first excited state (Scenario Ⅰ) or the lowest lying state (Scenario Ⅱ), the branching ratios and the direct CP-violating asymmetries for decays B_s⁰→K₀^*0(1430)η^(') are studied by employing the perturbative QCD factorization approach. We find the following results: (a) The CP averaged branching ratios of B_s⁰→K₀^*0(1430)η and B_s⁰→K₀^*0(1430)η' are small and both in the order of 10^-7. If one views K₀^*(1430) as the lowest lying state, B (B_s⁰→K₀^*0(1430)η)≈3.9×10^-7 and B (B_s⁰→K₀^*0(1430)η')≈7.8×10^-7. (b) While the direct CP-violating asymmetries of these two decays are not small: if we still take the parameters of K₀^*(1430) in scenario Ⅱ, A_CP^dir (B_s⁰→K₀^*0(1430)η)≈56.2% and A_CP^dir (B_s⁰→K₀^*0(1430)η')≈2.4%. (c) The annihilation contributions will play an important role in accounting for future data, because both the branching ratios and the direct CP asymmetries of these two decays are sensitive to the annihilation type contributions.     

Location of the181Os isomeric state

The decay of¹⁸¹Ir has been studied on-line with mass-separated sources from the ISOCELE facility. The level scheme of¹⁸¹ Os has been established. The isomeric state has been located at 48.9 keV above the ground state. Thus the isomeric and ground states are identified as the 7/2?(T1/2 =2.7 m) and 1/2?(T1/2=105 m) levels respectively.