Band Structures of the Nucleus 129Cs

High-spin states in ^129Cs are populated via the ^122Sn （^11B, 4n） reaction at beam energies of 55 and 60MeV. Two additional bands are placed in the level scheme and the previously known bands are extended to higher spins. The results are compared to the cranked shell model calculations and to the systematics of the adjacent Cs isotpoes. One of the new bands is interpreted as the 7-vibrational band built on the πh11/2 orbital. The possible configuration for another new band is discussed. Upbend caused by （Vh11/2）^2 alignment is observed both in the favored and unfavored sequences of the πh11/2 configuration. The band based on the πgτ/2 configuration at low spins forks around spin 17//2, and the two different S-bands are attributed to （Vh11/2）^2 and （πh11/2）^2 rotational alignments, respectively.     

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.     

Search for the chiral Band in the N=71 Odd—odd Nucleus ^126Cs

High-spin states in ^126Cs are studied via the ^116Cd(^14N,4n) reaction at a beam energy of 65MeV.The sideband of the πvh11/2 yrast band,a ΔI=2 band known from previous study,is developed into a ΔI=1 coupled structure at low spins.This sideband is assigned to be built on the same configuration as the yrast band according to the measured ratios of directional correlation of orientation and observed alignment properties.On the basis of comparisons with the previously proposed chiral doublet bands for ^128,130Cs,the observed two πh11/2 vh11/2 bands are proposed to be candidates for chiral doublet bands in ^126Cs.     

Proposed Chiral Doublet Bands in ^98Tc

High spin states in odd-odd ^98 Tc nuclei are studied by in-beam γ-ray spectroscopy with the ^96 Zr（^6Li, 412） fusionevaporation reaction at a beam energy of 35MeV. The previous level scheme is updated. A band based on 1090.7keV is expanded, and another band based on 1920.6 keV is newly identified. The observed two negative parity bands in ^98 Tc are proposed to be a pair of chiral doublet bands with the configuration πg9/2 vh11/2. The evidence supporting the assignment of the chiral doublet bands is discussed. Signature splitting and signature inversion are observed in the πg9/2 vh11/2 band in ^98Tc.     

Clarification of Confusion in Level Scheme of 124Cs

Low-lying and high-spin states of ^124 Cs are studied through the ^116 Sn（^11 B,3n）^124 Cs reaction at a beam energy of 45 MeV. Several new linking transitions are observed, including three transitions between the yrast and πh11/2 vd3/2 bands and two transitions between the yrast and πh11/2 v（d5/2, g7/2） bands. These transitions fix the excitation energy of the yrast band and its decay path, and confirm the existence of eight E1 finking transitions between the yrast and πh11/2 v（d5/2, 97/2） bands observed before. These E1 linking transitions infer the oetupole correlation in ^124Cs. The decay paths of the yrast band are investigated, and discrepancies in the level scheme of ^124Cs in the latest two studies are clarified. The reason for the discrepancies is discussed. A new decoupled band is established and temporarily assigned as the unfavored signature partner of πh11/2 vd3/2 configuration.     

Identification of a New Band and Its Signature Inversion in ^174Re

High spin states in ^174Re are investigated via the ^152Sm（^27 AL,5nγ）^174Re reaction and γ - γ coincidence relationships are analysed carefully. A new band is identified due to its spectroscopic connection with the known π1/2^-[541] × ν1/2^-[521] band. This band is proposed to be the ground-state band built on the π1/2^-[541]× ,ν5/2^-[512] configuration in view of the low-lying intrinsic states in the neighbouring odd-mass nuclei. It is of particular interesting that the new band exhibits a phenomenon of low-spin signature inversion, providing a new situation for theoretical investigations.     

πg9/2(⊕)vh11/2 doublet bands in A～100 mass region

Using the model with one particle and one hole coupled with a triaxial rotor, the πg(-1)(9/2)(⊕)vh11/2 doublet bands in the A ～ 100 mass region are studied, and compared with the πh11/2(⊕)vh(-1)(11/2) doublet bands.It is found that the calculated results for the configuration of πg(-1)(9/2)(⊕)vh11/2 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.     

Study of the νi13/2－1 band in 189Pt

High-spin levels of ^189Pt have been studied with the in-beam T-spectroscopy method via the ^176Yb（^18O,5n） reaction at the beam energies of 88 and 95 MeV. The previously known ＂vi-1 13/2 band has been confirmed, and its unfavored signature branch extended up to the 31/2^＋ state. Within the framework of the triaxial particle-rotor model, the vi-1 13/2 band is suggested to be associated with the 11/2[615] configuration, and to have triaxial deformation.     

Nuclear Current and Magnetic Rotation

The magnetic rotational bands based on the configuration πh11/2^2 vh11/2^-2 in ^142Gd are investigated with the newly developed tilted axis cranking relativistic mean field （RMF） theory with and without nuclear current. The effect of the nuclear current is discussed by comparing the total Routhians, single particle levels, electromagnetic transition probabilities B（M1） and B（E2） in self-consistent tilted axis cranking RMF caIculation with those obtained without the nuclear current. The nuclear currents are found to play an important role in the magnetic rotation of nuclei.     

Collective Band Structures and Identification of One-Phonon and Two-Phonon γ-Vibrational Bands in 109Tc

The high spin states of the neutron-rich 109Tc nucleus are reinvestigated by observing prompt γ-rays from the spontaneous fission of 252 Cf. The previously known yrast band based on the 7/2＋ state is updated. A side band built on the 11/2＋ state is expanded and a new band based on the 15/2＋ state is identified. Band crossing in the yrast band occurs around fω≈ 0.36 MeV. This band crossing is associated with the alignment of two h11/2 neutrons according to the cranked shell model calculations. The band based on the 11/2＋ state is proposed as a candidate for the one-phonon γ-vibrational band, and the band built on the 15/2＋ state is proposed as a candidate for the two-phonon γ-vibrational band. Other characteristics for the observed bands are discussed.     

Reinvestigation of Collective Bands in 107Tc

The high spin states of a neutron-rich ^107 Tc nucleus are reinvestigated by observing prompt γ-rays from the spontaneous fission of ^252 Cf. The previous level scheme is updated. A collective band based on the π5/2- [303] orbital is confirmed and extended. Inconsistencies in the configuration assignments for a type of positive parity bands of odd-A 105,107,109 Tc in the previous reports are clarified according to the g factor calculations. A new band based on the 1499.5 keV level in ^107Tc is proposed as a two-phonon γ-vibrational band.     

New Physics Effects on Rare Decays Bu^＋ → π^＋e^＋e^-, ρ^＋e^＋e^- in a Top Quark Two-Higgs-Doublet Model

Using the form factors from light-cone sum rules, we study the branching ratios and forward-backward asymmetries （FBAs） of the exclusive decays Bu^＋→π^＋e^＋e^- and Bu^＋ →ρ^＋e^＋e^- （e= e,μ） in the standard model （SM） and the top quark two-Higgs-doublet model （T2HDM）. From the numerical results, we find that the new physics contributions cannot provide very large enhancement to the branching ratios and the theoretical predictions are in good agreement with the SM ones. The T2HDM effects on FBAs of these decays are small. Precision measurements of the dilepton invariant mass distributions, especially in the lower dilepton mass region, and the FBAs in the decays Bu^＋ → π^＋ （ρ^＋ ）e^＋ e^- will greatly help in discriminating among the SM and the new physics models.     

101Pd晕线的结构演化

High-spin states in ^101Pd have been investigated experimentally via the ^76Ge（^28Si, ^3nγ）^101pd reaction. The previously known bands based on the d5/2 and h11/2 neutron orbitals have been extended to higher-spin states, and two new structures have been observed. Spin and parity were assigned to the levels on the basis of the experimental results of the angular distribution of y rays deexciting the oriented states. For the ground-state band, the E-COS （E-Gamma Over Spin） curve strongly suggests a structure transition from vibration to rotation while increasing spin.     

Observation of High-j Two-Quasiparticle Bands in Odd-Odd ^174Re

High spin states in ^174Re have been investigated via the ^152Sm （^27 Al, 5nγ） ^174Re reaction. Gamma-ray excitation functions, x-γ and γ-γ coincidences have been measured. Two rotational bands built on the πh9/2 × vi13/2 and πh11/2 × vi13/2 configurations have been identified and extended up to high-spin states. The relative spin and parity of the band levels have been unambiguously fixed due to observations of several inter-band transitions. Both the bands show the low-spin signature inversion, which is consistent with systematic expectations for the high-j two-quasiparticle bands in the A = 170 mass region.     

Experiment of constraining symmetry energy at supra-saturation density with π^-/π^＋ at HIRFL-CSR

The possibility of the experiment for constraining the symmetry energy Esym（ρ） at supra-densities via π^-/π^＋ probe on the external target experiment of phase I （ ETE（I） ） with part coverage at forward angle at HIRFL-CSR is studied for the first time by using the isospin and momentum dependent hadronic transport model IBUU04. Based on the transport simulation with Au＋Au collisions at 400 MeV/u, it is found that the differential π^-/π^＋ ratios are more sensitive to Esym（ρ） at forward angles in laboratory reference, compared with the total yield ratio widely proposed. The insufficient coverage at lower transverse momentum maintains the sensitivity of the dependence of π^-/π^＋ ratio on the Esym（ρ） at high density, indicating that the ETF （I） under construction in Lanzhou provides the possibility of performing the experiment for probing the asymmetric nuclear equation of state.     

Influence of Traxiality on the Signature Inversion in Odd-Odd Nuclei

The nature of signature inversion in the πg/2vh11/2 bands of odd-odd^98.102Rh nuclei is studied. Calculations are performed by using a triaxial rotor plus two-quasiparticle model and are compared with the experimentally observed signature inversions. The calculations reproduce well the observations and suggest that, in these bands, the signature inversion can be interpreted mainly as a competition between the Coriolis and the proton-neutron residual interactions in low K space. The triaxiality applied in the Hamiltonian enlarges the amplitudes of high spin signature zigzags at small triaxial deformation and might push the signature inversion point to higher spin at large triaxial deformation.     

Emission of Neutral Pions with High Transverse Momenta in A-A and p-p Collisions at Energies Available at the BNL Relativistic Heavy Ion Collider

Invariant neutral pion （π^0） yields in Au-Au and Cu-Cu collisions and invariant π^0 cross sections in p-p collisions are studied in the framework of a two-cylinder model. The considered distributions of neutral pions at the maximum energy of the relativistic heavy ion eollider （RFIIC） have a tail part in the region of high transverse momentum. A two-component distribution based upon the two-cylinder model is used to describe the experimental data of the PHENIX collaboration.     

Calculation of Energy Levels of Nucleus ^127I in the Particle-Triaxial-Rotor Model

Theoretical calculations have been performed for nucleus ^127I in the framework of the particle-triaxial-rotor model.The calculated results indicate that both the 5^ /2 and 7^ /2 bands are oblate deformed bands.Their comfigurations are associated with the πd5/2[402]5/2 and πg7/2[404]7/2 orbitals and the strong mixing between them.Meanwhile a possible explanation of the strong mixing is given.     

Quantum Fisher information and spin squeezing in one-axis twisting model

We investigate the dependence of the average parameter estimation precision （APEP）, which is defined by the quantum Fisher information, on the polar angle of the initial coherent spin state ｜θ0,φ0〉 in a one-axis twisting model. Jin et al. [New J. Phys. 11 （2009） 073049] found that the spin squeezing sensitively depends on the polar angle θ0 of the initial coherent spin state. We show explicitly that the APEP is robust to the initial polar angle θ0 in the vicinity of π/2 and a near- Heisenberg limit 2IN in quantum single-parameter estimation may still be achieved for states created with the nonlinear evolution of the nonideal coherent spin states θ0- π/2. Based on this model, we also consider the effects of the collective dephasing on spin squeezing and the APEE