Search

We evaluate the partial decay widths for the semileptonic ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{l}l{\mathrm{\ensuremath{\Lambda}}}_{c}(2595)$ and ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{l}l{\mathrm{\ensuremath{\Lambda}}}_{c}(2625)$ decays from the perspective that these two ${\mathrm{\ensuremath{\Lambda}}}_{c}^{*}$ resonances are dynamically generated from the $DN$ and ${D}^{*}N$ interaction with coupled channels. We find that the ratio of the rates obtained for these two reactions is compatible with present experimental data and is very sensitive to the ${D}^{*}N$ coupling, which becomes essential to obtain agreement with experiment. Together with the results obtained for the ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\mathrm{\ensuremath{\Lambda}}}_{c}^{*}$ reactions, it gives strong support to the molecular picture of the two ${\mathrm{\ensuremath{\Lambda}}}_{c}^{*}$ resonances and the important role of the ${D}^{*}N$ component neglected in prior studies of the ${\mathrm{\ensuremath{\Lambda}}}_{c}(2595)$ from the molecular perspective.

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.

Levels in the neutron-rich 109Ru have been studied by observing the prompt γ-rays following the spontaneous fission fragments of 252Cf. The ground state band and the negative parity bands have been confirmed and extended. A positive parity band with the band head level at 332.5 keV is newly identified and suggested as a single-neutron excitation band built on the 7/2+[404] Nilsson orbital. Some structural characteristics of these bands are discussed.

To study the generation mechanism and propagation rule of Rayleigh surface waves, and to accelerate the corresponding development of data processing method, the paper applies the finite-difference method with staggered grids to simulate full-wave-fields, including both Rayleigh surface wave and body waves, in shallow isotropic media based on elastic wave equations. Meanwhile, a variable coefficient absorbing boundary condition, which makes the treatment of boundary condition more simplified and more effective, is developed. Furthermore, a method to process angle points is also proposed. Simulations have been done for continuous and stratified media which are common in the field of engineering survey, and more realistic seismograms are obtained. According to the synthetic records, the condition of Rayleigh surface wave excitation is investigated, and the influence of the depth of epicenter on the energy of surface wave is discussed.

Levels in the neutron-rich 105Mo nucleus have been investigated by observing prompt γ-rays following the spontaneous fission fragments of 252Cf with the Gammasphere detector array. The yrast band has been confirmed and updated. The other two collective bands with the band head levels at 870.5 and 1534.6 keV are newly observed, and they are suggested as the candidates for one-phonon K = 9/2 and two-phonon K = 13/2 double γ-vibrational bands, respectively. Systematic characteristics of these bands have been discussed.

Levels in the neutron-rich 112Ru nucleus have been investigated by observing prompt gamma-rays from the spontaneous fission of 252Cf with the Gammasphere detector array. The ground-state band and the one-phonon γ-vibrational band have been confirmed and extended with spin up to 16 and 15 , respectively. The other two side bands, one proposed as two-phonon γ-vibrational band and the other proposed as two-quasiparticle band, have been observed for the first time. The total-Routhian-surface calculations show that rotational 112Ru nucleus has triaxial deformation with parameters β2~0.27 and γ = −29°. The observed band crossing in the yrast band is due to the alignment of a pair of h11/2 neutrons according to the cranked shell model calculations. The possible configuration for the quasiparticle band has also been discussed.

The reflection asymmetric shell model has been applied to describe the octupole deformed bands in neutron-rich even-even 142Ba and odd-N 145Ba nuclei. The alternating parity bands of 142Ba and the simplex s = −i bands of 145Ba are calculated and compared with the available experimental data. The calculated results are in good agreement with the experimental data. The spin and parity assignments of ground-state of 145Ba are discussed. The results show that the present work is a useful attempt to further explore the nuclear reflection asymmetry in neutron rich region.

Rotational bands in neutron-rich 98Sr nucleus have been investigated by measuring high-fold prompt γ-ray coincidence events of the spontaneous fission of 252Cf with the Gammasphere detector array. A deformed K = 3 band built on the 1838 keV level has been confirmed and extended. Another deformed K = 6 band based on the 2535 keV level has been established. Both the bands originate most probably from the ν9/2[404]⊗ν3/2[411] two-quasiparticle configuration with Ω = |Ω1−Ω2| and Ω = |Ω1+Ω2|, respectively. Based on the delay-coincidence measurements, the half-lives for the K = 3 and K = 6 band head levels have been obtained to be 13±3 ns and 4.5±1.0 ns, respectively.

High spin states in the neutron-rich 108Ru nucleus have been studied through measuring prompt γ-ray coincidences following the spontaneous fission of 252Cf with the Gammasphere detector array. The yrast band has been confirmed. The one-phonon γ-vibrational band and the two-quasiparticle band based on the 5− level have been extended up to 13+ and 15−, respectively. In addition, two levels at 1644.8 keV and 1826.5 keV excitation energies are newly identified and proposed to be the members of a two-phonon γ-vibrational band. It is shown that the 108Ru nucleus has triaxial deformation with parameters β2~0.29 and γ = −22 degrees from the total Routhian surface calculations. The observed band crossing in the yrast band is due to the alignment of a pair of h11/2 neutrons according to the cranked shell model calculations. The possible configuration for the two-quasiparticle band has been discussed.

High spin states in neutron-rich 110Ru nucleus have been investigated by measuring high-fold prompt γ-ray coincidence events of the spontaneous fission of 252Cf with the Gammasphere detector array. The ground-state band and the γ-vibrational band have been confirmed and extended with spin up to 18 and 13 , respectively. The other three side bands, two proposed as two-quasiparticle bands and one proposed as a four-quasiparticle band, have been observed for the first time. The possible configurations for the quasi-particle bands are discussed. The cranked shell model calculations show that 110Ru nucleus may have oblate triaxial deformation with parameters β2 = -0.30 and γ = 24°, and the band crossing in the yrast band is due to the alignment of a pair of h11/2 neutrons.

The quantum nature of bulk ensemble NAIR quantum computing - the center of recent heated debate, is addressed. Concepts of the mixed state and entanglement arc examined, and the data in a two-qubit liquid NAIR quantum computation are analyzed. The main points in this paper are: i) Density matrix describes the "state" of an average particle in an ensemble. It does not describe the state of an individual particle in an ensemble; ii) Entanglement is a property of the wave function of a microscopic particle (such as a molecule in a liquid NAIR sample), and separability of the density matrix cannot be used to measure the entanglement of mixed ensemble; iii) The state evolution in bulk-ensemble NAIR quantum computation is quantum-mechanical; iv) The coefficient before the effective pure state density matrix, c, is a measure of the simultaneity of the molecules in an ensemble. It reflects the intensity of the NAIR signal and has no significance in quantifying the entanglement in the bulk ensemble NAIR system. The decomposition of the density matrix into product states is only an indication that the ensemble can be prepared by an ensemble with the particles unentangled. We conclude that effective-pure-state NAIR quantum computation is genuine, not just classical simulations.

Excitation energies and electromagnetic transition strengths in even-even 96-108Mo nuclei have been described systematically by using the proton-neutron interacting boson model (IBM-2). It appears that the properties of low-lying levels in these isotopes, for which the comparison between experiment and theory is possible, can be satisfactorily described by the IBM-2 model, provided proper account is taken of the presence at low energy of states having a mixed-symmetry character. It seems possible to identify, in each isotope, a few states having such a character, the lowest ones being either or levels. It is found that these nuclei are in the transition from U(5) to SU(3).

The rotational bands up to a spin of 16 in the neutron-rich 106Mo nucleus have been investigated by measuring high-fold prompt γ-ray coincidence events following spontaneous fission of 252Cf with a Gammasphere detector array. The ground-state band, the one-phonon and two-phonon γ-vibrational bands, as well as a quasi-particle band have been confirmed and expanded. The other four collective rotational bands, three proposed as two-quasi-particle bands and one proposed as a β-vibrational band, have been newly observed. The characteristics of these collective bands and the possible configurations for the quasi-particle bands are discussed.

The high spin states in neutron-rich 104Nb have been investigated from study of prompt γ-rays in spontaneous fission of 252Cf with the Gammasphere detector array. A new rotational band has been identified for the first time. This band is proposed as a semi-decoupled band based on the configuration γ5/2−[303]Λν1/2−[541].

The high spin states of the neutron-rich odd-odd 106Tc nucleus have been reinvestigated by observing prompt γ-rays from the spontaneous fission of 252Cf. A previously known collective band is confirmed and expanded, and a new collective band is newly identified. Several levels in previous report in 106Tc are reexamined and they belong to the members of a band in 107Tc. The total Routhian surface (TRS) calculations show that the 106Tc has triaxial shape. The spins and parities as well as the configurations for these bands have been tentatively assigned according to the analysis of the angular momentum alignments.

High spin states in A ~ 110 neutron-rich 106Mo, 110Ru and 112Ru nuclei have been reinvestigated by measuring the prompt γ-rays from the spontaneous fission of 252Cf. Two similar sets of bands are observed to high spins in each of three nuclei. Through analyzing of characters of the band structures, the chiral doublet bands are suggested in 106Mo, 110Ru and 112Ru.

High-spin states in 139Nd nucleus have been reinvestigated with the reaction 128Te (16O, 5n) at a beam energy of 90 MeV. The level scheme has been expanded with spin up to 47/2 ħ. At the low spin states, the yrast collective structure built on the vh11/2−1 multiplet shows a transitional shape with γ ≈ 32° according to calculations of the triaxial rotor-plus-particle model. Three collective oblate bands with γ ~ −60° at the high spin states were identified for the first time. A band crossing is observed around ħω ~0.4 MeV in one oblate band based on the 25/2− level.

High-spin states in neutron-rich 102Mo nucleus have been studied by measuring the prompt γ-rays in the spontaneous fission of 252Cf. The previous level scheme has been updated and some new levels and transitions are identified. The one-phonon γ-band is expanded and a band head level of the two-phonon γ-band is proposed. The systematic characteristics of yrast bands, one-phonon γ-bands, two-phonon γ-bands and quasi-particle bands in 102Mo, 104Mo and 106Mo are discussed.

It is pointed out that the difficulty in boson models in explaining the large B(E2) experimental data is not due to the lack of collectivity in boson model wavefunction. This long standing problem of reduction in collectivity of wavefunction in boson models can be solved by choosing an appropriate E2 transition operator in the SU(3) limit of the sdg-interacting boson model. The ratio B(E2, L + 2 → L) / B(E2, 2 → 0) can be almost any large number.

Level schemes for the neutron-rich 140,143Ba nuclei have been determined by study of prompt γ-rays in spontaneous fission of 252Cf. The level pattern and enhanced E1 transitions between π = + and π = - bands show reflection asymmetric shapes with simplex quantum number s = +1 in 140Ba and s = ±i in 143Ba, respectively. The octupole deformation stability with spin variation has been discussed.

By analysing the known low-lying levels and the E2 transition rates, it is shown that the empirical scheme of 114Cd is in good overall agreement with the predictions of the transitional dynamical symmetry E(5) proposed by Iachello [Phys. Rev. Lett. 85 (2000) 3580]. This suggests that 114Cd may be better described by an E(5) nucleus than a U(5) nucleus as known before.

The lifetime measurements of the high-spin states in the yrast band of 130Ce have been performed using the Doppler shift attenuation method in conjunction with the reaction 116Sn(16O,2n)130Ce at a projectile energy of 73 MeV. The reduced transition probabilities B(E2) deduced from these measurements show a great reduction in the vicinity of the backbending region. The previously reported anomalously high B(E2) value was not observed in the present experiment. This result is in agreement with theoretical prediction based on a realistic nucleon-nucleon interaction.

High-spin states in 122Ba have been investigated in the 107Ag(19F, 4n) reaction by in-beam γ-ray spectroscopic methods. The ground-state band has been observed with spin up to 20 and a negative-parity band is identified with spin state up to 19. A band-crossing in the yrast band is observed at a rotational frequency of ω≈ 0.36 MeV and, in accordance with cranked shell model calculations, is interpreted as arising from the alignment of two h11/2 protons. Strong E1 transitions between the negative-parity and the yrast bands have been observed, which are proposed as possible evidence for octupole correlations.

Levels in the neutron-rich 104Mo nucleus have been investigated by observing prompt γ-rays from the spontaneous fission of 252Cf with the Gammasphere detector array. The ground-state band, the one-phone and the two-phone γ-vibrational bands as well as a quasiparticle band have been confirmed and expanded with spin up to 14. Other two side bands probably built on new quasiparticle states are identified. The possible configurations for the quasiparticle bands are discussed. Two of the quasiparticle bands show larger moments of inertia and may have pair-free characteristics. The levels of the ground-state band, the one-phonon γ-band and the two-phonon γ-band calculated from a general collective model are in close agreement with the experimental data. PACS: 21. 10. Re, 23. 20. Lv, 27. 60. +j, 25. 85. Ca

High spin states in 137Ce have been studied by using the heavy-ion induced reaction 124Sn(18O, 5n) carried out at China Institute of Atomic Energy. Partial level scheme with spin up to (43/2-), including a high spin collective rotational band observed for the first time, has been established. The collective band shows the properties similar to those oblate bands with ? ~ -60? in neighboring nuclei and probably originates from the five quasi-particle configuration ?s1/2 ? [?h11/2]2 ? ?g7/2 ? ?h11/2. The characteristics of this oblate band have been discussed.

High spin states in odd-odd98 Tc nuclei are studied by in-beam γ-ray spectroscopy with the 96Zr(6Li, 4n) fusion-evaporation reaction at a beam energy of 35 MeV. The previous level scheme is updated. A band based on 1090.7 keV is expanded, and another band based on 1920.6 keV is newly identified. The observed two negative parity bands in 98Tc are proposed to be a pair of chiral doublet bands with the configuration πg9/2 ⊗ νh11/2. The evidence supporting the assignment of the chiral doublet bands is discussed. Signature splitting and signature inversion are observed in the πg9/2 ⊗ νh11/2 band in 98Tc.

The high spin states of the neutron-rich 109Tc nucleus are reinvestigated by observing prompt γ-rays from the spontaneous fission of 252Cf. 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 ħω ≈ 0.36MeV. 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.

The high spin states of a neutron-rich 107Tc nucleus are reinvestigated by observing prompt γ-rays from the spontaneous fission of 252Cf. 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 105,107,109Tc 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.

We discuss some basic principles that should be followed when processing the satellite laser ranging (SLR) data in a general relativistic framework. Some existing problems in the various methods of relativistic correction of SLR data are analysed and reviewed, and our own views presented. We also demonstrate that processing SLR data in the solar system barycentric frame is equivalent to processing in the earth-centered frame within the present desired degree of accuracy.