Decay characteristics of 0 2 + and 0 3 + states in112Cd and114Cd

Absolute rates ofE0 andE2 transitions depopulating 0 ₂ ⁺ and 0 ₃ ⁺ states in¹¹²Cd and¹¹⁴Cd have been determined using conversion-electron andγ-ray spectroscopy, and double Coulomb excitation. The collectivity of these states is established and discussed.     

Decay of 0 2 + states in88,92,94Zr andE0 systematics of Zr isotopes

Branching ratios ofE0 andE2 transitions depopulating the 0 ₂ ⁺ states of^{88, 92, 94}Zr have been determined using conversion-electron and γ-ray spectroscopy. Two different lifetime-measurement methods were applied in the remeasurement of the half-lives of the 0 ₂ ⁺ states in^{92, 94}Zr, yielding consistent results ofT _1/2(0 ₂ ⁺ ,⁹²Zr)=85(15) ps andT _1/2(0 ₂ ⁺ ,⁹⁴Zr)=280(40) ps. The monopole strengths extracted areρ ²(⁹²Zr)=8.4(17) ×10^?3 andρ ²(⁹⁴Zr)=11.9(20)×10^?3. The proton configurations of the 0 ₂ ⁺ states are discussed in view of these values and proton transfer data.     

Calculation of the properties of quadrupole vibrational states for shape isomers

Properties of the quadrupole vibrational β and γ states are studied for the spontaneously fissioning even-even shape isomers. Calculations are done in the quasiboson approximation with the use of the single particle Nilsson potential.     

Nuclear structure of low-lying 0+ states in Ge and Se isotopes

The following meanlives of levels in⁷²Se have been measured using the recoildistance Doppler-shift method:Τ(2⁺, 862 keV)=3.1±0.6 ps,Τ(2⁺′, 1317 keV)=12.5±2.6 ps,Τ(4⁺, 1638 keV)=1.2±0.3 ps andΤ(6⁺, 2469 keV)≦0.7 ps. These meanlives yield sixB(E2) values which are discussed together with the known data of the depopulation of the excited 0⁺′ state at 937 keV. Systematics of 0⁺′ states in the mass region 70?A?100 show that the low excitation energy of the 0⁺′ states is correlated with subshell closures. This suggests that the previous interpretation of the 0⁺′ state in⁷²Se as a rotational band head is questionable.     

Enhanced density of low-lying 0+ states: A corroboration of shape phase transitional behavior

A (p, t) study of eight nuclei in the rare earth region identified 96 0⁺ states (67 new). Their density at low energy is used to corroborate a fundamental property of quantum phase transitional behavior and to provide a new signature of nuclei near the critical point.     

Boson structure of the low-lying states of 1p0f-shell nuclei

The boson structure of the low-lying states of A = 44 and A = 60 nuclei is investigated by studying the eigenvalue problem of the boson image of the shell-model Hamiltonian in spaces expanded in terms of bosons corresponding to the collective nuclear pairs allowed in the 1p0f shell. The text was submitted by the authors in English.     

Double resonance spectra of predissociating states as a probe for continuum structure in a strong electro-magnetic field

The absorption spectrum for a probe field from a bound state to a predissociative resonance is calculated in presence of a second field coupling the same resonance to another bound state. The spectra, which strongly depend on the intensity of the second field, exhibit new features, which are analysed and discussed.     

Nondynamical structure of inelastic scattering or reactions of spin type 1+0 → 1+0

The nondynamicalM-matrix formalism is applied to the inelastic scattering or to reactions of spin type 1+0→1+0. It is shown how the parameters of theM-matrix, which contain all dynamical information, can be determined by experiments. There are twoM-matricesM ₊ andM _?, one (M ₊) for the case in which the product of the intrinsic parities of all interacting particles is +1 and one (M _?) where this product is ?1. In the case ofM _? one can avoid triple scattering parameters to determine fully theM _?-matrix.     

Decay of the mixed states

We study the classical escape from local minima for 2d multi-well Hamiltonian systems, realizing the mixed state. We show that escape from such local minima has a diversity of principally new features, representing an interesting topic for conceptual understanding of chaotic dynamics and applications.     

Excited states of light hadrons as a probe of QCD

The dynamics of light hadrons being highly sensitive to the confinement force, it is suggested that a careful study of the excitation pattern of light hadrons might be the most effective way to unravel the mechanisms of confinement dynamics. As a case study, it is shown how the recently confirmed doubling of the ρ' (1600) (which in potential models relies on an accidental level degeneracy) finds a simple interpretation in the framework of a string picture for flux-tube dynamics.     

关于D0→π－l+νl衰变过程的研究

用光锥QCD求和规则研究D⁰→π^－l⁺ν_l衰变过程, 首先计算D→π跃迁形状因子, 通过构造新的关联函数, 消除了twist-3波函数的不确定性给计算结果所带来的影响, 从而使计算结果更加精确. 计算得到的分支比与最近的实验数据相一致.     

The large probability of the 0+ ground states

We investigate the dominance of 0⁺ states as the lowest states in shell model calculations with random two-body interactions in a single j-shell. We have found an explanation of the large probability of the 0⁺ ground state. Received: 1 May 2001 / Accepted: 4 December 2001     

Rotational coupling of the β 1 and E 0+ ion-pair states of lodine bromide

The $\text{E(}\text{Ω}\text{= 0}{}^{\mathrm{+}}\text{)}$ and $\text{β(}\text{Ω}\text{= 1)}$ ion-pair states of IBr are coupled by an electronic Coriolis interaction. A nonlinear, least-squares fit of term values for both states yields a set of potential and rotational constants purged of the effects of this interaction. The magnitude of the coupling constant, |W_1,0| = 2.41 cm^?1, is 98% of the value predicted for pure precession. Principal constants of the previously unreported β state of I⁷⁹Br are T_e = 39507.76, ω_e = 122.09, ω_eχ_e = 0.2546, B_e = 0.02937, and α_e = 8.2 × 10^?4cm^?1.     

Description of collective 0+ states in the Tamm-Dancoff approximation

The Tamm-Dancoff approximation is applied to the correlated FBCS ground state. This procedure proves very successful for medium and heavy nuclei both superconducting and non-superconducting. The accuracy of the Tamm-Dancoff approximation is equivalent to forth order boson methods. Calculations have been performed for the nickel isotopes, for Sn¹¹⁴ and for the lead isotopes. The connection with the broken-pair approximation is established. The influence of a nucleus withN?2 nucleons on the spectrum of a nucleus withN particles is exhibited.     

Positronium as a probe of sorption states of vapor molecules in polymers

Positron lifetime measurements were performed for two different polymers (low density polyethylene and a polyimide 6FDA-TMPD) during sorption of various vapors (n-hexane, cyclohexane, benzene, acrylic acid, methyl acrylate). The vapor sorption affected the long-lived component (ortho-positronium component) in a systematic way regardless of the kind of vapor, i.e. for the polyethylene both the lifetime and the intensity of the long-lived component were enhanced, while for the polyimide they were decreased significantly. These different effects are interpreted in terms of the different aggregation states, i.e. rubbery for the polyethylene and glassy for the polyimide.     

Teleportation fidelity as a probe of sub-Planck phase-space structure

We investigate the connection between sub-Planck structure in the Wigner function and the output fidelity of continuous-variable teleportation protocols. When the teleporting parties share a two-mode squeezed state as an entangled resource, high fidelity in the output state requires a squeezing large enough that the smallest sub-Planck structures in an input pure state are teleported faithfully. We formulate this relationship, which leads to an explicit relation between the fine-scale structure in the Wigner function and large-scale extent of the Wigner function, and we treat specific examples, including coherent, number, and random states and states produced by chaotic dynamics. We generalize the pure-state results to teleportation of mixed states.