Transition strengths of Gamow–Teller decay of Tz ±1 nuclei to N Z odd-odd nuclei have been calculated in a two-nucleon approximation for spherical and deformed nuclei. The results obtained for the ...latter are quite close to the values obtained by full-space shell-model calculations and to the experiment.
A method is developed to derive simple relations among the reduced matrix elements of the quadrupole operator between low-lying collective states. As an example, the fourth-order scalars of Q are ...considered. The accuracy and validity of the proposed relations is checked for the ECQF Hamiltonian of the IBM-1 in the whole parameter space of the Casten triangle. Furthermore these relations are successfully tested for low-lying collective states in nuclei for which all relevant data is available.
A method for lifetime determination via the description of the
γ-ray line shapes observed in coincidence measurements using the Doppler-shift attenuation method is proposed for the case where the ...gate is set on a transition which depopulates the level of interest. The method presented takes precisely into account the time-velocity correlations inherent to coincidence measurements. The new procedure is illustrated and checked by an application to simulated data.
A new method for the analysis of delayed-coincidence lifetime experiments is proposed following the approach of the Differential decay-curve method. Examples of application of the procedure using ...simulated and experimental data reveal its reliability for lifetimes in the nanosecond and sub-nanosecond range. The procedure is expected to improve the treatment of systematic errors and scarce data. Possible further expansions and practical aspects of the procedure are also discussed.
The M1 transitions between low-lying
T=1 and
T=0 states in deformed odd–odd
N=
Z nuclei are analyzed in the frames of the rotor-plus-particle model. Using the representation of an explicit coupling ...of angular momenta we show that strong coupling of the quasideuteron configurations to the axially deformed core results in a distribution of the total 0
+→1
+ strength among a few low-lying 1
+ states. Simple analytical formulae for B(M1) values are derived. The realization of the M1 sum rule for the low-lying 1
+,
T=0 states is indicated. The calculated B(M1) values are found to be in good agreement with experimental data and reveal specific features of collectivity in odd–odd
N=
Z nuclei.
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