11,173 research outputs found

    The Effect of Deformation on the Twist Mode

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    Using 12^{12}C as an example of a strongly deformed nucleus we calculate the strengths and energies in the asymptotic (oblate) deformed limit for the isovector twist mode operator [rY1l⃗]λ=2t+[rY^{1}\vec{l}]^{\lambda=2}t_{+} where l is the orbital angular momentum. We also consider the λ=1\lambda =1 case. For λ=0\lambda=0, the operator vanishes. Whereas in a ΔN=0\Delta N=0 Nilsson model the summed strength is independent of the relative P3/2_{3/2} and P1/2_{1/2} occupancy when we allow for different frequencies ωi\omega_{i} in the x, y, and z directions there is a weak dependency on deformation.Comment: 9 page

    Degeneracies when T=0 Two Body Interacting Matrix Elements are Set Equal to Zero : Talmi's method of calculating coefficients of fractional parentage to states forbidden by the Pauli principle

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    In a previous work we studied the effects of setting all two body T=0 matrix elements to zero in shell model calculations for 43^{43}Ti (43^{43}Sc) and 44^{44}Ti. The results for 44^{44}Ti were surprisingly good despite the severity of this approximation. In this approximation degeneracies arose in the T=1/2 I=(1/2)1−({1/2})^-_1 and (13/2)1−({13/2})^-_1 states in 43^{43}Sc and the T=1/2 I=(13/2)2−I=({13/2})_2^-, (17/2)1−({17/2})^-_1, and (19/2)1−({19/2})_1^- in 43^{43}Sc. The T=0 32+3_2^+, 72+7_2^+, 91+9_1^+, and 101+10_1^+ states in 44^{44}Ti were degenerate as well. The degeneracies can be explained by certain 6j symbols and 9j symbols either vanishing or being equal as indeed they are. Previously we used Regge symmetries of 6j symbols to explain these degeneracies. In this work a simpler more physical method is used. This is Talmi's method of calculating coefficients of fractional parentage for identical particles to states which are forbidden by the Pauli principle. This is done for both one particle cfp to handle 6j symbols and two particle cfp to handle 9j symbols. The states can be classified by the dual quantum numbers (Jπ,JνJ_{\pi},J_{\nu})

    The Productivity Impact of Skills in English Manufacturing, 2001: Evidence from Plant-Level Matched Data

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    Microeconomic analyses of productivity for the UK have generally not been able to control for the quality of the labour input, primarily due to data availability, and yet the supply of suitably skilled labour is thought to be a major contributing factor to productivity levels. This paper combines the Annual Respondents Database with the Employers’ Skills Survey for 2001, which allows for a more detailed analysis of the role of skills in determining plant level productivity. Using an augmented Cobb-Douglas production function, the analysis shows that plants experiencing skills shortages were generally less productive than those who did not perceive a skills gap, having controlled for industry and regional effects. In more detail, the analysis reveals some interesting results: the impact that skills gaps have on productivity vary by industry, and higher qualifications do not always result in higher productivity, although innovative plants are seen to be on average 5 per cent more productive, as a result of their more qualified workforce.

    Full major-shell calculation for states that were degenerate in a single-j-shell calculation

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    A full fp calculation is performed for states which were degenerate in a single-j-shell calculation in which isospin-zero two-body matrix elements were set to zero energy. Most of the splitting in a complete shell calculation (but not all) comes from the T=0 part of the interaction.Comment: 5 pages, RevTeX4. Submitted to Physical Review

    Ratio of Isoscalar to Isovector Core Polarization for Magnetic Moments

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    In calculations of isoscalar magnetic moments of odd-odd N=Z nuclei it was found that for medium to heavy mass nuclei large scale shell model calculations yielded results which were very close to much simpler single j shell ones. To understand this we compare isoscalar and isovector configuration mixing in first order perturbation theory using a spin dependant delata interaction.The isoscalar corrections are much smalle
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