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Interrelationship of Isospin and Angular Momentum

L. Zamick·A. Z. Mekjian·S. J. Lee
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Abstract

It is noted that the simple interaction in isospin variables $a (1/4 - t(i)\cdot t(j))$, in a single $j$ shell calculation, can also be written with angular momentum variables. For the configuration $(j^2) J_A$ for even $J_A$ the isospin is one; for odd $J_A$ it is zero. Hence the above interaction can also be written as $a (1 - (-1)^{J_A})/2$. For the I=0 state of an even-even Ti isotope with $n$ neutrons, the hamiltonian matrix element of this interaction is $\bra [J'J']_0 |H| [JJ]_0\ket/a = (n+1) δ_{JJ'} - (n+1) (j^n Jj|\} j^{n+1} j) (j^n J'j|\} j^{n+1} j)$. The eigenvalues of this interaction can be found by using the isospin form of the interaction. They are $(n+1)a$ for $T = |N-Z|/2$ and zero for $T = |N-Z|/2 + 2$. One can apply this to some extent to obtain the number of pairs of nucleons with given total angular momentum $J_A$ in a given Ti isotope.

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L. Zamick, A. Z. Mekjian, S. J. Lee. 2005-03-04. Interrelationship of Isospin and Angular Momentum. https://arxiv.org/abs/nucl-th/0402089

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