Effects of Tensor Correlations on the Positive Parity States of the Even-Even Nuclei in the sd Shell

Effects of tensor correlations on the positive parity states of 20Ne nucleus are examined. Two-body nuclear matrix elements are obtained by the lowest order constrained variational technique with and without tensor correlations. The matrix elements calculated are used as input into the NUSHELL shell model code to calculate the energy spectrum of 20Ne nucleus with and without tensor correlations. We have found that the effects of tensor correlations is to open up the calculated energy spectrum and provide reasonable agreement with experiment, whereas the energy spectrum calculated without tensor correlations is compressed and provides significant disagreement with experimental data. This feature is consistent with our observations for nuclei in the range 18≤A≤40 The results presented here re-emphasize the strong evidence found in nuclear structure calculations that tensor correlations are very important in nuclei and their presence cannot be ignored.