arXiv:2006.00889v1 [nucl-th] 1 Jun 2020 June 2, 2020 1:1 WSPC/INSTRUCTION FILE Manuscript International Journal of Modern Physics E c  World Scientific Publishing Company Modification of tensor force in p -shell effective interaction Kanhaiya Jha * , Pawan Kumar, Shahariar Sarkar and P. K. Raina Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab, 140001, India Received Day Month Year Revised Day Month Year In many shell model interactions, the tensor force monopole matrix elements often re- tain systematic trends originating in the bare tensor force. However, in the present work, we find that Isospin T = 0 tensor force monopole matrix elements of p-shell effective interaction CK(8-16) do not share these systematic. We correct these discrepancies by modifying T = 0 tensor force two-body matrix elements (TBMEs) of CK(8-16) by the analytically calculated tensor force TBMEs. With some additional modification of single- particle energies and TBMEs, the revised effective interaction is named as CKN. The effective interaction CKN has been tested for the calculations of p-shell nuclei of normal parity states from various physics viewpoints such as excitation spectra, electromag- netic moments, and electromagnetic and Gamow-T eller (GT ) transitions. The obtained results are found to be satisfactory. Keywords : Shell model; effective interaction; spin-tensor decomposition; tensor force. PACS numbers: 1. Introduction The success of the nuclear shell model mainly depends on the employed effective two-nucleon interaction which is generally derived using bare NN interaction. 1–5 However, the effective interaction made this way is further adjusted empirically to incorporate the in-medium effect, and many-body force effect to successfully explain the nuclear structural properties. 5–8 For example, the interactions USD 9 and GXPF1 10 are derived jointly by ETBME+G hamiltonians. 2 The monopole 11, 12 modification of the effective interaction is one of the most extensively used empirical methods which significantly improve the description of experimental data. 13–17 In recent years, the importance of individual components of NN effective inter- action i.e., central, spin-orbit and tensor forces to the single-particle energy gaps and shell evolution in neutron-rich nuclei have been extensively explored. 15, 18–24 The tensor force of bare NN interaction in particular gains lot of interest due to its * E-mail: kanhaiya.jha@iitrpr.ac.in 1