Properties of the tensor correlation in neutron halo nuclei

We investigate the tensor and pairing correlations in 11Li with the extended 9Li+n+n model. A special attention was paid for 9Li, where the tensor correlation prefers a shrunk spatial extension using the shell model type wave function. In 11Li, the tensor and pairing correlations in 9Li are Pauli-blocked by additional two neutrons, which make the 2(1s) and 2(0p) configurations close to each other and hence activate the pairing interaction to mix equal amount of two configurations and develop the halo structure in 11Li.