Nuclear Spin Orientation Created in Heavy Ion Collisions and the Sign of the Q Moment of 13B

Abstract

The momentum dependences of the nuclear spin polarization P and alignment A of 13B(\(I^{\pi } = 3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2^{ + } \), T1/2 = 17.36 ms) produced in the 100A MeV 15N + Be collisions have been measured by detecting β-ray asymmetry. Because both the P and A were significantly smaller than the prediction from a simple kinematical model, some relaxation mechanisms must be take into account. Comparing the signs of the observed alignment of 12B, the sign of the quadrupole coupling constant eqQ of 13B in TiO2 was determined to be positive.