The interplay of single-particle and collective motions in the low-lying states of $$_\Lambda ^{21}$$ with quadrupole-octupole correlations

The beyond mean-field approach for low-lying hypernuclear states is extended by mixing the configurations associated with both single-particle and quadrupole-octupole collective excitations within generator coordinate method based on a covariant density functional theory. demonstrated in application to of $$_\Lambda ^{21}$$ , where Λ hyperon occupying first (Λs) second (Λp) lowest-energy are considered. results indicate that positive-parity dominated α + 12C Λs structure. In contrast, negative-parity strong admixture +16O structure Λp due inclusion octupole correlations. As result, become much lower than what expected from previous studies without mixing, electric multipole transition strengths significantly quenched.