Five-body structure of double $\Lambda$ hypernuclei

Recently, in KEK-E373 experiment, new double $\Lambda$ hypernucleus, 'hida' event, $^{11}_{\Lambda \Lambda}$Be was reported. This observation is important to get information on $\Lambda \Lambda$ interaction. For study of stucture of this $\Lambda$ hypernucleus, we perform five-body calculation of $\alpha +\alpha +n+\Lambda +\Lambda$ model. In this symposium, the level structure of this hypernucleus will be discussed.