Transitions.

Dipion transitions of the subthreshold bottomonium levels Υ(nS) → Υ(n ′ S)ππ with n > n ′ , n = 2, 3, 4, n ′ = 1, 2 are studied in the framework of the chiral decay Lagrangian, derived earlier. The channels B ¯ B, B ¯ B * + c.c, B * ¯ B * are considered in the intermediate state and realistic wave functions of Υ(nS), B and B * are used in the overlap matrix elements. Imposing the Adler zero requirement on the transition matrix element , one obtains 2d and 1d dipion spectra in reasonable agreement with experiment.