Collective states and shape competition in ¹²⁶Te

High-spin states in ¹²⁶Te have been investigated by using in-beam γ ray spectroscopy with the ¹²⁴Sn(⁷Li, 1p4n)¹²⁶Te reaction at a beam energy of 48 MeV. The previously known level scheme has been enriched, and a new negative-parity sequence has been established. The yrast positive-parity band shows a shape change between triaxial shape and collective oblate shape as a function of spin. In particular, three competitive minima appear in the potential energy surface for the I^π = 8⁺ states, with one aligned state at γ = -120 ° and two triaxial states at γ 30 ° and -45 °, respectively. The signature splitting behavior of the negative-parity band is discussed.The shape change with increasing angular momentum and the signature splitting can be interpreted well in terms of the Cranked Nilsson-Strutinsky-Bogoliubov and Cranked Nilsson-Strutinsky model calculations. (authors)