Backbending in 180W: a t-band crossing

Abstract A Fermi-aligned ( i 13 2 ) 2 rotational band, with K ≈8, has been observed in an even-even nucleus, 180 W. Its structure corresponds to a t-band in the tilted-cranking representation. It crosses the ground-state band at I = 16 h , giving rise to backbending in the yrast sequence. Contrary to the usual interpretation, backbending in this case is not caused by the s-band. Comparison is made with other possible t-band crossings in the A ≈ 180 region.