Eur. Phys. J. A (2006) 28: 1-4
https://doi.org/10.1140/epja/i2005-10276-x

Letter

Identification of band structures in the ¹³⁷La nucleus

¹ Department of Physics, Tsinghua University, 100084, Beijing, PRC
² China Institute of Atomic Energy, 102413, Beijing, PRC

^* e-mail: liml03@mails.tsinghua.edu.cn

Received: 15 December 2005
Accepted: 25 April 2006
Published online: 29 May 2006

Abstract

High-spin states of ¹³⁷La have been investigated with the reaction ¹³⁰Te(¹¹B, 4n) at a beam energy of 50MeV. The level scheme of ¹³⁷La has been expanded with spin up to 33/2ℏ. Several new bands have been found in this nucleus. A band crossing in the band based on the 17/2^- level has been observed at a rotational frequency of ℏω ∼ 0.48MeV. From systematic comparison, this band crossing probably originates from the alignment of protons. One of the bands with strong M1 transitions is proposed as a collective oblate band ( γ ∼ -60^°).