Regular Article - Experimental Physics
High-spin states of At: isomeric states and shears band structure
Department of Physics, Raiganj Surendranath Mahavidyalaya, 733134, Raiganj, West Bengal, India
2 Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, I/AF Bidhan Nagar, 700064, Kolkata, India
3 KEK, Tsukuba, Japan
4 Tata Institute of Fundamental Research, 400005, Mumbai, India
5 Mody University of Science and Technology, 332311, Sikar, Rajasthan, India
6 Indian Institute of Engineering Science and Technology, 711103, Shibpur, Howrah, India
7 Indian Institute of Technology (Banaras Hindu University), 221005, Varanasi, India
8 TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada
Accepted: 5 August 2022
Published online: 31 August 2022
High-spin states of neutron-deficient trans-lead nucleus were populated up to excitation through the fusion evaporation reaction. Decay of the associated levels through prompt and delayed -ray emissions were studied to evaluate the underlying nuclear structure. The level scheme, which was partly known, was extended further. An isomeric level with observed mean lifetime , was established from our measurements. Attempts were made to interpret the excited states based on multi quasiparticle and hole structures involving , , and shell model states, along with moderate core excitation. Magnetic dipole band structure over the spin parity range: – was confirmed and evaluated in more detail, including the missing cross-over E2 transitions. Band-crossing along the shears band was observed and compared with the evidence of similar phenomena in the neighbouring , isotones and the isotope. Based on comparison of the measured B(M1)/B(E2) values for transitions along the band with the semiclassical model based estimates, the shears band of was established along with the level scheme.
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