Revealing new structures in odd–odd Mn nucleus

S. Basu; G. Mukherjee; S. Nandi; S. S. Nayak; S. Bhattacharyya; Soumik Bhattacharya; Shabir Dar; Sneha Das; S. Basak; D. Kumar; D. Paul; K. Banerjee; Pratap Roy; S. Manna; Samir Kundu; T. K. Rana; R. Pandey; S. Chatterjee; R. Raut; S. S. Ghugre; S. Samanta; R. Banik; A. Karmakar; S. Chattopadhyay; S. Das Gupta; P. Pallav; S. Rajbanshi; S. Ali; H. Pai

doi:10.1140/epja/s10050-023-01147-9

2024 Impact factor 2.8

Hadrons and Nuclei

Eur. Phys. J. A (2023) 59: 229
https://doi.org/10.1140/epja/s10050-023-01147-9

Regular Article – Experimental Physics

Revealing new structures in odd–odd $^{54}$ $^{54}$ Mn nucleus

S. Basu¹^,2, G. Mukherjee¹^,2^b, S. Nandi¹^,2^,12, S. S. Nayak¹^,2, S. Bhattacharyya¹^,2, Soumik Bhattacharya¹^,3, Shabir Dar¹^,2, Sneha Das¹^,2, S. Basak¹^,2, D. Kumar¹^,2, D. Paul¹^,2, K. Banerjee¹^,2, Pratap Roy¹^,2, S. Manna¹^,2, Samir Kundu¹^,2, T. K. Rana¹^,2, R. Pandey¹^,2, S. Chatterjee⁴, R. Raut⁴, S. S. Ghugre⁴, S. Samanta⁴^,13, R. Banik⁵, A. Karmakar²^,6, S. Chattopadhyay⁶, S. Das Gupta⁷, P. Pallav⁷^,8, S. Rajbanshi⁹, S. Ali¹⁰ and H. Pai⁶^,11

¹ Variable Energy Cyclotron Centre, 700064, Kolkata, India
² Homi Bhabha National Institute, Training School Complex, Anushaktinagar, 400094, Mumbai, India
³ Florida State University, Tallahassee, FL, USA
⁴ UGC-DAE CSR, Kolkata Centre, LB-8, Sector III, 700106, Bidhannagar, Kolkata, India
⁵ Institute of Engineering and Management, Saltlake Sector V, 700091, Kolkata, India
⁶ Saha Institute of Nuclear Physics, 1/AF Bidhannagar, 700064, Kolkata, India
⁷ Victoria Institution (College), 700009, Kolkata, India
⁸ Department of Physics, School of Basic and Applied Sciences, Adamas University, 700126, Kolkata, India
⁹ Department of Physics, Presidency University, 700073, Kolkata, India
¹⁰ Government General Degree College at Pedong, Kalimpong, India
¹¹ Extreme Light Infrastructure - Nuclear Physics, Horia Hulubei National Institute for R &D in Physics and Nuclear Engineering, 077125, Bucharest-Magurele, Romania
¹² Argonne National Laboratory, 9700 S Cass Ave, 60439, Lemont, IL, USA
¹³ University of Genoa, Genoa, Italy

^b gopal@vecc.gov.in

Received: 28 April 2023
Accepted: 5 October 2023
Published online: 16 October 2023

Abstract

The excited states of odd–odd $^{54}$ $^{54}$ Mn ( $Z = 25, N = 29$ $$Z=25, N=29$$ ) nucleus have been investigated using the fusion evaporation reaction $^{55}$ $^{55}$ Mn( $α$ $\alpha$ , $α$ $\alpha$ n) $^{54}$ $^{54}$ Mn at the beam energy of 34 MeV. A new and improved level scheme of $^{54}$ $^{54}$ Mn has been proposed in this work with the placement of 22 new $γ$ $\gamma$ -ray transitions. Spin and parity (J $^{π}$ $^\pi$ ) of most of the levels in the revised level scheme have been firmly assigned. The placement of some of the already known $γ$ $\gamma$ rays in the level scheme and J $^{π}$ $^\pi$ assignments of some of the levels reported earlier have also been revised. The new level scheme, which has been extended up to $\sim$ $\sim$ 6 MeV, provides new insight and interesting structural aspects of the generation of high angular momentum in this odd–odd Mn isotope with neutron number ( $N = 29$ $$N=29$$ ) just above the $N = 28$ $$N=28$$ shell gap. Three octupole-phonon-coupled negative parity states have been identified for the first time in this nucleus. E3 transitions have also been observed to decay from these states. Shell model calculations with two different interactions i.e. kb3gpn and gx1pn have been performed which well reproduced the low-lying, few-particle states but fail to reproduce the higher-lying multi-particle states. These higher-lying states have been understood as resulting from collective excitations. An oblate minimum obtained from the Total Routhian Surface calculations provides support to this conjecture.

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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.