Eur. Phys. J. A (2025) 61: 148
https://doi.org/10.1140/epja/s10050-025-01619-0

Regular Article - Experimental Physics

Spectroscopic investigation of $_{}^{54}$Cr via $\alpha$-transfer reaction

¹ Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, 400005, Mumbai, India
² Department of Physics and Astronomy, University of Notre Dame, 46556, Notre Dame, IN, USA
³ Department of Physics, Manipal Institute of Technology, Manipal Academy of Higher Education, 576104, Manipal, India
⁴ Istituto Nazionale di Fisica Nucleare, Sezione di Milano, 20133, Milano, Italy
⁵ Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, 700064, Kolkata, India

^a palit@tifr.res.in

Received: 22 February 2025
Accepted: 14 June 2025
Published online: 26 June 2025

Abstract

Low-lying states in $_{}^{54}$Cr have been investigated via the $\alpha$-transfer reaction $_{}^{50}$Ti($_{}^7$Li,t) at a bombarding energy of 20 MeV. The exclusive $\alpha$-transfer channel is separated from other reaction channels through the appropriate energy gate on the complementary particle, triton. Levels of $_{}^{54}$Cr populated exclusively by the $\alpha$-transfer process could be identified up to $\approx$ 5 MeV excitation energy and angular momentum up to ${(8)}^{+}$, by identifying the corresponding known $\gamma$-rays. These include multiple low-lying non-yrast 2$_{}^{+}$ and 4$_{}^{+}$ states, which would otherwise be unfavorable via fusion evaporation reactions. The feeding-subtracted $\gamma$-ray yields have been extracted to estimate the population of various excited states through the transfer process. The measured integrated transfer cross sections for all the observed yrast and non-yrast states are compared with Coupled Channels calculations using fresco to extract the $\alpha$+$_{}^{50}$Ti core spectroscopic factors. For the yrast states, a higher $\alpha$+core overlap is seen for the $2^{+}$ and $4^{+}$ states, while it is seen to be less favorable for the $6^{+}$ and ${(8)}^{+}$ states when $\alpha$-transfer is considered to occur predominantly as a direct one-step process to the $_{}^{50}$Ti core ground state. The yrast $2^{+}$, and $4^{+}$ states are predominantly populated by single-step transfer, while for the states with spin $\ge$ 5, the possibility of core excitation followed by $\alpha$-transfer shows a larger $\alpha$-core overlap. For the non-yrast $0^{+}$, $2^{+}$, and $4^{+}$ states, single-step transfer shows moderate to small $\alpha$-core overlap. No higher spin non-yrast states are observed.