Isoscalar giant monopole strength in \(^{58}\)Ni, \(^{90}\)Zr, \(^{120}\)Sn and \(^{208}\)Pb

• Published in: arXiv.org
• Main Authors: Bahini, A, Neveling, R, P von Neumann-Cosel, Carter, J, Usman, I T, Adsley, P, Botha, N, Brümmer, J W, Donaldson, L M, Jongile, S, Khumalo, T C, Latif, M B, Li, K C W, Mabika, P Z, Molema, P T, Moodley, C S, Olorunfunmi, S D, Papka, P, Pellegri, L, Rebeiro, B, Sideras-Haddad, E, Smit, F D, Triambak, S, Wiedeking, M, van Zyl, J J
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 22.02.2023
• Subjects: Alpha rays; Cyclotrons; Experiments; Forward scattering; Inelastic scattering; Lead; Monopoles; Nuclear physics; Nuclei; Physics - Nuclear Experiment; Research facilities; Scattering angle; Tin; Zirconium
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2212.00327

Inelastic \(\alpha\)-particle scattering at energies of a few hundred MeV and very-forward scattering angles including \(0^\circ\) has been established as a tool for the study of the isoscalar giant monopole (IS0) strength distributions in nuclei. An independent investigation of the IS0 strength in nuclei across a wide mass range was performed using the \(0^\circ\) facility at iThemba Laboratory for Accelerator Based Sciences (iThemba LABS), South Africa, to understand differences observed between IS0 strength distributions in previous experiments performed at the Texas A\&M University (TAMU) Cyclotron Institute, USA and the Research Center for Nuclear Physics (RCNP), Japan. The isoscalar giant monopole resonance (ISGMR) was excited in \(^{58}\)Ni, \(^{90}\)Zr, \(^{120}\)Sn and \(^{208}\)Pb using \(\alpha\)-particle inelastic scattering with \(196\) MeV \(\alpha\) beam and scattering angles \(\theta_{\text{Lab}} = 0^\circ\) and \(4^\circ\). The K\(600\) magnetic spectrometer at iThemba LABS was used to detect and momentum analyze the inelastically scattered \(\alpha\) particles. The IS0 strength distributions in the nuclei studied were deduced with the difference-of-spectra (DoS) technique including a correction factor for the \(4^\circ\) data based on the decomposition of \(L > 0\) cross sections in previous experiments. IS0 strength distributions for \(^{58}\)Ni, \(^{90}\)Zr, \(^{120}\)Sn and \(^{208}\)Pb are extracted in the excitation-energy region \(E_{\rm x} = 9 - 25\) MeV.Using correction factors extracted from the RCNP experiments, there is a fair agreement with their published IS0 results. Good agreement for IS0 strength in \(^{58}\)Ni is also obtained with correction factors deduced from the TAMU results, while marked differences are found for \(^{90}\)Zr and \(^{208}\)Pb.