Validity of scaling property and iso-centrifugal approximation in quasielastic barrier distribution: the first experimental verification

Rohan Biswas; S. Nath; J. Gehlot; Gonika Gonika; Chandra Kumar; A. Parihari; N. Madhavan; A. Vinayak; Amritraj Mahato; Shoaib Noor; Phurba Sherpa

doi:10.1140/epja/s10050-024-01380-w

2023 Impact factor 2.6

Hadrons and Nuclei

Open Access

Eur. Phys. J. A (2024) 60: 159
https://doi.org/10.1140/epja/s10050-024-01380-w

Letter

Validity of scaling property and iso-centrifugal approximation in quasielastic barrier distribution: the first experimental verification

Rohan Biswas¹^,6, S. Nath¹^b, J. Gehlot¹, Gonika¹, Chandra Kumar¹, A. Parihari²^,7, N. Madhavan¹, A. Vinayak³, Amritraj Mahato⁴, Shoaib Noor⁵ and Phurba Sherpa²

¹ Nuclear Physics Group, Inter-University Accelerator Centre, Aruna Asaf Ali Marg, 110067, New Delhi, India
² Department of Physics and Astrophysics, Delhi University, 110007, Delhi, India
³ Department of Physics, Karnatak University, 580003, Dharwad, India
⁴ Department of Physics, Central University of Jharkhand, 835205, Ranchi, India
⁵ School of Physics and Materials Science, Thapar Institute of Engineering and Technology, 147004, Patiala, India
⁶ Life Science Division, Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, OX11 0DE, Didcot, Oxfordshire, UK
⁷ Department of Physics, Rajdhani College, University of Delhi, Mahatma Gandhi Marg, Raja Garden, 110015, New Delhi, India

^b subir@iuac.res.in

Received: 11 March 2024
Accepted: 14 July 2024
Published online: 31 July 2024

Abstract

For the first time, we have simultaneously measured fusion and quasielastic excitation functions for an intermediate mass system for angular momentum, $ℓ \sim 0$ $\ell \sim 0$ using a recoil mass spectrometer. We have extracted barrier distributions using three different sets of data recorded simultaneously for the reaction $^{16}$ $^{16}$ O+ $^{142}$ $^{142}$ Ce: (a) fusion excitation function from measurement of evaporation residues at angle, $θ_{lab} = 0^{\circ}$ $\theta _{\text {lab}} = 0^{\circ }$ , (b) quasielastic excitation function at center of mass scattering angle, $θ_{c.m.} = π$ $\theta _{\text {c.m.}} = \pi$ via measurement of scattered target-like ions at $θ_{lab} = 0^{\circ}$ $\theta _{\text {lab}} = 0^{\circ }$ and (c) quasielastic excitation functions from measurement of scattered projectile-like ions at two large angles. We show that the four barrier distributions yield nearly identical results with a single peak. However, the centroids of the barriers extracted from quasielastic data at large angles are lower by $\sim 600$ $\sim 600$ keV compared to the same of the barriers extracted from fusion and quasielastic data for $ℓ \sim 0$ $\ell \sim 0$ . This is the first experimental verification of the validity of scaling property with respect to $ℓ$ $\ell$ and iso-centrifugal approximation in extracting fusion barrier distribution from quasielastic scattering. This work also points to the importance of extracting barrier distribution from quasielastic measurements at $θ_{c . m .} = π$ $\theta _{\mathrm {c.m.}} = \pi$ for systems for which measuring fusion excitation function with high precision is not feasible.