21-25 March 2022
Salon de actos del IATA
Europe/Madrid timezone

New lifetime measurements for the 2$_1^+$ level in $^{112,120}Sn by the Doppler-shift attenuation method

Not scheduled
Salon de actos del IATA

Salon de actos del IATA

Carrer del Catedràtic Agustín Escardino Benlloch, 7, 46980 Paterna, Valencia


Dr. Ananya Kundu (Tata Institute of Fundamental Research)


The tin (Sn; Z = 50) isotopes constitute the longest chain of semi-magic even-even nuclei between the 100Sn (N = 50) and 132Sn (N = 82) double-shell closures, seven of which, 112,114,116,118,120,122,124Sn, are stable. These isotopes have become a prototypical benchmark of extensive microscopic theory and experiment, reflected in the large number of studies investigating the decay of their low-lying first-excited 2+ excited state. The transition characteristics are inferred through the B(E2; 0+g.s.→2+) values, which, in principle, are contingent on the lifetime of the corresponding level, and are the most direct and unambiguous test of the collective nature of the transitions.

There has been a considerable interest focused on the study of enhancement or suppression in collectivity of the excited 21+ state in the stable Sn isotopes. Independent experiments on Coulomb excitation, heavy-ion scattering and 21+ level lifetime measurements report discrepant transition probabilities, with the lifetime estimates indicating significantly reduced collectivity. A re-examination of the same has been carried out in the present work on two of the stable isotopes, 112,120Sn.

Low-lying levels in the 112,120Sn isotopes have been excited by inelastic scattering with heavy-ion beams. Level lifetime measurements have been carried out using the Doppler shift attenuation method, wherein the Doppler affected γ-ray peaks from the decay of the 21+ level in each isotope have been analyzed using updated methodologies, and corresponding B(E2; 0+g.s.→2+) values become indicative of the underlying collectivity. The present results are compared with existing estimates of the B(E2; 0+g.s.→2+) values in the stable Sn isotopes. The results are also found to be in good agreement with generalized seniority model as well as state-of-the-art Monte Carlo shell model (MCSM) calculations.

Primary authors

Dr. Ananya Kundu (Tata Institute of Fundamental Research) Dr. Md S. R Laskar (TIFR, Mumbai) Prof. R. Palit (TIFR, Mumbai) Dr. S. Santra (Bhabha Atomic Research Centre, Mumbai)

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