0(gs)+ -->2(1)+ transition strengths in 106Sn and 108Sn

Area of Science:

• Nuclear Physics
• Atomic Physics
• Quantum Mechanics

Background:

• Understanding nuclear structure and electromagnetic transitions is crucial in nuclear physics.
• The N=Z=50 shell closure is a significant feature in nuclear shell models.
• Radioactive isotopes provide unique insights into nuclear properties away from stability.

Purpose of the Study:

• To measure reduced transition probabilities B(E2; 0(gs)+ -->2(1)+) for radioactive tin isotopes (108,106)Sn.
• To compare experimental data with theoretical predictions from shell-model and generalized seniority models.
• To investigate the stability and characteristics of the N=Z=50 shell closure.

Main Methods:

• Subbarrier Coulomb excitation experiments were conducted at the REX-ISOLDE facility at CERN.
• Deexcitation gamma rays were detected using the highly segmented MINIBALL Germanium detector array.
• Reduced transition probabilities were determined relative to a stable 58Ni target.

Main Results:

• Experimental values for B(E2; 0(gs)+ -->2(1)+) were determined as 0.222(19)e2b2 for 108Sn and 0.195(39)e2b2 for 106Sn.
• The measured B(E2) values are approximately 30% larger than predicted by shell-model calculations.
• The results deviate from predictions of the generalized seniority model.

Conclusions:

• The experimental findings challenge the robustness of the N=Z=50 shell closure in these tin isotopes.
• The observed deviations suggest that nuclear structure in this region is more complex than current models indicate.
• This study provides critical experimental data for refining nuclear structure theories.