Intermediate-energy Coulomb excitation of 104Sn: Moderate E2 strength decrease approaching 100Sn

TL;DR

This study measures the B(E2) transition probability in 104Sn via Coulomb excitation, revealing a moderate decrease in E2 strength near 100Sn and highlighting discrepancies with shell-model predictions.

Contribution

It provides the first measurement of B(E2) in 104Sn using Coulomb excitation at intermediate energies, challenging existing theoretical models.

Findings

B(E2) in 104Sn is 0.163(26) e^2b^2.

Results show a decrease in E2 strength approaching 100Sn.

Shell-model predictions underestimate the measured B(E2) values.

Abstract

The reduced transition probability B(E2) of the first excited 2+ state in the nucleus 104Sn was measured via Coulomb excitation in inverse kinematics at intermediate energies. A value of 0.163(26) e^2b^2 was extracted from the absolute cross-section on a Pb target, while the method itself was verified with the stable 112Sn isotope. Our result deviates significantly from the earlier reported value of 0.10(4) e^2b^2 and corresponds to a moderate decrease of excitation strength relative to the almost constant values observed in the proton-rich, even-A 106-114Sn isotopes. Present state-of-the-art shell-model predictions, which include proton and neutron excitations across the N=Z=50 shell closures as well as standard polarization charges, underestimate the experimental findings