The pygmy quadrupole resonance and neutron-skin modes in Sn-124

Spieker, M, Tsoneva, N, Derya, V, Endres, J, Savran, D, Harakeh, MN, Harissopulos, S, Herzberg, R-D ORCID: 0000-0001-9876-1518, Lagoyannis, A, Lenske, H
et al (show 8 more authors) (2016) The pygmy quadrupole resonance and neutron-skin modes in Sn-124. Physics Letters B: Nuclear Physics and Particle Physics, 752. pp. 102-107.

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We present an extensive experimental study of the recently predicted pygmy quadrupole resonance (PQR) in Sn isotopes, where complementary probes were used. In this study, and experiments were performed on 124Sn. In both reactions, states below an excitation energy of 5 MeV were populated. The E2 strength integrated over the full transition densities could be extracted from the experiment, while the experiment at the chosen kinematics strongly favors the excitation of surface modes because of the strong α-particle absorption in the nuclear interior. The excitation of such modes is in accordance with the quadrupole-type oscillation of the neutron skin predicted by a microscopic approach based on self-consistent density functional theory and the quasiparticle-phonon model (QPM). The newly determined γ-decay branching ratios hint at a non-statistical character of the E2 strength, as it has also been recently pointed out for the case of the pygmy dipole resonance (PDR). This allows us to distinguish between PQR-type and multiphonon excitations and, consequently, supports the recent first experimental indications of a PQR in 124Sn.

Item Type: Article
Uncontrolled Keywords: Atomic nuclei, Collective quadrupole excitations, Pygmy quadrupole resonance, Sn-124
Depositing User: Symplectic Admin
Date Deposited: 01 Feb 2017 12:34
Last Modified: 19 Jan 2023 07:19
DOI: 10.1016/j.physletb.2015.11.004
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