TY - JOUR
T1 - The pygmy quadrupole resonance and neutron-skin modes in 124Sn
AU - Spieker, M.
AU - Tsoneva, N.
AU - Derya, V.
AU - Endres, J.
AU - Savran, D.
AU - Harakeh, M.N.
AU - Harissopulos, S.
AU - Herzberg, R.-D.
AU - Lagoyannis, A.
AU - Lenske, H.
AU - Pietralla, N.
AU - Popescu, Lucia-Ana
AU - Scheck , M.
AU - Schlüter, F.
AU - Sonnabendl, K.
AU - Stoica, V.I.
AU - Wörtche , H.J.
AU - Zilges, A.
N1 - score=10
PY - 2016/1/10
Y1 - 2016/1/10
N2 - 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, (α, α'γ ) and (γ , γ') experiments were performed on 124Sn. In both reactions, Jπ = 2+ states below an excitation energy of 5MeV were populated. The E2 strength integrated over the full transition densities could be extracted from the (γ , γ') experiment, while the (α, α'γ ) 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.
AB - 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, (α, α'γ ) and (γ , γ') experiments were performed on 124Sn. In both reactions, Jπ = 2+ states below an excitation energy of 5MeV were populated. The E2 strength integrated over the full transition densities could be extracted from the (γ , γ') experiment, while the (α, α'γ ) 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.
KW - Pygmy quadrupole resonance
KW - neutron skin
UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/19513829
U2 - 10.1016/j.physletb.2015.11.004
DO - 10.1016/j.physletb.2015.11.004
M3 - Article
SN - 0370-2693
VL - 752
SP - 102
EP - 107
JO - Physics Letters B
JF - Physics Letters B
ER -