caa a22 4500 445871822 CHVBK 20180317145514.0 cr unu---uuuuu 170323e20110101xx s 000 0 eng 10.1140/epja/i2011-11014-7 doi (NATIONALLICENCE)springer-10.1140/epja/i2011-11014-7 Isoscalar dipole coherence at low energies and forbidden E1 strength [Elektronische Daten] [P. Papakonstantinou, V. Ponomarev, R. Roth, J. Wambach] Abstract.: In 16O and 40Ca an isoscalar, low-energy dipole transition (IS-LED) exhausting approximately 4% of the isoscalar dipole (ISD) energy-weighted sum rule is experimentally known, but conspicuously absent from recent theoretical investigations of ISD strength. The IS-LED mode coincides with the so-called isospin-forbidden E1 transition. We report that for N = Z nuclei up to 100Sn the fully self-consistent Random-Phase Approximation (RPA) with finite-range forces, phenomenological and realistic, yields a collective IS-LED mode, typically overestimating its excitation energy, but correctly describing its IS strength and electroexcitation form factor. The presence of E1 strength is solely due to the Coulomb interaction between the protons and the resulting isospin-symmetry breaking. The smallness of its value is related to the form of the transition density, due to translational invariance. The calculated values of E1 and ISD strength carried by the IS-LED depend on the effective interaction used. Attention is drawn to the possibility that in N $ \neq$ Z nuclei this distinct mode of IS surface vibration can develop as such or mix strongly with skin modes and thus influence the pygmy dipole strength as well as the ISD strength function. In general, theoretical models currently in use may be unfit to predict its precise position and strength, if at all its existence. SIF, Springer-Verlag Berlin Heidelberg, 2011 Papakonstantinou P. Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289, Darmstadt, Germany aut Ponomarev V. Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289, Darmstadt, Germany aut Roth R. Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289, Darmstadt, Germany aut Wambach J. Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289, Darmstadt, Germany aut The European Physical Journal A Springer-Verlag 47/1(2011-01-01), 1-10 1434-6001 47:1<1 2011 47 10050 https://doi.org/10.1140/epja/i2011-11014-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1140/epja/i2011-11014-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Papakonstantinou P. Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289, Darmstadt, Germany aut NATIONALLICENCE 700 1- Ponomarev V. Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289, Darmstadt, Germany aut NATIONALLICENCE 700 1- Roth R. Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289, Darmstadt, Germany aut NATIONALLICENCE 700 1- Wambach J. Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289, Darmstadt, Germany aut NATIONALLICENCE 773 0- The European Physical Journal A Springer-Verlag 47/1(2011-01-01), 1-10 1434-6001 47:1<1 2011 47 10050 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer