Eur. Phys. J. A (2019) 55: 243
https://doi.org/10.1140/epja/i2019-12789-y

Regular Article - Theoretical Physics

Characterization of vorticity in pygmy resonances and soft-dipole modes with two-nucleon transfer reactions

¹ The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100, Copenhagen, Denmark
² Dipartimento di Fisica, Università degli Studi Milano, Via Celoria 16, I-20133, Milano, Italy
³ Departamento de Fìsica Aplicada III, Escuela Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos, Sevilla, Spain
⁴ National Superconducting Cyclotron Laboratory, Michigan State University, 48824, East Lansing, MI, USA
⁵ INFN Sezione di Milano, Via Celoria 16, I-20133, Milano, Italy

^* e-mail: potel@nscl.msu.edu

Received: 8 May 2019
Accepted: 2 June 2019
Published online: 3 December 2019

Abstract

The properties of the two-quasiparticle-like soft E1-modes and Pygmy Dipole Resonances (PDR) have been and are systematically studied with the help of inelastic and electromagnetic experiments which essentially probe the particle-hole components of these vibrations. It is shown that further insight in their characterisation can be achieved with the help of two-nucleon transfer reactions, in particular concerning the particle-particle components of the modes, in terms of absolute differential cross sections which take properly into account successive and simultaneous transfer mechanisms corrected for non-orthogonality, able to reproduce the experimental findings at the 10% level. The process ⁹Li(t, p)¹¹Li(1^-) is discussed, and absolute cross sections predicted.