29 October 2018 to 2 November 2018
Protea Hotel Fire & Ice
Africa/Johannesburg timezone
Registration closes on 17 October

NATURE OF PYGMY DIPOLE EXCITATION IN 74Ge

Not scheduled
20m
Protea Hotel Fire & Ice

Protea Hotel Fire & Ice

64 New Church Street, Tamboerskloof Cape Town 8001
Oral Track A

Speaker

Dr Dinesh Negi (Centre for Excellence in Basic Sciences, Mumbai, India)

Description

In recent times, considerable progress has been made in the understanding of isospin nature of the pygmy dipole excitation both experimentally and theoretically. On experimental side, this has been due to advancement of techniques which now make it possible to compare the excitation pattern by probes of different isospin nature [1].

In this conference, we present results of such comparative study done on the pygmy dipole excitation in 74Ge. The pygmy dipole states built on the ground state are excited by the inelastic alpha scattering. The excitation pattern thus observed is compared to that of observed in the photon scattering done on the same nucleus [2]. Experiment for the 74Ge(alpha,alpha')74Ge' reaction was done with the AFRODITE array and a set of two identical charged particle telescopes of square silicon detectors [3]. The results show the presence of two energy regions between 6 to 9 MeV, which adhere to the scenario of the recently found splitting of the region of dipole excitations into two separated parts: one at low energy, being populated by both isoscalar and isovector probes, and the other at high energy, excited only by the electromagnetic probe. Relativistic quasiparticle time blocking approximation (RQTBA) calculations show a reduction in the isoscalar E1 strength with an increase in excitation energy, which is consistent with the measurement. This study may be the first step to learn more about the relation between isospin-splitting and neutron skin.

REFERENCES
[1] D. Savran et al., Phys. Rev. Letts 97, 172502 (2006) .
[2] R. Massarczyk et al., Phys. Rev. C 92, 044309 (2015).
[3] D. Negi et al., Phys. Rev. C 94, 024322 (2016).

Primary authors

Dr Dinesh Negi (Centre for Excellence in Basic Sciences, Mumbai, India) Mathis Wiedeking (itl) Dr Edoardo Lanza (INFN, Catania, Italy) Prof. Elena Litvinova (Western Michigan University, Michigan, USA) Dr Andrea Vitturi (INFN, Padova, Italy) Robert Bark (iThemba LABS) Dr Lee Bernstein (University of California, Berkeley, USA) Dr Darren Bleuel (Lawrence Livermore National Laboratory, California, USA) Suzan Phumudzo Bvumbi (University of Johannesburg) Thifhelimbilu Daphney Bucher (iThemba LABS) Dr Brian Daub (Lawrence Livermore National Laboratory, California, USA) Tshepo Dinoko (University of the Western Cape/ iThemba LABS) Mr Jason Easton (University of the Western Cape, South Africa) Prof. Andreas Gorgen (University of Oslo, Norway) Prof. Magne Guttormsen (University of Oslo, Norway) Pete Jones (iThemba LABS) Bonginkosi Kheswa (iThemba LABS) Ms Nontobaco Khumalo (University of the Western Cape, South Africa) Dr Ann-Cecilia Larsen (University of Oslo, Norway) Elena Lawrie (iThemba LABS) Kobus Lawrie (iThemba LABS) Siyabonga Majola (UCT/ITHEMBA LABS) Paulus Masiteng (University of Johannesburg) Rudolph Nchodu (iThemba LABS) Joram Ndayishimye (Stellenbosch University) Richard Newman (Stellenbosch University) Sive Noncolela (UWC) Nico Orce (University of the Western Cape) Paul Papka (Stellenbosch University) Luna Pellegri (University of the Witwatersrand and iThemba LABS) Dr Therese Renstrom (University of Oslo, Norway) David G. Roux (Rhodes University) Dr Ronald Schwengner (Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany) Obed Shirinda (iThemba LABS) Prof. Sunniva Siem (University of Oslo, Norway)

Presentation Materials