Speaker
Dr
Paul Davies
(University of York)
Description
The measurement of mirror energy differences between excited states in pairs of nuclei, with the same mass but interchanged proton and neutron numbers, provides a unique test of the nucleon-nucleon interaction. The origin of these energy differences lies in the isospin breaking components of the nucleon-nucleon interaction (see for example the review by Bentley and Lenzi [1] and references quoted therein). As protons and neutrons can be considered as different states of the nucleon, differences in energy should be associated with the Coulomb field. However, shell model calculations have demonstrated that the Coulomb interaction cannot account for the measured mirror energy differences.
Isospin breaking effects have been studied in the Tz=-3/2 and Tz=-2 nuclei 51Co and 48Fe, respectively, and their isobaric analogue partners. This talk will present new excited states in these nuclei. Shell model calculations in the fp-shell for these nuclei will interpret the results in terms of Coulomb contributions to the isospin breaking effect of the nucleon-nucleon interaction. The importance of the non-Coulomb component of such isospin breaking effects will be discussed. A two step fragmentation process developed by Bentley and Brown et al [2], was employed which allowed access to these highly proton rich nuclei and to produce the mirror via a mirrored fragmentation of a 54Ni beam. The work represents the second time this technique has been used in the study of mirror nuclei and builds on the very successful test case performed by Bentley and Brown et al [2].
[1] M. A. Bentley and S. M. Lenzi, Coulomb energy differences between high-spin states in isobaric multiplets, Prog. Part. Nucl. Phys., 59, 497-561 (2007).
[2] J. R. Brown et al., Phys. Rev. C80, 11306 (2009).
Primary author
Dr
Paul Davies
(University of York)
Co-authors
Dr
A Gade
(NSCL, Michigan State University)
Dr
A Ratkiewicz
(NSCL, Michigan State University)
Dr
D Bazin
(NSCL, Michigan State University)
Dr
D Weisshaar
(NSCL, Michigan State University)
Dr
J M Cook
(NSCL, Michigan State University)
Dr
K Siwek
(NSCL, Michigan State University)
Prof.
M Bentley
(University of York)
Dr
P Adrich
(NSCL, Michigan State University)
Dr
S Lenzi
(Dipartimento di Fisica and INFN, Padova)
Dr
S McDaniel
(NSCL, Michigan State University)
Dr
T Glasmacher
(NSCL, Michigan State University)
