Physics Letters B 736 (2014) 137–141
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
Neutron spectroscopic factors of
55
Ni hole-states
from
(p, d) transfer reactions
A. Sanetullaev
a,1
, M.B. Tsang
a,∗
, W.G. Lynch
a
, Jenny Lee
a
, D. Bazin
a
, K.P. Chan
a,b
,
D. Coupland
a
, V. Henzl
a
, D. Henzlova
a
, M. Kilburn
a
, A.M. Rogers
a
, Z.Y. Sun
a,c
,
M. Youngs
a
, R.J. Charity
d
, L.G. Sobotka
d
, M. Famiano
e
, S. Hudan
f
, D. Shapira
g
,
W.A. Peters
h
, C. Barbieri
i
, M. Hjorth-Jensen
a,j
, M. Horoi
k
, T. Otsuka
l
,
T. Suzuki
m
, Y. Utsuno
n
a
National Superconducting Cyclotron Laboratory & Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
b
Physics Department, Hong Kong Chinese University, Shatin, Hong Kong, China
c
Institute of Modern Physics, CAS, Lanzhou 730000, China
d
Department of Chemistry, Washington University, St. Louis, MO 63130, USA
e
Department of Physics, Western Michigan University, Kalamazoo, MI 49008, USA
f
Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
g
Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
h
Rutgers University, Piscataway, NJ 08854, USA
i
Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
j
Department of Physics and Center of Mathematics for Applications, University of Oslo, N-0316 Oslo, Norway
k
Department of Physics, Central Michigan University, Mount Pleasant, MI 48859, USA
l
Department of Physics, University of Tokyo, Tokyo, Japan
m
Department of Physics, Nihon University, Tokyo, Japan
n
Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
a r t i c l e i n f o a b s t r a c t
Article history:
Received
30 January 2014
Received
in revised form 2 July 2014
Accepted
2 July 2014
Available
online 7 July 2014
Editor: D.F.
Geesaman
Spectroscopic information has been extracted on the hole-states of
55
Ni, the least known of the quartet
of nuclei (
55
Ni,
57
Ni,
55
Co and
57
Cu), one nucleon away from
56
Ni, the N = Z = 28 double magic nucleus.
Using the
1
H(
56
Ni, d)
55
Ni transfer reaction in inverse kinematics, neutron spectroscopic factors, spins and
parities have been extracted for the f
7/2
, p
3/2
and the s
1/2
hole-states of
55
Ni. These new data provide a
benchmark for large basis calculations that include nucleonic orbits in both the sd and pf shells. State of
the art calculations have been performed to describe the excitation energies and spectroscopic factors of
the s
1/2
hole-state below Fermi energy.
© 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/3.0/). Funded by SCOAP
3
.
Doubly-magic nuclei, with both the proton number (Z) and the
neutron number (N) corresponding to closed shells, have played a
simplifying role in nuclear structure. Low lying states in somewhat
heavier nuclei are often approximated by ignoring the closed shell
single particle orbits and considering only the occupied nucleon
orbits in higher lying “particle” states in the next major shell. Sim-
ilarly,
low-lying states in lighter nuclei are often approximated by
considering only unoccupied nucleon orbits (“holes”) within the
doubly closed shell. In this approximation, effective operators on
the particle- or hole-states provide a means to model the nucle-
*
Corresponding author.
E-mail
address: tsang@nscl.msu.edu (M.B. Tsang).
1
Present address: TRIUMF, Vancouver, BC, Canada.
onic wavefunctions in the closed shell “core”. This simplification
works extremely well in the vicinity of the doubly-magic closed sd
shell nucleus
40
Ca.
56
Ni is the first doubly-magic N = Z nucleus, beyond
40
Ca. Pro-
duced
abundantly in stellar reactions, it plays important roles in
many astrophysical processes [1,2]. Despite its importance, its six-
day
half-life hindered key investigations of
56
Ni and its neighbors
until radioactive beams became available. Consequently, there are
very little data for
55
Ni with one neutron less than
56
Ni. Only six
out of 22 known states below 7 MeV in this nucleus have tentative
spins and parities [3]. The only firmly established spin and parity
in
55
Ni is the ground state with spin and parity of 7/2
−
[3,4]. To
clarify the extent to which
56
Ni in calculations can be treated as
a closed 1f
7/2
core, measurements of hole-states in
55
Ni provide
http://dx.doi.org/10.1016/j.physletb.2014.07.003
0370-2693/
© 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/). Funded by
SCOAP
3
.