E. Sahin, G. de Angelis
description
Transcript of E. Sahin, G. de Angelis
E. Sahin, G. de Angelis
Breaking of the Isospin Symmetry and CED in the A70 mass region: the T
z=-1 70Kr
N~Z A=70 Nuclei: 70Se, 70Br, 70KrCharacteristic features can be extracted through CED?
Strong Collective Effects (Np=Nn) (Shape co-existence)Nuclear Isospin Symmetry
A=70 isobaric nuclei has an unusual behavior of the CED, a negative tendency with increasing spin.
Strong Collective Effects (Np=Nn)
Shape co-existence
Coulomb Energy Difference (CED)
But in reality, Isospin non-conserving interactions with Coulomb force break the isospin symmetry!!
A plot of CED with increasing angular momentum will be a good tool to study the collective properties of the nuclei N/=Z
D.D. Warner et al.,Nature Physics 2, 311 (2006)
M.A. Bentley, S. Lenzi, Prog.Part.Nucl.Phys. (2006)
Tz>=Tz<+1CED(Jπ)=E
Jπ(T
z<)-E
Jπ(T
z>)
Negatif CED values in A=70 isobars
CED(2+)=-11 keV
CED(4+)=-36 keV
CED(6+)=-37 keV
Tz< Tz>70Br:G.de Angelis Eur. Phys.J.A.12,51 (2001)
N. Singh et al., Phys.Rev.C75, 061301 (2007)
Coulomb Energy Difference (CED)
70Se:J. Ljungvall et al., PRL 100, 102502 (2008)
Excited Vampire Predictions Microscopic description of mirror nuclei in the A=70 mass region
Shape coexistence and mixing
70/29
p/o o/p
81/18
95/4
84/16
Mixing ratios
A.Petrovici Nuc.Phy. A 728, 396 (2003)70Br:G.de Angelis Eur.Phys.J.A.12,51 (2001)
Isospin symmetric G-matrix(A) + Coulomb Interaction between valence protons
70Se:J. Ljungvall et al., PRL 100, 102502 (2008)
Exp. data 66As: G. de Angelis (to be submitted)
Excited Vampire Predictions
Vampire Calculations:
First minimum is predominantly prolate in 70BrFirst minimum is predominantly oblate in 70Se
A.Petrovici Nuc.Phy. A 728, 396 (2003)
59/41
p/o o/p
58/41
80/20
64/36
Mixing ratios
59/41
64/36
39/61
57/42
Excited Vampire Predictions
The Coulomb interaction is included for the valence protons
The mirror nuclei 70Se-70Kr have different shapes in their ground state
The comparison of the microscopic structure of the mirror nuclei 70Se and 70Kr
A.Petrovici private comm.
Excited Vampire Predictions
B(E2) Values B(E2) Values ee22fmfm44
Ji J
f
70Kr 70Se
2+ 0+ 603 492
4+ + 864 713
6+ + 933 779
342 Exp.J. Ljungvall et al.
Experiment1neutron-knockout reaction: 71Kr + 9Be →70Kr
71Kr 9Be70Kr
1neutronTarget
56Fe
Identification of the 2+→0+ transition : 71Kr + 9Be → 70Kr Lifetime measurement : 71Kr + 56Fe → 70Kr
Beam Production
LISE++ calculations: LISE++ calculations: Primary beam78Kr 1.3x1010 pps
Be target5000 mg/cm2
Secondary beam 71Kr ~ 100 pps at 170 MeV/u
Be target1000 mg/cm2
AGATA
Identification of the 2+ → 0+ transition
71Kr on 9Be targetd
target=1 g/cm2
Ibeam
=100 pps=2 mb (for 1n knock-out) =20% (1 MeV) N=200 day-1
1-2 days of beamtime
Lifetime determination
71Kr on 56Fe targetd
target=700 mg/cm2
Ibeam
=100 pps=2.7 mb (for 1n knock-out) =20% (1 MeV) N=35 day-1
2+
0+
950
955 keV