1. Experimental determination of isospin mixing in nuclear states;
the cases of 52Mn, 59Cu, 71As and 104gAg e+ ne
nucleus q
Isospin workshop
Paris, April 26-29, 2011
Nathal Severijns
Kath. University Leuven, Belgium
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

2. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
1. observable and physics content
2. experimental details
3. results
4. discussion
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

3. 1. observable and physics content
J  J  + transitions
(F component forbidden
by isospin selection rule)
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

4. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

5. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011 p
 emission asymmetry parameter :
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

6. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
sensitivity
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

7. 2. Experimental details Low Temperature Nuclear Orientation
principle :
HPGe
HPGe
Si p-i-n
angular distribution :
D. Venos et al., NIM A 454 (2000) 403
D. Zákoucký, et al., NIM A 520 (2004) 80
F. Wauters et al., NIM A 604 (2009) 563

8. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
52Mn - P. Schuurmans et al., Nucl. Phys. A 622 (2000) 89
71As - N. Severijns et al., Phys. Rev. C 71 (2005)
59Cu, 104mAg - V. Golovko, Ph.D. thesis, K.U.Leuven
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

9. 52Mn and 71As beta asymmetry parameter measurements
used GEANT4 code to account for:
- detection geometry
- magnetic field effects
- scattering
Si p-i-n diode
(500 m,  = 9 mm)
operating at 10 K
Leuven 3He - 4He dilution refrigerator setup
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

10. 59Cu and 104mAg beta asymmetry parameter measurements
HPGe
NICOLE - ISOLDE on-line 3He - 4He dilution refrigerator setup
N. Severijns, 2-5 April 2007, ECT*

11. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
59Cu
 spectra
104mAg
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

12. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
 anisotropy - 1
71As
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

13. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
 anisotropy - 2
71As
keV
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

14. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
 anisotropy - 3
104mAg
keV
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

15. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
3. Results
G. Colò, M. A. Nagarajan, P. Van Isacker, and A. Vitturi, Phys. Rev. C 52, 1175(R) (1995)
admixture of all states with isospin T0+1 into state with isospin T0 :
with (E0 – EM) = energy of isovector giant monopole resonance
V1  25 MeV = proton-neutron exchange potential
E0 = excitation energy of state with isospin T0
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

16. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

17. N. Severijns, Isospin workshop - Paris - April 26-29, 2011
Conclusions
isospin mixing amplitude from analog state was determined for
four J  J transitions with isospin T ranging from 1/2 to 5
isospin impurities ranging from about 0.1% to 1% were observed
comparison with calculations for total isospin impurity show the
analog state contributes about 2% to 10% of the total impurity
no calculations for the isospin impurity from the analog state alone are available
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N. Severijns, Isospin workshop - Paris - April 26-29, 2011

18. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
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19. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
+ decays
based on: S. Raman et al., Atom. Data and Nucl. Data Tabl. 16 (1975) 451
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20. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
- decays
based on: S. Raman et al., Atom. Data and Nucl. Data Tabl. 16 (1975) 451
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21. N. Severijns, Isospin Workshop - Paris - April 26-29, 2011
distribution in
- electron and neutrino directions and in
- electron energy
from polarized nuclei :
Correlation measurements I  
Fermi
function
phase space e+ ne
nucleus q
-
correlation
Fierz
interference term
( b  0 in
standard model )
-asymmetry
R-correlation
J,D, Jackson, S.B. Treiman, H.W. Wyld, Nucl. Phys. 4 (1957) 206
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011

22. Geant 4 Aexp (60Co) = - 1.014 (12)stat (16)syst
region
analysed 
Geant 4
(P from anisotropy of -rays )
Analysis of measured and simulated spectra:
performance of GEANT simulation code --
F. Wauters, NS et al., submitted to NIM A
Aexp (60Co) = (12)stat (16)syst
( ASM = (9) )
no energy dependence left
 corrections OK
F. Wauters et al., submitted
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N. Severijns, Isospin Workshop - Paris - April 26-29, 2011