Isospin symmetry . Beta- decay studies of Tz =-1 nuclei at Rising . B. Rubio for the

1. Isospinsymmetry. Beta-decaystudies ofTz=-1 nuclei at Rising. B. Rubio forthe Valencia-Osaka-Surrey-Leuven-Santiago-GSI Istambul-Lund-Legnaro Collaboration Ph. D Thesisof F. Molina (spokespersons, Y. Fujita, B. Rubio, W. Gelletly) Brighton 12-13 Jan 2011

2. In this paper we are interested in extracting information about the B(GT) strength in f-shell nuclei from beta decay studies Theoretically Experimentally Parent half life From the present experiment Beta feeding to states in the daughter nucleus Brighton 12-13 Jan 2011

3. In this work I will present the study Of the beta-decay of the Tz=-1 nuclei 54Ni, 50Fe,46Cr and 42Ti N=Z Fragmentation of 58Ni Z=28 Z=20 N=28 Brighton 12-13 Jan 2011 N=20

4. 2 p 1/2 1 f 5/2 1 f 5/2 2 p 3/2 2 p 3/2 28 28 1 f 7/2 1 f 7/2 First reason We choose Tz=-1 nuclei with Z=22 to 28 because these cases are specially “clean” since they involve only f7/2 tof7/2 and f7/2 tof5/2 2 p 1/2   and  Brighton 12-13 Jan 2011

5. This is the pattern we expect “in isospin symmetry space” + 1 (f7/2)2f7/2 f5/2 (f7/2)2f7/2 f7/2 (f7/2)2f7/2 f7/2 1+ CE reactions + b -decay 1+ (p,n)-type For instance (3He,t) st st V 1+ , IAS 0+ 0+ 0+ t t V T =+1 T =0 T =-1 z z z Brighton 12-13 Jan 2011

6. Second Reason We choose the Tz=-1 Tz=0 cases because the mirror Tz=+1 Tz=0 cases exists + 1 1+ CE reactions + b -decay 1+ If isospin symmetry exists, mirror nuclei should populate the same states with the same probability, in the daughter nuclei, in the two mirror processes: CE reactions and Beta Decay (p,n)-type For instance (3He,t) st st V 1+ , IAS 0+ 0+ 0+ Advantages : t t V CE reactions: No restriction in excitation energy of Gamow-Teller states T =+1 T =0 T =-1 z z z Beta Decay: Absolute Normalization of B(GT) Brighton 12-13 Jan 2011

7. Adventages of studying f Shell Nuclei with T=1 N=Z We have large Q-values Tz=-1 54Ni 50Fe 54Fe 46Cr 50Cr 42Ti ß+ We have the stable targets Tz=+1 46Ti Tz= -1 (3He,t) Tz=0 4220Ca22 Tz= +1 Tz=(N-Z)/2 Brighton 12-13 Jan 2011

8. triton (3He,t) CE Reactions @ RCNP(Osaka) θlab = 0° (3He,t) CE reaction Stable Target 3He 5830Zn28 54Ni 50Fe 58Ni 46Cr 54Fe 42Ti 50Cr 46Ti 3He (3He,t) N=Z 4220Ca22 Brighton 12-13 Jan 2011

9. Brighton 12-13 Jan 2011

10. 50Fe ~2 millions counts Typically 300 counts/sec Of the nucelus of interest III.Beta Decay Experiments @ RISING Production of 54Ni,50Fe, 46Cr and 42Ti Beam 58Ni@680 MeV/u 109 pps Target Be 4g/cm2 Separation in flight with the Fragment Separator (FRS) Brighton 12-13 Jan 2011

11. Beta(keV) and H.I.(GeV) detector RISING (Ge Array) 15 Euroball Cluster Ge Detectors (7 crystals each) Brighton 12-13 Jan 2011 Francisco Molina IFIC(Valencia) Santiago, December 2009

12. 4828 1+ 3895 1+ 4550 1+ 3395 1+ 3895 1+ 4550 1+ 3395 1+ 4828 1+ 1+ 1+ 1+ 1+ Brighton 12-13 Jan 2011

13. 1+ 1+ 1+ 1+ Brighton 12-13 Jan 2011

14. RISING Efficiency Simulation Rising Ge simulation Including + Si + Box y = p0+p1*x + p2*x2 + p3*x3 +p4*x4+p5*x5 , y=log(eff) and x=log(E) Z.Hu et al. : Nucl. Instr. and Meth. In Phys. Res. A 419 (1998) 121-131

15. Combined Analysis (CE – βDecay) Fujita et al PRL 95 (2005) 212501 In β decay In charge exchange j  A precise value of the parent half-life is very important!!!

16. T1/2 analysis of 54Ni g.s nuclei was done using heavyionimplantation-beta correlations foridentified 54Ni ionsproducedandimplantaion beta-gamma correlations . Each decay was correlated with all implants happening before and after the decay To assure no-systematic errors and well defined background

17. T1/2 analysis of 54Ni g.s nuclei was done using heavyionimplantation-beta correlations foridentified 54Ni ionsproducedandimplantaion beta-gamma correlations . HI-beta correlations same pixel Each decay was correlated with all implants happening before and after the decay To assure no-systematic errors and well defined background Background normalised HI-beta correlations opposite pixel

18. Least square fit

19. Experimental value of the ground state to ground state feeding estimation Parent ? T1/2 =114.20.3 T1/2 =114.71.7 Systematic errors such as beta efficiency error or survival probability errors cancels!, only gamma efficiency counts!!! Experimental Resultg.s. feed 54Ni =0.792

20. Comparison of “g.s to g.s feeding” estimated from Fermi transition probability and our experimental result 0+ This is a super-allowed 0+0+ Fermi transition with B(F)=N-Z And hence 1+ Tz=-1 1+ 1+ st 1+ , IAS 0+ t Tz=0

21. Many 1+ 0+ , few 1+ 2+, but never 1+ 1+ M1 transitions were observed!!!!

22. M1 transitions from T=0 to T=0 in self-conjugate nuclei are strongly suppressed!!!! Strongly supressed 0+ T=0 1+ Tz=-1 T=0 1+ T=0 1+ st allpwed T=1 2+ 1+ T=0 T=1 0+ t IAS Tz=0

23. Results: BGT values from beta decay Isospin symmetry works in general (full strength) but some differences appear at high excitation energy, which should be understood This is the first experimental test of BGT symmetry in the f shell. These cases are specially “clean” since they involve only f7/2 to f7/2 and f7/2 to f5/2 kind of transitions and we compare only the two gsstates Brighton 12-13 Jan 2011

24. summary We have studied the beta decay of four Tz=-1 nuclei in the f7/2 shell They were all produce in fragmentation of 58Ni beams In spite of the complex set-up we could get extremely clean results Very accurate T1/2 and g.s beta decay feeding values were obtained The four decay schemes were obtained and the corresponding B(GT) values for all observed levels could be determined where only Q-beta A very selective isospin Quasi selection rule of was clearly observed The results were compared with the mirror CE reaction process thanks to the Efficiency and high quality of the RISING array . The isospin symmetry works well for the strong transitions but small transitions show difference up to 50% which still have to be understood. ONE CAN PERFORME DELICATE SPECTROSCOPY STUDIES IN FRAGMENTATION REACTIONS IF ONE ACHIEVES CLEAN IMPLANTATION Brighton 12-13 Jan 2011

25. FIN Brighton 12-13 Jan 2011

26. Results: BGT values from beta decay Isospin symmetry works in general (full strength) but some differences appear at high excitation energy, which should be understood This is the first experimental test of BGT symmetry in the f shell. These cases are specially “clean” since they involve only f7/2 to f7/2 and f7/2 to f5/2 kind of transitions and we compare only the two gsstates Brighton 12-13 Jan 2011

27. Estaes la últimatablaque me entregóPancho sin errors en los valores de CE Brighton 12-13 Jan 2011

28. Brighton 12-13 Jan 2011

29. Luckly enough we have all Stable targets in the f shell N=Z Z=28 β+ or β- Z=20 N=28 Brighton 12-13 Jan 2011 N=20

30. Absolute BGT normalisation is always needed: It can be obtained using the combined analysis Y. Fujita… et al. PRL 95 (2005) From -decay From (3He,t) B(F)=N-Z We set up a series of experiments to test this idea Brighton 12-13 Jan 2011

31. T1/2 analysis of 54Ni g.s nuclei was done using heavyionimplantation-beta correlations foridentified 54Ni ionsproducedandimplantaion beta-gamma correlations . HI-beta correlations same pixel Each decay was correlated with all implants happening before and after the decay To assure no-systematic errors and well defined background Possible systematic errors Deadtime contaminants HI-beta correlations opposite pixel

32. Maximum likelihood fit

33. T1/2 from gammas 46Cr missing

34. Gamma spectrum after background subtraction from opposite pixel 46Cr missing

37. Results: preliminary BGT values from beta decay Isospin symmetry works in general (full strength) but some differences appear at high excitation energy, which should be understood Large B(GT) uncertainties are due to the errors in the beta decay half-life. A better value should come from the present experiment. This is the first experimental test of BGT symmetry in the f shell. These cases are specially “clean” since they involve only f7/2 to f7/2 and f7/2 to f5/2 kind of transitions and we compare only the two gsstates Francisco Molina Analysis in progress IFIC(Valencia) Brighton 12-13 Jan 2011

38. Beta Decay Results and comparison with CE A=54, T=1 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 2598 counts 937 (1+) 1816 counts 4550 (1+) 5921 (1+) 9402 counts 4828 (1+) 3895 (1+) 3377 (1+) 937 (1+) First 4th GT States till 4.5MeV were seen by beta decay 347 counts 3377 (1+) 94448 counts 3895 (1+) 4550 (1+) 150 counts Brighton 12-13 Jan 2011

39. 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ A=50, T=1 3392 (1+) 652 (1+) 3654 (1+) 2411 (1+) 2694 (1+) 4332 (1+) 5728 (1+) First 4th GT States till 3.3 MeV were seen by beta decay 652 (1+) 2411 (1+) 2694 (1+) 3392 (1+) Brighton 12-13 Jan 2011

40. 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ 0+ 1+ A=46, T=1 2978 (1+) 994 (1+) 2461 (1+) 2699 (1+) 1433 (1+) 3870 (1+) All the GT States were seen by beta decay 994 (1+) 1432 (1+) 2460 (1+) 2697 (1+) 2978 (1+) 3870 (1+)   T. Adachi et al., PRC 73, 024311 (2006). Brighton 12-13 Jan 2011

41. RISING Efficiency Simulation Rising Ge simulation Including + Si + Box 2.26% y = p0+p1*x + p2*x2 + p3*x3 +p4*x4+p5*x5 , y=log(eff) and x=log(E) Z.Hu et al. : Nucl. Instr. and Meth. In Phys. Res. A 419 (1998) 121-131

44. 3392 1+ 2411 1+ 3654 1+ 2694 1+ 1+ 4332 1+ 5728 1+ 1+ Brighton 12-13 Jan 2011

45. 1+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ Brighton 12-13 Jan 2011