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AARHUSUNIVERSITY
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HANS FYNBOAarhus UniversityDenmark
12C and 3a studied with small accelerators
496th WE-Heraeus-Seminar
Bad Honnef
February 6-10 2012
• Introduction to the 3 areaction
• 3a breakup of the Hoyle state
• Search for “missing” states in 12C
AARHUSUNIVERSITY
2
4He+4He
-0.092 g.s. 0+
8Be
12Cg.s. 0+
AARHUSUNIVERSITY
3
4He+4He-0.092 g.s. 0+
8Be
7.65 0+
g.s. 0+
12C
7.27
g4.44 2+
g
3
AARHUSUNIVERSITY
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Q1 = -92 keV
+ a a
G
g
Gp
Q2= -287 keV
a +8Be
Hoyle state
Quantity Value Error(%)
Q3a 379.4(2)keV 1.2
Grad/G 4.12(11) ×10-4 2.7
Ge+e-/G 6.7(6) × 10-4 9.2
Ge+e- 52.0(1.4) meV 2.7 Crannell 2005
Ge+e- 59.6(1.5) meV 2.5 Chernykh 2010
G(8Be)/Gtot >0.96 4 Freer 1994
G(8Be)/Gtot 0.83(5) 6 Raduta 2011
AARHUSUNIVERSITY
12C+40Ca 25MeV/u5
AARHUSUNIVERSITY
6arXiv:1112.2136v1 [nucl-th]
3a-rate at low temperatures
8Be resonance
AARHUSUNIVERSITY
12C
≈10.3 (0+)
4.44 2+
g.s. 0+
7.65 0+
9.64 3-
10.84 1-
7.27Haruhiko Morinaga (TUM)
J=2+ E≈9.7 MeV
2+ ?
3a-rate at high temperatures
AARHUSUNIVERSITY
Phys. Lett. B 2011.Phys. Rev. C36 (1987) 54..
The et al. APJ 1998
Tur et al. APJ 2010Magkotsios et al. APJs 2010Magkotsios et al. APJ 2011
AARHUSUNIVERSITY
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• 3a breakup of the Hoyle state
• Search for “missing” states in 12C
AARHUSUNIVERSITY
CMAM, Madrid
3He+11B d+12C* d+3 @ 8.5 MeV
3He
Oliver Kirsebom(now at Triumf)
AARHUSUNIVERSITY
115000 events
12C
12.71 1+
≈10 0,2+
4.44 2+
g.s. 0+
7.65 0+
9.64 3-
10.84 1-
11.83 2-
7.27
AARHUSUNIVERSITY
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Limits:
Raduta et al.
DDE = 7.5±4 %
DDE = 9.5±4 %
SD = 83±5 %
(O. Kirsebom et al. to be submitted)
AARHUSUNIVERSITY
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• 3a breakup of the Hoyle state
• Search for “missing” states in 12C
AARHUSUNIVERSITY
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2+?
Stellenbosch: Freer et al. (2009): 12C(p,p´)12C
Yale : Zimmerman et al. (2011): 12C(p,p´)12C
3-
1-
3- 1-
Osaka: Itoh et al. (2011): 12C(, ´)12C
3- 3-
AARHUSUNIVERSITY
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Journal of Physics: Conference Series 202 (2010) 012016Journal of Physics: Conference Series 267 (2011) 012046
AARHUSUNIVERSITY Idea 1 : Remove 3- state using b-decay
Only 0+, 1+, and 2+ states
AARHUSUNIVERSITY
ab
12N/12BMagnetp/d12N/12B+X
12C/11B Direct Kinematics+ISOL
12N/12B+X12N/12B
abp/d12C/11B
Magnets
Inverse Kinematics+Separator
AARHUSUNIVERSITY
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R.Raabe
12N/12B
K. JungmannH. Wilschut
TRIP separator
Solveig Hyldegaard
AARHUSUNIVERSITY
1+
12C
12.71 1+
≈10 0+
4.44 2+
g.s. 0+
7.65 0+
15.11 1+
12N Qbeta=16.32
AARHUSUNIVERSITY
12C
12.71 1+
≈10 0+
4.44 2+
g.s. 0+
7.65 0+
15.11 1+
12B Qbeta=13.37
AARHUSUNIVERSITY
C. Diget(York)
Solveig Hyldegaard
12N/12B
IGISOL Experiment
AARHUSUNIVERSITY
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12C
12.71 1+
≈10
4.44 2+
g.s. 0+
7.65 0+
15.11 1+
12N Qbeta=16.32
Natural parity states
AARHUSUNIVERSITY
12C
12.71 1+
≈10 0+
4.44 2+
g.s. 0+
7.65 0+
15.11 1+
12B Qbeta=13.37
AARHUSUNIVERSITY
PL B678, 459 (2009)PR C80, 044304 (2009)PR C80, 034316 (2009)PR C81, 024303 (2010) S. Hyldegaard, C. Diget
AARHUSUNIVERSITY
How to get selectivity between 0+ and 2+ ?
×
×2+
Only 0+, 1+, and 2+ states Only 1+, 2+, and 3+ states
AARHUSUNIVERSITY
“-delayed” breakup
C
Oliver Kirsebom(Triumf)
Martin Alcorta(Argonne)
AARHUSUNIVERSITY
3He+10B p+12C* p+3 @ 4.9 MeV
M. Alcorta et al., NIM A 605, 318–325 (2009)
CMAM, Madrid
3He+11B d+12C* d+3 @ 8.5 MeV
3He
AARHUSUNIVERSITY
O. S. Kirsebom et al., Phys. Lett. B680, 44-49 (2009)
1st case : g-decay of 1+ states (proof-of-principle)
3He+10B p+12C* p+3
3He
AARHUSUNIVERSITY
1st case : g-decay of 1+ states (proof-of-principle)
M1 g-decay ≈ GT b-decay
AARHUSUNIVERSITY
2nd case : g-decay of 2+ T=1 state
+ M1 >> E2 1+ ,2+, 3+ no 0+ !
− E1 decay populate negative parity 1- ,2-, 3-
31
AARHUSUNIVERSITY
2+2-
1-
2+2-1-
11B(p,a)aa
400keV van de Graafin Aarhus.
AARHUSUNIVERSITY
12C
12.71 1+
≈10 0,2+
4.44 2+
g.s. 0+
7.65 0+
9.64 3-
10.84 1-
11.83 2-
13.35 (2-)
14.08 4+
15.11 1+
7.27
16.1 2+
AARHUSUNIVERSITY
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12C
12.71 1+
≈10 0,2+
4.44 2+
g.s. 0+
7.65 0+
9.64 3-
10.84 1-
11.83 2-
13.35 (2-)
14.08 4+
15.11 1+
7.27
16.1 2+
240h 1nA @ 165keV
AARHUSUNIVERSITY
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12C
12.71 1+
≈10 0,2+
4.44 2+
g.s. 0+
7.65 0+
9.64 3-
10.84 1-
11.83 2-
13.35 (2-)
14.08 4+
15.11 1+
7.27
16.1 2+
16.6 2-3rd case : g-decay of 2- T=1 state
40h 1nA @ 350keV
35
AARHUSUNIVERSITY
C. Zemach, Phys Rev. 133 (1964) 1201 : Decay to 3pFynbo et al. Phys Rev C79 (2009) 054009 : Decay to 3a
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AARHUSUNIVERSITY
2+ 16.11MeV
2- 16.57MeV11B(p,a)aa
AARHUSUNIVERSITY
Outlook
5 MV van de Graaf in Aarhus (HV 1965)
Upgrade of detector setup
Other case where the method can be used?• 8Be• 16O• …..
AARHUSUNIVERSITY
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Quantity Value Error(%)
Q3a 379.38(20)keV 1.2
Grad/G 4.12(11) ×10-4 2.7
Ge+e-/G 6.74(62) × 10-4 9.2
Ge+e- 52.0(1.4) meV 2.7 Crannell 2005
Ge+e- 59.6(1.5) meV 2.5 Chernykh
G(8Be)/Gtot >0.96 4 Freer 1994
G(8Be)/Gtot 0.83(5) 6 Raduta 2011
AARHUSUNIVERSITY
THANK YOU FOR YOUR ATTENTION !
AARHUSUNIVERSITY
BONUS MATERIAL…
AARHUSUNIVERSITY
Decay channels
4He+4He+4
He
7.65 0+
3.03 2+
g.s. 0+ -0.092
8Be+4He
12C7.27
12.71 1+
15.11 1+
≈10 0+/2+
The 1+ states cannot decay via the 8Be ground state because it would require L=1 and therefore a change in parity
Natural parity states
AARHUSUNIVERSITY
0+ 2+ 0+2 2+2 0+3 1+ 2+ 2+0.0002
0.002
0.02
0.2
2
B(GT)
B(M1)1+,T=1
B(M1)2+,T=1
0+ 2+ 0+2 2+2 0+3 1+ 2+ 2+0.0002
0.002
0.02
0.2
2 Data FMD
0+ 2+ 0+2 2+2 0+3 1+ 2+ 2+0.001
0.01
0.1
1
AARHUSUNIVERSITY
12C
12.71 1+
≈10.3 (0+)
4.44 2+
g.s. 0+
7.65 0+
9.64 3-
10.84 1-
11.83 2-
13.35 (2-)
14.08 4+
15.11 1+
16.11 2+
7.27
p+11B15.96
AARHUSUNIVERSITY
12C
12.71 1+
≈10.3 (0+)
4.44 2+
g.s. 0+
7.65 0+
9.64 3-
10.84 1-
11.83 2-
13.35 (2-)
14.08 4+
15.11 1+
16.11 2+
7.27
p+11B15.96
Experimental Dalitz plots
AARHUSUNIVERSITY
12C
12.71 1+
≈10.3 (0+)
4.44 2+
g.s. 0+
7.65 0+
9.64 3-
10.84 1-
11.83 2-
13.35 (2-)
14.08 4+
15.11 1+
16.11 2+
7.27
p+11B15.96
The 13.35 MeV state
2– 4–
√X
AARHUSUNIVERSITY
12C
12.71 1+
≈10.3 (0+)
4.44 2+
g.s. 0+
7.65 0+
9.64 3-
10.84 1-
11.83 2-
13.35 (2-)
14.08 4+
15.11 1+
16.11 2+
7.27
p+11B15.96
The 11.83 MeV state
2–
2–
1) A.A.Korsheninnikov, Sov. J. Nucl. Phys. 52 (1990)2) H.Fynbo et al., PRL 91 (2003)3) R.Alvarez-Rodriguez et al., PRL 99 (2007)
1) 2)
2)3)
AARHUSUNIVERSITY
4He+4He
3.03 2+
-0.092 g.s. 0+
8Be
7.65 0+
≈10 0+,2+
g
8Be10-16s
g.s. 0+
12C
7.2712C* g
4.44 2+
g
47
AARHUSUNIVERSITY
12C* a1+ 8Be a1+a2+a3
E1 = m23/(m1+m23) x QI = 2/3 xQI
12C
8Be
a2 + a3
QI
QII
E1
E2 E3
ai
2/3QI
R.H. Dalitz, Philos. Mag. 44, 1068 (1953).
Energy conservation
Momentum conservatio
n
Dalitz plot