Unbound states near the proton emission threshold. The case of 16 F. I. Ştefan (1), F. de Oliveira...
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Transcript of Unbound states near the proton emission threshold. The case of 16 F. I. Ştefan (1), F. de Oliveira...
![Page 1: Unbound states near the proton emission threshold. The case of 16 F. I. Ştefan (1), F. de Oliveira Santos (2) (1) IPN Orsay (2) GANIL.](https://reader036.fdocument.pub/reader036/viewer/2022070310/551d9dd9497959293b8e7740/html5/thumbnails/1.jpg)
Unbound states near the proton emission threshold. The case of 16F.
I. Ştefan(1) , F. de Oliveira Santos(2)
(1) IPN Orsay(2) GANIL
![Page 2: Unbound states near the proton emission threshold. The case of 16 F. I. Ştefan (1), F. de Oliveira Santos (2) (1) IPN Orsay (2) GANIL.](https://reader036.fdocument.pub/reader036/viewer/2022070310/551d9dd9497959293b8e7740/html5/thumbnails/2.jpg)
Nova explosions
X-ray bursts15O
14N(p,γ)
15O(α,γ)19Ne
15O(pp,γ)17Ne
15O + p <=> 16F (unbound)15O – decay β+ ( T1/2=122 s )
The case of 16F
![Page 3: Unbound states near the proton emission threshold. The case of 16 F. I. Ştefan (1), F. de Oliveira Santos (2) (1) IPN Orsay (2) GANIL.](https://reader036.fdocument.pub/reader036/viewer/2022070310/551d9dd9497959293b8e7740/html5/thumbnails/3.jpg)
β+ (Qβ=15 MeV)
15O+p
16F
E0= 0.536 MeV
p
1/2-
0- Γp=25 keV
16O
β+
Qβ=15 MeV
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β+ (Qβ=15 MeV)
15O+p
16F
E0= 0.536 MeV
p
1/2-
0- Γp=25 keV
16O
β+
Qβ=15 MeV
Mirror nucleus - 16N
Γβ=6.6 10-22 MeV
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β+ (Qβ=15 MeV)
15O+p
16F
E0= 0.536 MeV
p
1/2-
0- Γp=25 keV
16O
β+
Qβ=15 MeV
(pp,γ) – Gorres et al 1995
(α,γ) – Taux estimé
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Vc (
MeV
)
r (fm)
E0
16Fgs
Coulomb barrier
ECM (MeV)
)()( EPE lp
MeV2210*6.6
Wid
th (
MeV
)
15O+p 16F
15O+p
16O+β++ν
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r (fm)
p
β+
E0
Vc (
MeV
)
ECM (MeV)
High ECM for the 15O – p system:
•Γp >> Γβ
•High probability to form 16F compound nucleus
•Beta decay improbable
)()( EPE lp
MeV2210*6.6
Wid
th (
MeV
)
15O+p 16F
15O+p
16O+β++ν
![Page 8: Unbound states near the proton emission threshold. The case of 16 F. I. Ştefan (1), F. de Oliveira Santos (2) (1) IPN Orsay (2) GANIL.](https://reader036.fdocument.pub/reader036/viewer/2022070310/551d9dd9497959293b8e7740/html5/thumbnails/8.jpg)
ECM (MeV)
Low ECM for 15O – p system:
•Γp << Γβ
•Decreased probability to form the 16F compound nucleus
•Beta decay branching ratio increased
)()( EPE lp
MeV2210*6.6
r (fm)
p
β+
E0
p
β+
Vc (
MeV
)
Wid
th (
MeV
)
γ
15O+p 16F
15O+p
16O+β++ν
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r (fm)
Vc (
MeV
)
E0
2201 )
2
)(()(
EEEE
ctresonancetheofShape
tot
Hypothesis:
β+ (Qβ=15 MeV)
15O+p16F
E0= 0.536 MeVγ
dEEEPEPEE pppp
),()(),(),())(,(
γ
1/2-
0- Γp=25 keV
16O
pE1
p
Γp=70 keV
E0= 0.729 MeV
1-
β+
β+
Qβ=15 MeVβ+
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Vc (
MeV
)
E0
γ
dEEEPEPEE pppp
),()(),(),())(,(
β+
β+
pE1
Facteur 109 !!
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Vc (
MeV
)
E0
γ
dEEEPEPEE pppp
),()(),(),())(,(
β+
β+
pE1
Factor 109 !!
r (fm)
2201 )
2
)(()(
EEEE
ctresonancetheofShape
tot
Hypothesis:
![Page 12: Unbound states near the proton emission threshold. The case of 16 F. I. Ştefan (1), F. de Oliveira Santos (2) (1) IPN Orsay (2) GANIL.](https://reader036.fdocument.pub/reader036/viewer/2022070310/551d9dd9497959293b8e7740/html5/thumbnails/12.jpg)
Vc (
MeV
)
E0
γ
dEEEPEPEE pppp
),()(),(),())(,(
β+
β+
pE1
Factor 109 !!
r (fm)
2201 )
2
)(()(
EEEE
ctresonancetheofShape
tot
Hypothesis:
Let’s check it!
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Let’s check it!!
• EURISOL 15O, 14O beam ?
• Different consequences?
p + p ↔ 2He → d + e+ +
p + 4He ↔ 5Li → γ + e+ + ν +4He + n
15O intensity = 1010 pps
E = 0.8 A MeV
N reactions = 8 / day.Continuum Shell Model
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• Astro?
• Unbound state isomer !
16F radioactive??
•Non exponential decay!
•More surprises to come …
Future
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Application for other unbound nuclei
- 15F (very interesting case)
- 5Li
- 4Li
- 19Na
…….
Outlook
Proposition of a new reaction pathway - 15O(p,γ)(β+)16O
- Consequences in different astrophysical scenarios
- Sequential decay ?
- Shape of the resonance ?
- γ decay between two unbound states ? σ(p,γ)~ 1 μb
- Experimental Confirmation
Questions related with the model
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End
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β+ (Qβ=15 MeV)
15O+2p 16F+p
0.536 MeV
p
1/2-
0-
0.732 MeV
16O+p
17Ne
2-
5/2-
1/2+ E1= 0.892 MeV
0.324 MeV
0 MeV
-0.958 MeV
-15 MeV
γ γ
γ
β+
15O(p,γ)(p,γ)17Ne
1/2-
15O(p,γ)(β+)16O
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15O(β+)15N (2 min)15O(α,γ)19Ne 15O(p,γ)(β+)16O15O(p,γ)(p,γ)17Ne
Conclusions
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Futur
• Astro à revoir ?
• Expérience SPIRAL 2 ?
• D’autres conséquences en astro ?p + p ↔ 2He → d + e+ +
15O intensité = 1010 pps
E = 0.8 A MeV
N réactions = 8 / jour.Continuum shell model
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• Intrastate decay !
• Isomère de noyaux non liés ! 16F radioactif ??
• Décroissance non exponentielle !
• Test Heisenberg ?????
• D’autres surprises …
Futur
En physique nucléaire 1%
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Ex(keV) Γp (keV) Jπ
0 25 ± 10 0-
193 (10) 70 ± 5 1-
424 (2) 6 ± 3 2-
721 (4) 15± 5 3-
1H(15O,p)15O
~1.4 107 pps 15O1+ SPIRAL beam
E = 1.2 MeV/A
Thick polypropylene target (CH3)
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e-print at the address:
http://arxiv.ccsd.cnrs.fr/abs/nucl-ex/0603020
General context
Astrophysical motivation
Experimental measurements
Implications Conclusions
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β+ (Qβ=15 MeV)
15O+2p 16F+p
0.536 MeV
p
1/2-
0-
0.732 MeV
16O+p
17Ne
2-
5/2-
1/2+ E1= 0.892 MeV
0.324 MeV
0 MeV
-0.958 MeV
-15 MeV
γ γ
γ
β+
15O(p,γ)(p,γ)17Ne
1/2-
15O(p,γ)(β+)16O
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15O(p,β+)16O
Contexte général
Motivation astrophysique
Mesures expérimentales
Résultats obtenus
Conséquences Conclusions
β+ (Qβ=15 MeV)
15O+p
16F
E0= 0.536 MeV
p
1/2-
0- Γp=25 keV
16O
β+
Qβ=15 MeV
E (MeV)ECM (MeV)
σ(p,β)=(Facteur Géométrique) Γp(E)(Forme de la résonance)Γβ
22
2)(
1
rEE
résonanceladeForme )()( EPE lp
MeV2210*6.6
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ECM (MeV)
15O(p,γ)(β+)16O15O(p,β+)16O
Contexte général
Motivation astrophysique
Mesures expérimentales
Résultats obtenus
Conséquences Conclusions
p
r (fm)
p
β+
E0
p
β+
γE1
Vc (
MeV
)
Lar
geur
(M
eV)
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Contexte général
Motivation astrophysique
Mesures expérimentales
Résultats obtenus
Conséquences Conclusions
Théorie matrice R
Canal d’entré
15N+p Canal sortie 15N+p
Canal sortie
12 C+αRégion intérieure
16O
Paramètre de la matrice R (ra)
• r > ra les seules forces sont les forces coulombiennes;
• r < ra les forces nucléaires et coulombiennes;
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