TY - JOUR
T1 - Direct Capture Cross Section and the Ep=71 and 105 keV Resonances in the Ne 22 (p,γ) Na 23 Reaction
AU - Ferraro, F.
AU - Takács, M. P.
AU - Piatti, D.
AU - Cavanna, F.
AU - Depalo, R.
AU - Aliotta, M.
AU - Bemmerer, D.
AU - Best, A.
AU - Boeltzig, A.
AU - Broggini, C.
AU - Bruno, C. G.
AU - Caciolli, A.
AU - Chillery, T.
AU - Ciani, G. F.
AU - Corvisiero, P.
AU - Davinson, T.
AU - D'Erasmo, G.
AU - Di Leva, A.
AU - Elekes, Z.
AU - Fiore, E. M.
AU - Formicola, A.
AU - Fülöp, Zs
AU - Gervino, G.
AU - Guglielmetti, A.
AU - Gustavino, C.
AU - Gyürky, Gy
AU - Imbriani, G.
AU - Junker, M.
AU - Karakas, A.
AU - Kochanek, I.
AU - Lugaro, M.
AU - Marigo, P.
AU - Menegazzo, R.
AU - Mossa, V.
AU - Pantaleo, F. R.
AU - Paticchio, V.
AU - Perrino, R.
AU - Prati, P.
AU - Schiavulli, L.
AU - Stöckel, K.
AU - Straniero, O.
AU - Szücs, T.
AU - Trezzi, D.
AU - Zavatarelli, S.
AU - LUNA Collaboration
PY - 2018/10/23
Y1 - 2018/10/23
N2 - The Ne22(p,γ)Na23 reaction, part of the neon-sodium cycle of hydrogen burning, may explain the observed anticorrelation between sodium and oxygen abundances in globular cluster stars. Its rate is controlled by a number of low-energy resonances and a slowly varying nonresonant component. Three new resonances at Ep=156.2, 189.5, and 259.7 keV have recently been observed and confirmed. However, significant uncertainty on the reaction rate remains due to the nonresonant process and to two suggested resonances at Ep=71 and 105 keV. Here, new Ne22(p,γ)Na23 data with high statistics and low background are reported. Stringent upper limits of 6×10-11 and 7×10-11 eV (90% confidence level), respectively, are placed on the two suggested resonances. In addition, the off-resonant S factor has been measured at unprecedented low energy, constraining the contributions from a subthreshold resonance and the direct capture process. As a result, at a temperature of 0.1 GK the error bar of the Ne22(p,γ)Na23 rate is now reduced by 3 orders of magnitude.
AB - The Ne22(p,γ)Na23 reaction, part of the neon-sodium cycle of hydrogen burning, may explain the observed anticorrelation between sodium and oxygen abundances in globular cluster stars. Its rate is controlled by a number of low-energy resonances and a slowly varying nonresonant component. Three new resonances at Ep=156.2, 189.5, and 259.7 keV have recently been observed and confirmed. However, significant uncertainty on the reaction rate remains due to the nonresonant process and to two suggested resonances at Ep=71 and 105 keV. Here, new Ne22(p,γ)Na23 data with high statistics and low background are reported. Stringent upper limits of 6×10-11 and 7×10-11 eV (90% confidence level), respectively, are placed on the two suggested resonances. In addition, the off-resonant S factor has been measured at unprecedented low energy, constraining the contributions from a subthreshold resonance and the direct capture process. As a result, at a temperature of 0.1 GK the error bar of the Ne22(p,γ)Na23 rate is now reduced by 3 orders of magnitude.
UR - http://www.scopus.com/inward/record.url?scp=85055687036&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.121.172701
DO - 10.1103/PhysRevLett.121.172701
M3 - Article
C2 - 30411966
AN - SCOPUS:85055687036
VL - 121
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 17
M1 - 172701
ER -