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Improved astrophysical rate for the 18O(p,α)15N reaction by underground measurements

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  • P Descouvemont
  • A. Best
  • D. Bemmerer
  • A. Boeltzig
  • C. Broggini
  • Antonio Caciolli
  • F. Cavanna
  • Thomas Chillery
  • G. F. Ciani
  • Piero Corvisiero
  • R. Depalo
  • Di Leva Antonino
  • Z Elekes
  • F. Ferraro
  • Alba Formicola
  • Zs Fülöp
  • Giampiero Gervino
  • Alessandra Guglielmetti
  • C Gustavino
  • Gy Gyürky
  • Gianluca Imbriani
  • Matthias Junker
  • M. Lugaro
  • P. Marigo
  • Roberto Menegazzo
  • V Mossa
  • F R Pantaleo
  • D Piatti
  • P Prati
  • K. Stöckel
  • O Straniero
  • F Strieder
  • T Szucs
  • M. P. Takács
  • Davide Trezzi

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Original languageEnglish
Pages (from-to)237-242
JournalPhysics Letters B
Early online date17 Jan 2019
Publication statusPublished - 10 Mar 2019


The 18O(p,)15N reaction aects the synthesis of 15N, 18O and 19F isotopes, whose abundances can be used to probe the
nucleosynthesis and mixing processes occurring deep inside asymptotic giant branch (AGB) stars. We performed a lowbackground
direct measurement of the 18O(p,)15N reaction cross-section at the Laboratory for Underground Nuclear
Astrophysics (LUNA) from center of mass energy Ec:m: = 340 keV down to Ec:m: = 55 keV, the lowest energy measured
to date corresponding to a cross-section of less than 1 picobarn/sr. The strength of a key resonance at center of mass
energy Er = 90 keV was found to be a factor of 10 higher than previously reported. A multi-channel R-matrix analysis
of our and other data available in the literature was performed. Over a wide temperature range, T = 0:01􀀀1:00 GK, our
new astrophysical rate is both more accurate and precise than recent evaluations. Stronger constraints can now be placed
on the physical processes controlling nucleosynthesis in AGB stars with interesting consequences on the abundance of
18O in these stars and in stardust grains, specically on the production sites of oxygen-rich Group II grains.

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