Maqola

Monte Carlo uncertainty of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi mathvariant="normal">He</mml:mi><mml:mprescripts/><mml:none/><mml:mn>3</mml:mn></mml:mmultiscripts><mml:mo>(</mml:mo><mml:mi>α</mml:mi><mml:mo>,</mml:mo><mml:mi>γ</mml:mi><mml:mo>)</mml:mo><mml:mmultiscripts><mml:mi mathvariant="normal">Be</mml:mi><mml:mprescripts/><mml:none/><mml:mn>7</mml:mn></mml:mmultiscripts></mml:mrow></mml:math>reaction rate

R. J. deBoerThe Joint Institute for Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USAJ. GörresThe Joint Institute for Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USAK. SmithThe Joint Institute for Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USAE. UbersederThe Joint Institute for Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USAM. WiescherThe Joint Institute for Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USAA. KontosThe Joint Institute for Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USAG. ImbrianiThe Joint Institute for Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USAA. Di LevaThe Joint Institute for Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USAF. StriederThe Joint Institute for Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA

2014lv

ABI

Annotatsiya

Background: The $^{3}\mathrm{He}(\ensuremath{\alpha},\ensuremath{\gamma})^{7}\mathrm{Be}$ reaction is of critical importance in determining the flux of solar neutrinos through the $pp$-II and $pp$-III chains. For this reason and others, the description of the cross section and its extrapolation towards low-energy has always been a matter of intense debate. While large systematic differences have been present in the past, several recent measurements are all in excellent statistical agreement.Purpose: The convergence of the recent individual experimental measurements of the $^{3}\mathrm{He}(\ensuremath{\alpha},\ensuremath{\gamma})^{7}\mathrm{Be}$ reaction prompts a global analysis of the reaction data. From the combined data, a more precise estimate of the low-energy cross section can be determined.Results: A global $R$-matrix fit is used to describe the $^{3}\mathrm{He}(\ensuremath{\alpha},\ensuremath{\gamma})^{7}\mathrm{Be}$ data as well as scattering data over a similar energy range. The $R$-matrix fit is then subjected to a Monte Carlo analysis to extract the uncertainties on the cross section and corresponding reaction rate.Conclusion: By combining several recent measurements of the $^{3}\mathrm{He}(\ensuremath{\alpha},\ensuremath{\gamma})^{7}\mathrm{Be}$ reaction, the combined data yield a zero energy $S$ factor of $S(0)=0.542\ifmmode\pm\else\textpm\fi{}0.011(\text{MC}\phantom{\rule{4.pt}{0ex}}\text{fit})\ifmmode\pm\else\textpm\fi{}0.006{(\text{model})}_{\ensuremath{-}0.011}^{+0.019}(\text{phase}\phantom{\rule{4.pt}{0ex}}\text{shifts})$ keV b. This gives a total uncertainty in $S(0)$ of $+0.023/\ensuremath{-}0.017$ keV b.

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Identifikatorlar

DOI: 10.1103/physrevc.90.035804

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