Observation of Substantial <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi></math>-Wave Capture Strength in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi mathvariant="normal">Li</mi></mrow><mprescripts></mprescripts><mrow></mrow><mrow><mn>7</mn></mrow><mrow></mrow><mrow></mrow></mmultiscripts></mrow><mrow><msup><mrow><mo>(</mo><mrow><mrow><mover><mrow><mi>p</mi></mrow><mrow><mo>→</mo></mrow></mover></mrow></mrow><mo>,</mo><mi>γ</mi><mo>)</mo></mrow><mrow><mn>8</mn></mrow></msup></mrow><mi mathvariant="normal">Be</mi></math> Reaction for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>p</mi></mrow></msub></mrow><mo>=</mo><mn>80</mn><mo>−</mo><mn>0</mn><mn></mn></math> keV and Implications for Astrophysical <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math> Factors

R. M. Chasteler; H. R. Weller; D. R. Tilley; R. M. Prior

doi:10.1103/PhysRevLett.72.3949

Observation of Substantial $p$ -Wave Capture Strength in the ${}^{7}{Li} {(\vec{p}, γ)}^{8} Be$ Reaction for $E_{p} = 80 - 0$ keV and Implications for Astrophysical $S$ Factors

R. M. Chasteler, H. R. Weller, D. R. Tilley, and R. M. Prior

Phys. Rev. Lett. 72, 3949 – Published 20 June 1994

Abstract

The ${}^{7}{Li} {(\vec{p}, γ)}^{8} Be$ reaction has been studied using polarized protons having an incident energy in the range $E_{p} (lab) = 80 - 0$ keV. The measured angular distributions of the cross section $\frac{σ (θ)}{A_{0}}$ and analyzing power $A_{y} (θ)$ were interpreted using a model independent transition-matrix element analysis. The large (Å40%) analyzing power at 90° indicates the presence of an appreciable $p$ -wave capture strength at these energies. The direct-capture model is used to show that this could reduce the astrophysical $S$ factor by as much as 40%.