Study of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Mg</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>22</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> Waiting Point Relevant for X-Ray Burst Nucleosynthesis via the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Mg</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>22</mml:mn></mml:mrow></mml:mmultiscripts><mml:mo stretchy="false">(</mml:mo><mml:mi>α</mml:mi><mml:mo>,</mml:mo><mml:mi>p</mml:mi><mml:mo stretchy="false">)</mml:mo><mml:mmultiscripts><mml:mrow><mml:mi>Al</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>25</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> Reaction
H. Jayatissa, M. L. Avila, K. E. Rehm, P. Mohr, Z. Meisel, J. Chen, C. R. Hoffman, J. F. Liang, C. Müller-Gatermann, D. Neto, W.-J. Ong, A. Psaltis, D. Santiago-Gonzalez, T. L. Tang, C. Ugalde, G. L. Wilson
Abstract
The ^{22}Mg(α,p)^{25}Al reaction rate has been identified as a major source of uncertainty for understanding the nucleosynthesis flow in Type-I x-ray bursts. We report a direct measurement of the energy- and angle-integrated cross sections of this reaction in a 3.3-6.9 MeV center-of-mass energy range using the MUlti-Sampling Ionization Chamber (MUSIC). The new ^{22}Mg(α,p)^{25}Al reaction rate is a factor of ∼4 higher than the previous direct measurement of this reaction within temperatures relevant for x-ray bursts, resulting in the ^{22}Mg waiting point of x-ray burst nucleosynthesis flow to be significantly bypassed via the (α,p) reaction.