Constraining the Neutron Star Compactness: Extraction of the ^{23}Al(p,γ) Reaction Rate for the rp Process

Area of Science:

• Nuclear astrophysics
• Stellar evolution
• X-ray burst physics

Background:

• The ^{23}Al(p,γ)^{24}Si reaction rate is critical for energy generation in type-I X-ray bursts.
• Current uncertainties in this reaction rate limit our ability to constrain neutron star properties through burst model-observation comparisons.

Purpose of the Study:

• To present a novel technique for constraining the ^{23}Al(p,γ)^{24}Si reaction rate.
• To resolve conflicting results from previous measurements of ^{24}Si states.
• To enable more accurate astrophysical models by providing precise reaction rate inputs.

Main Methods:

• Utilized the GRETINA array and the LENDA neutron detector coupled to the S800 spectrograph.
• Employed the ^{23}Al(d,n) reaction to populate astrophysically relevant states in ^{24}Si.
• Performed a complete kinematics measurement to extract all necessary inputs for reaction rate calculations.

Main Results:

• Successfully disentangled a previously unresolved close-lying doublet of 2_{2}^{+} and (4_{1}^{+},0_{2}^{+}) states in ^{24}Si.
• Resolved conflicting results from two prior experimental measurements.
• Extracted spectroscopic factors using simultaneous GRETINA and LENDA data.

Conclusions:

• The developed technique provides a precise method for constraining the ^{23}Al(p,γ)^{24}Si reaction rate.
• This advancement will improve constraints on neutron star properties derived from X-ray burst observations.
• The novel technique is applicable to constraining other astrophysically important reaction rates.