Using Inertial Fusion Implosions to Measure the T+^{3}He Fusion Cross Section at Nucleosynthesis-Relevant Energies

Area of Science:

• Nuclear Astrophysics
• Plasma Physics
• Cosmology

Background:

• Big Bang Nucleosynthesis (BBN) theory explains light nuclei formation.
• Observed high lithium-6 (⁶Li) abundances in low-metallicity stars contradict standard BBN models.
• The T(³He,γ)⁶Li reaction is a potential source for anomalous ⁶Li production.

Purpose of the Study:

• To experimentally determine the T(³He,γ)⁶Li reaction rate under conditions relevant to Big Bang nucleosynthesis.
• To assess the contribution of this reaction to the observed high ⁶Li abundances in metal-poor stars.

Main Methods:

• Utilized high-energy-density plasmas to simulate astrophysical conditions.
• Measured the T(³He,γ)⁶Li reaction rate directly for the first time.
• Compared experimental rates with those used in standard BBN models.

Main Results:

• The measured T(³He,γ)⁶Li reaction rate is significantly lower than previously inferred values.
• The experimental rate is insufficient to account for the high observed ⁶Li levels in low-metallicity stars.
• The findings indicate discrepancies with rates used in common BBN models.

Conclusions:

• The T(³He,γ)⁶Li reaction does not explain the observed high ⁶Li abundances.
• This study provides the first direct experimental data on a key BBN reaction.
• Laboratory plasmas offer a novel approach to investigate nuclear astrophysics problems.