Ab Initio Prediction of the 4$$\mathrm{H}$$e($d, γ$)6$$\mathrm{L}$$i Big Bang Radiative Capture
- Facility for Rare Isotope Beams, East Lansing, MI (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Université Paris-Saclay, Orsay (France)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- TRIUMF, Vancouver, BC (Canada); University of British Columbia, Vancouver, BC (Canada)
- TRIUMF, Vancouver, BC (Canada); Univ. of British Columbia, Vancouver, BC (Canada)
We report the rate at which helium (4He ) and deuterium (d) fuse together to produce lithium-6 (6Li) and a γ ray, 4$$\mathrm{H}$$e($d, γ$)6$$\mathrm{L}$$i, is a critical puzzle piece in resolving the discrepancy between big bang predictions and astronomical observations for the primordial abundance of 6Li . The accurate determination of this radiative capture rate requires the quantitative and predictive description of the fusion probability across the big bang energy window (30 keV ≲ E ≲ 400 keV), where measurements are hindered by low counting rates. We present first-principle (or, ab initio) predictions of the 4$$\mathrm{H}$$e($d, γ$)6$$\mathrm{L}$$i astrophysical S factor using validated nucleon-nucleon and three-nucleon interactions derived within the framework of chiral effective field theory. By employing the ab initio no-core shell model with continuum to describe 4He-d scattering dynamics and bound 6Li product on an equal footing, we accurately and consistently determine the contributions of the main electromagnetic transitions driving the radiative capture process. Our results reveal an enhancement of the capture probability below 100 keV owing to previously neglected magnetic dipole (M1) transitions and reduce by an average factor of 7 the uncertainty of the thermonuclear capture rate between 0.002 and 2 GK.
- Research Organization:
- Michigan State Univ., East Lansing, MI (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Nuclear Physics (NP); USDOE Laboratory Directed Research and Development (LDRD) Program; National Research Council of Canada
- Grant/Contract Number:
- SC0013617; AC52-07NA27344; SAPIN-2016-00033; SAPPJ-2019-00039; PGSD3-535536-2019
- OSTI ID:
- 1923671
- Alternate ID(s):
- OSTI ID: 1887494
- Report Number(s):
- LLNL-JRNL-832850; SAPIN-2016-0003; SAPPJ-2019-00039; PGSD3-535536-2019; TRN: US2312452
- Journal Information:
- Physical Review Letters, Vol. 129, Issue 4; ISSN 0031-9007
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Solving The Long-Standing Problem Of Nuclear Reactions At The Highest Microscopic Level: Annual Continuation And Progress Report
Microscopic investigation of the 8Li(n,γ)Li9 reaction