Programme

O.30 -- Oral, VCTP-51

Date: Thursday, 6 August 2026

Time: 08:30 - 08:50

From the First Radiative Capture Reactions to the Primordial Deuterium Abundance

Dao Nhut Anh (1), Nguyen Gia Huy (1), Hoang Thai An (1), Nguyen Le Anh (1)

(1) Department of Physics, Ho Chi Minh City University of Education, Ho Chi Minh City

The primordial deuterium abundance provides one of the most sensitive probes of Big Bang nucleosynthesis and the baryonic content of the Universe. In this work, the two earliest radiative capture reactions, $p(n,\gamma)d$ and $d(p,\gamma)^3\mathrm{He}$, are investigated within a two-body potential framework based on the Malfliet--Tjon interaction. The nuclear model parameters are constrained by the thermal capture data of the $p(n,\gamma)d$ reaction and consistently applied to the calculation of the $d(p,\gamma)^3\mathrm{He}$ reaction rate. The resulting reaction rate is incorporated into a Big Bang nucleosynthesis network to evaluate the primordial deuterium abundance, yielding \[ \mathrm{D/H}=2.479^{+0.350}_{-0.177}\times10^{-5}. \] The predicted value is consistent with observational constraints from metal-poor astrophysical systems, indicating that simple microscopic descriptions of low-energy radiative capture reactions can provide reliable nuclear inputs for cosmological studies.

Presenter: Dao Nhut Anh