A New Measurement of the $$^{2}\mathrm {H}_{}(\mathrm {p},\gamma )^{3}He_{}$$ Cross Section in the BBN Energy Range at LUNA

Abstract

Deuterium is the first nucleus produced in the Universe whose accumulation marks the beginning of the so called Big Bang Nucleosynthesis (BBN). Its primordial abundance is very sensitive to some cosmological parameters like the baryon density and the number of the neutrino families. Presently the main obstacle to an accurate theoretical deuterium abundance evaluation is due to the poor knowledge of the \(^{2}\mathrm {H}_{}(\mathrm {p},\gamma )^{3}He_{}\) cross section at BBN energies. This paper reports on the measurements of the \(^{2}\mathrm {H}_{}(\mathrm {p},\gamma )^{3}\mathrm {He}_{}\) reaction cross section performed at the Laboratory for Underground Nuclear Astrophysics (LUNA) facility in the Gran Sasso Laboratory (LNGS). After a general introduction on the astrophysical and cosmological relevance of \(^{2}\mathrm {H}_{}(\mathrm {p},\gamma )^{3}\mathrm {He}_{}\) reaction cross section, the experimental setup used for the measurement campaign is described. The results obtained so far and the perspectives of the still on-going measurements are also discussed.