Towards the study of 2H(p, γ)3He reaction in the Big Bang Nucleosynthesis energy range in LUNA

8th European Summer School on Experimental Nuclear Astrophysics (Santa Tecla School)

物理学;天文学

Kochanek, Izabela^1

Laboratori Nazionali del Gran Sasso, INFN, Italy^1

关键词: Ab initio calculations;    Astrophysical S factors;    Big bang nucleosynthesis;    Cosmic microwave backgrounds;    Cosmological parameters;    High-accuracy measurements;    Nuclear cross sections;    Systematic uncertainties;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/703/1/012023/pdf
DOI  :  10.1088/1742-6596/703/1/012023

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

The Big Bang Nucleosynthesis began a few minutes after the Big Bang, when the Universe was sufficiently cold to allow deuterium nuclei to survive photo-disintegration. The total amount of deuterium produced in the Universe during the first minutes depends on the cosmological parameters (like the energy density in baryons, ωbh2, and the effective neutrino number, Neff) and on the nuclear cross sections of the relevant reactions. The main source of uncertainty in the deuterium estimation comes from the2H(p, γ)3He cross section. Measurements of Cosmic Microwave Background (CMB) anisotropies obtained by the Planck satellite are in very good agreement with the theoretical predictions of the minimal ΛCDM cosmological model, significantly reducing the uncertainty on its parameters. The Planck data allows to indirectly deduce with very high precision the abundances of primodial nuclides, such as the primodial deuterium fraction2H/H = (2.65 ± 0.07) .10-5(68% C.L.). The astrophysical observations in damped Lyman-a systems at high redshifts provide a second high accuracy measurement of the primodial abundance of deuterium2H/H = (2.53 ± 0.04) • 10-5(68% C.L.). The present experimental status on the astrophysical S-factor of the2H(p, γ)3He reaction in the BBN energy range, gives a systematic uncertainties of 9%. Also the difference between ab-initio calculations and experimental values of S12 is at the level of 10%. In order to clarify the actual scenario, a measurement of2H(p, γ)3He cross section with a precision of a few percent in the 70-400 keV energy range is planned at LUNA in 2016. A feasibility test of the measurement has been performed in October 2014, giving the preliminary results on the cross section. The experimental setup for the test and final measurement campaign will be presented.