Direct and Indirect Measurements for a Better Understanding of the Primordial Nucleosynthesis

Abstract

The Big Bang Nucleosynthesis (BBN) model is a great success of nuclear astrophysics due to the outstanding agreement between observational and predicted light elements abundances. One exception, however, is the so-called "lithium problem." In this context, experimental efforts to measure the relevant reactions have been brought to an increased level of accuracy in measuring primordial abundances, and the introduction of indirect methods has allowed researchers to overcome the natural limitations of direct measurements in the energy range of interest for BBN. Here we review the results obtained from the application of the Trojan Horse Method to some of the most influential reactions of the standard network, such as 2 H(d,p) 3 H, 2 H(d,n) 3 He, 3 He(d,p) 4 He, 7 Li(p,α) 4 He, and 7 Be(n,α) 4 He. The relevant cross sections have been then used as new inputs to a classical BBN code, resulting in important constraints that make suggestions for a possible solution for the lithium problem outside of nuclear physics.

Comparative role of the 7Li(n, γ ) reaction in Big Bang nucleosynthesis

“…Among the 16 ones we selected 8 reactions leading to the 7 Li destruction, but to the creation of the heavier nuclei with A > 7 and provided by the analytical reaction rates illustrated in figure 5. These are four (curves 1-4) radiative capture reactions 7 Li(n, γ) To do the data in figure 5 more 'readable', let us remind that the BBN temperature range is 0.2 < T 9 < 3.2 [59,66]. The BBN end is T 9 ≈ 1, and corresponds to the maximum of D and 7 Li abundances.…”

Few-Body Reactions with the Trojan Horse Method

“…In this framework, many indirect methods have been developed with the aim of measuring the bare nucleus cross section for reactions of astrophysical interest, avoiding experimental problems due to Coulomb barrier and electron screening effect. The THM has been applied in the last decades to the study of charged-particle reactions as well as neutroninduced reactions involved in several astrophysical scenarios (see [7][8][9][10][11][12][13][14][15][16][17] for recent results and reviews). THM has also been employed to study reaction induced by radioactive nuclei [18][19][20][21], expanding the THM research field to nuclear processes that take place in explosive astrophysical environments.…”

Design and first operations of a ECR based He source at INFN-LNS

“…In particular, they are quite attractive for Tandem accelerators, which are largely used worldwide for performing nuclear physics and nuclear astrophysics experiments. The demand of, among the others, He − beams is steadily increasing since these nuclides are responsible of a number of nuclear reactions of astrophysical interest (see for example [5,6,7]). In addition, intense beams of noble gases are also used in applied research and industry, e.g.…”