Dr. Marco La Cognata (INFN)
August 1(Thu) - August 1(Thu), 2024
13:00 KST
IBS HQ C312
Abstract
Nuclear reactions among charged particles in stars take place at energies generally well below the
Coulomb barrier, so its penetration factor exponentially suppresses the cross section down to values
as small as few nanobarns or picobarns. Approaching astrophysical energies opens new challenges
and calls for new approaches. I will introduce the mission of nuclear astrophysics and discuss how
experiments are usually conducted. I will focus on the use of indirect methods as complementary
approaches to direct measurements, discussing the asymptotic normalisation coefficient (ANC) and
the Trojan Horse Method (THM), used to deduce the cross sections of reactions with photons and
charged particles in the exit channel, respectively, with no need of extrapolation.
I will present recent results of the application of the two methods: the 6Li(3He,d)7Be measurement
used to deduced the ANC’s of the 3He+4He→ 7Be [1] and p+6Li→ 7Be [2] channels and the
corresponding radiative capture cross sections. Then, I will discuss about the THM measurement
of the 27Al(p, α)24Mg [3] cross section through the 2H(27Al,α24Mg)n reaction and of the 12C+12C
[4] fusion reaction cross section measured down to astrophysical energies, using 14N to transfer a
deuteron and induce the reaction of astrophysical importance. The indirect measurements made
it possible to assess the occurrence of several resonances that are responsible significant changes of
the reaction rate at relevant temperatures.
References
[1] G. G. Kiss et al., Physics Letters B 807 (2020) 135606.
[2] G. G. Kiss et al., Physical Review C 104 (2021) 015807.
[3] M. La Cognata et al., The Astrophysical Journal 941 (2022) 96.
[4] A. Tumino et al., Nature 557 (2018) 687.