Improved information on astrophysical S-factor for the 10B(p,α0)7Be reaction using the Trojan Horse method

The 10B(p,α0)7Be reaction has been studied by applying the Trojan Horse method to the 2H(10B,α0 7Be)n reaction. The bare-nucleus astrophysical S(E)-factor in absolute units was extracted in a wide energy range, from 2.2 MeV to 3 keV and normalized to the direct experimental data, thus allowing determination of the electron screening potential for which a value of Ue=391±74 eV was obtained

Indirect Study of the 16O+16O Fusion Reaction Toward Stellar Energies by the Trojan Horse Method

The 16 O+ 16 O fusion reaction is important in terms of the explosive oxygen burning process during late evolution stage of massive stars as well as understanding of the mechanism of low-energy heavy-ion fusion reactions. We aim to determine the excitation function for the most major exit channels, α + 28 Si and p + 31 P, toward stellar energies indirectly by the Trojan Horse Method via the 16 O( 20 Ne , α 28 Si) α and 16 O( 20 Ne , p 31 P) α three-body reactions. We report preliminary results involving reaction identification, and determination of the momentum distribution of α - 16 O intercluster motion in the projectile 20 Ne nucleus

On the magnitude of the 8Li + 4He → 11B + n reaction cross section at the Big-Bang temperature

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The 19F(α, p)22Ne and 23Na(p,α)20Ne reaction in AGB nucleosynthesis via THM

In AGB environment, fluorine and sodium abundances are still matter of debate. About 19F (only stable isotope of fluorine), its abundance in the universe is strictly related to standard and extra-mixing processes taking place inside AGB-stars, that are considered to be the most important sites for its production. Nevertheless the way in which it is destroyed is far from being well understood. On the other hand, 23Na presence in Globular Clusters, along with is well-known anticorrelation with oxygen has made clear that this element must be produced in previous generations stars, and intermediatemass AGB stars are one of the possible candidates for its production. For this reason we studied the 19F(α,p)22Ne and 23Na(p,α)20Ne reactions in the energy range of relevance for astrophysics via the Trojan Horse Method (THM), using the three-body reactions 6Li(19F, p22Ne)d and 23Na(d, pn)20Ne

A new high-precision upper limit of direct α-decays from the Hoyle state in 12C

International audience; The Hoyle state in 12C(Ex = 7.654MeV) is characterized by a pronounced 3α cluster configuration. It is involved in the so-called 3α process in stars, that is responsible of 12C nucleosynthesis. We studied the decay path of the Hoyle state by using the 14N(d, α2)12C(7.654) reaction at 10.5MeV incident energy. We found, with a precision higher of a factor 5 than any other previous experiment, an almost total absence of direct decays by-passing the ground state of 8Be. A new upper limit of such a decay width is placed at 0.043% (95% C.L.). Astrophysical 3α process reaction rate calculations have to be consequently revised

Study of 3He(n,p)3H reaction at cosmological energies with trojan horse method

In the network of reactions present in the Big Bang nucleosynthesis, the 3He(n, p)3H has an important role which impacts the final 7Li abundance. The Trojan Horse Method (THM) has been applied to the 3He(d, pt)H reaction in order to extract the astrophysical S(E)-factor of the 3He(n, p)3H in the Gamow energy range. The experiment will be described in the present work together with the first preliminary results

Resonance Strength Measurement at Astrophysical Energies: The 17O(p,α)14N Reaction Studied via THM

In recent years, the Trojan Horse Method (THM) has been used to investigate the low-energy cross sections of proton-induced reactions on 17O nuclei, overcoming extrapolation procedures and enhancement effects due to electron screening. We will report on the indirect study of the 17O(p,α)14N reaction via the Trojan Horse Method by applying the approach developed for extracting the resonance strength of narrow resonance in the ultralow energy region. The mean value of the strengths obtained in the two measurements was calculated and compared with the direct data available in literature