Indirect7Li(p,α)4Hereaction at astrophysical energies

Lithium and boron burning S(E)-factor measurements at astrophysical energies via the Trojan Horse Method

“…These data have been used as new normalization points together with the other experimental data provided by the NACRE compilation [31]. For the 6 Li case, the THM analysis of [34] gives S(0)=3.44±0.39MeV barns and U e =355±100 eV. The THM reaction rate deviates from ∼5% to ∼15% as the temperature decreases from 1 down to 10 −2 T 9 , if compared with the evaluation of [35] (left panel of Fig.1).…”

“…The THM reaction rate deviates from ∼5% to ∼15% as the temperature decreases from 1 down to 10 −2 T 9 , if compared with the evaluation of [35] (left panel of Fig.1). To evaluate the astrophysical implications of these results, the FRANEC code has been used for pre-main sequence (PMS) models since the surface 6 Li is essentially burned in this stellar phase [36]. From such calculations, a clear influence of the temperature at the bottom of the convective envelope on the final amount of lithium has been found, i.e., the higher the metallicity, and/or the lower the stellar mass, the deeper and hotter the base of the convective envelope.…”

“…Thus the energy region of interest for astrophysics is usually explored by means of extrapolation procedures on the bare-nucleus S(E) b -factor because it smoothly varies with the energy, thus removing the exponential drop of the cross section ( [4]). In order to avoid extrapolation procedures on low-energy direct data, strongly affected by electron screening effects, the application of the Trojan Horse Method (THM) ( [5][6][7]) allows one to measure the bare nucleus S(E) b -factor for charged-particle induced reactions at astrophysical energies without experiencing both Coulomb penetrability and electron screening effects (see [8,9]). In addition, thanks to the pole-invariance effects, it allows for the study of the same binary reaction of interest for astrophysics by using different Trojan Horse (TH) nuclei, as explained in [10].…”

New determination of proton spectroscopic factors and reduced widths forBe8states in the 16.5–18.0 MeV excitation energy region via the study of theLi7(Belhout1, Ouichaoui2, Beaumevieille3 et al. 2017Phys. Rev. C4000View full textAdd to dashboardCite

“…In this respect, a careful, new and thorough R-Matrix analysis of up-dated, appropriately normalised angular distribution and integrated cross section experimental data sets available in the literature both via direct [33,59,60] and indirect [61][62][63] measurement methods for the 7 Li(p,α) 4 He hydrogen burning reaction of main astrophysical concern with considering the current DWBA results appears to us as highly desirable.…”

From the microcosm of the atomic nuclei to the macrocosm of the stars

“…In most cases, however, they are evaluated indirectly through the use of different techniques (e.g., [1,21,22]). …”