arXiv subjects

Livio Lamia

Publications and source records attributed to Livio Lamia.

6 recordsLinked to original sources

arXiv2025

Big Bang Nucleosynthesis results refined via the Trojan Horse Method

This work presents the Trojan Horse Method (THM) as a powerful technique for measuring nuclear reaction cross sections at astrophysical energies. We then explore the impact of THM-derived reaction rates on the predictions of Standard Big Bang Nucleosynthesis (SBBN) using the PRIMAT code. Primordial abundances are shown for the single rate impact and, for the first time, also for all the THM rates together. The result shows significant differences with the use of THM rates, which in some cases goes in the direction of improving the agreement with the observations with respect to the use of only reaction rates from direct data, especially for the $^7$Li and deuterium abundances, which are still open issues for SBBN.

nucl-ex↗

arXiv2025

Solid Target production for Astrophysical Reasearch: the European target laboratory partnership in ChETEC-INFRA

The joint work of European target laboratories in the ChETEC-INFRA project is presented, to face the new experimental challenges of nuclear astrophysics. In particular, results are presented on innovative targets of 12,13C, 16O, and 19F that were produced, characterized, and, in some cases, tested under beam irradiation. STAR (Solid Targets for Astrophysics Research) is already acting to increase collaboration among laboratories, to achieve shared protocols for target production, and to offer a characterization service to the entire nuclear astrophysics community.

physics.ins-det↗

arXiv2021

The 27Al(p,a)24Mg reaction at astrophysical energies studied by means of the Trojan Horse Method applied to the 2H(27Al,a24Mg)n reaction

The 27Al(p,a)24Mg reaction, which drives the destruction of 27Al and the production of 24Mg in stellar hydrogen burning, has been investigated via the Trojan Horse Method (THM) by measuring the 2H(27Al,a24Mg)n three-body reaction. The experiment covered a broad energy range (-0.5 MeV < E_cm < 1.5 MeV), aiming to investigate those of interest for astrophysics.The results confirm the THM as a valuable technique for the experimental study of fusion reactions at very low energies and suggest the presence of a rich pattern of resonances in the energy region close to the Gamow window of stellar hydrogen burning (70-120 keV), with potential impact on astrophysics. To estimate such an impact a second run of the experiment is needed, since the background due the three-body reaction hampered to collect enough data to resolve the resonant structures and extract the reaction rate.

nucl-ex↗

arXiv2021

The impact of the new measurement of the $\rm ^{12}C+^{12}C$ fusion cross section on the final compactness of the massive stars

We discuss how the new measurement of the $^{12}C+^{12}C$ fusion cross section carried out with the Trojan Horse Method (Tumino, A., Spitaleri, C., La Cognata, M., et al., 2018, Nature 57, 687) affects the compactness of a star, i.e. basically the binding energy of the inner mantle, at the onset of the core collapse. In particular, we find that this new cross section significantly changes the dependence of the compactness on the initial mass with respect to previous findings obtained in Chieffi & Limongi 2020 (ApJ 890, 43) by adopting the classical cross section provided by Caughlan, G.R., and Fowler, W.D. 1988 (At. Data Nucl. Data Tables 40, 283). A non monotonic but well defined behavior is confirmed also in this case and no scatter of the compactness around the main trend is found. Such an occurrence could impact the possible explodability of the stars.

astro-ph.SR↗

arXiv2021

Re-evaluation of the $^{22}$Ne($α,γ$)$^{26}$Mg and $^{22}$Ne($α,n$)$^{25}$Mg reaction rates

The competing $^{22}$Ne($α,γ$)$^{26}$Mg and $^{22}$Ne($α,n$)$^{25}$Mg reactions control the production of neutrons for the weak $s$-process in massive and AGB stars. In both systems, the ratio between the corresponding reaction rates strongly impacts the total neutron budget and strongly influences the final nucleosynthesis. The $^{22}$Ne($α,γ$)$^{26}$Mg and $^{22}$Ne($α,n$)$^{25}$Mg reaction rates was re-evaluated by using newly available information on $^{26}$Mg given by various recent experimental studies. Evaluations of The evaluated $^{22}$Ne($α,γ$)$^{26}$Mg reaction rate remains substantially similar to that of Longland {\it et al.} but, including recent results from Texas A\&M, the $^{22}$Ne($α,n$)$^{25}$Mg reaction rate is lower at a range of astrophysically important temperatures. Stellar models computed with NEWTON and MESA predict decreased production of the weak branch $s$-process due to the decreased efficiency of $^{22}$Ne as a neutron source. Using the new reaction rates in the MESA model results in $^{96}$Zr/$^{94}$Zr and $^{135}$Ba/$^{136}$Ba ratios in much better agreement with the measured ratios from presolar SiC grains.

nucl-ex↗

arXiv2014

Experimental study to explore the $\rm ^8Be$ induced nuclear reaction via the Trojan Horse Method

To explore a possible indirect method for $\rm ^8Be$ induced astrophysical reactions, the $\rm ^9Be=({}^8Be+\it n)$ cluster structure was studied via the Trojan Horse Method. It is the first time to study a super short life nucleus $\rm ^8Be$ via the Trojan Horse Method, and it is the first time to make a valid test for $l=1$ Trojan-horse nucleus. The $\rm ^9Be$ nucleus is assumed to have a ($\rm {}^8Be+\it n$) cluster structure and used as the Trojan-horse nucleus. The $\rm ^8Be$ nucleus acts as a participant, while the neutron is a spectator to the virtual $\rm ^8Be +{\it d}\rightarrow α+ {}^6Li$ reaction via a suitable 3-body reaction $\rm ^9Be +{\it d}\rightarrow α+ {}^6Li +\it n$. The experimental neutron momentum distribution inside $\rm ^9Be$ was reconstructed. The agreement between experimental and theoretical momentum distribution indicates that there should be a ($\rm {}^8Be+\it n$) cluster structure inside $\rm ^9Be$. Therefor the experimental study of $\rm ^8Be$ induced reactions, for example the experimental measurement of the $\rm ^8Be +α\rightarrow {}^{12}C$ reaction proceeding through the Hoyle state, is possible.

nucl-ex↗