Nuclear astrophysics

Nuclear astrophysics aims at investigating nuclear reactions which play a role in both energy generation and synthesis of the elements in stellar sites (stellar nucleosynthesis) as well as the ones involved in the primordial Big Bang nucleosynthesis (BBN). Regarding stellar nucleosynthesis, charged-particle induced reactions mostly drive the energy production in stars via the pp-chain or the CNO-cycle, according to the initial stellar mass. However, nuclear reactions play also a significant role in the genesis of the elements for which detailed measurements of the corresponding cross section are needed.  Regarding BBN, nuclear astrophysics aims at solving some of the most challenging open problems of interest for the primordial nucleosynthesis, such as the still unsolved lithium-problem for which the observed lithium abundances do not match the inferred ones from CMB analysis.

Although the improvements in our understanding of stellar phsysics, some reactions are of paramount importance and, unfortunately, their full understanding is far to be completely reached.  In details, in both stellar or primordial nucleosynthesis, charged-particle induced reactions occur at energies lower than the Coulomb barrier between the interacting nuclei thus implying the play of the quantistic tunnel effect for their interaction. This effect strongly reduces the cross section values to the nano or picobarn regime and therefore represents a serious difficulty for experimentalist.

The AsFiN  (AstroFisica Nucleare) research group in Catania has been active in the field of experimental nuclear astrophysics over the last 25 years. The ASFIN's studies are supported by Commissione Scientifica Nazionale 3 (CSNIII) of INFN. The goal of the AsFiN group is to measure the cross section for astrophysically relevant nuclear reactions by means of indirect methods.

In particular, the AsFiN group is widely recognized by the scientific community as the leader in the application of the Trojan Horse Method (THM). This indirect method has been largely adopted for shedding light on several astrophysical problems, such as primordial nucleosynthesis, light-elements burning, neutron source or poison in stellar evolution, advanced stellar phases nucleosynthesis and explosive nucleosynthesis.  The main result about the THM 13C(α,n)16O study is shown on the right as published in Phys. Rev. Letters.

The experimental activity of the AsFiN group is usually performed at Laboratori Nazionali del Sud (LNS-INFN) of Catania, even if the existing international collaborations allow to perform different experiments in both national (Padova, Napoli, Frascati) and international (Riken-Tokyo, ASCR-Prague, TAMU-College Station, FSU-Thallassee, CIAE-Bejing…) institutions. In addition, the AsFiN group has recently started to measure laser induced and plasma induced nuclear reactions of interest for astrophysics. The results of such experiments have been already published in top quality journal (PRL, PRC, ApJ, A&A, JpG…).

The AsFiN group organizes the biennial school “European Summer School on Experimental Nuclear Astrophysics” since 2001. The aim of the school is the education of young researchers working in the field of nuclear astrophysics by organizing a series of lectures on the most important topics in the field given by top quality scientist. Info about the 10th edition of 2019 can be found here.

L. Lamia (Spokesperson-UniCT), R. G. Pizzone (Spokesperson-INFN), P. Figuera (Local resp.-INFN)
- UniCT-DFA: S. Cherubini, M. Lattuada, A.A. Oliva, S. Romano, M.L. Sergi, C. Spampinato, C. Spitaleri, R. Spartà;
- INFN-LNS: R. Alba, M. La Cognata, A. Di Pietro, G.L. Guardo, M. Gulino, P. Prajapati, D. Lattuada, G.G. Rapisarda, D. Santonocito, A. Tumino;
- INFN-NA: M. La Commara (Local resp.) & collaborators ;
- INFN-PD: M. Mazzocco (Local resp.) & collaborators;
- INFN-PG: S. Palmerini (Local resp.) & collaborators.

1) "Cross section measurement of the cosmologically relevant 7Be(n,alpha)4He reaction over a broad energy range in a single experiment" L. Lamia et al. 2019, Astrophys. Journ., 879, 23;
2) "Observation of 15N+alpha resonant structures in 19F using the thick target in inverse kinematics scattering method" M. La Cognata et al. 2019, Phys. Rev. C, 99, 034301;
3) "An increase in the 12C+12C fusion rate from resonances at astrophysical energies" A. Tumino et al. 2018, Nature, 557, 687;
4) "Measurement of the 10B(p,alpha)7Be cross section from 5 keV to 1.5 MeV in a single experiment using the THM" C. Spitaleri et al. 2017, Phys. Rev. C, 95, 035801;
5) "First measurement of the 19F(alpha,p)22Ne reaction at energies of astrophysical relevance" R.G. Pizzone et al. 2017, Astrophys. Journ., 836, 57.

Additional info about our research activities as well as about our latest experiments and contributions to international conferences can be found on our Facebook page ASFIN

CONTACT PERSON: Livio Lamia and Stefano Romano