Experimental challenges in low-energy nuclear astrophysics

Nuclear astrophysics is an interdisciplinary field at the border between nuclear physics and astrophysics. It aims at answering fundamental questions such as how and where are elements synthesised, how energy is generated in stars and how stars evolve and eventually die. Nuclear astrophysics experiments use Earth-bound facilities to investigate nuclear reactions and nuclear properties of interest in stellar scenarios. This review will focus in particular on thermonuclear reactions occurring in relatively low temperature scenarios (T < 1 GK) such as quiescent burning stars and classical novae. Because of the hindering effect of the Coulomb repulsion between nuclei, nuclear cross sections in these scenarios can be extremely small (10(-12) barn and even lower) and the signals produced can be challenging to disentangle from the natural background on the Earth's surface. Moving underground to reduce the background induced by cosmic rays is one possible solution to this problem. For more than 20 years, the LUNA experiment has studied nuclear reactions employing accelerators based deep underground in the Gran Sasso Laboratory in Italy. In this review, recent results obtained at LUNA, as well as future prospects at the new LUNA-MV accelerator, soon to be installed underground will be reviewed. Another possible approach is to employ indirect methods to probe nuclear properties of astrophysical interest. This review work will mention in particular the novel possibility of carrying out nuclear astrophysics experiments at the newly commissioned CRYRING storage ring in GSI, Germany.