Experiments in astroparticle physics study radiation and cosmic particles. Laboratories on the ground, underground, under the sea, at high altitudes and in space provide the natural settings for these experiments. At the Gran Sasso national laboratory, the biggest underground laboratory in the world, cutting-edge detectors are currently being used to study the dark matter, neutrinos and rare phenomena that can only be detected in conditions of “cosmic silence”, guaranteed by the protection of the rock. The environment protected against penetration by cosmic rays is also ideal for astrophysics research, such as the study of solar neutrinos and supernova neutrinos. Astroparticle physics has also found new openings in different environments: in space, where satellite detectors have direct access to primary cosmic rays that would be mitigated by the atmosphere on the earth’s surface; high-altitude laboratories, for high-energy gamma-ray astronomy; laboratories under the sea for astronomy with high-energy neutrinos, which travel unhindered through the entire globe before being detected by detectors on the seafloor. Italian physicists also carry out pioneering work in the measurement of gravitational waves, both using resonant bar antennae and in developing large interferometric detectors.

The research activities of CSN4, involving around 1,000 scientists from all divisions of the INFN and three of the four national laboratories, regard so-called “Specific Initiatives” and are conducted in close collaboration with the academic world.

The theoretical research carried out by the INFN is of huge international interest. This is borne out by more than 1,200 scientific works and papers published in international journals with referees, the large number of citations and presentations at the most authoritative international conferences. The INFN works in close collaboration with theoretical physics researchers from around the world, in a constant exchange of ideas and experience among the various research agencies and with a significant contribution by young people (post-graduate and/or post-doctoral students), as reflected by some 300 theses and 70 doctoral dissertations produced each year.

In recent years, the INFN has also made a notable contribution to the development of parallel computers, for instance under the APE (Array Processor Experiment) project, of particular interest for research in the field of strong interactions and lattice gauge theories.

Current experiments use high-energy particle collisions to study how the elementary particles of matter, quarks, come together to form the nuclei of atoms. The collision between an electron and a nucleus – in research pursued by the INFN collaboration at the Jefferson Lab – will provide a three-dimensional image of the inside of the nucleus while collisions between lead nuclei – at CERN in Geneva – can, for a short instance, produce a bubble of quark-gluon plasma, the primordial state of matter. The formation of the stars, which only appeared as the universe expanded and cooled, is the subject of research at the INFN’s national laboratories. At the Gran Sasso national laboratory, for instance, the small LUNA accelerator is used to study the formation of nuclei with energies comparable to those of stars, which are much lower than the energies obtained with normal particle accelerators. The Legnaro and Southern national laboratories house some of the most advanced accelerators and detectors in the world, which are used to produce and study the characteristics of unstable nuclei. One of the main aims of these experiments is to understand the mechanisms underlying the formation of heavy nuclei, with a mass greater than that of iron, in large stars. Scientists at the Frascati national laboratory are involved in ongoing research into nuclear force in the presence of “strange” quarks, which is important for understanding the behaviour of neutron stars.

The INFN is involved in some major experimental projects that will open up new frontiers for research into detectors and detector electronics. R&D activity in this field regards high-energy, high-intensity electron accelerators, proton and ion accelerators to produce radioactive beams and for hadron therapy applications. Other projects are concerned with accelerators for producing very-high-energy and highly coherent electromagnetic radiation (X-FEL) and the ESS (European Spallation Source) project being developed at Lund in Sweden.

The INFN’s research work in biomedicine has important implications for medical imaging, cancer treatment, dosimetry and the study of cell growth and neurological models. Furthermore, the highly advanced, extremely sensitive measurement technologies and systems developed as the result of experiments in fundamental physics are increasingly being used in the analysis of objects of artistic, archaeological and historical interest.

The INFN collaborates through CSN5 with the leading national and regional research and monitoring agencies operating in the public health sector, including the Italian National Institute of Health (ISS), the Ministry of Health, foundations and national and regional health authorities, as well as with other research agencies (ITT, CNR, INGV) and, of course, with universities. Technological transfer is also fostered through the development of specific collaboration agreements with industrial associations (CONFINDUSTRIA and CONFAPI).