The study of the structure of the atomic nucleus and strong nuclear interaction was the first step towards a deeper understanding of matter: from protons and neutrons to quarks, towards the Standard Model of particle physics.
The Frascati National Laboratories have always played a key role in this research field, implementing experiments on site or at other international laboratories, at the frontier of physics knowledge for a deeper understanding of fundamental interactions in the field of nuclear physics and their role in the Universe, from the Big Bang to the present day.
Strong interaction, one of the four fundamental interactions in the Universe, is described by quantum chromodynamics (QCD). Many aspects of QCD, especially at low energies, remain unclear due to the lack of experimental data.
Just a few millionths of a second after the Big Bang, the entire Universe was filled with a plasma composed of quarks and gluons, fundamental entities of matter and nuclear force.
Photoproduction of mesons as a probe of the excitation structure of the nucleon has been exploited since the 1960s. The use of GeV-range energy polarised tagged photon beams at high duty cycle electron accelerators in combination with large acceptance detectors, like CLAS and GLUEX at Jefferson Laboratory, A2 at MAMI, Crystal Barrel at ELSA, GrAAL at ESRF, and LEPS at SPring8, has in recent years put the technique on par with pion scattering to unravel the complex nucleon excitation patterns, allowing for a better understanding ...
Atomic nuclei are made up by protons and neutrons (or nucleons) that together constitute more than 99% of the visible matter in the universe. They are made by elementary constituents, quarks and gluons, whose interactions are described by the Quantum Chromo Dynamics (QCD).
One of the fundamental principles of quantum mechanics and modern physics is the Pauli Exclusion Principle (PEP). The most direct consequence is the structure of atoms: the way in which electrons fill the different atomic layers around the nucleus. Without this principle, matter would not exist in the known form.