Large high energy accelerators provide tools for investigation at the frontiers of our knowledge in subnuclear physics by probing the ultimate constituents of matter within always smaller space-time regions, and by generating new patterns of matter at always increasing energies. A complementary approach to the understanding of the fundamental properties of nature is the study at a very high degree of precision of rare phenomena, which clarify critical items of the theories and open the possibility of discriminating between different models of the physical reality. This latter line of research in subnuclear physics, requires dedicated colliders with very high peak luminosity and high operation reliability, in order to collect a huge amount of data.
At the beginning of the 90s the quest for high precision measurements of rare phenomena paved the way to the realization of lepton colliders, called “Factories”, aiming at an unprecedented high luminosity in the “low energy” region. DAFNE, the LNF “F-Factory” is an accelerator complex consisting of a double ring lepton collider working at the c.m. energy of the Φ-resonance (1.02 GeV).
The Phi particle is unstable and decays in a very short time into other lower energy particles, the most interesting being K mesons. This kind of particles showed up, right at their discovery in 1947, such unexpected features that a new physical entity, called “strangeness”, was introduced to explain them.
The Main Research Program at DAFNE, dedicated to the extremely precise study of the different decays of Phi and K mesons, has been carried out by the KLOE and KLOE-2 experiments. KLOE has been taking data on the DAFNE IR1 between 2001 and 2005. KLOE-2 is an upgrade of the KLOE detector taking data since 2014 until end of March 2018, on the IR1 Interaction Region, which was rebuilt to apply the “Crab-waist” scheme.
The FINUDA experiment, installed on the IR2 Interaction Region in 2003 was dedicated to studies on the spectroscopy and decay modes of hypernuclei, e.g. special nuclei, where a nucleon is replaced by a baryon made up of “strange” quarks (Lambda, Sigma, Csi). In DAFNE, Lambda hypernuclei were produced by stopping K mesons of known energy inside nuclear targets.
The SIDDHARTA (Silicon Drift Detector for Hadronic Atom Research by Timing Application) experiment, successor of DEAR (DAΦNE Exotic Atom Research), has performed precision measurements of the kaonic hydrogen and other kaonic atoms X-ray transitions using the unique DAFNE “beam” of negative kaons. SIDDHARTA has taken data in 2009 on IR1 with the first application of the “Crab-waist” scheme Interaction Region. SIDDHARTA-2, an upgrade of the SIDDHARTA detector will installed on IR1 in 2018 and will start with the first measurement of kaonic deuterium.
Due to the very large stored current, DAFNE is also an interesting high flux source of synchrotron radiation in the UV and soft X-ray wavelength region. DAFNE Light (link) are the synchrotron radiation beamlines from the bending magnets and wigglers of the DAFNE electron ring, which are in operation at the same time as colliding beams.