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Electron Positron Collider DAΦNE
It's a φ-factory consisting of a double ring collider for electrons and positrons with 510 MeV energy per beam. More in detail, a high current linac produces up to 500 mA electron and 100 mA positron beams, feeding them to a ring where they are stacked and damped; from the damping ring they are injected into two identical but separate storage rings. The two rings cross at two interactions points where the experiments are installed. DAΦNE is a multi-bunch accelerator, with 120 bunches/beam, with a peak luminosity of 2×1032 cm-2 s-1 and an integrated luminosity of 16 pb-1 /day
| PARTICLE AND NUCLEAR PHYSICS |
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The KLOE experiment has been designed for the study of CP, CPT violation in the neutral kaon system. Its unique feature consists in producing kaon pairs, KS0 KL0 and K+ K- , in a pure quantum state from the two body φ-decay, thus allowing to get intense, pure, monochromatic and tagged kaon beams. It is composed of two main detectors: a fine sampling lead scintillating fiber calorimeter, EMC, for the energy and time measurement and neutral vertex reconstruction, and a light material cylindrical drift chamber, DC, for high precision and efficient tracking of charged particles. The detector is immersed in a 0.52 T magnetic field provided by a large superconductive coil. The detector is read out by a very high bandwidth data acquisition system. A powerful computing farm, with a large and robotized storage system, is then used for online monitoring, offline data reconstruction, simulation and users analysis.
A lot of interesting interferometry tests in the KS0 KL0 system is accessible in the experiment thus allowing to test the basic foundations of quantum mechanics, QM. Indeed, in case of similar final state for KS0 and KL0, QM forbids the two kaons to decay at same distance from the interaction point (EPR paradox). Tests of coherence-loss in the time evolution of the KS0-KL0 state, or quantum gravity related effects modifying the initial state definition, can be carried out with large statistical samples.
The same characteristic allows also to tag in a simple way pure KS0, KL0, K+ and K- beams by identify the other kaon in the opposite direction. In particular DAΦNE is the only source of a pure KS0 beam.
Last but not least, the radiative φ decays make DAΦNE also a high production source of η, η’, a0(980), f0(980) mesons. For instance, in the η case the tagging is provided by identification of a mono-energetic photon of 363 MeV with an overall production rate of ~ 40 x 106 η/fb-1.
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A very relevant upgrade of KLOE, dubbed kloe2, has been carried out.
Two subdetectors aimed at tagging the forward scattered leptons of 2-photon collisions have been installed. They consist of a pair of calorimeters placed at 1.5 m from the IP and a pair of hodoscopes installed after the machine’s bending dipoles. Moreover, a deep modification of the innermost part of the detector has been performed. A new internal chamber, based on the GEM technology, has been built. A tungsten-scintillating tiles calorimeter now covers the machine’s focusing quadrupoles. A LySO crystals calorimeter has been installed in the forward region.
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The SIDDHARTA2 setup experiment represents a major upgrade of the SIDDHARTA apparatus for a complete, much richer, series of hadronic (mainly kaonic) atoms transition measurements. SIDDARTHA2 will use a much improved setup: bigger and denser target cell; more efficient cooling; new trigger system and use of a veto system against background, as well as new SDD and crystal detectors for X and γ rays precision measurements . SIDDHARTA2 is planning a series of measurements, a real many-years campaign, representing the biggest effort ever done in this sector, combining the best low-energy kaon beam from DAΦNE with the best possible setup, to perform the first kaonic deuterium measurement. The final goal of the deuterium measurement is to determine both antikaon-nucleon isospin dependent scattering lengths, quantities never measured before. Measuring the antikaon-nucleon scattering lengths with the precision of a few percent will drastically change the present status of low-energy antikaon-nucleon phenomenology and also provide a clear assessment of the SU(3) chiral effective Lagrangian approach to low energy hadron interactions giving so a strong boost to the low-energy kaon-nucleon/nuclei interaction physics.
Other measurements planned within the SIDDHARTA2 experiment are; the first kaonic 3,4He measurements of the transitions to the 1s level; other kaonic atoms transitions measurements, for light and heavier targets; feasibility measurements of the kaon radiative capture, of charged kaon mass and of sigmonic atoms.
- The AMADEUS experiment plans to perform unprecedented measurements in the sector of the low-energy kaons interactions in nuclei, by combining the unique quality of the kaon beam delivered by DAΦNE with a high-performance detector system. As a first step AMADEUS is performing studies for the low-energy kaons interacting in the KLOE materials (Drift Chamber entrance window and gas; beam pipe, inner tracker), in collaboration with KLOE2. As a second dedicated stage AMADEUS plans to realize a new detector system by using the KLOE magnet and calorimeter, implementing in the central region a high technology pressurized cryogenic target (containing high density gaseous hydrogen; deuterium; 3,4He), a trigger and a tracker system (which could be an active target).
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| The DAΦNE Beam-Test Facility (BTF), operating at the Frascati National Laboratory of INFN (LNF), provides electron or positron beams with tuneable energy from 50 MeV to 750 MeV, while the intensity can be varied from 1010 particles per pulse, down to a single particle per pulse. The pulse width is 1 or 10 ns, with a maximum repetition rate of 50 Hz. Since the end of 2005 a photon tagging system has been designed and built. During 2006 a pulsed dipole magnet has been inserted at the end of the LINAC, allowing to continuously deliver beam in the BTF experimental area also during DAΦNE main ring injection. |
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