The goal of the AMADEUS experiment is to shed light on unsolved fundamental issues in the non-perturbative strangeness QCD sector through the study of lowenergy K
-
hadronic interactions with light ...nuclear targets. The main open questions are the controversial nature of the Δ(1405) state, which is investigated in hyperon-pion correlation studies, and the possible existence of exotic antikaon multi-nucleon clusters, whose search in K
-
induced reactions is intimately related to the studies of the K
-
multi-nucleon absorption processes in hyperon-nucleon/nucleus channels. The DAΦNE collider at the INFN-LNF provides unique monochromatic low-momentum kaons from the φ meson decay almost at-rest, suitable for the AMADEUS studies. The KLOE detector is exploited as an active target, in order to obtain excellent acceptance and resolution data for K
-
nuclear capture on H,
4
He,
9
Be and
12
C, both at-rest and in-flight.
The E2 nuclear resonance effect in kaonic atoms occurs when the energy of atomic de-excitation closely matches the energy of nuclear excitation, leading to the attenuation of some X-ray lines in the ...resonant isotope target. This phenomenon provides crucial information on the strong interaction between kaons and nuclei. The only nuclear E2 resonance effect observed so far was in the K
−
−
98
42
Mo isotope, measured by G. L. Goldfrey, G-K. Lum, and C. E. Wiegand at Lawrence Berkeley Laboratory in 1975. However, the 25 hours of data taking were not sufficient to yield conclusive results. In four kaonic Molybdenum isotopes (
94
42
Mo,
96
42
Mo,
98
42
and Mo, and
100
42
Mo), the nuclear E2 resonance effect is expected to occur at the same transition with similar energy values. To investigate this, the KAMEO (Kaonic Atoms Measuring Nuclear Resonance Effects Observables) experiment plans to conduct research on kaonic Molybdenum isotopes at the DAΦNE e
+
e
−
collider during the SIDDHARTA-2 experiment. The experimental strategy involves exposing four solid strip targets, each enriched with one Molybdenum isotope, to negatively charged kaons and using a germanium detector to measure X-ray transitions. In addition, a non-resonant
92
42
Mo isotope solid strip target will be used as a reference for standard non-resonant transitions.
The kaonic 3He and 4He 3d→2p transitions in gaseous targets were observed by the SIDDHARTA experiment. The X-ray energies of these transitions were measured with large-area silicon-drift detectors ...using the timing information of the K+K− pairs produced by the DAΦNE e+e− collider. The strong-interaction shifts and widths both of the kaonic 3He and 4He 2p states were determined, which are much smaller than the results obtained by the previous experiments. The “kaonic helium puzzle” (a discrepancy between theory and experiment) was now resolved.
The Pauli Exclusion Principle is one of the most fundamental rules of nature and represents a pillar of modern physics. According to many observations the Pauli Exclusion Principle must be extremely ...well fulfilled. Nevertheless, numerous experimental investigations were performed to search for a small violation of this principle. The VIP experiment at the Gran Sasso underground laboratory searched for Pauli-forbidden X-ray transitions in copper atoms using the Ramberg-Snow method and obtained the best limit so far. The follow-up experiment VIP2 is designed to reach even higher sensitivity. It aims to improve the limit by VIP by orders of magnitude. The experimental method, comparison of different PEP tests based on different assumptions and the developments for VIP2 are presented.
The kaonic helium-4 3d→2p X-ray transition was measured in a gaseous target, where Compton scattering in helium is negligible. The X-rays were detected with large-area Silicon Drift Detectors (SDDs) ...using the timing information of the K+K− pairs produced by ϕ decays at the DAΦNE e+e− collider. A new value of the strong interaction shift of the kaonic 4He 2p state was determined to be 0±6 (stat)±2 (syst) eV, which confirms the recently obtained result by the KEK-PS E570 group.
KAMEO (Kaonic Atoms Measuring Nuclear Resonance Effects Ob-servables) is a proposal for an experiment aiming to perform the first consistent measurement of the E2 nuclear resonance effects in kaonic ...molybdenum A=94,96,98,100 isotopes. The E2 nuclear resonance mixes atomic states, due to the electrical quadrupole excitation of nuclear rotational states. It occurs in atoms having the energy of a nuclear excitation state closely matching an atomic de-excitation state energy, and affects the rates of X-ray atomic transitions matching the energy of the resonance. The measurement E2 nuclear resonance effect in KMO isotopes allows the study of the strong kaon-nucleus interaction in a rotational excited nuclear state. Moreover, the effect enables the K - to access an inner atomic level not easily reachable by the kaon normal cascade, due to the nuclear absorption. The KAMEO proposed apparatus consists of 4 enriched Mo A=94,96,98,100 isotope strips, exposed to the kaons produced by the DAφNE collider, for kaonic atoms formation, with a high-purity germanium detector, cooled with liquid nitrogen, used to measure the X-ray atomic transitions. The DAφNE collider is located at the National Laboratories of Frascati (LNF-INFN), in Italy. It is already suited for kaonic atoms measurement by the SIDDHARTA-2 collaboration.
One of the fundamental rules of nature and a pillar in the foundation of quantum theory and thus of modern physics is represented by the Pauli Exclusion Principle. We know that this principle is ...extremely well fulfilled due to many observations. Numerous experiments were performed to search for tiny violation of this rule in various systems. The experiment VIP at the Gran Sasso underground laboratory is searching for possible small violations of the Pauli Exclusion Principle for electrons leading to forbidden X-ray transitions in copper atoms. VIP is aiming at a test of the Pauli Exclusion Principle for electrons with high accuracy, down to the level of 10−29 – 10−30, thus improving the previous limit by 3–4 orders of magnitude. The experimental method, results obtained so far and new developments within VIP2 (follow-up experiment at Gran Sasso, in preparation) to further increase the precision by 2 orders of magnitude will be presented.
In the exotic atoms where one atomic 1s electron is replaced by a K−, the strong interaction between the K− and the nucleus introduces an energy shift and broadening of the low-lying kaonic atomic ...levels which are determined by only the electromagnetic interaction. By performing X-ray spectroscopy for Z = 1,2 kaonic atoms, the SIDDHARTA experiment determined with high precision the shift and width for the 1s state of K− p and the 2p state of kaonic helium-3 and kaonic helium-4. These results provided unique information of the kaon-nucleus interaction in the low energy limit.
The main steps for the analysis of the Λp correlated production in low-energy K− captures on Carbon nuclei, performed by the AMADEUS collaboration, are presented. The goal is to perform the first ...comprehensive study of the K− absorption on two, three and four nucleons, exploiting the lowmomentum K−s (pK ~ 127 MeV/c) produced at the DAΦNE collider, and to measure the low-energy cross sections and branching ratios of the K− multinucleon absorption processes in both the Λp and Σ0p channels. An integrated luminosity of 1.74 fb−1 collected during the KLOE 2004/2005 data campaign is analysed by reconstructing the Λp final state.
Detector setup of the VIP2 underground experiment at LNGS Marton, J.; Pichler, A.; Shi, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
Odprti dostop
The VIP2 experiment tests the Pauli Exclusion Principle with high sensitivity, by searching for Pauli-forbidden atomic transitions from the 2p to the 1s shell in copper at about 8keV. The transition ...energy of Pauli-forbidden Kα X-rays is shifted by about 300 eV with respect to the normal allowed Kα line. This energy difference can be resolved using Silicon Drift Detectors. The data for this experiment is taken in the Gran Sasso underground laboratory (LNGS), which provides shielding from cosmic radiation. An overview of the detection system of the VIP2 experiment will be given. This includes the Silicon Drift Detectors used as X-ray detectors which provide an energy resolution of around 150 eV at 6 keV and timing information for active shielding. Furthermore, the low maintenance requirement makes them excellent X-ray detectors for the use in an underground laboratory. The VIP2 setup will be discussed which consists of a high current target system and a passive as well as an active shielding system using plastic scintillators read out by Silicon Photomultipliers.
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