The VIP experiment, operated at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN, aims to perform high sensitivity tests of the Pauli Exclusion Principle (PEP) for electrons. In the context of Local Quantum Field Theories, deviations from PEP are strongly constrained by the Messiah Greenberg Superselection (MGS) rule, which forbids superpositions of states with different symmetry. Such...
We report on a search for a bound diproton, or 2He nucleus, by analyzing the results of irradiation of Tb and Ta samples with protons of 5.8 and 6.9 MeV energy, correspondingly. These proton energies are about threshold energies for corresponding (p,2p) nuclear reaction channel. The irradiated Tb and Ta samples were then counted with application of HPGe gamma-spectrometer. The peaks of 511 keV...
Possible existence of η′ meson nucleus bound states (η′-mesic nuclei) has been attracting both theoretical and experimental interests due to their relation to axial U(1) anomaly and chiral symmetry breaking in QCD. Experiments to search for η′-mesic nuclei were recently performed by using the (p,d) reaction at GSI and by the (γ, p) reaction at SPring-8. However, no significant peak structure...
The DAΦNE machine at the INFN Laboratories of Frascati is still the most suitable facility in the world, in terms of purity of the kaon beam, luminosity, and kinematic conditions, to perform measurements of kaonic atoms.
Recent progress in the field of X-ray detectors and their readout electronics contributed, in these last years, to a renewed interest in new and more precise...
The deeply bound pionic atom is known to be a very useful system to investigate the pion properties and the aspects of chiral symmetry at finite density. The pion-nucleon sigma term σπN is one of the essential quantities to investigate the value of the chiral condensate in the nuclear medium. However, the σπN value has not been determined accurately enough. Therefore, it seems to be very...
