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Raffaele Del Grande

Publications and source records attributed to Raffaele Del Grande.

21 records · Page 2Linked to original sources

On self-gravitating strange dark matter halos around galaxies

A new family of nonrelativistic, Newtonian, non-quantum equilibrium configurations describing galactic halos is introduced, by considering strange quark matter conglomerates with masses larger than about 8 GeV as new possible components of the dark matter. Originally introduced to explain the state of matter in neutron stars, such conglomerates may also form in the high-density and temperature conditions of the primordial Universe and then decouple from ordinary baryonic matter, providing the fundamental components of dark matter for the formation of pristine gravitational potential wells and the subsequent evolution of cosmic structures. The obtained results for halo mass and radius are consistent with the rotational velocity curve observed in the Galaxy. Additionally, the average density of such dark matter halos is similar to that derived for halos of dwarf spheroidal galaxies, which can therefore be interpreted as downscaled versions of larger dark matter distributions around Milky Way-sized galaxies and hint for a common origin of the two families of cosmic structures.

astro-ph.GA↗

Formation of $Σπ$ pairs in nuclear captures of K$^-$ mesons

The capture of K$^-$ mesons on nucleons bound in nuclei offer a chance to study the $Σπ$ pairs below the kinematic threshold of the $\bar{\mathrm{K}}$N systems. Various hyperon-pion charged combination are presently under investigation by AMADEUS. These data allow to test both isospin 0 and 1 amplitudes giving the possibility to detect the structure of resonant $Λ$(1405) state. Contrasted against similar electro-production data, it is possible to detect changes of $Λ$(1405) in nuclear media. Expected spectra and their uncertainties are calculated.

nucl-ex↗

Low-energy Antikaon Interaction with Nuclei: The AMADEUS Challenge

The low-energy strong interaction of antikaons (K-) with nuclei has many facets and rep- resents a lively and challenging research field. It is interconnected to the peculiar role of strangeness, since the strange quark is rather light, but still much heavier than the up and down quarks. Thus, when strangeness is involved one has to deal with spontaneous and explicit symmetry breaking in QCD. It is well known that the antikaon interaction with nucleons is attractive, but how strong ? Is the interaction strong enough to bind nucleons to form kaonic nuclei and, if so, what are the properties (binding energy, decay width)? There are controversial indications for such bound states and new results are expected to come soon. The existence of antikaon mediated bound states might have important consequences since it would open the possibility for the formation of cold baryonic matter of high density which might have a severe impact in astrophysics for the understanding of the composi- tion of compact (neutron) stars. New experimental opportunities could be provided by the AMADEUS experiment at the DA?NE electron-positron collider at LNF-INFN (Frascati, Italy). Pre-AMADEUS studies on the antikaon interaction with nuclei are carried out by analysis of data collected by KLOE in till 2005 and in special data runs using a carbon target insert. Studies for the dedicated AMADEUS detector setup taking advantage of the low-energy antikaons from Phi-meson decay delivered by DAFNE are in progress. Some re- sults obtained so far and the perspectives of the AMADEUS experiment are presented and discussed.

nucl-ex↗