944 research outputs found
Strangeness in Nuclei and Neutron Stars
We review the present status of the experimental and theoretical developments
in the field of strangeness in nuclei and neutron stars. We start by discussing
the interaction, that is governed by the presence of the
. We continue by showing the two-pole nature of the
, and the production mechanisms in photon-, pion-, kaon-induced
reactions as well as proton-proton collisions, while discussing the formation
of bound states. We then move to the theoretical and experimental
analysis of the properties of kaons and antikaons in dense nuclear matter,
paying a special attention to kaonic atoms and the analysis of strangeness
creation and propagation in nuclear collisions. Next, we examine the
meson and the advances in photoproduction, proton-induced and pion-induced
reactions, so as to understand its properties in dense matter. Finally, we
address the dynamics of hyperons with nucleons and nuclear matter, and the
connection to the phases of dense matter with strangeness in the interior of
neutron stars.Comment: 103 pages, 53 figures, 3 tables, invited review to appear in Progress
in Particle and Nuclear Physic
Novel parameter-free coalescence model for deuteron production
A microscopic understanding of (anti)deuteron production in hadron-hadron
collisions is the subject of many experimental and theoretical efforts in
nuclear physics. This topic is also very relevant for astrophysics, since the
rare production of antinuclei in our Universe could be a doorway to discover
new physics. In this work, we describe a new coalescence afterburner for event
generators based on the Wigner function formalism and we apply it to the
(anti)deuteron case, taking into account a realistic particle emitting source.
The model performance is validated using the EPOS and PYTHIA event generators
applied to proton-proton collisions at the centre-of-mass energy 13
TeV, triggered for high multiplicity events, and the experimental data measured
by ALICE in the same collision system. The model relies on the direct
measurement of the particle emitting source carried out by means of
nucleon-nucleon femtoscopic correlations in the same collision system and
energy. The resulting parameter-free model is used to predict deuteron
differential spectra assuming different deuteron wavefunctions within the
Wigner function formalism. The predicted deuteron spectra show a clear
sensitivity to the choice of the deuteron wavefunction. The Argonne
wavefunction provides the best description of the experimental data. This model
can now be used to study the production of (anti)deuterons over a wide range of
collision energies and be extended to heavier nuclei.Comment: 13 pages, 9 Figures, submitted to PR
Evidence of a p- bound state
The existence of a nucleon- (N-) bound state has been subject of
theoretical and experimental investigations for decades. In this letter a
re-analysis of the p- correlation measured at the LHC is presented, using
as input recent lattice calculations of the N- interaction in the spin
3/2 channel obtained by the HAL QCD collaboration. A constrained fit of the
experimental data allows to determine the spin 1/2 channel of the p-
interaction with evidence of the formation of a p- bound state. The
scattering length and effective range extracted from the spin 1/2 channel are
fm and
fm, respectively. The corresponding binding energy is estimated to be in the
range MeV. This is the first experimental evidence of a p-
bound state
Development of a GEM-TPC prototype
The use of GEM foils for the amplification stage of a TPC instead of a con-
ventional MWPC allows one to bypass the necessity of gating, as the backdrift
is suppressed thanks to the asymmetric field configuration. This way, a novel
continuously running TPC, which represents one option for the PANDA central
tracker, can be realized. A medium sized prototype with a diameter of 300 mm
and a length of 600 mm will be tested inside the FOPI spectrometer at GSI using
a carbon or lithium beam at intermediate energies (E = 1-3AGeV). This detector
test under realistic experimental conditions should allow us to verify the
spatial resolution for single tracks and the reconstruction capability for
displaced vertexes. A series of physics measurement implying pion beams is
scheduled with the FOPI spectrometer together with the GEM-TPC as well.Comment: 5 pages, 4 figures, Proceedings for 11th ICATTP conference in como
(italy
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