The DAΦNE electron-positron collider of the Laboratori Nazionali di Frascati of INFN is a worldwide unique low-energy kaon source and for this reason is suitable for low-energy kaon physics like ...kaonic atoms and kaon-nucleons/nuclei interaction studies. Kaonic atoms are atomic systems where an electron is replaced by a negatively charged kaon, containing the strange quark, which interacts in the lowest orbits with the nucleus also by the strong interaction. As a result, their study offers the unique opportunity to perform experiments equivalent to scattering at vanishing relative energy. This allows to study the strong interaction between the antikaon and the nucleon or the nucleus "at threshold", without the need of ad hoc extrapolation to zero energy, as in scattering experiments. The most precise kaonic hydrogen measurement to date, together with an exploratory measurement of kaonic deuterium, were carried out by the SIDDHARTA collaboration at the DAΦNE electron-positron collider of LNF-INFN, by combining the excellent quality kaon beam delivered by the collider with new experimental techniques, as fast and precise Silicon-Drift X-ray Detectors. The measurement of kaonic deuterium will be realized in the near future by SIDDHARTA-2, a major upgrade of SIDDHARTA.
The study of antinuclei in cosmic rays provides a unique opportunity to probe physics beyond the Standard Model. Antinuclei in our Galaxy may stem either from annihilation or decay of dark matter, or ...from collisions of cosmic rays with the interstellar medium, which constitute the background of indirect dark matter searches. Understanding the formation mechanism of (anti)nuclei is crucial for setting limits on their production in space. Coalescence models, which describe the formation of light nuclei from final-state interaction of nucleons, have been widely employed in high-energy collisions. In this work, we introduce ToMCCA (Toy Monte Carlo Coalescence Afterburner), which allows for detailed studies of the nuclear formation processes without the overload of general-purpose event generators. ToMCCA contains parameterizations of the multiplicity dependence of the transverse momentum distributions of protons and of the baryon-emitting source size, extracted from ALICE measurements in pp collisions at \(\sqrt{s} = 5 - 13\) TeV, as well as of the event multiplicity distributions, taken from the EPOS event generator. ToMCCA provides predictions of the deuteron transverse momentum distributions, with an agreement of \(\sim5\%\) with the experimental data. The results of ToMCCA show that the coalescence mechanism in pp collisions depends only on the event multiplicity rather than on the collision system or its energy. This allows the model to be utilized for predictions at lower center-of-mass collision energies, which are the most relevant for the production of antinuclei from processes related to dark matter. This model can also be extended to heavier nuclei as long as the target nucleus wave function and its Wigner function are known.
Si Λ ViO: A trigger for Λ -Hyperons Münzer, Robert; Fabbietti, Laura; Berger, Martin ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Volume:
617, Issue:
1
Journal Article
Peer reviewed
The production of bound kaon–nucleon-states (kaonic-cluster) in the reaction
p
+
p
→
ppK
-
+
K
+
should be investigated in a dedicated measurement at the FOPI detector system at the SIS-accelerator ...of GSI, by looking for the decay
ppK
-
→
p
+
Λ
→
p
+
p
+
π
-
. To select the final states, the detector system
Si
Λ
ViO
has been build up as a trigger for
Λ
-Hyperons. This detector consists of two layers of segmented silicon-strip-detectors, which are able to measure online the particle multiplicity. These two layers are arranged such, that most of the
Λ
-Hyperons will decay between them. The trigger signal is generated by comparing online the hit multiplicity on the two layers.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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 \(\bar K N\) interaction, that is ...governed by the presence of the \(\Lambda(1405)\). We continue by showing the two-pole nature of the \(\Lambda(1405)\), and the production mechanisms in photon-, pion-, kaon-induced reactions as well as proton-proton collisions, while discussing the formation of \(\bar K NN\) 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 \(\phi\) 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.
The excellent quality kaon beam provided by the
DA
\Phi
Φ
NE
collider of LNF-INFN (Italy) together with SIDDHARTA/SIDDHARTA-2 new
experimental techniques, as very precise and fast-response X-ray
...detectors, allow to perform unprecedented measurements on light kaonic
atoms crucial for a deeper understanding of the low-energy quantum
chromodynamics (QCD) in the strangeness sector. In this paper an
overview of the main results obtained by the SIDDHARTA collaboration, as
well as the future plans related to the SIDDHARTA-2 experiment, are
discussed.
The kaon nucleus (KN) interaction in dense nuclear matter is predicted to be repulsive and increasing with density. However, determined values for this potential are not yet consistent with each ...other (Benabderrahmane et al., Phys Rev Lett 102:182501,
2009
; Agakishiev et al., Phys Rev C 82:044907,
2010
; Büscher et al., Eur Phys J A 22:301–317,
2004
). We analyze
mesons identified with the HADES detector in p+p and p+
93
Nb reactions at 3.5 GeV kinetic beam energy. To determine the KN potential at normal nuclear density we propose to compare the
differential distributions in p+
93
Nb and p+p collisions. High statistics of low
p
t
-kaons (
p
t
< 100 MeV/c) ensure the sensitivity of our measurements to the nuclear matter effects. We present the data analysis method and first results.
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