419 research outputs found
emission rates in absorptions at rest on Li, Li, Be, C and O
An experimental study of the reaction
on Li, Li, Be, C and O -shell nuclei is
presented. The data were collected by the FINUDA spectrometer operating at the
DANE -factory (LNF-INFN, Italy). Emission rates for the reaction in
the mentioned nuclei are measured and compared with the few existing data. The
spectra of several observables are discussed; indications of Quasi-Free
absorptions by a pair embedded in the nucleus can be obtained from
the study of the missing mass distributions.Comment: Version accepted by PR
Proton spectra from Non-Mesonic Weak Decay of p-shell Lambda-Hypernuclei and evidence for the two-nucleon induced process
New spectra from the FINUDA experiment of the Non Mesonic Weak Decay (NMWD)
proton kinetic energy for 9(Lambda)Be, 11(Lambda)B, 12(Lambda)C, 13(Lambda)C,
15 (Lambda)N and 16(Lambda)O are presented and discussed along with the
published data on 5(Lambda)He and 7(Lambda)Li. Exploiting the large mass number
range and the low energy threshold (15 MeV) for the proton detection of FINUDA,
an evaluation of both Final State Interactions (FSI) and the two nucleon
induced NMWD contributions to the decay process has been done. Based on this
evaluation, a linear dependence of FSI on the hypernuclear mass number A is
found and for the two nucleon stimulated decay rate the experimental value of
Gamma2/Gammap=0.43+-0.25 is determined for the first time. A value for the two
nucleon stimulated decay rate to the total decay rate
Gamma2/GammaNMWD=0.24+-0.10 is also extracted.Comment: 11 pages and 2 figure
First measurement of kaonic helium-3 X-rays
The first observation of the kaonic 3He 3d - 2p transition was made using
slow K- mesons stopped in a gaseous 3He target. The kaonic atom X-rays were
detected with large-area silicon drift detectors using the timing information
of the K+K- pairs of phi-meson decays produced by the DAFNE e+e- collider. The
strong interaction shift of the kaonic 3He 2p state was determined to be -2+-2
(stat)+-4 (syst) eV.Comment: Accepted for publication in Phys. Lett.
A study of the proton spectra following the capture of in Li and C with FINUDA
Momenta spectra of protons emitted following the capture of in Li
and C have been measured with 1% resolution. The C spectrum is
smooth whereas for Li a well defined peak appears at about 500 MeV/. The
first observation of a structure in this region was identified as a strange
tribaryon or, possibly, a -nuclear state. The peak is correlated with a
coming from decay in flight, selected by setting momenta
larger than 275 MeV/. The could be produced, together with a 500
MeV/ proton, by the capture of a in a deuteron-cluster substructure of
the Li nucleus. The capture rate for such a reaction is (1.62\pm
0.23_{stat} ^{+0.71}_{-0.44}(sys))%/K^-_{stop}, in agreement with the existing
observations on He targets and with the hypothesis that the Li nucleus
can be interpreted as a cluster.Comment: 21 pages, 10 figures. Accepted for publication in NP
The common NOD2/CARD15 variant P268S in patients with non-infectious uveitis: a cohort study
Background: The etiology of Autoimmune chronic uveitis (ACU) is still unknown; NOD2/CARD15 gene mutations are responsible for the Blau Syndrome and can induce uveitis in animal models. Presentation of the hypothesis: Aim of our study was to assess if NOD2/CARD15 variants have a role in the etiology or in the clinical course of patients with ACU, either idiopathic or associated with other inflammatory diseases. Testing the hypothesis: We consecutively enrolled 25 patients (19 pediatric and 6 adults) affected with ACU. For each patient medical history was reviewed and clinical data were recorded. Allelic and genotypic frequencies of NOD2/CARD15 variations were calculated in patients and matched with those of 25 healthy controls. The statistical analysis was performed. Fifteen patients showed the polymorphism P268S/SNP5 (SNP rs2066842) as heterozygous carriers while two patients were homozygous for the same polymorphism; one patient carried also the variant c647 18-16 TCT on intron 3, not previously reported in the literature. Statistical analysis for NOD2/CARD15 genotyping showed significant differences between patients and controls for allelic frequencies (p=0.04, OR: 4.03, 95 %; CI=1.2-13.5) but not for genotypic frequencies. We could not identify a significant phenotype-genotype correlation. Implications of the hypothesis: In our cohort of Italian patients, the NOD2/CARD15 common variant P268S/SNP5 could potentially be significantly associated with ACU
Production of H and H with the (K,) reaction
The production of neutron rich -hypernuclei via the
(,) reaction has been studied using data collected with the
FINUDA spectrometer at the DANE -factory (LNF). The analysis of the
inclusive momentum spectra is presented and an upper limit for the
production of H and H from Li and Li, is
assessed for the first time.Comment: 11 pages, 3 figures. Accepted for publication in PL
A New Measurement of Kaonic Hydrogen X rays
The system at threshold is a sensitive testing ground for low
energy QCD, especially for the explicit chiral symmetry breaking. Therefore, we
have measured the -series x rays of kaonic hydrogen atoms at the DANE
electron-positron collider of Laboratori Nazionali di Frascati, and have
determined the most precise values of the strong-interaction energy-level shift
and width of the atomic state. As x-ray detectors, we used large-area
silicon drift detectors having excellent energy and timing resolution, which
were developed especially for the SIDDHARTA experiment. The shift and width
were determined to be eV and
eV, respectively. The new
values will provide vital constraints on the theoretical description of the
low-energy interaction.Comment: 5 figures, submitted to Physics Letters
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