1,049 research outputs found
The momentum distribution of J/psi in B decays
The discrepancy between theory and data in the momentum distribution of slow
J/psi in B decays has been several times addressed as a puzzle. Using the most
recent results on exclusive B decays into J/psi and heavy kaons or exotic
mesons and reconsidering the non-relativistic-QCD calculation of the color
octet fragmentation component, we show that an improvement in the comparison
between data and theory can be obtained. There is still room for a better fit
to data and this may imply that new exotic mesons of the XYZ kind have yet to
be discovered.Comment: 4 pages, 2 figures, 2 tables. To appear in Physical Review
DAMA/NaI results
The DAMA/NaI set-up of the DAMA experiment has been operative during seven
annual cycles and has investigated several rare processes. In particular, it
has been realised in order to investigate the model independent annual
modulation signature for Dark Matter particles in the galactic halo. With the
total exposure collected in the seven annual cycles (107731 kg day) a model
independent evidence for the presence of a Dark Matter particle component in
the galactic halo has been pointed out at 6.3 sigma C.L.. Some of the many
possible corollary model dependent quests for the candidate particle have been
presented as well.Comment: Contributed paper to the Rencontres de Moriond "Electroweak
Interactions and Unified Theories", La Thuile, Aosta Valley, Italy, March
200
Particle Dark Matter and DAMA/LIBRA
The DAMA/LIBRA set-up (about 250 kg highly radiopure NaI(Tl) sensitive mass)
is running at the Gran Sasso National Laboratory of the I.N.F.N.. The first
DAMA/LIBRA results confirm the evidence for the presence of a Dark Matter
particle component in the galactic halo, as pointed out by the former DAMA/NaI
set-up; cumulatively the data support such evidence at 8.2 sigma C.L. and
satisfy all the many peculiarities of the Dark Matter annual modulation
signature. The main aspects and prospects of this model independent
experimental approach will be outlined.Comment: Contributed paper to the Int. Conf. SciNeGHE 2009, Assisi, Italy,
October 200
Investigating halo substructures with annual modulation signature
Galaxy hierarchical formation theories, numerical simulations, the discovery
of the Sagittarius Dwarf Elliptical Galaxy (SagDEG) in 1994 and more recent
investigations suggest that the dark halo of the Milky Way can have a rich
phenomenology containing non thermalized substructures. In the present
preliminary study, we investigate the case of the SagDEG (the best known
satellite galaxy in the Milky Way crossing the solar neighbourhood) analyzing
the consequences of its dark matter stream contribution to the galactic halo on
the basis of the DAMA/NaI annual modulation data. The present analysis is
restricted to some WIMP candidates and to some of the astrophysical, nuclear
and particle Physics scenarios. Other candidates such as e.g. the light bosonic
ones, we discussed elsewhere, and other non thermalized substructures are not
yet addressed here.Comment: 17 pages, 10 figures, to appear in Eur. Phys. J.
Prevalence and clinical features of celiac disease in a cohort of italian children with autism spectrum disorders
Background: Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental conditions whose etiopathogenesis derives from a complex interaction between genetic liability and environmental factors. In this framework, mounting evidence suggests that immune system dysfunction could be a risk factor contributing to the development of ASD in at least a subpopulation of individuals. In particular, some studies suggest an association between celiac disease (CD)âa longâterm autoimmune disorder that primarily affects the small intestine triggered by the ingestion of glutenâand ASD, while others hypothesized a random link. This investigation aimed to evaluate the prevalence of CD in a large sample of schoolâaged children with ASD and to characterize their clinical profile. Methods: Medical records of 405 children with ASD aged 5â11 years (mean age: 7.2 years; SD: 1.8 years) consecutively referred to a tertiaryâcare university hospital between January 2014 and December 2018 were reviewed; among them, 362 had carried out serological testing for CD. Results: Nine patients with positive CD serology were identified, eight of which satisfied the criteria for CD diagnosis. The estimated CD prevalence in ASD children was 2.18% (95% CI, 0.8â3.7), which was not statistically different (1.58%; p = 0.36) from that of an Italian population, matched for age range, considered as a control group (95% CI, 1.26â1.90). Three out of the eight ASD patients with CD did not have any symptoms suggestive of CD. Conclusions: Our findings did not show a higher prevalence of CD in ASD children than in the control population, but could suggest the utility of routine CD screening, given its frequent atypical clinical presentation in this population
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