We consider two-body and quasi-two-body decays of the type
f
1
→
f
2
B
, where
f
1
and
f
2
are spin-1/2 fermions and
B
a spin-0 or spin-1 boson. After recalling the non-covariant formalism for decay ...amplitudes, we derive the expression of the differential decay width and of the polarizations of the final spinning particles, both on- and off-shell. We find an intriguing geometrical interpretation of the results about the polarization. We also illustrate some methods for measuring the polarizations of the resonances and for optimizing data analysis. Then we propose applications to semi-leptonic weak decays, with a major attention to the
T
-odd component of the polarization; this may help to find, simultaneously, possible time-reversal violations and hints to physics beyond the standard model. We suggest also a
CPT
test. Last, we discuss some
T
-odd observables for the production process of
f
1
and for the study of the strong final state interactions of non-leptonic decays.
To assess the prevalence of skeletal dysplasias (SDs) in patients with idiopathic short stature (ISS) or small for gestational age (SGA) status.
Rare Endocrine/Growth Diseases Center in Paris, ...France.
A prospective study on consecutive patients with ISS and SGA enrolled from 2004 to 2009.
We used a standardized workup to classify patients into well-established diagnostic categories. Of 713 patients with ISS (n=417) or SGA status (n=296), 50.9% underwent a skeletal survey. We chose patients labeled normal or with a prepubertal slowdown of growth as a comparison group.
Diagnoses were ISS (16.9%), SGA (13.5%), normal growth (24.5%), transient growth rate slowing (17.3%), endocrine dysfunction (12%), genetic syndrome (8.9%), chronic disease (5.1%), and known SD (1.8%). SD was found in 20.9% of SGA and 21.8% ISS patients and in only 13.2% in our comparison group. SD prevalence was significantly higher in the ISS group than in the comparison group, especially (50%) for patients having at least one parent whose height was <-2 SDS. Dyschondrosteosis and hypochondroplasia were the most frequently identified SD, and genetic anomaly was found in 61.5 and 30% respectively. Subtle SD was found equally in the three groups and require long-term growth follow-up to evaluate the impact on final height.
SD may explain more than 20% of cases of growth retardation ascribed to ISS or SGA, and this proportion is higher when parental height is <-2 SDS. A skeletal survey should be obtained in patients with delayed growth in a context of ISS or SGA.
Λb decays into Λ-vector Ajaltouni, Z.J.; Conte, E.; Leitner, O.
Physics letters. B,
05/2005, Letnik:
614, Številka:
3-4
Journal Article
Recenzirano
Odprti dostop
A complete study of the angular distributions of the processes, Λb→ΛV(1−), with Λ→pπ− and V(J/Ψ)→ℓ+ℓ− or V(ρ0)→π+π−, is performed. Emphasis is put on the initial Λb polarization produced in the ...proton–proton collisions. The polarization density-matrices as well as angular distributions are derived and help to construct T-odd observables which allow us to perform tests of both time-reversal and CP violation.
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