Here, we discuss the first observation of the radiative charm decay D0 → ρ0γ and the first search for CP violation in decays D0 → ρ0γ , φγ , and K ¯ *0 ( 892 ) γ , using a data sample of 943fb-1 ...collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The branching fraction is measured to be B ( D0 → ρ0γ ) = ( 1.77±0.30±0.07 ) ×10-5 , where the first uncertainty is statistical and the second is systematic. The obtained CP asymmetries A CP ( D0 → ρ0γ ) =+0.056±0.152±0.006 , A CP ( D0 → φγ ) = -0.094±0.066±0.001 , and A CP ( D0 → K ¯ *0γ ) =-0.003±0.020±0.000 are consistent with no CP violation. Furthermore, we present an improved measurement of the branching fractions B ( D0 → φγ ) = ( 2.76±0.19±0.10 ) ×10-5 and B ( D0 → K ¯ *0γ ) = ( 4.66±0.21±0.21 ) ×10-4 .
A
bstract
Using a data sample of 980 fb
−
1
collected with the Belle detector at the KEKB asymmetric-energy
e
+
e
−
collider, we study for the first time the singly Cabibbo-suppressed decays
$$ ...{\Omega}_c^0\to {\Xi}^{-}{\pi}^{+} $$
Ω
c
0
→
Ξ
−
π
+
and Ω
−
K
+
and the doubly Cabibbo-suppressed decay
$$ {\Omega}_c^0\to {\Xi}^{-}{K}^{+} $$
Ω
c
0
→
Ξ
−
K
+
. Evidence for an
$$ {\Omega}_c^0 $$
Ω
c
0
signal in the
$$ {\Omega}_c^0 $$
Ω
c
0
→
Ξ
−
π
+
mode is reported with a significance of 4
.
5
σ
including systematic uncertainties. The ratio of branching fractions to the normalization mode
$$ {\Omega}_c^0 $$
Ω
c
0
→
Ω
−
π
+
is measured to be
$$ \mathcal{B}\left({\Omega}_c^0\to {\Xi}^{-}{\pi}^{+}\right)/\mathcal{B}\left({\Omega}_c^0\to {\Omega}^{-}{\pi}^{+}\right)=0.253\pm 0.052\left(\textrm{stat}.\right)\pm 0.030\left(\textrm{syst}.\right). $$
B
Ω
c
0
→
Ξ
−
π
+
/
B
Ω
c
0
→
Ω
−
π
+
=
0.253
±
0.052
stat
.
±
0.030
syst
.
.
No significant signals of
$$ {\Omega}_c^0\to {\Xi}^{-}{K}^{+} $$
Ω
c
0
→
Ξ
−
K
+
and Ω
−
K
+
modes are found. The upper limits at 90% confidence level on ratios of branching fractions are determined to be
$$ \mathcal{B}\left({\Omega}_c^0\to {\Xi}^{-}{K}^{+}\right)/\mathcal{B}\left({\Omega}_c^0\to {\Omega}^{-}{\pi}^{+}\right)<0.070 $$
B
Ω
c
0
→
Ξ
−
K
+
/
B
Ω
c
0
→
Ω
−
π
+
<
0.070
and
$$ \mathcal{B}\left({\Omega}_c^0\to {\Omega}^{-}{K}^{+}\right)/\mathcal{B}\left({\Omega}_c^0\to {\Omega}^{-}{\pi}^{+}\right)<0.29. $$
B
Ω
c
0
→
Ω
−
K
+
/
B
Ω
c
0
→
Ω
−
π
+
<
0.29
.
Future vertex detection at an upgraded KEK-B factory, currently the highest luminosity collider in the world, will require a detector technology capable of withstanding the increased track density ...and the larger radiation exposure. Near the beam pipe, the current silicon strip detectors have projected occupancies in excess of 100%. Advances in monolithic active-pixel sensors (MAPS) look very promising to address this problem. These devices are also quite attractive due to the possibility of making them very thin-essential for improved tracking and vertexing in the low-momenta environment of a B-factory. In the context of the Belle vertex detector upgrade, the major obstacles to realizing such a device have been concerns about radiation hardness and readout speed. Two prototypes implemented in the TSMC 0.35 /spl mu/m process have been developed to address these issues. Denoted the continuous-acquisition pixel (CAP), the two variants of this architecture are distinguished in that CAP2 includes an eight-deep sampling pipeline within each 22.5 /spl mu/m/sup 2/ pixel. Experience with this deep submicron process indicates tolerable threshold voltage shifts for ionizing radiation in excess of 20 Mrad. In order to maintain low occupancy and insensitivity to radiation-induced increased leakage current, correlated double sampling with a 10 /spl mu/s frame period is needed. Device description, hit resolution, and irradiation results are presented.
Le Lepréchaunisme ou syndrome de Donohue est une maladie congénitale d’insulinorésistance sévère caractérisée par un retard de croissance intra-utérin (RCIU) et postnatal, une dysmorphie ...caractéristique et des perturbations métaboliques (hyperinsulinisme, hyperandrogénisme). Elle est due à des mutations bi-alléliques du gène INSR codant le récepteur de l’insuline. Le but de ce travail était d’étudier les caractéristiques cliniques et génétiques du lepréchaunisme chez une série de patients tunisiens. Nous avons mené une étude rétrospective chez 13 patients adressés au service de génétique de Sfax pour suspicion de Lepréchaunisme. Il s’agit de 13 familles différentes dont 7 sont consanguines. Le sexe ratio est égale à 1. L’âge moyen de diagnostic était de 12jours. La dysmorphie faciale évocatrice et le RCIU sont les motifs les plus fréquents (11/13 patients) associé à une hypo et/ou hyperglycémie chez 9 patients. Hirsutisme a été décrit chez 3 cas et l’hypertrophie de clitoris chez 2 filles. Biologiquement, un hyperinsulinisme a été objectivé chez 3 patients. La recherche ciblée de la mutation trouvée en Tunisie 1, c.3002-3012delinsGGAAG, était positive uniquement chez 2 patients. Pour les autres, le séquençage de tout le gène est en cours. La mutation c.3002-3012delinsGGAAG, située au niveau de l’exon 16 qui code le domaine juxta-membranaire de la protéine, perturbe la structure secondaire de l’ADN et de l’ARN du gène INSR, ainsi que la structure primaire et secondaire du récepteur de l’insuline 1.
We search for lepton-flavor and lepton-number-violating τ decays into a lepton (ℓ= electron or muon) and two charged mesons (h,h′=π± or K±) using 854 fb−1 of data collected with the Belle detector at ...the KEKB asymmetric-energy e+e− collider. We obtain 90% confidence level upper limits on the τ→ℓhh′ branching fractions in the range (2.0–8.4)×10−8. These results improve upon our previously published upper limits by factors of about 1.8 on average.
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