Calibration and alignment of the Belle II central drift chamber Dong, T.V.; Uno, S.; Uchida, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2019, Letnik:
930
Journal Article
Recenzirano
The Belle II central drift chamber (CDC) is crucial in the momenta measurements of charged particles. We present methods for calibration and alignment of the CDC. Using cosmic ray data acquired with ...and without a magnetic field, the CDC was calibrated and aligned, and its performance was evaluated. The position resolution is better than 120 μm, depending on the layer and incident angles of the tracks. The alignment of the CDC improves the resolution of track parameters and reduces their systematic shifts. The transverse momentum (PT) resolution for charged tracks is 0.127PT⊕0.321 (%), PT is in GeV/c.
TiO2 nanotube arrays have been extensively investigated for optoelectronic applications besides their excellent photocatalytic activity. The present work aims to study TiO2 nanotubes (NTs) fabricated ...with the anodization of Ti substrates. CuxOy nanoparticles (NPs) were deposited on TiO2 nanotubes (NTs) using the Successive ionic layer adsorption and reaction (SILAR) method. The obtained nanocomposite was used in the photocatalytic degradation of synthetic organic pollutants (amido black). Particular emphasis was focused on the effect of the morphological, optical, and structural properties of the CuxOy (i.e., the number of SILAR cycles) on the photocatalytic efficiency of the formed heterostructure. The morphological structural and optical properties were investigated by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction analysis (XRD), UV–vis spectroscopy, and photoluminescence (PL), respectively. The results show the formation of TiO2 anatase NTs decorated with CuO and Cu2O NPs. The density and size of the Cu2O NPs were found to increase with the number of SILAR cycles, whereas the energy band gap is narrowed by 0.7 eV. Photocatalytic tests demonstrate that at 15 SILAR cycles, the Cu2O.CuO-NPs/TiO2-NTs heterostructure exhibits the highest photocatalytic performance, reaching 94 % of amido black degradation under UV irradiation (256 nm) for 90 min. The experimental data modeling indicates that the faster the degradation, the better the photocatalytic performance; i.e., the reaction rate k = 0.025 min-1. The current study highlights the potential of CuxOy decorated TiO2 substrates as efficient photocatalytic systems for degrading hazardous organic pollutants.
This study investigates the effect of the diameter of TiO nanotubes and silver decorated nanotubes on optical properties and photocatalytic inactivation of Escherichia coli under visible light. The ...TiO nanotubes (TiO-NTs) were prepared using the electrochemical method varying the anodization potential starting from 20 V until 70 V. The Ag nanoparticles were carried out using the photoreduction process under the same experimental conditions. The diameter size was determined using the scanning electronic microscopy (SEM). TiO-NTs diameter reached ∼100 nm at 70 V. Transmission electronic microscopy (TEM) imaging confirmed the TiO-NTs surface decoration by silver nanoparticles. The Ag-NPs average size was found to be equal to 8 nm. The X-Ray diffraction (XRD) analysis confirm that all TiO-NTs crystallize in the anatase phases regardless the used anodization potential. The decrease of the photoluminescence (PL) intensity of Ag NPs decorated TiO-NTs indicates the decrease of the specific area when the nanotubes diameter increases. The UV-vis absorbance show that the absorption edges was bleu shifted with the increasing of nanotubes diameter, which can be explained by the increase of the crystallites average size. The bacterial adhesion and inactivation tests were carried in the dark and under light. Bacteria were seen to adhere on TiO-NTs in the dark; however, under light the bacteria were killed before they establish a strong contact with the TiO-NTs and Ag/TiO-NTs surfaces. Bacterial inactivation kinetics were faster when the anodizing potential of the NTs-preparation increases. A total bacterial inactivation was obtained on ∼100 nm nanotubes diameter within 90 min. This result was attributed to the enhancement of the TNTs crystallinity leading to reduced surface defects. Redox catalysis was seen to occur under light on the TiO-NTs and Ag/TiO-NTs. the photo-induced antibacterial activity on the AgO/AgO decorated TiO-NTs was attributed to the interfacial charge transfer mechanism (IFCT).
A method is proposed to measure the photon polarisation parameter Formula omitted in Formula omitted transitions using an amplitude analysis of Formula omitted decays. Simplified models of the ...Formula omitted system are used to simulate Formula omitted and Formula omitted decays, validate the amplitude analysis method, and demonstrate the feasibility of a measurement of the Formula omitted parameter irrespective of the model parameters. Similar sensitivities to Formula omitted are obtained with both the charged and neutral hadronic systems. In the absence of any background and distortion due to experimental effects, the statistical uncertainty expected from an analysis of Formula omitted decays in an LHCb data set corresponding to an integrated luminosity of 9 Formula omitted is estimated to be 0.009. A similar measurement using Formula omitted decays in a Belle II data sample corresponding to an integrated luminosity of 5 Formula omitted would lead to a statistical uncertainty of 0.018.
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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