A
bstract
We measure the branching fractions and
CP
asymmetries for the singly Cabibbo-suppressed decays
D
0
→
π
+
π
−
η
,
D
0
→
K
+
K
−
η
, and
D
0
→
ϕη
, using 980 fb
−
1
of data from the Belle ...experiment at the KEKB
e
+
e
−
collider. We obtain
B
D
0
→
π
+
π
−
η
=
1.22
±
0.02
stat
±
0.02
syst
±
0.03
B
ref
×
10
−
3
,
B
D
0
→
K
+
K
−
η
=
1.80
−
0.06
+
0.07
stat
±
0.04
syst
±
0.05
B
ref
×
10
−
4
,
B
D
0
→
ϕη
=
1.84
±
0.09
stat
±
0.06
syst
±
0.05
B
ref
×
10
−
4
,
where the third uncertainty (
B
ref
) is from the uncertainty in the branching fraction of the reference mode
D
0
→
K
−
π
+
η
. The color-suppressed decay
D
0
→
ϕη
is observed for the first time, with very high significance. The results for the
CP
asymmetries are
A
CP
D
0
π
+
π
−
η
=
0.9
±
1.2
stat
±
0.5
syst
%
,
A
CP
D
0
→
K
+
K
−
η
=
−
1.4
±
3.3
stat
±
1.1
syst
%
,
ACP
D
0
→
ϕη
=
−
1.9
±
4.4
stat
±
0.6
syst
%
.
The results for
D
0
→
π
+
π
−
η
are a significant improvement over previous results. The branching fraction and
A
CP
results for
D
0
→
K
+
K
−
η
, and the
ACP
result for
D
0
→
ϕη
, are the first such measurements. No evidence for
CP
violation is found in any of these decays.
Single-photon avalanche diodes (SPADs) in the CMOS technology are very attractive solution for photon detection due to the excellent timing resolution achievable. Unfortunately, such devices suffer ...from large values of the dark count (DC) pedestals. In this paper, we analyzed a test chip containing SPADs with different layouts, implemented in the 150-nm CMOS technology. The behavior of such devices has been investigated after proton irradiation. It is observed that, after irradiation, the DC rate switches between two or more discrete levels, phenomenon known as random telegraph signal (RTS). The effect is related to the density and distribution of defects in the semiconductor lattice. RTS characteristics have been studied as the function of both temperature and bias voltage. Discussion of results and main hypotheses on defect types responsible for RTS are reported.
The OPERA detector at the Gran Sasso underground laboratory (LNGS) was used to measure the atmospheric muon charge ratio
in the TeV energy region. We analyzed 403069 atmospheric muons corresponding ...to 113.4 days of livetime during the 2008 CNGS run. We computed separately the muon charge ratio for single and for multiple muon events in order to select different energy regions of the primary cosmic ray spectrum and to test the
R
μ
dependence on the primary composition. The measured
R
μ
values were corrected taking into account the charge-misidentification errors. Data have also been grouped in five bins of the “vertical surface energy” ℰ
μ
cos
θ
. A fit to a simplified model of muon production in the atmosphere allowed the determination of the pion and kaon charge ratios weighted by the cosmic ray energy spectrum.
We present the first model-independent measurement of the CKM unitarity triangle angle ϕ3 using B±→ D(KS0\ {K}_{\mathrm{S}}^0 \π+π−π0) K± decays, where D indicates either a D0 or D¯\ \overline{D} \0 ...meson. Measurements of the strong-phase difference of the D →KS0\ {K}_{\mathrm{S}}^0 \π+π−π0 amplitude obtained from CLEO-c data are used as input. This analysis is based on the full Belle data set of 772 × 106BB¯\ \overline{B} \ events collected at the Υ(4S) resonance. We obtain ϕ3 = (5.7−8.8+10.2\ {5.7}_{-8.8}^{+10.2} \±3.5±5.7)° and the suppressed amplitude ratio rB = 0.323±0.147±0.023±0.051. Here the first uncertainty is statistical, the second is the experimental systematic, and the third is due to the precision of the strong-phase parameters measured from CLEO-c data. The 95% confidence interval on ϕ3 is (−29.7, 109.5)°, which is consistent with the current world average.
The VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an innovative design for a hybrid photodetector. The idea, born with the purpose to use a SiPM for large detection volumes, consists in replacing ...the classical dynode chain with a special SiPM. In this configuration, we match the large sensitive area of a photocathode with the performances of the SiPM technology, which therefore acts like an electron detector and so like a current amplifier. The excellent photon counting capability, fast response, low power consumption and the stability are among the most attractive features of the VSiPMT.We now present the progress on the realization of a 1-in. prototype and the preliminary tests we are performing on it.
•The VSiPMT is a new high gain photodetector with very good photon counting capability.•Simulations to realize a good focusing system have been done.•A test bench was set up to verify the simulations.•A 1-in. VSiPMT prototype has been realized and tested, with good results.•A 1-in. industrial prototype has been realized by Hamamatsu and is now under test.
The efficient and accurate interpretation of radiologic images is paramount.
To evaluate whether a deep learning-based artificial intelligence (AI) engine used concurrently can improve reader ...performance and efficiency in interpreting chest radiograph abnormalities.
This multicenter cohort study was conducted from April to November 2021 and involved radiologists, including attending radiologists, thoracic radiology fellows, and residents, who independently participated in 2 observer performance test sessions. The sessions included a reading session with AI and a session without AI, in a randomized crossover manner with a 4-week washout period in between. The AI produced a heat map and the image-level probability of the presence of the referrable lesion. The data used were collected at 2 quaternary academic hospitals in Boston, Massachusetts: Beth Israel Deaconess Medical Center (The Medical Information Mart for Intensive Care Chest X-Ray MIMIC-CXR) and Massachusetts General Hospital (MGH).
The ground truths for the labels were created via consensual reading by 2 thoracic radiologists. Each reader documented their findings in a customized report template, in which the 4 target chest radiograph findings and the reader confidence of the presence of each finding was recorded. The time taken for reporting each chest radiograph was also recorded. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC) were calculated for each target finding.
A total of 6 radiologists (2 attending radiologists, 2 thoracic radiology fellows, and 2 residents) participated in the study. The study involved a total of 497 frontal chest radiographs-247 from the MIMIC-CXR data set (demographic data for patients were not available) and 250 chest radiographs from MGH (mean SD age, 63 16 years; 133 men 53.2%)-from adult patients with and without 4 target findings (pneumonia, nodule, pneumothorax, and pleural effusion). The target findings were found in 351 of 497 chest radiographs. The AI was associated with higher sensitivity for all findings compared with the readers (nodule, 0.816 95% CI, 0.732-0.882 vs 0.567 95% CI, 0.524-0.611; pneumonia, 0.887 95% CI, 0.834-0.928 vs 0.673 95% CI, 0.632-0.714; pleural effusion, 0.872 95% CI, 0.808-0.921 vs 0.889 95% CI, 0.862-0.917; pneumothorax, 0.988 95% CI, 0.932-1.000 vs 0.792 95% CI, 0.756-0.827). AI-aided interpretation was associated with significantly improved reader sensitivities for all target findings, without negative impacts on the specificity. Overall, the AUROCs of readers improved for all 4 target findings, with significant improvements in detection of pneumothorax and nodule. The reporting time with AI was 10% lower than without AI (40.8 vs 36.9 seconds; difference, 3.9 seconds; 95% CI, 2.9-5.2 seconds; P < .001).
These findings suggest that AI-aided interpretation was associated with improved reader performance and efficiency for identifying major thoracic findings on a chest radiograph.
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