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Exclusive Charmless Semileptonic Decays B -> Xu l nu from BaBar
The latest results of exclusive charmless semileptonic decays B {yields} {pi}{ell}v and B {yields} {rho}{ell}v from the BABAR Collaboration are presented. They are based on samples of B{bar B} events recorded on the {Upsilon}(4S) resonance. Several different experimental techniques are compared. Measurements of partial branching fractions in intervals of q{sup 2}, the four-momentum transfer squared, allow a study of the shape of the B {yields} {pi}{ell}v form factor and a comparison with theoretical calculations. The Cabibbo-Kobayashi-Maskawa matrix element |V{sub ub}| is determined using the measured branching fractions combined with recent form-factor predictions
Online Data Reduction for the Belle II Experiment using DATCON
The new Belle II experiment at the asymmetric accelerator SuperKEKB
at KEK in Japan is designed to deliver a peak luminosity of
. To perform high-precision track
reconstruction, e.g. for measurements of time-dependent CP-violating decays and
secondary vertices, the Belle II detector is equipped with a highly segmented
pixel detector (PXD). The high instantaneous luminosity and short bunch
crossing times result in a large stream of data in the PXD, which needs to be
significantly reduced for offline storage. The data reduction is performed
using an FPGA-based Data Acquisition Tracking and Concentrator Online Node
(DATCON), which uses information from the Belle II silicon strip vertex
detector (SVD) surrounding the PXD to carry out online track reconstruction,
extrapolation to the PXD, and Region of Interest (ROI) determination on the
PXD. The data stream is reduced by a factor of ten with an ROI finding
efficiency of >90% for PXD hits inside the ROI down to 50 MeV in
of the stable particles. We will present the current status of the
implementation of the track reconstruction using Hough transformations, and the
results obtained for simulated \Upsilon(4S) events
Search for Anomalous Production of Single Top Quarks with the H1 Experiment at HERA
Eine Suche nach der Produktion einzelner Top-Quarks durch flavor-Ă€ndernde neutrale Ströme in ep-Kollisionen wird vorgestellt. Die Suche ist motiviert durch die Beobachtung von Ereignissen mit dem H1-Detektor, die ein isoliertes Lepton sowie einen hohen fehlenden und einen hohen hadronischen Transversalimpuls aufweisen. Die HĂ€ufigkeit und Topologie dieser Ereignisse ist mit Standardmodellprozessen nur schwer in Einklang zu bringen. Das Ziel dieser Arbeit ist eine umfassende Suche nach der Produktion von Top-Quarks. ZerfĂ€lle des Top-Quarks in ein b-Quark und ein W Boson werden sowohl fĂŒr leptonische als auch fĂŒr hadronische Zerfallsmoden des W-Bosons untersucht. Die Trennung des Top-Signals vom Standardmodelluntergrund erfolgt mittels einer multivariaten Analyse. Die gesamten mit dem H1-Experiment aufgenommenen HERA I Daten, entsprechend einer integrierten LuminositĂ€t von 118 pb^-1, werden untersucht. Als Resultat dieser Analyse wird gefunden, daĂ ein Teil der beobachteten Leptonereignisse kinematisch deutlich besser zu Top-Produktion als zu Standardmodellprozessen paĂt. Anomale Top-Produktion mĂŒĂte auch an einer Erhöhung der beobachten Ereignisrate mit hadronischen W-ZerfĂ€llen sichtbar sein. Es wird keine signifikante Abweichung vom Standardmodelluntergrund beobachtet. Die Kombination aller ZerfallskanĂ€le in einer Likelihoodanpassung ergibt einen Wirkungquerschnitt fĂŒr die Produktion einzelner Top-Quarks von 0.31 +0.16 -0.15 pb bei sqrt(s)=320 GeV. Diese Kombination liefert eine deutlich bessere Beschreibung der Daten als das Standardmodell alleine. Aufgrund der momentan noch kleinen Anzahl von Top-Kandidaten wird auch eine AusschluĂgrenze fĂŒr den Wirkungsquerschnitt der Top-Produktion und fĂŒr die StĂ€rke der flavor-Ă€ndernden Kopplung ermittelt. FĂŒr die t-u-gamma-Kopplungskonstante ergibt sich kappa(t-u-gamma)<0.25 mit 95% CL. Dieses Resultat verbessert die existierenden AusschluĂgrenzen anderer Experimente bei LEP und am TeVatron
Breakdown Performance of Guard Ring Designs for Pixel Detectors in CMOS Technology
Silicon pixel sensors manufactured using commercial CMOS processes are
promising instruments for high-energy particle physics experiments due to their
high yield and proven radiation hardness. As one of the essential factors for
the operation of detectors, the breakdown performance of pixel sensors
constitutes the upper limit of the operating voltage. Six types of passive CMOS
test structures were fabricated on high-resistivity wafers. Each of them
features a combination of different inter-pixel designs and sets of floating
guard rings, which differ from each other in the geometrical layout,
implantation type, and overhang structure. A comparative study based on leakage
current measurements in the sensor substrate of unirradiated samples was
carried out to identify correlations between guard ring designs and breakdown
voltages. TCAD simulations using the design parameters of the test structures
were performed to discuss the observations and, together with the measurements,
ultimately provide design features targeting higher breakdown voltages
BDAQ53, a versatile pixel detector readout and test system for the ATLAS and CMS HL-LHC upgrades
BDAQ53 is a readout system and verification framework for hybrid pixel
detector readout chips of the RD53 family. These chips are designed for the
upgrade of the inner tracking detectors of the ATLAS and CMS experiments.
BDAQ53 is used in applications where versatility and rapid customization are
required, such as in laboratory testing environments, test beam campaigns, and
permanent setups for quality control measurements. It consists of custom and
commercial hardware, a Python-based software framework, and FPGA firmware.
BDAQ53 is developed as open source software with both software and firmware
being hosted in a public repository.Comment: 6 pages, 6 figure
Charge collection and efficiency measurements of the TJ-Monopix2 DMAPS in 180nm CMOS technology
Monolithic CMOS pixel detectors have emerged as competitive contenders in the
field of high-energy particle physics detectors. By utilizing commercial
processes they offer high-volume production of such detectors. A series of
prototypes has been designed in a 180nm Tower process with depletion of the
sensor material and a column-drain readout architecture. The latest iteration,
TJ-Monopix2, features a large 2cm x 2cm matrix consisting of 512 x 512
pixels with 33.04um pitch. A small collection electrode design aims at low
power consumption and low noise while the radiation tolerance for high-energy
particle detector applications needs extra attention. With a goal to reach
radiation tolerance to levels of MeV ncm of
NIEL damage a modification of the standard process has been implemented by
adding a low-dosed n-type silicon implant across the pixel in order to allow
for homogeneous depletion of the sensor volume. Recent lab measurements and
beam tests were conducted for unirradiated modules to study electrical
characteristics and hit detection efficiency.Comment: Conference proceedings for PIXEL2022 conference, submitted to Po
Characterization of passive CMOS sensors with RD53A pixel modules
Both the current upgrades to accelerator-based HEP detectors (e.g. ATLAS, CMS) and also future projects (e.g. CEPC, FCC) feature large-area silicon-based tracking detectors. We are investigating the feasibility of using CMOS foundries to fabricate silicon radiation detectors, both for pixels and for large-area strip sensors. A successful proof of concept would open the market potential of CMOS foundries to the HEP community, which would be most beneficial in terms of availability, throughput and cost. In addition, the availability of multi-layer routing of signals will provide the freedom to optimize the sensor geometry and the performance, with biasing structures implemented in poly-silicon layers and MIM-capacitors allowing for AC coupling. A prototyping production of strip test structures and RD53A compatible pixel sensors was recently completed at LFoundry in a 150nm CMOS process. This presentation will focus on the characterization of pixel modules, studying the performance in terms of charge collection, position resolution and hit efficiency with measurements performed in the laboratory and with beam tests. We will report on the investigation of RD53A modules with 25x100 ÎŒm cell geometry
Characterization of passive CMOS sensors with RD53A pixel modules
Both the current upgrades to accelerator-based HEP detectors (e.g. ATLAS, CMS) and also future projects (e.g. CEPC, FCC) feature large-area silicon-based tracking detectors. We are investigating the feasibility of using CMOS foundries to fabricate silicon radiation detectors, both for pixels and for large-area strip sensors. A successful proof of concept would open the market potential of CMOS foundries to the HEP community, which would be most beneficial in terms of availability, throughput and cost. In addition, the availability of multi-layer routing of signals will provide the freedom to optimize the sensor geometry and the performance, with biasing structures implemented in poly-silicon layers and MIM-capacitors allowing for AC coupling. A prototyping production of strip test structures and RD53A compatible pixel sensors was recently completed at LFoundry in a 150nm CMOS process. This presentation will focus on the characterization of pixel modules, studying the performance in terms of charge collection, position resolution and hit efficiency with measurements performed in the laboratory and with beam tests. We will report on the investigation of RD53A modules with 25x100 ÎŒm cell geometry
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