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 $e^+ e^-$ accelerator SuperKEKB at KEK in Japan is designed to deliver a peak luminosity of $8\times10^{35}\text{cm}^{-2}\text{s}^{-1}$. 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 $p_\text{T}$ 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) $\rightarrow \, B\bar{B}$ 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-ändernde 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 Häufigkeit 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. Zerfälle des Top-Quarks in ein b-Quark und ein W Boson werden sowohl für leptonische als auch für 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 Luminosität von 118 pb^-1, werden untersucht. Als Resultat dieser Analyse wird gefunden, daß ein Teil der beobachteten Leptonereignisse kinematisch deutlich besser zu Top-Produktion als zu Standardmodellprozessen paßt. Anomale Top-Produktion müßte auch an einer Erhöhung der beobachten Ereignisrate mit hadronischen W-Zerfällen sichtbar sein. Es wird keine signifikante Abweichung vom Standardmodelluntergrund beobachtet. Die Kombination aller Zerfallskanäle in einer Likelihoodanpassung ergibt einen Wirkungquerschnitt für 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 Ausschlußgrenze für den Wirkungsquerschnitt der Top-Produktion und für die Stärke der flavor-ändernden Kopplung ermittelt. Für die t-u-gamma-Kopplungskonstante ergibt sich kappa(t-u-gamma)<0.25 mit 95% CL. Dieses Resultat verbessert die existierenden Ausschlußgrenzen anderer Experimente bei LEP und am TeVatron

A beam-driven proton irradiation setup for precision radiation damage tests of silicon detectors

A proton irradiation site for silicon detectors has been developed and commissioned at the Bonn Isochronous Cyclotron. The accelerator provides 14 MeV proton beams of up to 1 $\mu$A at beam widths of a few mm to the setup. Devices Under Test (DUTs) are irradiated inside a cooled, thermally-insulated box at $\le$-20{\deg}C, while being moved through the beam in a row-based scan pattern to achieve uniform fluence distributions. Custom-made diagnostics allow for beam-based, on- and offline dosimetry, enabling a beam-driven irradiation routine which produces uniform fluence distributions with standard deviations $\ll 1 \%$. Dedicated irradiations of thin titanium foils are performed to compare the commonly-used dosimetry via metallic foil activation to the beam-based approach. Within the error margins, both methods are in agreement, whereas the beam-based technique yields lower uncertainties of typically $\le 2 \%$. Simulations indicate a reduction of the initial proton energy to 12.28(6) MeV on the DUT. Characterization of six, 150 $\mu$m-thin, passive LFoundry sensors before and after irradiation yield a proton hardness factor of $\kappa_\text{p}=3.71(11)$, which is in agreement with expectations, allowing to irradiate up to $10^{16} \text{n}_{eq} / \text{cm}^2$ within a few hours

Breakdown Performance of Guard Ring Designs for Pixel Detectors in 150 nm150~\mathrm{nm} 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 180 \,nm 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 180$\,$nm Tower process with depletion of the sensor material and a column-drain readout architecture. The latest iteration, TJ-Monopix2, features a large 2$\,$cm x 2$\,$cm matrix consisting of 512 x 512 pixels with 33.04$\,$um 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 $10^{15}\,1\,$MeV n$_\text{eq}\,$cm$^{-2}$ 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 μm$^{2}$ cell geometry