J. Thom

A search for the exotic meson $X(5568)$ decaying into the $B^0_s \pi^{\pm}$ final state is performed using data corresponding to $9.6 \textrm{fb}^{-1}$ from $p{\bar p}$ collisions at $\sqrt{s} = 1960$ GeV recorded by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7\% at the 95\% confidence level is set on the fraction of $B^0_s$ produced through the $X(5568) \rightarrow B^0_s \, \pi^{\pm}$ process.

We have developed a new technique for inclusive reconstruction of the energy of B hadrons. The excellent efficiency and resolution of this technique allow us to make the most precise determination of the b-quark fragmentation function, using e(+)e(-)-->Z0 decays recorded in the SLAC Large Detector experiment. We compared our measurement with the predictions of a number of fragmentation models. We excluded several of these models and measured the average scaled energy of weakly decaying B hadrons to be <x(B)> = 0.714+/-0. 005(stat)+/-0.007(syst)+/-0.002 (model dependence).

Dieser Rapid Review untersucht Veränderungen der psychischen Gesundheit von Kindern und Jugendlichen in der Allgemeinbevölkerung in Deutschland während der COVID-19-Pandemie auf Grundlage von 39 Publikationen, die mittels systematischer Literaturrecherche (Stand 19.11.2022) und Handrecherche identifiziert wurden. Die Datengrundlagen der eingeschlossenen Publikationen wurden bezüglich ihrer Repräsentativität für die Allgemeinbevölkerung systematisiert, die verwendeten Indikatoren hinsichtlich der abgebildeten Konstrukte und ihrer Verlässlichkeit kategorisiert. Die große Mehrzahl der Studien bezog sich auf den Pandemiebeginn bis zum Sommerplateau 2020. Aus repräsentativen Studien wurde überwiegend ein hohes Ausmaß an pandemiebezogenen Belastungen, Zunahmen psychischer Auffälligkeiten und Beeinträchtigungen der Lebensqualität berichtet. Nichtrepräsentative Studien zeigten gemischte Ergebnisse. Vulnerable Gruppen ließen sich nur eingeschränkt identifizieren. Routine- und versorgungsbezogene Daten wiesen Rückgänge der ambulanten und stationären Inanspruchnahme während der Pandemiewellen mit Nachholeffekten aus. Kinder und Jugendliche erweisen sich in der Pandemie als vulnerabler im Vergleich zu Erwachsenen, ihre Belastung variierte jedoch mit den Pandemiewellen und den assoziierten Eindämmungsmaßnahmen. Ein zukünftiges vorausschauendes Krisen- und Pandemiemanagement erfordert eine engmaschige und kontinuierliche Surveillance der psychischen Kindergesundheit sowie eine bessere Identifikation von Risikogruppen.

We investigate the potential of the compact muon solenoid detector at the CERN Large Hadron Collider (LHC) to discriminate between two theoretical models predicting anomalous events with jets and large missing transverse energy, minimal supersymmetry, and little Higgs with $T$ parity. We focus on a simple test-case scenario, in which the only exotic particles produced at the LHC are heavy color-triplet states (squarks or $T$ quarks), and the only open decay channel for these particles is into the stable missing-energy particle (neutralino or heavy photon) plus a quark. We find that in this scenario, the angular and momentum distributions of the observed jets are sufficient to discriminate between the two models with a few inverse femtobarns of the LHC data, provided that these distributions for both models and the dominant standard model backgrounds can be reliably predicted by Monte Carlo simulations.

Three dimensional integrated circuit technologies offer the possibility of fabricating large area arrays of sensors integrated with complex electronics with minimal dead area, which makes them ideally suited for applications at the LHC upgraded detectors and other future detectors. We describe ongoing R&D efforts to demonstrate functionality of components of such detectors. This includes the study of integrated 3D electronics with active edge sensors to produce "active tiles" which can be tested and assembled into arrays of arbitrary size with high yield.

We describe technologies which can be developed to produce large area, low cost pixelated tracking detec- tors. These utilize wafer-scale 3D electronics and sensor technologies currently being developed in industry. This can result in fully active sensor/readout chip tiles which can be assembled into large area arrays with good yield and minimal dead area. The ability to connect though the bulk of the device can also provide better electrical performance and lower mass.

We describe a project to demonstrate fully active sensor/readout chip tiles which can be assembled into large area arrays with good yield and minimal dead area. Such tiles can be used as building blocks for next generation trackers, such as the tracking trigger system for CMS in LHC, or for precise, low mass pixelated sensors.

The Collider Detector at Fermilab collected a unique sample of jets originating from bottom-quark fragmentation ($b$-jets) by selecting online proton-antiproton ($p\overline{p}$) collisions with a vertex displaced from the $p\overline{p}$ interaction point, consistent with the decay of a bottom-quark hadron. This data set, collected at a center-of-mass energy of 1.96 TeV, and corresponding to an integrated luminosity of $5.4\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, is used to measure the $Z$-boson production cross section times branching ratio into $b\overline{b}$. The number of $Z\ensuremath{\rightarrow}b\overline{b}$ events is determined by fitting the dijet-mass distribution, while constraining the dominant $b$-jet background, originating from QCD multijet events, with data. The result, $\ensuremath{\sigma}(p\overline{p}\ensuremath{\rightarrow}Z)\ifmmode\times\else\texttimes\fi{}\mathcal{B}(Z\ensuremath{\rightarrow}b\overline{b})=\phantom{\rule{0ex}{0ex}}1.11\ifmmode\pm\else\textpm\fi{}0.08(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.14(\mathrm{syst})\text{ }\text{ }\mathrm{nb}$, is the most precise measurement of this process, and is consistent with the standard-model prediction. The data set is also used to search for Higgs-boson production. No significant signal is expected in our data and the first upper limit on the cross section for the inclusive $p\overline{p}\ensuremath{\rightarrow}H\ensuremath{\rightarrow}b\overline{b}$ process at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ is set, corresponding to 33 times the expected standard-model cross section, or $\ensuremath{\sigma}=40.6\text{ }\text{ }\mathrm{pb}$, at the 95% confidence level.

We investigate the potential of the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) to discriminate between two theoretical models predicting anomalous events with jets and large missing transverse energy, minimal supersymmetry and Little Higgs with T Parity. We focus on a simple test case scenario, in which the only exotic particles produced at the LHC are heavy color-triplet states (squarks or T-quarks), and the only open decay channel for these particles is into the stable missing-energy particle (neutralino or heavy photon) plus a quark. We find that in this scenario, the angular and momentum distributions of the observed jets are sufficient to discriminate between the two models with a few inverse fb of the LHC data, provided that these distributions for both models and the dominant Standard Model backgrounds can be reliably predicted by Monte Carlo simulations.

Quantum chromodynamics (QCD), the electroweak theory and general relativity currently give an accurate description of all known phenomena in fundamental physics. No experimental facts are known that disagree with these theories. The Standard Model (SM) incorporates QCD and the electroweak theory. Its matter content consists of spin 1/2 quarks and leptons, and spin 1 gauge bosons. They are considered to be elementary, meaning that they have no constituents. There are six quark flavors (up, down, charm, strange, top and bottom) and in addition to its spin each of the quarks has a second degree of freedom, called color, which can have three different values. There are also six different leptons, e, {nu}{sub e}, {mu}, {nu}{sub {mu}}, {tau} and {nu}{sub {tau}}. Forces between fermions due to the electroweak interaction are mediated by exchanges of four gauge bosons ({gamma}, W{sup +}, W{sup -} and Z{sup 0}); and the forces due to the strong interaction, or QCD, are mediated by eight gauge bosons, the gluons. An in depth description of the SM can be found in [1], [2].

We have searched for time-dependent Bs0–B̄s0 mixing using a sample of 400 000 hadronic Z0 decays collected by the SLD experiment at the SLC. The analyses take advantage of the excellent vertexing efficiency and resolution of the pixel-based CCD Vertex Detector which provides a B decay length resolution of approximately 100μm. All analyses determine the B hadron flavor at production by exploiting the large forward–backward asymmetry of polarized Z0→bb̄ decays. This flavor tag is enhanced by incorporating additional information from the hemisphere opposite that of the reconstructed B decay. In one analysis, B decay vertices are reconstructed inclusively with a topological technique, and separation between Bs0 and B̄s0 decays is based on the reconstruction of a “charge dipole” of the topological vertices to exploit the Bs0→Ds− cascade charge structure. The other two analyses select semileptonic decays to tag the B flavor at decay and reconstruct the B decay vertex by intersecting the lepton with either all tracks in the nearest jet or the trajectory of a topologically reconstructed D vertex. The three analyses are combined to exclude the following values of the oscillation frequency: Δms<5.3 and 6.0ps−1<Δms<11.5ps−1. Future prospects are outlined.

Tracking detectors with intrinsic momentum discrimation capabilities will necessarily require communication between nearby layers to correlate hits and establish an approximate curvature determination. Interlayer communication may be approached in many ways. Herein we describe design and fabrication issues associated with a fully 3D approach in which vias through a bulk interposer provide one-to-one contact between pixels of the two layers.

For the field of high energy physics to continue to have a bright future, priority within the field must be given to investments in the development of both evolutionary and transformational detector development that is coordinated across the national laboratories and with the university community, international partners and other disciplines. While the fundamental science questions addressed by high energy physics have never been more compelling, there is acute awareness of the challenging budgetary and technical constraints when scaling current technologies. Furthermore, many technologies are reaching their sensitivity limit and new approaches need to be developed to overcome the currently irreducible technological challenges. This situation is unfolding against a backdrop of declining funding for instrumentation, both at the national laboratories and in particular at the universities. This trend has to be reversed for the country to continue to play a leadership role in particle physics, especially in this most promising era of imminent new discoveries that could finally break the hugely successful, but limited, Standard Model of fundamental particle interactions. In this challenging environment it is essential that the community invest anew in instrumentation and optimize the use of the available resources to develop new innovative, cost-effective instrumentation, as this is our best hope to successfully accomplish the mission of high energy physics. This report summarizes the current status of instrumentation for high energy physics, the challenges and needs of future experiments and indicates high priority research areas.

The CDFII silicon detector consists of 8 layers of double-sided silicon micro-strip sensors totalling 722,432 readout channels, making it one of the largest silicon detectors in present use by an HEP experiment. After two years of data taking, we report on our experience operating the complex device. The performance of the CDFII silicon detector is presented and its impact on physics analyses is discussed. We have already observed measurable effects from radiation damage. These results and their impact on the expected lifetime of the detector are briefly reviewed.

Precision studies of top quark properties are a primary goal of the Run II physics program at the Fermilab Tevatron. Marking the first stages of this program, the CDF collaboration presents recent results on top pair production cross section, single top physics and top mass, using between 109 and 200 pb{sup -1} of Run II data.

We report several preliminary studies of the time dependence of B{sub s}{sup 0}-{bar B}{sub s}{sup 0} and B{sub d}{sup 0}-{bar B}{sub d}{sup 0} mixing using a sample of 400,000 hadronic Z decays collected by the SLD experiment at the SLC. The study of B{sub d}{sup 0}-{bar B}{sub d}{sup 0} mixing determines a value of {Delta}m{sub d} = 0.503 {+-} 0.028(stat) {+-} 0.020(sys)ps{sup -1}. In the study of B{sub s}{sup 0}-{bar B}{sub s}{sup 0} mixing, oscillation frequencies up to {Delta}m{sub s} < 11.1ps{sup -1} are excluded at 95% C.L. The combined sensitivity is 13.2 ps{sup 1}.

We report several preliminary studies of the time dependence of B 0 s -B 0 s and B 0 d -B 0 d mixing using a sample of 400,000 hadronic Z decays collected by the SLD experiment at the SLC.The study of B 0 d -B 0 d mixing determines a value of ∆m d = 0.503±0.028(stat)±0.020(sys)ps - .In the study of B 0 s -B 0 s mixing, oscillation frequencies up to ∆m s < 11.1ps -1 are excluded at 95% C.L. The combined sensitivity is 13.2 ps -1 .* Speaker.

Cotton roving was produced at speeds above 200 m/min by applying alternating twist by the self-twist technique (ST) and was then parallel-wound onto large tapered packages for use in ring-spinning cotton yarns. The cyclic ply and strand twist in the ST structure increased the variability of roving cohesion and tenacity relative to conventionally-twisted roving.