J. Strologas

The CDF-II experiment is a multipurpose detector designed to study a wide range of processes observed in the high energy proton–antiproton collisions produced by the Fermilab Tevatron. With event rates greater than 1 MHz, the CDF-II trigger system is crucial for selecting interesting events for subsequent analysis. This document provides an overview of the Track Extrapolation System (XTRP), a component of the CDF-II trigger system. The XTRP is a fully digital system that is utilized in the track-based selection of high momentum lepton and heavy flavor signatures. The design of the XTRP system includes five different custom boards utilizing discrete and FPGA technology residing in a single VME crate. We describe the design, construction, commissioning and operation of this system.

The well-known diffusion capacitance is critical in determining the modulation response of p-n junctions and particularly of laser diodes. In this brief, we investigate the diffusion capacitance of a diode, as a function of the physical length of the diode and the carrier lifetimes in the narrow active region. We show that diode length and lifetime together, and not just the lifetime (which is well known), determine the bandwidth of the diode.

The chargino-neutralino production with subsequent leptonic decays is one of the most promising supersymmetry (SUSY) signatures at the Tevatron proton-antiproton collider. We present the most recent results on the search for the three-lepton and missing-transverse-energy SUSY signature using 3.2 fb-1 of data collected with the CDF II detector. The results are interpreted within the minimal supergravity (mSUGRA) scenario.

Improving system sensitivity without sacrificing imaging resolution is the key to improving the performance of cardiac SPECT imaging. This sensitivity increase is needed for reducing imaging time, or radiation dose, and/or motion artifacts for clinical imaging studies, as well as for exploration of new clinical applications. In addition, attenuation correction is necessary to yield quantitative information - the long-standing goal of SPECT imaging. These goals can be met by C-SPECT - our proposed dedicated cardiac platform for SPECT imaging. High sensitivity is accomplished by C-SPECT's optimized detection and system geometry, which wraps around patients' left-front thorax and provides the highest practical geometric efficiency for any spatial resolution of collimation. The first generation of C-SPECT platform - C-SPECT-I - is the simplified version that uses parallel axial collimation instead of the ultimate 3D converging collimation. In the presented final design, C-SPECT-I's variable collimation system provides 5 slit-arcs, for transaxial collimation to match with 2 slat-stacks, for axial collimation, to provide high system sensitivity and a large number of simultaneous projections. This lab-prototype will provide a system sensitivity that is 2.5 times that of a dual-head SPECT system for heart imaging with the same hardware resolution at the center of the imaging volume as well as unprecedented functionality and operational versatility.

We present the standard model prediction for the eight angular coefficients of the $W$ boson, which completely describes its differential cross section in hadron collisions. These coefficients are ratios of the $W$ helicity cross sections and the total unpolarized cross section. We also suggest a technique to experimentally extract the coefficients, which we demonstrate in the Collins-Soper azimuthal-angle analysis.

By collecting photons scattered out of the therapy beam, scatter imaging creates images of the treated volume. Two phantoms were used to assess the possible application of scatter imaging for markerless tracking of lung tumors during stereotactic body radiation therapy (SBRT) treatment. A scatter-imaging camera was assembled with a CsI flat-panel detector and a 5 mm diameter pinhole collimator. Scatter images were collected during the irradiation of phantoms with megavoltage photons. To assess scatter image quality, spherical phantom lung tumors of 2.1–2.8 cm diameters were placed inside a static, anthropomorphic phantom. To show the efficacy of the technique with a moving target (3 cm diameter), the position of a simulated tumor was tracked in scatter images during sinusoidal motion (15 mm amplitude, 0.25 Hz frequency) in a dynamic lung phantom in open-field, dynamic conformal arc (DCA), and volumetric modulated arc therapy (VMAT) deliveries. Anatomical features are identifiable on static phantom scatter images collected with 10 MU of delivered dose (2.1 cm diameter lung tumor contrast-to-noise ratio of 4.4). The contrast-to-noise ratio increases with tumor size and delivered dose. During dynamic motion, the position of the 3.0 cm diameter lung tumor was identified with a root-mean-square error of 0.8, 1.2, and 2.9 mm for open field (0.3 s frame integration), DCA (0.5 s), and VMAT (0.5 s), respectively. Based on phantom studies, scatter imaging is a potential technique for markerless lung tumor tracking during SBRT without additional imaging dose. Quality scatter images may be collected at low, clinically relevant doses (10 MU). Scatter images are capable of sub-millimeter tracking precision, but modulation decreases accuracy.

The key to reaching SPECT's full diagnostic potential lies in optimizing the imaging geometry to maximize the system geometric efficiency (SGE) at a given resolution. The optimal geometry differs for different imaging applications, for different imaging tasks within a single application, and for different patients. The C-SPECT cardiac SPECT/Tct platform unifies innovative sub-systems in a cardiocentric system. These components enable the use of a large curved detector to acquire up to 17 simultaneous minified projections from a small field of view (FOV). C-SPECT's cost-effective modular NaI (Tl) detector relies on pixelation to yield high intrinsic spatial resolution for projection minification, and to eliminate unusable edge areas of the modules. The detector arc is matched by the slit-slat collimator capable of switching between several resolution/sensitivity and FOV modes without disturbing the patient. This supports patient positioning and adaptive imaging operations and optimizes the imaging geometry for a given patient. The high SGE for cardiac imaging is augmented by additional functionality achieved with minimal costs. The multiple simultaneous projections, combined with the small FOV, provide sufficient angular sampling without system motion. This enables dynamic imaging to be performed in the high sensitivity collimator mode. We present preliminary imaging results obtained with a section of the C-SPECT lab-prototype, which includes 3 of the ultimate 14 detector modules and a corresponding section of the collimator arc capable of two resolution/sensitivity/FOV modes. These results, combined with Monte Carlo simulations and analytic predictions, demonstrate the validity and feasibility of the C-SPECT approach to advancing the capabilities of SPECT cardiac imaging.

We construct three-dimensional GATE-based models of the C-SPECT proposed cardiac tomographer and of a typical dual-head gamma camera. The models are used to compare the two systems performance in geometric efficiency and image reconstruction. A digital phantom that includes a cylindrical annulus that emulates the myocardium is used for imaging. The working example of C-SPECT is not representing the final optimized design. Maximizing the number of nonoverlapping projections coming from the C-SPECT slits, we confirm that C-SPECT demonstrates an improvement by a factor of 2.5 in system geometric efficiency compared to the dual-head camera. For statistics close to a clinical acquisition, and for a resolution in the center of the FOV close to 9.5 mm, C-SPECT's higher sensitivity results in better contrast in the center of FOV, but decreased uniformity (due to angular undersampling) in the cylindrical annulus for the given high spatial resolution. The artifacts are removed when we double the angular sampling by acquiring half the data after a 7-degree rotation of the phantom. The improvement in system geometric efficiency can eventually lead to faster imaging, lower patient dose, or improved quality of myocardium images. Our modeling and simulations infrastructure will be used for the final optimization of C-SPECT.

We report on the performance of jet reconstruction in CMS during the LHC Run 2. The jet energy scale and resolution measurements are performed on a data sample collected from protonproton collisions at a center-of-mass energy of 13 TeV.The calibration is extracted from data and simulated events and employs combination of several channels and methods.We also report on boosted object tagging, which is particularly relevant for searches for new physics.Finally we discuss techniques to identify and reject jets originating from pileup and to discriminate between jets originating from quarks or gluons.

Single-photon emission computed tomography (SPECT) is the leading medical-imaging method for the study myocardial perfusion, which is important for the diagnosis and treatment of coronary-artery disease, the number-one killer in the western world.C-SPECT is a proposed dedicated cardiac SPECT system designed to achieve at least double the geometric efficiency compared to general-purpose dual-head gamma cameras, for the same resolution.This improvement can be used to reduce patient radiation dose, achieve fast or dynamic imaging, and enhance the quality of images.The system consists of stationary detector modules of pixelated NaI(Tl), a slit-slat collimator with interchangeable slits and collapsible slats, and an integrated CT for attenuation correction.The collimator slits provide pinhole collimation in the transverse plane, whereas the slats offer parallel-beam collimation in the axial direction.The adaptive power of the collimator allows us to adjust, in situ, the sensitivity and resolution depending on the imaging task.This way, superior reconstructed-image resolution could be achieved if the system operates with the usual geometric efficiency of the industry's benchmark.The system gantry wraps around patients' left-front thorax and provides a transverse projection minification of ∼ 50%, for a maximal number of minimally-overlapping projections, given the limitations from the spatial resolution of the pixelated detector.We present the design principles and preliminary imaging performance using three-dimensional iterative reconstruction with resolution recovery and data from the newly-built laboratory prototype as well as Monte-Carlo (MC) simulations of the full system.

Single-photon emission computed tomography (SPECT) is the leading medical-imaging method for the study myocardial perfusion, which is important for the diagnosis and treatment of coronary-artery disease, the number-one killer in the western world. C-SPECT is a proposed dedicated cardiac SPECT system designed to achieve at least double the geometric efficiency compared to general-purpose dual-head gamma cameras, for the same resolution. This improvement can be used to reduce patient radiation dose, achieve fast or dynamic imaging, and enhance the quality of images. The system consists of stationary detector modules of pixelated NaI(Tl), a slit-slat collimator with interchangeable slits and collapsible slats, and an integrated CT for attenuation correction. The collimator slits provide pinhole collimation in the transverse plane, whereas the slats offer parallel-beam collimation in the axial direction. The adaptive power of the collimator allows us to adjust, in situ, the sensitivity and resolution depending on the imaging task. This way, superior reconstructed-image resolution could be achieved if the system operates with the usual geometric efficiency of the industry's benchmark. The system gantry wraps around patients' left-front thorax and provides a transverse projection minification of ~50%, for a maximal number of minimally-overlapping projections, given the limitations from the spatial resolution of the pixelated detector. We present the design principles and preliminary imaging performance using three-dimensional iterative reconstruction with resolution recovery and data from the newly-built laboratory prototype as well as Monte-Carlo (MC) simulations of the full system. This work was supported by NIH grant HL108119 and utilized resources provided by the Open Science Grid, which is supported by the National Science Foundation and the U.S. Department of Energy's Office of Science.

We present recent results from searches for new physics beyond supersymmetry performed at the Tevatron accelerator at Fermilab. The CDF and D0 analyses presented here utilized data of integrated luminosity up to 6 fb{sup -1}. We cover leptonic and bosonic resonances interpreted in the Randall-Sundrum graviton and new-boson models, rare final states, and the search for vector-like quarks. The search for new phenomena beyond the weak-scale supersymmetry is a vital part of the Fermilab program. Both CDF and D0 experiments at the Tevatron collider actively look for signals not expected by the standard model (SM) or minimal supersymmetric models. The searches can be sorted in three categories: (a) searches for generic resonances that can be interpreted in several new-physics models; (b) searches for exotic combinations of final-state objects or abnormal kinematics (not necessarily predicted by current theories); and (c) model-dependent searches that test a particular theory. We present here latest results from all these categories: searches for new dilepton and diboson resonances (interpreted as gravitons and new gauge bosons), searches for anomalous {gamma} + E{sub T} + X production, and searches for vector-like quarks.

We present a search for Randall-Sundrum (RS) gravitons decaying to diphotons or dielectrons or dimuons, performed with the CDF II detector and using up to 5.7 fb{sup -1} of integrated luminosity. The respective mass spectra are consistent with the ones expected by the standard model. For the RS-model parameter k/{bar M}{sub Pl} = 0.1, RS-gravitons with mass less than 1111 GeV/c{sup 2} are excluded at 95% CL.

We present a simulations study of the collimator sensitivity/resolution compromise as it affects the image quality of hot lesions in SPECT iterative reconstruction. We investigate three parallel-beam hexagonal-hole collimators with resolution in the center of the field of view equal to 11 mm, 15 mm, and 19 mm. We scan the Esser hot-rod phantom with 60 views and we reconstruct the images using MLEM iterative reconstruction with no regularization or filtering. As the image-quality figure of merit we use the reconstructed-image contrast vs noise. We repeat the study for three levels of object-contrast (2.3, 4, and 9). We conclude that the higher-sensitivity collimator (15-mm in resolution) offers an improvement (lower noise for same contrast or higher contrast for same noise) in the reconstruction of medium-sized lesions (12-mm and 16-mm), at medium to low contrasts (4, 2.3). At high contrast (9) and low lesions sizes (8-mm) the higher resolution (11-mm) collimator is still favorable. The conclusions are task-dependent, and apply to hot lesions of the particular sizes and contrasts. Similar studies can be performed to address a range of realistic clinical problems. We intend to repeat this study for cold lesions in a cardiac anthropomorphic phantom.

In SPECT imaging with iterative reconstruction, one potential source of image noise is the limited (data or MC) statistics used for the determination of the system matrix. In this paper we present a simulations study of the effect of the system-matrix statistics on the background and signal noise. We simulate a parallel-beam, hexagonal-hole collimator and we study hot cylindrical lesions with contrasts of 1, 2.3, and 9. We investigate 5 levels of projection statistics (1K, 5K 10K, 50K, 100K counts per head position) and 7 levels of system-matrix statistics (N/2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</sup> counts per head position, where N = 2M and k = 0-6). The levels and structure of reconstructed-image noise depends on both the projection and system-matrix statistics, for any given level of object contrast. We present plots that determine the minimum number of system-matrix counts required so that the background noise is not degraded more than a particular level. The better the projection statistics, the more system-matrix statistics we need to maintain the low levels of background noise. Similar effects are observed for the signal noise withing the hot lesions. Determining the appropriate system-matrix statistics (for a particular level of object contrast and projection counts) is critical for not canceling the diagnostic value of higher projection statistics (higher dose).

We present a search for Randall-Sundrum (RS) gravitons decaying to diphotons or dielectrons or dimuons, performed with the CDF II detector and using up to 5.7 fb-1 of integrated luminosity. The respective mass spectra are consistent with the ones expected by the standard model. For the RS-model parameter k/M_Pl=0.1, RS-gravitons with mass less than 1111 GeV/c^2 are excluded at 95% CL.

We present recent results from searches for new physics beyond supersymmetry performed at the Tevatron accelerator at Fermilab. The CDF and D0 analyses presented here utilized data of integrated luminosity up to 6 fb-1. We cover leptonic and bosonic resonances interpreted in the Randall-Sundrum graviton and new-boson models, rare final states, and the search for vector-like quarks.

We report an analysis of the {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} decay in a data sample collected by the CDF II detector at the Fermilab Tevatron corresponding to 2.4 fb{sup -1} of integrated luminosity. We reconstruct the currently largest samples of the decay modes {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}(2595){sup +}{pi}{sup -} (with {Lambda}{sub c}(2595){sup +} {yields} {Lambda}{sub c}{sup +}{pi}{sup +}{pi}{sup -}), {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}(2625){sup +}{pi}{sup -} (with {Lambda}{sub c}(2625){sup +} {yields} {Lambda}{sub c}{sup +}{pi}{sup +}{pi}{sup -}), {Lambda}{sub b}{sup 0} {yields} {Sigma}{sub c}(2455){sup ++}{pi}{sup -}{pi}{sup -} (with {Sigma}{sub c}(2455){sup ++} {yields} {Lambda}{sub c}{sup +}{pi}{sup +}), and {Lambda}{sub b}{sup 0} {yields} {Sigma}{sub c}(2455)0{pi}{sup +}{pi}{sup -} (with {Sigma}{sub c}(2455)0 {yields} {Lambda}{sub c}{sup +}{pi}{sup -}) and measure the branching fractions relative to the {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -} branching fraction. We measure the ratio {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -})/ {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -})=3.04 {+-} 0.33(stat){sub -0.55}{sup +0.70}(syst) which is used to derive {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -})=(26.8{sub -11.2}{sup +11.9}) x 10{sup -3}.

We present recent results from searches for new physics beyond supersymmetry performed at the Tevatron accelerator at Fermilab. The CDF and D0 analyses presented here utilized data of integrated luminosity up to 6 fb-1. We cover leptonic and bosonic resonances interpreted in the Randall-Sundrum graviton and new-boson models, rare final states, and the search for vector-like quarks.

We present a search for Randall-Sundrum (RS) gravitons decaying to diphotons or dielectrons or dimuons, performed with the CDF II detector and using up to 5.7 fb-1 of integrated luminosity. The respective mass spectra are consistent with the ones expected by the standard model. For the RS-model parameter k/M_Pl=0.1, RS-gravitons with mass less than 1111 GeV/c^2 are excluded at 95% CL.

We present the current status of the search for new physics at CDF, using integrated luminosity up to 3.2 fb{sup -1}. We cover searches for supersymmetry, extra dimensions, new heavy bosons, and generic dilepton resonances.

The chargino-neutralino production with subsequent leptonic decays is one of the most promising supersymmetry (SUSY) signatures at the Tevatron proton-antiproton collider. We present the most recent results on the search for the three-lepton and missing-transverse-energy SUSY signature using 3.2 fb{sup -1} of data collected with the CDF II detector. The results are interpreted within the minimal supergravity (mSUGRA) scenario.

We present the current status of searches for supersymmetry performed at the Tevatron accelerator at Fermilab by the CDF and D0 collaborations using luminosity of up to 2.1 fb-1. We focus on searches for charginos, neutralinos, squarks, gluinos and sneutrinos in several supersymmetric scenarios. No supersymmetric signal is detected and limits on the masses and production cross sections for the supersymmetric particles are set.

We present the current status of the search for new physics at CDF, using integrated luminosity up to 3.2 fb-1. We cover searches for supersymmetry, extra dimensions, new heavy bosons, and generic dilepton resonances.

We present the current status of searches for supersymmetry performed at the Tevatron accelerator at Fermilab by the CDF and D0 collaborations using luminosity of up to 2.1 fb-1. We focus on searches for charginos, neutralinos, squarks, gluinos and sneutrinos in several supersymmetric scenarios. No supersymmetric signal is detected and limits on the masses and production cross sections for the supersymmetric particles are set.

We present the current status of the search for new physics at CDF, using integrated luminosity up to 3.2 fb-1. We cover searches for supersymmetry, extra dimensions, new heavy bosons, and generic dilepton resonances.

The chargino‐neutralino production is one of the most promising SUSY processes that could be observed at the Tevatron. Cross sections of the order of 0.1 pb have not been excluded yet under the mSUGRA scenario, whereas the trilepton signature of the process is not contaminated by significant standard model backgrounds. We report on the status of CDF search for chargino‐neutralino production at the Tevatron by presenting the results of five multilepton subanalyses as well as the result of their combination which leads to our current lower limit on the chargino mass of 127 GeV/c2 and upper limit on the production cross section times branching ratio to leptons of 0.25 pb at 95% confidence level.

We present some of the latest results of the CMS experiment, covering analyses in QCD multijet, top, bottom, Higgs, forward/small-x QCD, heavyion, exotic, and supersymmetry physics utilizing LHC integrated luminosity up to ~80 fb -1 .

By collecting photons Compton-scattered from the therapy megavoltage x-ray beam, the irradiated volume may be imaged in real-time during treatment without additional imaging dose. The purpose of this IRB-approved, NIH grant-supported study is to provide an initial report on a scatter-imaging camera used to monitor lung tumor motion during SBRT delivery. The presented images are the first scatter images collected of patients during radiation therapy. A crane-mounted prototype camera was constructed with a pinhole collimator and flat panel x-ray detector. Phantom scatter images collected with different collimator configurations were compared in order to optimize collimator thickness. Scatter images were collected during the treatment of 5 patients undergoing 3-5 fraction SBRT lung radiotherapy. Images were acquired at 2 Hz, and the camera was set up at various positions surrounding the patient to avoid direct irradiation by the beam and to prevent collision with the gantry head. To achieve these constraints, the scatter camera was placed in non-coplanar positions > 50 cm from the isocenter. For comparison to experimental images, expected scatter images for each patient and camera position were calculated with CT-based simulations. Over 6,000 scatter images were collected during 15 lung SBRT fractions at 13 different camera positions. Although the lung tumor and chest wall are discernable from lung tissue in some scatter image frames, the large isocenter-to-imager distance (50-110 cm) resulted in > 2 cm spatial resolution and > 5x lower photon counts than collected during preliminary phantom experiments, where sub-millimeter lung tumor tracking was demonstrated. Simulated and experimental images are in good agreement. During phantom studies we observed that increasing the collimator thickness from 8 to 35 mm Pb equivalent improved the scatter image contrast-to-noise ratio by a factor of 3.6. We present the first patient scatter images collected during radiation therapy. The constructed scatter camera allows for flexible placement around the patient. Although promising, improvements in image spatial resolution and quality are necessary to realize scatter image-guided, real-time lung tumor tracking. Camera design improvements to decrease collimator distance dependence (parallel-hole collimator), increase photon collection efficiency (thicker scintillator), and optimize camera position (dynamically moving camera), are under investigation at our institution.

The chargino-neutralino production is one of the most promising SUSY processes that could be observed at the Tevatron. Cross sections of the order of 0.1 pb have not been excluded yet under the mSUGRA scenario, whereas the trilepton signature of the process is not contaminated by significant standard model backgrounds. We report on the status of CDF search for chargino-neutralino production at the Tevatron by presenting the results of five multilepton subanalyses as well as the result of their combination which leads to our current lower limit on the chargino mass of 127 GeV/c{sup 2} and upper limit on the production cross section times branching ratio to leptons of 0.25 pb at 95% confidence level.

We present recent and legacy Quantum Chromodynamics (QCD) physics results based on jet final states from the CMS experiment at the LHC. The accumulated data were acquired from proton+proton collisions at center-of-mass energies of 8 and 13 TeV and integrated luminosity up to 19 fb−1 and 35.8 fb−1 respectively. Proton+lead collision results are also presented at 5.02 TeV.

dijet invariant mass distribution is performed to test for a potential Higgs boson signal. In the absence of an observed excess, we set a 95% Confidence Level (C.L.) upper limit on the production rate times branching ratio for a potential Higgs boson as a function of its mass. For a test mass of 115 GeV/c², the observed (expected) 95% C.L. upper limit is 28.7 (46.6) times the Standard Model expectation.