A. Soha

The BaBar experiment at PEPII relies on the instrumentation of the flux return (IFR) for both muon identification and KL detection. The active detector is composed of resistive plate chambers (RPCs) operated in streamer mode. Since the start of operation the RPCs have suffered persistent efficiency deterioration and dark current increase problems. The “autopsy” of bad BaBar RPCs revealed that in many cases uncured linseed oil droplets had formed on the inner surface of the Bakelite plates, leading to current paths from oil “stalagmites” bridging the 2 mm gap. In this paper, a possible model of this “stalagmite” formation and its effect on the dark current and efficiency of RPC chambers is presented. Laboratory test results strongly support this model. Based upon this model we are searching for solutions to eliminate the unfavorable effect of the oil stalagmites. The lab tests show that the stalagmite resistivity increases dramatically if exposed to the air, an observation that points to a possible way to remedy the damage and increase the efficiency. We have seen that flowing an oxygen gas mixture into the chamber helps to polymerize the uncured linseed oil. Consequently, the resistivity of the bridged oil stalagmites increases, as does that of the oil coating on the frame edges and spacers, significantly reducing the RPC dark currents and low-efficiency regions. We have tested this idea on two chambers removed from BaBar because of their low efficiency and high dark current. These test results are reported in the paper, and two other remediation methods also mentioned. We continue to study this problem, and try to find new treatments with permanent improvement.

The BaBar experiment uses a big system based on RPC detectors to discriminate muons from pions and to identify neutral hadrons. About 2000m2 of RPC chambers have been working at SLAC since the end of 1998. We report on the performances of the RPC chambers focusing on new problems discovered in the RPC behaviour. These problems started very soon after the installation of the chambers on the detector when the high-ambient temperature triggered an increase of dark currents inside the chambers and a reduction of the efficiency. Careful analysis of the BaBar data and dedicated R&D efforts in the laboratory have helped to identify the main source of the trouble in the linseed oil varnish on the bakelite electrodes.

Abstract A new silicon microstrip detector was designed by the CDF collaboration for the proposed high-luminosity operation of the Tevatron p p ¯ collider (Run IIb). The detector is radiation-tolerant and will still be functional after exposure to particle fluences of 10 14 1 - MeV equivalent neutrons / cm 2 and radiation doses of 20 MRad. The detector will maintain or exceed the performance of the current CDF silicon detector throughout Run IIb. It is based on an innovative silicon “supermodule” design. Critical detector components like the custom radiation-hard SVX4 readout chip, the beryllia hybrids and mini-port (repeater) cards, and the silicon sensors fulfill their specifications and were produced with high yields. The design goals and solutions of the CDF Run IIb silicon detector are described, and the performance of preproduction modules is presented in detail. Results relevant for the development of future silicon systems are emphasized.

The BaBar Collaboration has operated an instrumented flux return (IFR) system covering over 2000m2 with resistive plate chambers (RPCs) for nearly 3 years. The chambers are constructed of bakelite sheets separated by 2mm. The inner surfaces are coated with linseed oil. This system provides muon and neutral hadron detection for BaBar. Installation and commissioning were completed in 1998, and operation began mid-year 1999. While initial performance of the system reached design, over time, a significant fraction of the RPCs demonstrated significant degradation, marked by increased currents and reduced efficiency. A coordinated effort of investigations have identified many of the elements responsible for the degradation. This article presents our current understanding of the aging process of the BaBar RPCs along with the action plan to combat performance degradation of the IFR system.

The BaBar Collaboration has operated a system covering over 2000 m/sup 2/ with resistive plate chambers for nearly three years. The chambers are constructed of bakelite sheets separated by 2 mm. The inner surfaces are coated with linseed oil. This system provides muon and neutral hadron detection for BaBar. Installation and commissioning were completed in 1998, and operation began mid-1999. While initial performance of the system reached design, over time, a significant fraction of the resistive plate chambers demonstrated significant degradation, marked by increased currents and reduced efficiency. A coordinated investigative effort has identified many of the elements responsible for the degradation.

The production cross sections of 10Be and 26Al were measured by accelerator mass spectrometry using 89Y, 159Tb, and natCu targets bombarded by protons with energies Ep of 120 GeV and 392 MeV. The production cross sections obtained for 10Be and 26Al were compared with those previously reported using Ep = 50 MeV–24 GeV and various targets. It was found that the production cross sections of 10Be monotonically increased with increasing target mass number when the proton energy was greater than a few GeV. On the other hand, it was also found that the production cross sections of 10Be decreased as the target mass number increased from that of carbon to those near the mass numbers of nickel and zinc when the proton energy was below approximately 1 GeV. They also increased as the target mass number increased from near those of nickel and zinc to that of bismuth, in the same proton energy range. Similar results were observed in the production cross sections of 26Al, though the absolute values were quite different between 10Be and 26Al. The difference between these production cross sections may depend on the impact parameter (nuclear radius) and/or the target nucleus stiffness.

The CDF II eXtremely Fast Tracker (XFT) is the trigger processor which reconstructs charged particle tracks in the CDF II central outer tracking chamber. The XFT tracks are also extrapolated to the electromagnetic calorimeter and muon chambers and are associated to electromagnetic clusters and muon stubs to generate trigger electron and muon candidates. The steady increase of the Tevatron instantaneous luminosity and the resulting higher occupancy of the chamber demanded an upgrade of the original system, which performed tracking only in the transverse plane of the chamber and was consequently affected by a significant level of fake tracks. In the upgraded XFT, tracking is reinforced by using additional data from the stereo layers of the chamber to reduce the level of fake tracks and to perform three-dimensional track reconstruction. A review of this upgrade is presented.

With the growth in size and complexity of High Energy Physics experiments, and the accompanying increase in the number of collaborators spread across the globe, the importance of widely relaying timely monitoring and status information has grown. To this end, we present online Web Based Monitoring solutions from the CMS experiment at CERN. The web tools developed present data to the user from many underlying heterogeneous sources, from real time messaging systems to relational databases. We provide the power to combine and correlate data in both graphical and tabular formats of interest to the experimentalist, with data such as beam conditions, luminosity, trigger rates, detector conditions and many others, allowing for flexibility on the user side. We also present some examples of how this system has been used during CMS commissioning and early beam collision running at the Large Hadron Collider.

The central drift chamber for the BaBar detector at the SLAC B-factory is based on a hexagonal cell design with 7104 cells arranged in 40 layers and drift gas helium:isobutane (80%:20%). Performance optimization and integration requirements led to an electronics design that mounts the amplifier-discriminator and digitizing circuitry directly on the endplate. High channel density is achieved using a 4-channel custom amplifier-discriminator IC and an 8-channel custom CMOS TDC/FADC IC on a single circuit board. Data read from the front ends are multiplexed on 4 fiber optic links, and prompt trigger data are sent out continuously on 24 links. Analysis of cosmic ray data demonstrates that the electronics design meets the performance goals for the BaBar drift chamber. The final electronics were installed on the drift chamber in July, 1998. Installation of BaBar on beamline is scheduled for March, 1999.

The rate of performance improvements of the LHC at CERN has had a strong influence on the characteristics of the monitoring tools developed for the experiments. We present some of the latest additions to the suite of Web Based Monitoring services for the CMS experiment, and explore the aspects that address the roughly 20-fold increase in peak instantaneous luminosity over the course of 2011. One of these user-friendly tools allows collaborators to easily view, and make correlations among, accelerator configuration information such as bunch patterns, measured quantities such as intensities, vacuum pressures, and background conditions, as well as derived quantities such as luminosity and the number of simultaneous interactions per beam crossing. An additional tool summarizes the daily, weekly, and yearly luminosity and efficiency. Finally, we discuss a trigger cross section and rate fitting service that uses data from previous runs to validate current running conditions, as well as to serve as a predictive extrapolation tool for developing triggers for higher luminosity running.

The Compact Muon Solenoid is a large a complex general purpose experiment at the CERN Large Hadron Collider (LHC), built and maintained by many collaborators from around the world. Efficient operation of the detector requires widespread and timely access to a broad range of monitoring and status information. To that end the Web Based Monitoring (WBM) system was developed to present data to users located anywhere from many underlying heterogeneous sources, from real time messaging systems to relational databases. This system provides the power to combine and correlate data in both graphical and tabular formats of interest to the experimenters, including data such as beam conditions, luminosity, trigger rates, detector conditions, and many others, allowing for flexibility on the user's side. This paper describes the WBM system architecture and describes how the system has been used from the beginning of data taking until now (Run1 and Run 2).

The CDF II level 1 track trigger system reconstructs charged tracks in the plane transverse to the beam direction. The track trigger electronics uses the hit data from the 4 axial layers of the CDF II central outer tracking chamber, and has been recently upgraded to include the complementary information from the 3 stereo layers. Together with the existing system it provides improved fake track rejection at level 1. In addition, the high resolution segment information is delivered to the Level 2 processors, where software algorithms perform three-dimensional stereo track reconstruction. The 3D-tracks are further extrapolated to the electromagnetic calorimeter towers and muon chambers to generate trigger electron and muon candidates. The invariant mass of track pairs and track isolations are also calculated and used in the level 2 trigger decision. We describe the hardware and software for the level 2 part of the track trigger upgrade as well as the performance of the new track trigger algorithms.

The authors report on recent results from the Collider Detector at Fermilab (CDF) experiment, which is accumulating data from proton-antiproton collisions with {radical}s = 1.96 TeV at Run II of the Fermilab Tevatron. The new phenomena being explored include Higgs, Supersymmetry, and large extra dimensions. They also present the latest results of searches for heavy objects, which would indicate physics beyond the Standard Model.

The Compact Muon Solenoid (CMS) is a large and complex general purpose experiment at the CERN Large Hadron Collider (LHC), built and maintained by many collaborators from around the world. Efficient operation of the detector requires widespread and timely access to a broad range of monitoring and status information. To this end the Web Based Monitoring (WBM) system was developed to present data to users located anywhere from many underlying heterogeneous sources, from real time messaging systems to relational databases. This system provides the power to combine and correlate data in both graphical and tabular formats of interest to the experimenters, including data such as beam conditions, luminosity, trigger rates, detector conditions, and many others, allowing for flexibility on the user side. This paper describes the WBM system architecture and describes how the system was used during the first major data taking run of the LHC.

The Compact Muon Solenoid (CMS) is a large and complex general purpose experiment at the CERN Large Hadron Collider (LHC), built and maintained by many collaborators from around the world. Efficient operation of the detector requires widespread and timely access to a broad range of monitoring and status information. To this end the Web Based Monitoring (WBM) system was developed to present data to users located anywhere from many underlying heterogeneous sources, from real time messaging systems to relational databases. This system provides the power to combine and correlate data in both graphical and tabular formats of interest to the experimenters, including data such as beam conditions, luminosity, trigger rates, detector conditions, and many others, allowing for flexibility on the user side. This paper describes the WBM system architecture and describes how the system was used during the first major data taking run of the LHC.

For large international High Energy Physics experiments, modern web technologies make the online monitoring of detector status, data acquisition status, trigger rates, luminosity, etc., accessible for the collaborators anywhere and anytime.This helps the collaborating experts monitor the status of the experiment, identify the problems and improve data taking efficiency.We present the online Web-Based Monitoring project of the CMS experiment at the LHC at CERN.The data sources are relational databases and various messaging systems.The project provides a vast amount of in-depth information including real-time data, historical trends and correlations in a user-friendly way.

Extruded scintillator with wavelength shifting (wls) fiber for light collection and silicon avalanche photo-detection (SiPM), followed by modest amplification remains an attractive candidate for large area counters such as are required for muon detectors/tail catchers for collider detectors.We report on R & D for the optimization of such detectors which has included the development of ad hoc SiPMs and frontend electronics with 12 bit waveform digitization at 100 -200 MHz.Bias voltage is generated locally and provision is made for on board data storage and fast transfer to a local PC for immediate analysis.In addition to describing the data collection and counter assembly we will present representative data results from tests performed at the Fermilab Test Beam Facility.

Six days. Three frontiers. One amazing lab. From 2010 to 2012, a film crew followed a group of scientists at the Department of Energy's Fermilab and filmed them at work and at home. This 40-minute documentary shows the diversity of the people, research and work at Fermilab. Viewers catch a true behind-the-scenes look of the United States' premier particle physics laboratory while scientists explain why their research is important to them and the world.

With the growth in size and complexity of High Energy Physics experiments, and the accompanying increase in the number of collaborators spread across the globe, the importance of widely relaying timely monitoring and status information has grown. To this end, we present online Web Based Monitoring solutions from the CMS experiment at CERN. The web tools developed present data to the user from many underlying heterogeneous sources, from real time messaging system to relational databases. We provide the power to combine and correlate data in both graphical and tabular formats of interest to the experimentalist, with data such as beam conditions, luminosity, trigger rates, detector conditions and many others, allowing for flexibility on the user side. We also present some examples of how this system has been used during CMS commissioning and early beam collision running at the Large Hadron Collider.

A model-independent global search for new physics has been performed at the CDF experiment. This search examines nearly 400 final states, looking for discrepancies between the observed data and the standard model expectation in populations, kinematic shapes, and the tails of the summed transverse momentum distributions. A new approach also searches in approximately 5000 mass variables looking for 'bumps' that may indicate resonant production of new particles. The results of this global search for new physics in 2/fb are presented. In addition, a model-independent search for deviations from the Standard Model prediction is performed in e+p and e-p collisions at HERA II using all H1 data recorded during the second running phase. This corresponds to integrated luminosities of 178/pb and 159/pb for e+p and e-p collisions, respectively. A statistical algorithm is used to search for deviations in the distributions of the scalar sum of transverse momenta or invariant mass of final state particles, and to quantify their significance.

The CDF II eXtremely Fast Tracker (XFT) is a trigger processor which reconstructs charged particle tracks in the transverse plane of the central tracking chamber. The XFT tracks are also extrapolated to the electromagnetic calorimeter and muon chambers to generate trigger electron and muon candidates. The XFT is crucial for the entire CDF II physics program: it detects high Pt lepton from W/Z and heavy flavors decay and, in conjunction with the level 2 processor, it identifies secondary vertices from beauty decay. The XFT has thus been crucial for the recent measurement of the Bs0 oscillation and Σb. The increase of the Tevatron instantaneous luminosity demanded an upgrade of the system to cope with the higher occupancy of the chamber. In the upgraded XFT, three-dimensional tracking reduces the level of fake tracks and measures the longitudinal track parameters, which strongly reinforce the trigger selection. This allows to maintain the trigger perfectly efficient at the record luminosities 2–3×1032cm-2s-1 and to maintain intact the CDF II high luminosity physics program, which includes the Higgs search. In this paper we review the architecture, the used technology, the performance and the impact of the upgraded XFT on the entire CDF II trigger strategy.

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <?Pub Dtl=""?>The CDF II detector uses dedicated hardware to identify charged tracks that are used in an important class of level 1 trigger decisions. Until now, this hardware identified track segments based on patterns of hits on only the axial sense wires in the tracking chamber and determined the transverse momentum of track candidates from patterns of track segments. This identification is efficient but produces trigger rates that grow rapidly with increasing instantaneous luminosity. High trigger rates are a consequence of the large numbers of low momentum tracks produced in inelastic <formula formulatype="inline"> <tex>$p\bar p$</tex></formula> collisions which generate overlapping patterns of hits that match those expected for high-momentum tracks. A recently completed upgrade to the level 1 track trigger system makes use of information from stereo wires in the tracking chamber to reduce the rate of false triggers while maintaining high efficiency for real high momentum particles. We describe the new electronics used to instrument the additional sense wires, identify track segments and correlate these with the track candidates found by the original track trigger system. The performance of this system is characterized in terms of the efficiency for identifying charged particles and the improved rejection of axial track candidates that do not correspond to real particles. </para>

A model-independent global search for new physics has been performed at the CDF experiment. This search examines nearly 400 final states, looking for discrepancies between the observed data and the standard model expectation in populations, kinematic shapes, and the tails of the summed transverse momentum distributions. A new approach also searches in approximately 5000 mass variables looking for `bumps' that may indicate resonant production of new particles. The results of this global search for new physics in 2/fb are presented. In addition, a model-independent search for deviations from the Standard Model prediction is performed in e+p and e-p collisions at HERA II using all H1 data recorded during the second running phase. This corresponds to integrated luminosities of 178/pb and 159/pb for e+p and e-p collisions, respectively. A statistical algorithm is used to search for deviations in the distributions of the scalar sum of transverse momenta or invariant mass of final state particles, and to quantify their significance.

We present recent results from the Collider Detector at Fermilab (CDF) and D0 experiments using data from proton-antiproton collisions with sqrt(s) = 1.96 TeV at Run II of the Fermilab Tevatron. New physics may appear in events with high transverse momentum objects, including photons and quark or gluon jets. The results described here are of signature-based searches and model-based searches probing supersymmetry, leptoquarks, 4th generation quarks, and large extra dimensions.

At Run II of the Fermilab Tevatron, the CDF experiment provides good sensitivity for either discovery or setting limits on 1 st and 2 nd generation scalar, or 3 rd generation vector, leptoquark pair-production, where each leptoquark decays to a charged lepton and a quark with variable branching ratio β , or decays to a neutrino and quark with branching ratio (1β ).By comparison with the theoretical expectations, we set mass limits, in some cases as a function of β .New quark generations are predicted in various scenarios for physics beyond the Standard Model.Here we include results from searches for t and for b production.The t is searched for in decays to W q and the b in decays to Z 0 b.All of these measurements are based on an integrated luminosity of 200 -350 pb -1 , taken at √ s = 1.96TeV.

The CDF II detector uses dedicated hardware to identify charged tracks that are used in an important class of Level 1 trigger decisions. Until now, this hardware identified track segments based on patterns of hits on only the axial sense wires in the tracking chamber and determined the transverse momentum of track candidates from patterns of track segments. This identification is efficient but produces trigger rates that grow rapidly with increasing instantaneous luminosity. High trigger rates are a consequence of the large numbers of low momentum tracks produced in inelastic pp macr collisions which generate overlapping patterns of hits that match those expected for high-momentum tracks. A recently completed upgrade to the Level 1 track trigger system makes use of information from stereo wires in the tracking chamber to reduce the rate of false triggers while maintaining high efficiency for real high momentum particles. We describe the new electronics used to instrument the additional sense wires, identify track segments and correlate these with the track candidates found by the original track trigger system. The performance of this system is characterized in terms of the efficiency for identifying charged particles and the improved rejection of axial track candidates that do not correspond to real particles.

The CDF II eXtremely Fast Tracker is the trigger track processor which reconstructs charged particle tracks in the transverse plane of the CDF II central outer tracking chamber. The system is now being upgraded to perform a three dimensional track reconstruction. A review of the upgrade is presented here.

We present recent results from the Collider Detector at Fermilab (CDF) and D0 experiments using data from proton-antiproton collisions with sqrt(s) = 1.96 TeV at Run II of the Fermilab Tevatron. New physics may appear in events with high transverse momentum objects, including photons and quark or gluon jets. The results described here are of signature-based searches and model-based searches probing supersymmetry, leptoquarks, 4th generation quarks, and large extra dimensions.

The invariance of physical laws under the combination of exchange of particles with antiparticles (charge conjugation, C) and reversal of coordinates (parity, P) is called CP symmetry. The violation of CP symmetry was first discovered in 1964 in the neutral kaon system, and is in general one of the great puzzles of particle physics. The recent observation of CP violation in the B meson system has been a simultaneous success for model predictions and experiment. The opportunity now exists to probe details of the underlying mechanisms. This thesis presents measurements of the branching fraction and time-dependent CP-violating asymmetry in neutral B decays to J/{psi}{pi}{sup 0}. The decay amplitude for this channel features both tree and penguin diagram contributions, the interference of which can yield a result for the asymmetry differing from that found in the ''golden mode'' B{sup 0} {yields} J/{psi} K{sub s}{sup 0}. Using the measured branching fraction and CP asymmetry, constraints are placed on the ratio of penguin to tree amplitudes in B{sup 0} {yields} J/{psi}{pi}{sup 0}. In addition, the impact on the CP asymmetry measurement in B{sup 0} {yields} J/{psi} K{sub s}{sup 0} is discussed. The results are presented for e{sup +}e{sup -} annihilation data collected with the BABAR detector on the {Upsilon}(4S) resonance at the PEP-II asymmetric-energy B Factory at SLAC. The measurement of the branching fraction, based on about 23 million B{bar B} pairs collected between October 1999 and October 2000, yields BF(B{sup 0} {yields} J/{psi}{pi}{sup 0}) = (2.0 {+-} 0.6 (stat) {+-} 0.2(syst)) x 10{sup -5}. With about 88 million B{bar B} pairs collected during the years 1999-2002, our results for the coefficients of the cosine and sine terms of the CP asymmetry are C{sub J/{psi}{pi}{sup 0}} = 0.38 {+-} 0.41 (stat) {+-} 0.09 (syst) and S{sub J/{psi}{pi}{sup 0}} = 0.05 {+-} 0.49 (stat) {+-} 0.16 (syst).

Summary form only given. The BaBar Level 1 trigger system consists of three main subsystems: the Drift Chamber Trigger, the Calorimeter Trigger and the Global Trigger. Information from the Drift Chamber and Calorimeter is processed by the respective triggers and the resulting data is sent to the Global Trigger. The algorithms of the Drift Chamber Trigger System are executed on three types of modules. First, the track segments, i.e. series of hits contiguous in space and time, are found by a set of 24 Track Segment Finder Modules (TSFM). The track segments are then linked into complete tracks by the Binary Link Tracker Module (BLTM). A set of eight PT Discriminator Modules (PTDMs) determine if the segments are consistent with tracks of particles having a transverse momentum Pt greater than a specified minimum. The Global Trigger counts tracks and attempts to match the azimuthal locations of Calorimeter towers and Drift Chamber tracks, and generates Level 1 triggers based on the results of the processing. The event production time is determined by the Global Trigger, so all the upstream components of the Level 1 Trigger form a continuously operating pipeline. This paper describes the design and implementation of the Level 1 Charged Particle Trigger System, as well as test results from Dec. 1998 to Jan. 1999 Babar cosmic test runs, including the TSF segment finding efficiency, the BLT track finding efficiency, as well as the performance of the PTD and GLT.

The authors present the first study of the time-dependent CP-violating asymmetry in B{sup 0} {yields} J/{psi}{pi}{sup 0} decays using e{sup +}e{sup -} annihilation data collected with the BABAR detector at the {Upsilon}(4S) resonance during the years 1999-2002 at the PEP-II asymmetric-energy B Factor at SLAC. Using approximately 88 million B{bar B} pairs, the results for the coefficients of the cosine and sine terms of the CP asymmetry are C{sub J/{psi}{pi}{sup 0}} = 0.38 {+-} 0.41 (stat) {+-} 0.09 (syst) and S{sub J/{psi}{pi}{sup 0}} = 0.05 {+-} 0.49 (stat) {+-} 0.16 (syst).

We present our first study of the time-dependent CP-violating asymmetry in B{sup 0} {yields} J/{psi}{pi}{sup 0} decays using e{sup +}e{sup -} annihilation data collected with the BABAR detector at the {Upsilon}(4S) resonance during the years 1999-2002 at the PEP-II asymmetric-energy B Factory at SLAC. With about 88 million B{bar B} pairs, our preliminary results for the coefficients of the cosine and sine terms of the CP asymmetry are C{sub J/{psi}{pi}{sup 0}} = 0.38 {+-} 0.41 (stat) {+-} 0.09 (syst) and S{sub J/{psi}{pi}{sup 0}} = 0.05 {+-} 0.49 (stat) {+-} 0.16 (syst).