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The CEBAF Large Acceptance Spectrometer (CLAS)

Description: The CEBAF Large Acceptance Spectrometer (CLAS) is used to study photo- and electro-induced nuclear and hadronic reactions by providing efficient detection of neutral and charged particles over a good fraction of the full solid angle. A collaboration of about thirty institutions has designed, assembled, and commissioned CLAS in Hall B at the Thomas Jefferson National Accelerator Facility. The CLAS detector is based on a novel six-coil toroidal magnet which provides a largely azimuthal field distribution. Trajectory reconstruction using drift chambers results in a momentum resolution of 0.5% at forward angles. Cerenkov counters, time-of-flight scintillators, and electromagnetic calorimeters provide good particle identification. Fast triggering and high data acquisition rates allow operation at a luminosity of 10{sup 34} nucleon cm {sup -2}s{sup -1}. These capabilities are being used in a broad experimental program to study the structure and interactions of mesons, nucleons, and nuclei using polarized and unpolarized electron and photon beams and targets. This paper is a comprehensive and general description of the design, construction and performance of CLAS.
Date: January 1, 2003
Creator: Mecking, Bernhard & Collaboration, CLAS
Partner: UNT Libraries Government Documents Department

Search for exotic particles at CDF

Description: CDF has searched for 2nd generation leptoquarks, new gauge bosons W{prime} and Z{prime}, axigluons, excited quarks, color octet technirhos and E{sub 6} diquarks. We place the most stringent limits on direct production of these exotic particles.
Date: February 1, 1995
Creator: Harris, R.M.
Partner: UNT Libraries Government Documents Department

The BNL rare kaon decay program

Description: The rare kaon decay program at Brookhaven National Laboratory is reviewed. Results from the last round of experiments are briefly discussed. The three experiments currently collecting data are described. Prospects for future experiments are discussed.
Date: December 31, 1996
Creator: Littenberg, L.
Partner: UNT Libraries Government Documents Department

Prospects for HERMES-spin structure studies at HERA

Description: HERMES (HERA Measurement of Spin), is a second generation experiment to study the spin structure of the nucleon by using polarized internal gas targets in the HERA 35-GeV electron storage ring. Scattered electrons and coincident hadrons will be detected in an open geometry spectrometer which will include particle identification. Measurements are planned for each of the inclusive structure functions, g{sub 1},(x), g{sub 2}(x), b{sub 1}(x) and A(x), as well as the study of semi-inclusive pion and kaon asymmetries. Targets of hydrogen, deuterium and {sup 3}He will be studied. The accuracy of data for the inclusive structure functions will equal or exceed that of current experiments. The semi-inclusive asymmetries will provide a unique and sensitive probe of the flavor dependence of quark helicity distributions and properties of the quark sea. Monte Carlo simulations of HERMES data for experiment asymmetries and polarized structure functions are discussed.
Date: December 31, 1994
Creator: Jackson, H.E.
Partner: UNT Libraries Government Documents Department

Calorimetry at 0{degree} in RHIC: Some issues in the choice of detector technology

Description: The authors discuss briefly the case for a zero degree calorimeter at RHIC and space constraints on such a device. Two GEANT simulations of quartz fiber calorimeters are then studied and compared to the corresponding case of scintillator sampling. The authors find that the Q-cal calorimeter does provide some improvement in response uniformity near the calorimeter edge to hadronic showers (due to the filtering out of wide angle shower products). This may be an advantage when space is limited and the calorimeter transverse dimensions are small.
Date: May 1, 1994
Creator: Christie, B.; White, S.; Gorodetzky, P. & Lazic, D.
Partner: UNT Libraries Government Documents Department

Composite particle production in relativistic Au+Au collisions at AGS: First results from the E866 forward spectrometer @ 2, 4, and 10.8 A{center_dot}GeV

Description: Particle spectra were measured for Au + Au collisions at 2, 4, and 10. 8 A{center_dot}GeV using the E866 spectrometers. Recent results on proton emission and composite particle production form the E866 forward spectrometer data taken in 1994 together with the first results from the 1995/6 AGS running period are presented. Preliminary results indicate a decrease in the coalescence scaling coefficient with increasing projectile energy and centrality.
Date: December 31, 1996
Creator: Ashktorab, K.
Partner: UNT Libraries Government Documents Department

Interesting aspects of the STAR detector and physics program

Description: The Solenoidal Tracker At RHIC (STAR) is a large acceptance collider detector scheduled to begin operation at the Relativistic Heavy Ion Collider (RHIC) in the fall of 1999. Simply stated, the physics goals of STAR are, (1) to study the behavior of strongly interacting matter at high energy density; (2) to search for signatures of a deconfined partonic phase of matter; and (3) to study the importance of spin as a fundamental property of QCD interactions and measure the spin-dependent parton distributions (gluon, valence quark, sea quark) of the proton. The detector design and methods of accomplishing the physics goals are addressed in this report.
Date: December 31, 1996
Creator: Hallman, T.J. & Collaboration, STAR
Partner: UNT Libraries Government Documents Department

CDF evidence for the top quark & B physics at Fermilab

Description: We present the first direct evidence for the top quark with the Collider Detector at Fermilab (CDF) in a sample of {bar p}p collisions at {radical}s=1.8 TeV with an integrated luminosity of 19.3 pb{sup -1}. The recent B physics results at Fermilab from both collider and fixed target experiments are reviewed.
Date: February 1, 1997
Creator: Yao, Weiming
Partner: UNT Libraries Government Documents Department

Detector implications for eletroweak physics at the Tevatron

Description: D0 and CDF are two large, powerful, multipurpose detectors with outstanding tracking, calorimeter and muon systems that have done an excellent job in exploiting the Top Quark, b Quark, QCD, New Phenomena/Exotics and Electroweak Physics at the Fermilab Tevatron Collider. The upgrades of the D0 and CDF detectors will further enhance their capabilities for physics at the Tevatron. The addition of a magnetic field and silicon vertex chamber will open up new physical opportunities for D0, and the replacement of the plug and forward gas calorimeters with new scintillator based calorimeters will give CDF uniform calorimetry over all {eta}.
Date: December 1, 1996
Creator: Madaras, R.J.
Partner: UNT Libraries Government Documents Department

Proceedings of PIXEL98 -- International pixel detector workshop

Description: Experiments around the globe face new challenges of more precision in the face of higher interaction rates, greater track densities, and higher radiation doses, as they look for rarer and rarer processes, leading many to incorporate pixelated solid-state detectors into their plans. The highest-readout rate devices require new technologies for implementation. This workshop reviewed recent, significant progress in meeting these technical challenges. Participants presented many new results; many of them from the weeks--even days--just before the workshop. Brand new at this workshop were results on cryogenic operation of radiation-damaged silicon detectors (dubbed the Lazarus effect). Other new work included a diamond sensor with 280-micron collection distance; new results on breakdown in p-type silicon detectors; testing of the latest versions of read-out chip and interconnection designs; and the radiation hardness of deep-submicron processes.
Date: August 1, 1998
Creator: Anderson, D.F. & Kwan, S.
Partner: UNT Libraries Government Documents Department

The PHENIX experiment at RHIC

Description: The primary goals of the heavy-ion program of the PHENIX collaboration are the detection of the quark-gluon plasma and the subsequent characterization of its physical properties. To address these aims, PHENIX will pursue a wide range of high energy heavy-ion physics topics. The breadth of the physics program represents the expectation that it will require the synthesis of a number of measurements to investigate the physics of the quark-gluon plasma. The broad physics agenda of the collaboration is also reflected in the design of the PHENIX detector itself, which is capable of measuring hadrons, leptons and photons with excellent momentum and energy resolution. PHENIX has chosen to instrument a selective acceptance with multiple detector technologies to provide very discriminating particle identification abilities. Additionally, PHENIX will take advantage of RHIC`s capability to collide beams of polarized protons with a vigorous spin physics program, a subject covered in a separable contribution to these proceedings.
Date: December 1, 1997
Creator: Morrison, D.P.; Akiba, Y.; Alford, O. & Collaboration, PHENIX
Partner: UNT Libraries Government Documents Department

Experimental studies of rare K{sup +} decays

Description: Experiment E865 at the BNL AGS is a search for the lepton number violating decay K{sup +} {r_arrow} {pi}{sup +}{mu}{sup +}e{sup {minus}} with an expected sensitivity of 3 {times} 10{sup {minus}12}. The experimental apparatus involves a magnetic spectrometer with two Cerenkov counters, a calorimeter and a muon detector for particle identification. In addition, other rare K{sup +} decays are studied. The experiment has been collecting data since 1995, and preliminary results are presented.
Date: December 31, 1996
Creator: Appel, R.; Atoyan, G.S. & Bassalleck, B.
Partner: UNT Libraries Government Documents Department

Hadron fragmentation functions and leading particle effects in hadronic Z{sup 0} decays: New results from SLD

Description: The authors have measured the differential cross sections for the production of {pi}{sup {+-}}, K{sup {+-}}, K{sup 0}, K*(892), {phi}(1,020), p and {Lambda} in hadronic Z{sup 0} decays and in subsets of flavor-tagged Z{sup 0} {yields} light quark (u{anti u}, d{anti d}, or s{anti s}), Z{sup 0} {yields} c{anti c} and Z{sup 0} {yields} b{anti b} events. Charged hadrons were identified with the SLD Cherenkov ring imaging detector. The vertex detector was employed to select flavor enriched samples and the polarized electron beam from SLC was used to tag quark and anti-quark jets. The authors observe a flavor dependence in the hadron fragmentation functions. The authors present evidence for leading particle production in hadronic decays of the Z{sup 0} boson to light-flavor jets and a direct measurement of the strangeness suppression factor {gamma}{sub s}.
Date: May 1, 1997
Creator: Schwiening, J. & Collaboration, SLD
Partner: UNT Libraries Government Documents Department

Charm decays and high energy photoproduction. Final report, April 1994--May 1997

Description: This project involved continued participation by the Physics Department at the Mayaguez Campus of the University of Puerto Rico (UPR) in high energy physics experiments carried out at Fermilab. The UPR is a member of the E831 collaboration which includes Fermilab and leading US, Italian, Brazilian and Korean universities. E831 is an upgrade to the E687 spectrometer with the goal of a tenfold increase in the statistics for the study of the photoproduction and decay of charmed particles. This spectrometer has been significantly upgraded to maintain and expand its capabilities even at considerably higher beam intensities. E687 completed its last data run in January 1992. Approximately 100,000 charm events were fully reconstructed from this data and results of the analysis have appeared in several publications. The UPR has been participating in E687 since 1985 when the experiment was in its early stages of construction. A grant from the DOE Division of High Energy Physics (starting in April 1994) and another from the DOE EPSCoR Program (starting in October 1994) allowed a considerable increase in the activities of the UPR group. Given the group`s capable performance, the responsibilities assigned to it by the collaboration have increased to the point where they now include four major detectors in E831. All four detectors were ready on time for the start of the E831 run in July 1996. This is a remarkable performance if one considers that there is only one senior member in the group and that the students are all MS or undergraduate students. The group has also been active in the development of simulation, data acquisition and analysis software.
Date: December 31, 1997
Creator: Lopez, A. M.
Partner: UNT Libraries Government Documents Department

Final report of the High Energy Physics Group at the University of South Alabama, April 15, 1990--April 14, 1997

Description: The experimental high energy physics group at the University of South Alabama worked on three experiments conducted at the Fermi National Accelerator Laboratory. These experiments were E-705, E-771, and E-871. The group helped in taking data, analysis of data, and for one experiment in the construction of a new spectrometer. Experiment E-705 used 300 GeV/c p, {pi}{sup {minus}}, {anti p} and {pi}{sup +} on Li to study hadronic production of charmonium and direct photon production. The authors participated in the E-705 data analysis. They helped in the assembly of the E-771 spectrometer. E-771 used 800 GeV/c p-Si interactions to study hadronic beauty production and charmonium production. The groups task was to bring up the electromagnetic calorimeter and interface it into the data acquisition system. Off-line work done for the analysis of E-771 concentrated on the electromagnetic reconstruction package. Other work done in conjunction with E-771 included the development of a tracking program that used the Hough Transformation. In March of 1994, the group joined Experiment E-871. This experiment is a search for CP violation. The group took responsibility for the scintillation trigger hodoscopes to be used by the experiment.
Date: August 15, 1998
Creator: Jenkins, C.M. & Clark, R.K.
Partner: UNT Libraries Government Documents Department

High energy physics studies. Progress report for Task D

Description: The major research activity of Task D has been collaboration in experiments E791 and E871 at Brookhaven National Laboratory. During the past year, the collaboration has published results of the second major run, nearly completed analysis of the final data from the experiment and reported some of these results in conferences. The authors now have a substantially better understanding of the potential backgrounds and systematic uncertainties in the experiment. This understanding is important for both the results to be derived from the present data and for future experiments. In addition, they have conducted extensive tests for the new experiment at Brookhaven. Their goal is to improve the sensitivity to rare decay modes of kaons by a factor of 20 over the final E791 result. In the coming year the authors will finish the final analysis of all data from the experiment, including a consistent reanalysis of all data and preparation of a Phys. Rev. D article describing the measurement. Assuming approval of E871 by BNL, they will finalize detailed design of the experiment and begin prototype testing and construction. In addition to the ongoing efforts on E791 and E871 at BNL, they have begun looking at the possibility of mounting a substantially improved experiment to be performed at the proposed Main Injector at Fermilab. This effort would be part of a Main Injector Kaon Facility. In this contract renewal request, they will review the current status of lepton flavor violation in K decays, summarize the status of the experiment, report in some detail on a number of the specific projects in which personnel supported by this contract have been involved, discuss the possibilities for future directions of the experiment, and list specific requests to the funding agency.
Date: August 1, 1991
Creator: Molzon, W.R.
Partner: UNT Libraries Government Documents Department

Trigger and DAQ issues in low-mass Higgs searches

Description: Results from ongoing trigger and DAQ studies at the Superconducting Super Collider Laboratory are presented. Specific Higgs decay modes are identified, calorimetric triggering algorithms are examined, and implications for data acquisition are discussed.
Date: October 1, 1992
Creator: Wang, E.M.; Botlo, M.; Dorenbosch, J. & Walbran, S.
Partner: UNT Libraries Government Documents Department

Crystal ball single event display

Description: The Single Event Display (SED) is a routine that is designed to provide information graphically about a triggered event within the Crystal Ball. The SED is written entirely in FORTRAN and uses the CERN-based HICZ graphing package. The primary display shows the amount of energy deposited in each of the NaI crystals on a Mercator-like projection of the crystals. Ten different shades and colors correspond to varying amounts of energy deposited within a crystal. Information about energy clusters is displayed on the crystal map by outlining in red the thirteen (or twelve) crystals contained within a cluster and assigning each cluster a number. Additional information about energy clusters is provided in a series of boxes containing useful data about the energy distribution among the crystals within the cluster. Other information shown on the event display include the event trigger type and data about {pi}{sup o}`s and {eta}`s formed from pairs of clusters as found by the analyzer. A description of the major features is given, along with some information on how to install the SED into the analyzer.
Date: October 15, 1997
Creator: Grosnick, D.; Gibson, A.; Allgower, C. & Alyea, J.
Partner: UNT Libraries Government Documents Department

Tau jet signals for supersymmetry at the Tevatron

Description: The authors present a more detailed account of the study (hep-ph/9903238) for the supersymmetry reach of the Tevatron in channels with isolated leptons and identified tau jets. They review the theoretical motivations for expecting such signatures, and describe the relevant parameter space in the minimal supergravity and the minimal gauge-mediated models. With explicit Monte Carlo simulations they then show that for certain parameter ranges, channels with two leptons and one tau jet offer a better reach in Run 2 than the clean trilepton signal. They emphasize that improving on tau ID is an important prerequisite for successful searches in multiple tau jet channels. Finally, they discuss some triggering issues.
Date: January 25, 2000
Creator: Lykken, J.D. & Matchev, K.T.
Partner: UNT Libraries Government Documents Department

CP violation at CDF

Description: A major goal of experimental particle physics over the next decade is to measure the sides and angles of the Unitarity triangle redundantly, and as precisely as possible. Overconstraining the triangle will test the Cabbibo-Kobayashi-Maskawa model of quark mixing. The CDF collaboration, due to begin a second run in March 2001 with major upgrades to both the accelerator and the detector, will study the angle {beta} using B{sup 0} decays, the angle {gamma} using B{sup 0} and B{sub s}{sup 0} decays, and a side of the triangle through the observation of B{sub s}{sup 0}--{bar B}{sub s}{sup 0} mixing. Projected sensitivities are driven mostly by previous measurements using data from the first run. One highlight of the Run I B physics program is a measurement of the CP violating parameter sin 2{beta} = 0.79{sub {minus}0.44}{sup +0.41}, based on a tagged sample of 400 B{sup 0} decays in the mode B{sub 0}/{bar B}{sup 0} {r_arrow} J/{psi}K{sub s}{sup 0}. The technology of flavor tagging, used here as well as in numerous B{sup 0}-{bar B}{sup 0} mixing analyses in run I, is crucial and will be augmented in Run II with better particle identification capabilities. Exclusive all-hadronic final states will enter the data sample in Run II through a new displaced track trigger.
Date: April 16, 2001
Creator: Boudreau, J.
Partner: UNT Libraries Government Documents Department

D0 search for new phenomena

Description: Presented here are the results from three searches for non-standard model particles using approximately 13 pb{sup {minus}1} of data taken with the D0 detector at Fermilab`s Tevatron, a p{bar p} collider operating at center-of-mass energy {radical}s=1.8 TeV. A heavy right-handed W, predicted by left-right symmetric theories, is excluded at 95% confidence level with mass between 200 GeV/c{sup 2} and 540 GeV/c{sup 2}, for a right-handed neutrino mass less than 100 GeV/c{sup 2}, regardless of the decay-properties of the neutrino, and assuming the W{sub R}`s couplings and C-K-M matrix are the same as the standard model W. Stricter limits are given on the right-handed neutrino mass for W{sub R} masses near the upper limit, and for specific assumptions on the right-handed neutrino decay modes. A 95% confidence-level limit on the cross-section p{bar p} {yields} W{sub 1}Z{sub 2} {yields} 3 leptons, where {sub 1}, is the lightest supersymmetric partner of the charged vector bosom and charged higgs and Z{sub 2} is the second lightest supersymmetric partner of the Z, {gamma}, and neutral higgs, ranging from 3 pb for M{sub w1}, =45 GeV/c{sup 2} to 1 pb for M{sub W1}=100 GeV/c{sup 2} is presented, assuming mass relations between the supersymmetric particles predicted by a popular supergravity inspired model. Third, a 95% confidence-level limit on the mass of the supersymmetric partner of the gluon of 144 GeV/c{sup 2}, if the supersymmetric partner of the quarks are very heavy, or 212 GeV/c{sup 2}, if they have equal masses, is presented within the framework of the same popular model.
Date: May 1, 1995
Creator: Eno, S.
Partner: UNT Libraries Government Documents Department

Particle physics with kaons, muons and neutrinos. Summary of JHF K-Arena working groups 1a/1b

Description: The areas of rare K and {mu} decays and of neutrino oscillations are very active at the present time, and there is little reason to doubt that this will continue to be the case in the JHF era. The session featured talks describing the present status and projected future activity in these areas.
Date: August 1, 1998
Creator: Kuno, Yoshitaka & Littenberg, L.
Partner: UNT Libraries Government Documents Department

Physics with CLAS

Description: The authors describe the physics program and the experimental equipment of the CEBAF Large Acceptance Spectrometer, CLAS. The spectrometer is located in Hall B, one of the three experimental areas at the Continuous Electron Beam Accelerator Facility (CEBAF) operated by the Thomas Jefferson National Accelerator Facility. They review the program to study baryon resonances to demonstrate the multi-particle detection capabilities of the CLAS detector.
Date: September 1, 1997
Creator: Collaboration, E. Smith for the CLAS
Partner: UNT Libraries Government Documents Department

A recipe for the construction of confidence limits

Description: In this note, the authors present the recipe recommended by the Search Limits Committee for the construction of confidence intervals for the use of D0 collaboration. In another note, currently in preparation, they present the rationale for this recipe, a critique of the current literature on this topic, and several examples of the use of the method. This note is intended to fill the need of the collaboration to have a reference available until the more complete note is finished. Section 2 introduces the notation used in this note, and Section 3 contains the suggested recipe.
Date: April 12, 2000
Creator: al., Iain A Bertram et
Partner: UNT Libraries Government Documents Department