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Study of electron and neutrino interactions. Final report

Description: This is the final report for the DOE-sponsored experimental particle physics program at Virginia Tech to study the properties of the Standard Model of strong and electroweak interactions. This contract (DE-AS05-80ER10713) covers the period from August 1, 1980 to January 31, 1993. Task B of this contract, headed by Professor Alexander Abashian, is described in this final report. This program has been pursued on many fronts by the researchers in a search for axions at SLAC, in electron-positron collisions in the AMY experiment at the TRISTAN collider in Japan, in measurements of muon decay properties in the MEGA and RHO experiments at the LAMPF accelerator, in a detailed analysis of scattering effects in the purported observation of a 17 keV neutrino at Oxford, in a search for a disoriented chiral condensate with the MiniMax experiment at Fermilab, and in an R&D program on resistive plate counters that could find use in low-cost high-quality charged particle detection at low rates.
Date: March 18, 1997
Creator: Abashian, A.
Partner: UNT Libraries Government Documents Department

My recollections as a physicist

Description: This presentation is a talk presented by the author at a Physics Symposium of the 50th anniversary of the Taiwan University, in December 1996. The author describes how he became a physicist, and then presents a brief outline of his professional career, most of which has centered at Stanford Linear Accelerator Center. He was involved in the discovery of the {tau} lepton, and in studies of CP violation through decay of the {tau}, in addition to studies of semileptonic decay of t, B, D, K, and {pi}.
Date: March 1, 1997
Creator: Tsai, Yung-su
Partner: UNT Libraries Government Documents Department

Pion correlations and calorimeter design for high energy heavy ion collisions. Progress report

Description: Data analysis is in progress for recent experiments performed by the NA44 collaboration with the first running of 160 A GeV {sup 208}Pb-induced reactions at the CERN SPS. Identified singles spectra were taken for pions, kaons, protons, deuterons, antiprotons and antideuterons. Two-pion interferometry measurements were made for semi-central-triggered {sup 208}Pb + Pb collisions. An updated multi-particle spectrometer allows high statistics data sets of identified particles to be collected near mid-rapidity. A second series of experiments will be performed in the fall of 1995 with more emphasis on identical kaon interferometry and on the measurement of rare particle spectra and correlations. Modest instrumentation upgrades by TAMU are designed to increase the trigger function for better impact parameter selection and improved collection efficiency of valid events. An effort to achieve the highest degree of projectile-target stopping is outlined and it is argued that an excitation function on the SPS is needed to better understand reaction mechanisms. Analysis of experimental results is in the final stages at LBL in the EOS collaboration for two-pion interferometry in the 1.2 A GeV Au + Au reaction, taken with full event characterization.
Date: April 1, 1997
Creator: Wolf, K.L.
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

The gold flashlight: Coherent photons (and Pomerons) at RHIC

Description: The Relativistic Heavy Ion Collider (RHIC) will be the first heavy ion accelerator energetic enough to produce hadronic final states via coherent {gamma}{gamma}, {gamma}P, and PP interactions. Because the photon flux scales as Z{sup 2}, up to an energy of about {gamma}{h_bar}c/R {approx} 3 GeV/c, the {gamma}{gamma} interaction rates are large. RHIC {gamma}P interactions test how Pomerons couple to nuclei and measure how different vector mesons, including the J/{psi}, interact with nuclear matter. PP collisions can probe Pomeron couplings. Because these collisions can involve identical initial states, for identical final states, the {gamma}{gamma}, {gamma}P, and PP channels may interfere, producing new effects. The authors review the physics of these interactions and discuss how these signals can be detected experimentally, in the context of the STAR detector. Signals can be separated from backgrounds by using isolation cuts (rapidity gaps) and p{perpendicular}. The authors present Monte Carlo studies of different backgrounds, showing that representative signals can be extracted with good rates and signal to noise ratios.
Date: June 1, 1997
Creator: Klein, S. & Scannapieco, E.
Partner: UNT Libraries Government Documents Department

Ring-imaging Cerenkov studies. Final performance report

Description: This project involved collaboration in the design, construction and testing of a prototype chamber capable of detecting Cerenkov rings. The chamber incorporated several novel techniques in that it used parallel-plate pad readout and a Cesium-iodide (CsI) solid photocathode. The pad system used gas multiplication where the gas was kept at low pressure to minimize photon losses due to absorption and back-scattering and to minimize ion collection times. Low pressure also lowers the chamber response to charged particles. The chamber gas was ethane at 20 torr and the chamber was operated at room temperature. The chamber was built at the University of Pennsylvania by a University of Puerto Rico graduate student, Jorge Millan. Initial tests at Pennsylvania using a hydrogen-discharge lamp indicated a quantum efficiency of 13% at 190 nm. The chamber was then tested in the M-Test beam line at Fermilab and behind the C3 beamline dump at Brookhaven Lab. Cerenkov rings were clearly observed with each photoelectron typically exciting one pad. On average each ring had five struck pads and only 10% of the events had hits in the center due to the charged particle. These results indicate that a RICH detector using a solid CsI photocathode coupled to a low-pressure, parallel-plate pad chamber is an excellent device for particle identification in high-rate environments when there is a need to cover large areas with minimum expense.
Date: March 13, 1997
Creator: Lopez, A. M.
Partner: UNT Libraries Government Documents Department

A search for squarks and gluinos using the jets and missing energy signature at D-0

Description: This thesis reports on a search for evidence of production and decay of squarks (q) and gluinos (g) of Minimal Supergravity (mSUGRA) in p{bar p} collisions at a center of mass energy of 1.8 TeV using the D0 detector at the Fermi National Accelerator Laboratory. Data corresponding to 79.2 {+-} 4.2 pb{sup -1} were examined for events with large missing transverse energy (E{sub T}), three or more jets, high energy leading jet, and the absence of isolated leptons. Since no events were observed in excess of Standard Model background predictions, limits are placed in the mSUGRA M{sub 0} - M{sub {1/2}} plane for fixed parameters tan {beta} = 2, A{sub o} = 0, and {mu} < 0. The excluded region includes all mSUGRA models with m{sub q} < 250 GeV/c{sup 2}. For small M{sub 0}, gluinos with mass less than 300 GeV/c{sup 2} are excluded. If squarks and gluinos have the same mass, that common mass must be greater than 260 GeV/c{sup 2}.
Date: September 1, 1997
Creator: Lyon, A.L.
Partner: UNT Libraries Government Documents Department

High energy physics at UC Riverside

Description: This report discusses progress made for the following two tasks: experimental high energy physics, Task A, and theoretical high energy physics, Task B. Task A1 covers hadron collider physics. Information for Task A1 includes: personnel/talks/publications; D0: proton-antiproton interactions at 2 TeV; SDC: proton-proton interactions at 40 TeV; computing facilities; equipment needs; and budget notes. The physics program of Task A2 has been the systematic study of leptons and hadrons. Information covered for Task A2 includes: personnel/talks/publications; OPAL at LEP; OPAL at LEP200; CMS at LHC; the RD5 experiment; LSND at LAMPF; and budget notes. The research activities of the Theory Group are briefly discussed and a list of completed or published papers for this period is given.
Date: July 1, 1997
Partner: UNT Libraries Government Documents Department

Tau physics at CDF

Description: We discuss tau identification techniques at hadron colliders, and present the measurements and the searches performed so far. We report on the first evidence of t{anti t} production in the channel containing one hadronically decaying {tau} lepton. We also present a search for the charged Higgs boson in the tau decay channel, as well as for the leptoquark family containing tau leptons. In addition, we underline the importance of tau physics both at present and future collider experiments.
Date: August 1, 1997
Creator: Gallinaro, M.
Partner: UNT Libraries Government Documents Department

The DHG sum rule measured with medium energy photons

Description: The structure of the nucleon has many important features that are yet to be uncovered. Of current interest is the nucleon spin-structure which can be measured by doing double-polarization experiments with photon beams of medium energies (0.1 to 2 GeV). One such experiment uses dispersion relations, applied to the Compton scattering amplitude, to relate measurement of the total reaction cross section integrated over the incident photon energy to the nucleon anomalous magnetic moment. At present, no single facility spans the entire range of photon energies necessary to test this sum rule. The Laser-Electron Gamma Source (LEGS) facility will measure the double-polarization observables at photon energies between 0.15--0.47 MeV. Either the SPring8 facility, the GRAAL facility (France), or Jefferson Laboratory could make similar measurements at higher photon energies. A high-precision measurement of the spin-polarizability and the Drell-Hearn-Gerasimov sum rule is now possible with the advent of high-polarization solid HD targets at medium energy polarized photon facilities such as LEGS, GRAAL and SPring8. Other facilities with lower polarization in either the photon beam or target (or both) are also pursuing these measurements because of the high priority associated with this physics. The Spin-asymmetry (SASY) detector that will be used at LEGS has been briefly outlined in this paper. The detector efficiencies have been explored with simulations studies using the GEANT software, with the result that both charged and uncharged pions can be detected with a reasonable efficiency (> 30%) over a large solid angle. Tracking with a TPC, which will be built at LEGS over the next few years, will improve the capabilities of these measurements.
Date: December 31, 1997
Creator: Hicks, K.; Ardashev, K. & Babusci, D.
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

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

Production rates of strange vector mesons at the Z{sup 0} resonance

Description: This dissertation presents a study of strange vector meson production, {open_quotes}leading particle{close_quotes} effect and a first direct measurement of the strangeness suppression parameter in hadronic decays of the neutral electroweak boson, Z{sup 0}. The measurements were performed in e{sup +}e{sup -} collisions at the Stanford Linear Accelerator Center (SLAC) with the SLC Large Detector (SLD) experiment. A new generation particle ID system, the SLD Cerenkov Ring Imaging Detector (CRID) is used to discriminate kaons from pions, enabling the reconstruction of the vector mesons over a wide momentum range. The inclusive production rates of {phi} and K*{sup 0} and the differential rates versus momentum were measured and are compared with those of other experiments and theoretical predictions. The high longitudinal polarisation of the SLC electron beam is used in conjunction with the electroweak quark production asymmetries to separate quark jets from antiquark jets. K*{sup 0} production is studied separately in these samples, and the results show evidence for the {open_quotes}leading particle{close_quotes} effect. The difference between K*{sup 0} production rates at high momentum in quark and antiquark jets yields a first direct measurement of strangeness suppression in jet fragmentation.
Date: May 1997
Creator: Dima, M. O.
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

Production of {pi}{sup {+-}}, K{sup {+-}}, K{sup 0}, K*{sup 0}, {phi}, p and {Lambda}{sup 0} in hadronic Z{sup 0} decays

Description: The authors have measured production rates as a function of momentum of the identified hadrons {pi}{sup +}, K{sup +}, K{sup 0}, K*{sup 0}, {phi}, p, {Lambda}{sup 0} and their antihadrons in inclusive hadronic Z{sup 0} decays, as well as separately in decays into light, c and b flavors. In addition they have compared hadron and antihadron production rates in light quark (rather than antiquark) jets. The SLD Cherenkov Ring Imaging Detector was used to identify charged hadrons. The vertex detector was used to tag high-purity samples of light- and b-flavor events. The electron beam polarization was used to tag samples of quark and antiquark jets. Clear flavor dependences are observed, consistent with expectations based upon measured production and decay properties of heavy hadrons. They use the light-flavor results to test the predictions of MLLA QCD and of various fragmentation models. Differences between hadron and antihadron production in light quark jets are observed at high momentum fraction, providing direct evidence that higher-momentum particles are more likely to contain a primary quark or antiquark, and they use these results to make a new direct measurement of strangeness suppression in the jet fragmentation process.
Date: June 1, 1997
Creator: Abe, K.; Abe, K.; Akagi, T. & Collaboration, SLD
Partner: UNT Libraries Government Documents Department

Study of electron and neutrino interactions

Description: This is the final report for the DOE-sponsored experimental particle physics program at Virginia Tech to study the properties of the Standard Model of strong and electroweak interactions. This contract (DE-AS05-80ER10713) covers the period from August 1, 1980 to January 31, 1993. Task B of this contract, headed by Professor Alexander Abashian, is described in this final report. This program has been pursued on many fronts by the researchers-in a search for axions at SLAC, in electron-positron collisions in the AMY experiment at the TRISTAN collider in Japan, in measurements of muon decay properties in the MEGA and RHO experiments at the LAMPF accelerator, in a detailed analysis of scattering effects in the purported observation of a 17 keV neutrino at Oxford, in a search for a disoriented chiral condensate with the MiniMax experiment at Fermilab, and in an R&D program on resistive plate counters that could find use in low-cost high-quality charged particle detection at low rates.
Date: March 18, 1997
Creator: Abashian, A.
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

First commissioning results from Hall A at TJNAF

Description: The commissioning and resulting capabilities of Hall A at the Thomas Jefferson National Accelerator Facility for performing coincidence experiments with a continuous wave electron beam at energies of 0.8--6.0 GeV will be described. The facility consists of a pair of high-resolution magnetic spectrometers to detect scattered particles, together with instrumentation to measure beam properties. The installation of the base equipment has been completed. Commissioning of the spectrometers, including their detector packages, is well advanced, both in single-arm mode and in coincidence mode.
Date: May 1, 1997
Creator: Collaboration, Robert Michaels for the Hall A
Partner: UNT Libraries Government Documents Department

Recent developments on the STAR detector system at RHIC

Description: The STAR detector system is designed to provide tracking, momentum analysis and particle identification for many of the mid-rapidity charged particles produced in collisions at the RHIC collider. A silicon vertex detector (SVT) provides three layers of tracking near the interaction point. This is followed by the main time projection chamber (TPC), which continues tracking out to 200 cm radial distance from the interaction region. The detector design also includes an electromagnetic calorimeter, various trigger detectors, and radial TPCs in the forward region. The entire system is enclosed in a 0.5 T solenoid magnet. A progress report is given for the various components of the STAR detector system. The authors report on the recent developments in the detector proto-typing and construction, with an emphasis on the main TPC, recent TPC cosmic ray testing and shipping to Brookhaven National Laboratory.
Date: December 1997
Creator: Argonne National Laboratory
Partner: UNT Libraries Government Documents Department

The MINOS long-baseline experiment at Fermilab

Description: The MINOS (Main Injector Neutrino Oscillation Search) long-baseline experiment will search for neutrino oscillations by measuring an intense {nu}{sub {mu}} beam at the end of a 730 km flight path. The 10,000 ton MINOS far detector will utilize magnetized steel plates interleaved with track chambers to reconstruct event topologies and to measure the energies of the muons, hadrons and electromagnetic showers produced by neutrino interactions. The experiment is designed to detect {nu}{sub {mu}} {r_arrow} {nu}{sub {tau}} and {nu}{sub {mu}} {r_arrow} {nu}{sub e} oscillations with {Delta}m{sup 2} {ge} 0.001 eV{sup 2} and sin{sup 2} (2{theta}) {ge} 0.01. Any oscillation signal observed can be verified and studied by several independent tests: a near/far rate comparison, the NC/CC event ratio, the CC and NC event energy spectra, and the identification of electrons and {tau} leptons. The neutrino beam can be operated in both wide-band and narrow-band configurations, allowing the detailed study oscillation phenomena. The experiment is scheduled to begin operation in 2001.
Date: January 2, 1997
Creator: Ayres, D.S.
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

New ideas to improve searches for {mu}{sup +} {r_arrow} e{sup +}{gamma}

Description: Searching for decays that change total lepton family number is an excellent method to explore potential physics beyond the Standard Model because those processes are predicted to be zero except when new physics is present. Essentially all extensions of the Standard Model that introduce new, heavy particles predict the existence of these rare decays, though the most probable channel is highly model dependent. Recently, the prejudice has grown within the physics community that supersymmetry is an extension that is likely to be related to nature. Barbieri, Hall, and Strumia show that rare decays are signatures for grand unified supersymmetry and calculate the rates for {mu}{sup +} {r_arrow} e{sup +}{gamma} and related processes for a wide range of parameters of these models. They conclude that {mu}{sup +} {r_arrow} e{sup +}{gamma} has the largest rate by more than two orders of magnitude, and it ranges between the current experimental limit and 10{sup {minus}14}. Hence, there is continuing interest in the community for an experiment that could have a sensitivity near 10{sup {minus}14}. Lessons are drawn from the experience of the MEGA experiment in searching for {mu}{sup +} to e{sup +}{gamma}. In light of that experience, some ideas are evaluated regarding new searches that might take place in the ERA of a source of low-energy muons associated with a muon collider.
Date: November 1, 1997
Creator: Cooper, M.D.
Partner: UNT Libraries Government Documents Department

High energy ion collisions. Final technical report, December 14, 1995--March 17, 1997

Description: This grant supported one year of work on Relativistic Heavy Ion Collisions at the University of New Mexico. The Principal Investigator, an Adjunct Associate Professor at UNM, recruited a student (Mikhail Kopytine), sent him to CERN for several months to participate in the final data taking period of the NA44 experiment at CERN, then initiated analysis of the data collected during the run. A Hewlett-Packard workstation was purchased and Mr. Kopytine performed calibration, software development, and data analysis using it. A collaboration between Los Alamos National Laboratory and other faculty members at the University of New Mexico was begun, with the goal of working closely together on the PHENIX experiment for RHIC. At this time, a close collaboration continues, centered around the Muon tracking detectors for PHENIX. Station 1 of the tracking system is under construction at UNM, while stations 2 and 3 are the responsibility of LANL. The following accomplishments were made: (1) Participation in final data taking period of NA44; (2) Work on commissioning of aerogel Cerenkov trigger and performed offline analysis to demonstrate its performance; (3) Calibration of the uranium calorimeter in NA44 in preparation for Data Summary Tape production; (4) An optimized DST production for tapes with single pion, kaon, and proton triggers for Pb+Pb collisions was performed; (5) Analysis of pion and kaon distributions and production cross sections from Pb+Pb collisions; and (6) Participation in MVD development meetings and contributed to planning of the analysis software for MVD.
Date: December 31, 1997
Creator: Jacak, B. V.
Partner: UNT Libraries Government Documents Department

Spin physics with the PHENIX detector system

Description: The PHENIX experiment at RHIC has extended its scope to cover spin physics using polarized proton beams. The major goals of the spin physics at RHIC are elucidation of the spin structure of the nucleon and precision tests of the symmetries. Sensitivities of the spin physics measurements with the PHENIX detector system are reviewed.
Date: December 31, 1997
Creator: Saito, N. & Collaboration, PHENIX
Partner: UNT Libraries Government Documents Department