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Results obtained using the Plastic Ball

Description: Single-particle inclusive experiments, and experiments that additionally measure a few correlations like the associated multiplicity, have provided the main contribution to our present understanding of high-energy heavy-ion collisions. The results from those experiments are in overall agreement with calculations of the cascade and hydrodynamical models. In the cascade model the collision of two nuclei is simulated as a cascade of nucleon-nucleon collisions using measured N-N cross sections. The hydrodynamical model, on the other hand, describes the nuclear collision as that of two fluids and makes use of a nuclear equation of state relating thermal and compressional energy densities to pressure. The pressure field dominates the expansion phase and leads to collective flow of the reaction products in a preferred direction. The observation of such effects in inclusive experiments is not well established. Collective effects that manifest themselves in the shape of the event in phase space are expected to be seen best in complete event detectors that measure the final state as exclusively as presently possible by measuring most of the charged particles emitted in the reaction. In addition, those detectors are well suited to test macroscopic concepts such as equilibrium and temperature. Global methods like the sphericity or thrust analysis take into account all the correlations measured in the event and are specially designed to determine the shape of an event in phase space and thus to define a reaction plane. Recent data from the Plastic Ball experiment about the study of nuclear stopping and thermalization and on global analysis are presented.
Date: August 1, 1983
Creator: Ritter, H.G.; Gustafsson, H.A. & Gutbrod, H.H.
Partner: UNT Libraries Government Documents Department

A high rate transition radiation detector for particle identification in a hadron beam

Description: A Transition Radiation Detector (TRD) was built for the purpose of tagging beam particles in a high rate (/approximately/2 MHz) 250 GeV/c hadron beam during data taking for Experiment 769 at Fermilab. The availability of a good ''tool kit'', including a Monte Carlo program which could reliably predict the detector performance, made it possible to design and build the TRD in approximately one year. Pion or proton samples, each with a small contamination due to the other, could be selected with high efficiency by making cuts on the number of planes of the TRD registering hits for each incident beam particle. The detector is expected to work well to separate kaons from pions in the 500 GeV/c negative beam for E791. 15 refs., 8 figs., 1 tab.
Date: August 1, 1989
Creator: Errede, D.; Sheaff, M.; Fenker, H. & Mantsch, P.
Partner: UNT Libraries Government Documents Department

Z/sup 0/ decay modes - experimental measurements

Description: This report summarizes three lectures given at the Theoretical Advanced Study Institute at the University of Michigan at Ann Arbor. The lectures begin with an introduction to storage rings and linear colliders with special reference to the parameters of the SLC and LEP. The rigors of the Z/sup 0/ environment are presented along with the requirements for SLC and LEP detectors. The pedagogy needed for testing the Standard Model is developed, and some experimental tests of the Standard Model are discussed. Tests which involve extensions of the Standard Model (charged Higgs particles, more generations) as well as a few examples of how supersymmetry may show up at the Z/sup 0/ are discussed. 25 references, 34 figures. (WHK)
Date: August 1, 1984
Creator: Dorfan, J.M.
Partner: UNT Libraries Government Documents Department

The search for top at CDF

Description: We present results on the search for the top quark in {bar p}p collisions at {radical}s = 1.8 TeV. The data sample collected during the 1988--89 run with the Collider Detector at Fermilab (CDF) includes more than 4 pb{sup {minus}1}. We report here on an extension of previously published searches for the top quark in electron + jets and the dilepton channel electron-muon. The 95% confidence level limit on the top mass is 89 GeV/c{sup 2}.
Date: August 1, 1991
Creator: Liss, T.M. (Illinois Univ., Urbana, IL (United States). Loomis Lab. of Physics)
Partner: UNT Libraries Government Documents Department

B identification by topology with the SLD Detector

Description: At both the SLC and LEP large samples of Z/sup 0/ /yields/ b/bar b/ will soon be available. The challenge is to find experimental techniques to inclusively tag and identify the various particles b quarks may fragment into. The work described here makes use of the new generation of close-in tracking devices which will achieve unparalleled precision in particle trajectory resolution. Some of these devices provide three-dimensional information which is crucial in solving the pattern recognition problem discussed below. In the case where only two-dimensional information is available other than tracking information may be required. The tracking system is used to extrapolate tracks into some preselected point. The result is a picture of many crossing tracks and the problem is to find the real vertices among all the possible combinations. 1 ref., 3 figs., 1 tab.
Date: August 1, 1989
Creator: Atwood, W.B.
Partner: UNT Libraries Government Documents Department

Identifying the origin of new gauge bosons at the SSC and LHC

Description: The ability of an SCD-like detector to identify the origin of a new neutral gauge boson Z{sub 2}, once it has been discovered at the SSC and/or LHC, is examined. 9 refs., 3 figs.
Date: August 1, 1991
Creator: Hewett, J.L. (Argonne National Lab., IL (United States)) & Rizzo, T.G. (Argonne National Lab., IL (United States) Ames Lab., IA (United States))
Partner: UNT Libraries Government Documents Department

Evidence for B+ --> tau+ nu_tau Decays using Hadronic B Tags

Description: We present a search for the decay B{sup +} --> {tau}{sup +} {nu}{sub {tau}} using 467.8 x 10{sup 6} B{anti B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We select a sample of events with on completely reconstructed B{sup -} in an hadronic decay mode (B{sup -} --> D{sup (*)0}X{sup -} and B{sup -} --> J/{psi} X{sup -}). We examine the rest of the event to search for a B{sup +} --> {tau}{sup +} {nu}{sub {tau}} decay. We identify the {tau}{sup +} lepton in the following modes: {tau}{sup +} --> e{sup +} {nu}{sub e}{anti {nu}}{sub {tau}}, {tau}{sup +} --> {mu}{sup +} {nu}{sub {mu}}{anti {nu}}{sub {tau}}, {tau}{sup +} --> {pi}{sup +}{anti {nu}}{sub {tau}} and {tau}{sup +} --> {rho}{anti {nu}}{sub {tau}}. We find an excess of events with respect to expected background, which excludes the null signal hypothesis at the level of 3.3 {sigma} and can be converted to a branching fraction central value of B(B{sup +} --> {tau}{sup +} {nu}{sub {tau}})= (1.80{sup + 0.57}{sub - 0.54}(stat.) {+-} 0.26 (syst.)) x 10{sup -4}.
Date: August 11, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Progress on Development of the New FDIRC PID Detector

Description: We present a progress status of a new concept of PID detector called FDIRC, intended to be used at the SuperB experiment, which requires {pi}/K separation up to a few GeV/c. The new photon camera is made of the solid fused-silica optics with a volume 25x smaller and speed increased by a factor of ten compared to the BaBar DIRC, and therefore will be much less sensitive to electromagnetic and neutron background
Date: August 3, 2012
Creator: Vavra, Jerry
Partner: UNT Libraries Government Documents Department

Energy Spectra of Fragments from Silver and Uranium Bombarded with5.0 GeV Protons

Description: In this third paper in a series in which the characteristics of nuclear fragments produced in the interaction of 5 GeV protons with Ag and U targets were studied by means of dE/dx-E measurements with semiconductor detector telescopes new information was obtained on the energy spectra of light fragments. One set of measurements on fragments from a Ag target involved the use of a two-element telescope incorporating a {Delta}E detector as thin as 16 {micro}m. A new algorithm for processing the {Delta}E and E data to extract particle identification was developed and the resulting particle spectra showed superior resolution for the elements from Li(Z = 3) to S (Z = 16). Segments of the energy spectra of each of these elements were measured at 20{sup o} and, for many of them, also at 45{sup o}, 90{sup o}, 135{sup o} and 160{sup o} to the beam direction. By use of 3-element telescopes and absorbers the high energy part of the energy spectrum for isotopes of He, Li, Be, B, and C ejected from Ag and U targets was measured at 20{sup o}. The measurements extended beyond 300 MeV for {sup 6}Li and {sup 7}Li and to 400 MeV for {sup 7}Be. A distinct high-energy component was found in these cases. The suitability of nuclear evaporation as a description of the emission of the low-energy fragments was tested with two simple theoretical models, one specifying isotropic fragment emission from a moving nucleus at a fixed nuclear temperature and one specifying isotropic fragment emission from a set of moving nuclei with a Maxwellian distribution of excitation energies and forward momenta. The second could describe rather well all the 90{sup o} data, provided a Coulomb barrier 0.4 that of the classical tangent spheres barrier was used. However, the measured intensity in the forward direction ...
Date: August 1, 1972
Creator: Korteling, Ralph G.; Toren, C.R. & Hyde, Earl K.
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

A precision measurement of the branching ratio K{sup +} {r_arrow} {pi}{sup +}{pi}{sup 0}/K{sup +} {r_arrow} {mu}{sup +}{nu}{sub {mu}}

Description: A measurement of the branching ratio K{sup +} {r_arrow} {pi}{sup +}{pi}{sup 0}/K{sup +} {r_arrow} {mu}{sup +}{nu}{sub {mu}} was made using stopped kaons from p{anti p} annihilations at rest and a magnetic spectrometer to measure the momenta of the charged decay product to the 1% to 1.5% level. The determination is based on 45,500 events passing final data cuts. The resulting ratio is .3329 {+-} .0047 (statistical) {+-} .0010 (systematic).
Date: August 1, 1991
Creator: Usher, T.; Fero, M.; Gee, M.; Graf, N.A.; Mandelkern, M.; Shultz, D. et al.
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

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

Asymmetries in inclusive pion production at large x{sub F} = (0.5 to 0.8) and p{sub T} {ge} 0.8 GeV/c with a polarized beam for a RHIC polarimeter

Description: The authors propose to measure asymmetries in the inclusive reactions, using a transversely polarized beam, a liquid hydrogen target, and a carbon target. The measurements would be made using the 23-GeV/c proton beam in an extracted beam line from the AGS, a spectrometer consisting of an analyzing magnet, scintillation hodoscopes, scintillation trigger counters, and a gas threshold Cerenkov counter. The kinematic range covered by the experiments would be p{sub T} up to 1.0 GeV/c and x{sub F} = p*{sub L}/p*{sub max} {approx} 0.5 to 0.8. The purpose of this proposal is to obtain basic information in order to design a polarimeter for the RHIC polarized beams. The RHIC polarimeter is a crucial item for the success of the RHIC spin program.
Date: August 26, 1996
Creator: Krueger, K.; LeCompte, T. & Spinka, H.
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 production of {pi}{sup {+-}}, K{sup {+-}}, p, k{sup 0} and {Lambda}{sup 0} in hadronic Z{sup 0} decays

Description: The authors have measured production fractions and spectra for {pi}{sup {+-}}, K{sup {+-}} and p, and production spectra for K{sup 0} and {Lambda}{sup 0} in both hadronic Z{sup 0} decays and a Z{sup 0} {yields} light quark (uds) subset at SLD. The SLD Cherenkov Ring Imaging Detector was used to identify charged hadrons. The CCD vertex detector was used to select the enriched uds sample. For the global sample, the results are consistent with previous experiments. The authors observe a clear flavor dependence in production spectra, but only a small effect in hadron fractions and {xi} = ln(1/x{sub p}) peak positions.
Date: August 1, 1995
Creator: Baird, K.
Partner: UNT Libraries Government Documents Department

Observation of the top quark

Description: Top quark production is observed in {bar p}p collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron. The Collider Detector at Fermilab (CDF) and D{O} observe signals consistent with t{bar t} to WWb{bar b}, but inconsistent with the background prediction by 4.8{sigma} (CDF), 4.6a (D{O}). Additional evidence for the top quark Is provided by a peak in the reconstructed mass distribution. The kinematic properties of the excess events are consistent with the top quark decay. They measure the top quark mass to be 176{plus_minus}8(stat.){plus_minus}10(sys.) GeV/c{sup 2} (CDF), 199{sub -21}{sup +19}(stat.){plus_minus}22(sys.) GeV/c{sup 2} (D{O}), and the t{bar t} production cross section to be 6.8{sub -2.4}{sup +3.6}pb (CDF), 6.4{plus_minus}2.2 pb (D{O}).
Date: August 1, 1995
Creator: Kim, S.B.
Partner: UNT Libraries Government Documents Department

Status of the SLAC/LBL/LLNL B-Factory and the BaBar detector

Description: The primary motivation of the Asymmetric B-Factory is the study of CP violation. The decay of B mesons and, in particular, the decay of neutral B mesons, offers the possibility of determining conclusively whether CP violation is part and parcel of the Standard Model with three generations of quarks and leptons. Alternatively, the authors may discover that CP violation lies outside the present framework. In this paper the authors briefly describe the physics reach of the SLAC/LBL/LLNL Asymmetric B-Factory, the progress on the machine design and construction, the progress on the detector design, and the schedule to complete both projects.
Date: August 1, 1994
Creator: Oddone, P.
Partner: UNT Libraries Government Documents Department

Future high energy physics experiments using RICH detectors: The next generation

Description: This report describes some features of the new detectors now being constructed for use in high energy physics experiments that utilize RICH counters as a central element. The scope of this discussion is limited only to experiments which have been formally approved for construction as follows: (1) BaBar at PEP-II, which contains a quartz radiator DIRC counter; (2) CLEO III at the CESR upgrade, which utilizes a LiF/TEA Fast RICH; and (3) HERA-B at HERA, which uses a gas radiator RICH with either a TMAE- or a CsI-based photon detector. These experiments have much in common; all emphasize B-physics, run at the luminosity frontier, and plan to take first data either in 1998 or 1999. This review begins with a discussion of the physics goals and experimental context, and then explore the designs which have been chosen to confront the experimental issues. Particular emphasis is placed on the design and expected performance of the RICH detectors in these systems. Due to space limitations, only a few of the recent R and D results not covered elsewhere at the conference can be presented.
Date: August 1, 1995
Creator: Ratcliff, B.N.
Partner: UNT Libraries Government Documents Department

Results on top quark production from D0

Description: The D{O} Collaboration reports on a search for the Standard Model top quark in p{bar p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron, with an integrated luminosity of approximately 50 pb{sup -1}. We have searched for t{bar t} production in the dilepton and single lepton channels with and without tagging of b quark jets. We observe 17 events with an expected background of 3.8 {plus_minus} 0.6 events. The probability for an upward, fluctuation of the background to produce the observed signal is 2 x 10{sup -6} (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measure its mass to be 199{sub -21}{sup +19}(stat.){plus_minus}22 (syst.) GeV/c{sup 2} and its production cross section to be 6.4 {plus_minus} 2.2 pb.
Date: August 1, 1995
Creator: Wimpenny, S.J.
Partner: UNT Libraries Government Documents Department

Finding the Higgs boson: A status report

Description: The search for the Higgs boson of the minimal Standard Model has been a major focus of experimental high energy physics for some years now. Here, the authors review the current experimental limits and discuss the prospects for finding the Higgs boson at future accelerators, such as LEPII and the LHC. They consider only the Standard Model Higgs boson. Since a null result which definitively excluded a Higgs boson below some mass scale would be extremely important, they emphasize the case where the Higgs boson is much heavier than the relevant collider energy (or where there is no Higgs boson at all). Many of the results given here are a summary of those obtained by the DPF Committee on Long Term Planning.
Date: August 16, 1995
Creator: Dawson, S.
Partner: UNT Libraries Government Documents Department

DIRC Dreams: Research Directions for the Next Generation of Internally Reflected Imaging Counters

Description: Some conceptual design features of the total internally reflecting,imaging Cherenkov counter (DIRC) are described. Limits of the DIRC approach to particle identification, and a few features of alternative DIRC designs, are briefly explored.
Date: August 17, 1999
Creator: Ratcliff, Blair N
Partner: UNT Libraries Government Documents Department