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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

Search for new phenomena in CDF-I: Z{prime}, W{prime} and leptoquarks

Description: We present the latest results of CDF searches for Z{prime}, W{prime} and leptoquarks. Using about 70pb{sup -1} data from 1992-95 CDF runs, we have searched for Z{prime} {yields} l{sup +}l{sup -}, W{prime} {yields} WZ and pairs of second generation scalar leptoquark, S{sub 2}. We find no evidence for these new particles, and set new mass limits at 95% CL. We exclude M{sub Z{prime}} < 650 GeV/c{sup 2}, 205 < M{prime}{sub W} < 400 GeV/c{sup 2}, and M{sub S2} < 180 GeV/c{sup 2} for {beta} = 1 and M{sub S2} < 141 GeV/c{sup 2} for {beta} = 0.5. Two interesting strange events are also shown.
Date: July 1, 1995
Creator: Park, S.
Partner: UNT Libraries Government Documents Department

Strong interaction physics with pions at LAMPF: Report of the study group on future opportunities at LAMPF

Description: The LAMPF accelerator, with its high-intensity teams of pions and array of high-resolution spectrometers, provides opportunities for investigations of nuclear structure as well as of strong-interaction hadron dynamics. During operation of LAMPF as a national users facility, Nuclear Physics has undergone an evolution in the way it pictures nuclei: from a system of nucleons interacting through potentials to a system of mutually coupled nucleons, {Delta}(1232)`s, and mesons. While nuclear physics is in the midst of yet another shift of paradigm, with quarks and gluons playing a central role, the traditional picture still has great predictive power, and LAMPF has new opportunities to contribute to solving problems of current interest. At the same time, LAMPF is poised to make important contributions to the evolving area of nonperturbative QCD, where we will be learning how to connect phenomena at large momentum transfer to those at lower momentum scales. where the physically observable hadrons are the natural degrees of freedom. Within the traditional area, exploration of nuclei having extreme ratios of neutron/proton number is of growing interest in a variety of contexts, including astrophysics. Pion double charge exchange (the ({pi}{sup {plus_minus}}, {pi}{sup {plus_minus}}) processes) can produce proton-rich nuclei such as {sup 9}C, {sup 10}C, and {sup 11}N as well as neutron-rich nuclei such as {sup 10}He, {sup 11}Li, {sup 14}Be, and {sup 17}B. With spectrometers available for analyzing the outgoing pion spectra, one can study interesting and controversial modes of motion (soft-dipole modes) and obtain angular distributions that explore the spatial extent of neutron halos.
Date: July 1, 1995
Creator: Johnson, M.B. & Matthews, J.L.
Partner: UNT Libraries Government Documents Department

Searches for new gauge bosons using the D0 detector

Description: We present the results of searches for additional gauge bosons beyond the W and Z bosons using the 1992-1993 Tevatron data set collected with the D0 detector. The signatures studied are W{prime} {yields} e{nu}, W{prime} {yields} {tau}{nu} with {tau} {yields} e{nu}{bar {nu}}, assuming stable neutrinos; W{sub R} {yields} e + X and W{sub R} {yields} eejj, assuming massive neutrinos; and Z{prime} {yields} ee. Lower limits on the W{prime} mass and Z{prime} mass at the 95% confidence level, and the mass exclusion contour in the W{sub R} mass vs. neutrino mass plane are presented.
Date: July 1, 1995
Creator: Abachi, S.; Abbott, B. & Abolins, M.
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

Searches for SUSY by CDF

Description: Data from proton-antiproton collisions at center-of-mass energy of 1.8 TeV are searched for evidence of SUSY particles. One analysis looks for the three-lepton final state from chargino-neutralino production. No events are observed. Another analysis looks for three or more jets and large missing energy as a signal of squark or gluino pair production. No significant excess of data above background is observed. The results of these searches are to extend limits on SUSY models beyond previous limits within a restricted parameter space of the models.
Date: June 26, 1995
Creator: Hauser, J.
Partner: UNT Libraries Government Documents Department

Experimental studies of elementary particle interactions at high energies. Summary technical progress report

Description: This is a report of the research activities of the Experimental High Energy Physics group of The Rockefeller University. As this is an annual progress report, the emphasis is on last year`s research activities. However, since it is the last of a series of 5 such reports to be submitted to the DOE under the present 5 year contract, an effort has been made to provide comprehensive coverage of the research activities of the group throughout the contract period. In the past 5 years, the research program encompassed three major areas: the UA-6 experiment at CERN, the CDF experiment at Fermilab, and several SSC projects. The UA-6 experiment studies direct-{gamma} and J/{Psi} production in pp and {bar p}p interactions at {radical}s = 22.5 GeV.4. In the CDFF experiment the authors have concentrated in the area of small angle physics, where the objective has been to measure the elastic, diffractive and total cross sections, and to provide an absolute calibration of the machine luminosity. The SSC research projects related to two experiments: The Solenoidal Detector Collaboration and the ``low p{sub T} physics`` experiment.
Date: March 31, 1992
Partner: UNT Libraries Government Documents Department

Observation of the top quark

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 decay channels, with and without tagging of b quark jets. We observe 17 events with an expected background of 3.8 {+-} 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.) {+-}22 (syst.) GeV/c{sup 2}1 and its production cross section to be 6.4 {+-} 2.2 pb. Other decay channels are under study such as the t{bar t} to all-jets channel which might yield additional information about the top quark.
Date: October 1, 1995
Creator: Bantly, J.
Partner: UNT Libraries Government Documents Department

Experimental overview of axion searches

Description: Experimental methods to search for the ``invisible axion`` (f{sub a} {much_gt} 250 GeV) are reviewed. The report focuses on the axion-photon coupling, both for laboratory experiments as well as those looking for stellar or cosmologically produced axions. The conclusion is that while the axion-photon mixing in principle would permit laboratory axion searches which are broadband in mass, in fact no such experiment could have the sensitivity to the axion, where m{sub afa} {approx} m{sub {pi}f{pi}}. The only experiments which promise to have any chance to find the axion are the microwave cavity experiments, which presume axions to constitute our galactic halo dark matter. The conversion of axions into a monochromatic microwave signal in a resonant circuit affords the experiment the extraordinary sensitivity required to see the axion, at the expense of being narrow-band in mass, i.e. a tuning experiment. Two such efforts are underway in the world.
Date: June 28, 1995
Creator: van Bibber, K.
Partner: UNT Libraries Government Documents Department

Top physics at D0

Description: The D0 collaboration reports on the observation of the Standard Model top quark in p{anti p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron. The authors have searched for t{anti t} production with an integrated luminosity of approximately 50 pb{sup {minus}1} in the dilepton and single-lepton decay channels, with and without tagging of b quark jets. They observe 17 events with an expected background of 3.8 {+-} 0.6 events. The probability for an upward fluctuation of the background to produce the observed signal is 2 {times} 10{sup {minus}6} (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. They measure the top quark mass to be 199{sub {minus}21}{sup +19} (stat.) {sub {minus}21}{sup +14} (syst.) GeV/c{sup 2} and its production cross section to be 6.4 {+-} 2.2 pb. D0 also sees a hadronic W mass peak (W {yields} jj) in the t{bar t} data events. Preliminary results from multivariate analyses and from the t{bar t} data events. Preliminary results from multivariate analyses and from the t{bar t} {yields} all-jets channel are discussed. Preliminary determination of the top quark mass using dilepton events yields 145 {+-} 25 (stat.) {+-}20 (syst.) GeV/C{sup 2}.
Date: September 1, 1995
Creator: Klima, B.
Partner: UNT Libraries Government Documents Department

The search for proton decay

Description: The conservation of the quantum number called baryon number, like lepton (or family) number, is an empirical fact even though there are very good reasons to expect otherwise. Experimentalists have been searching for baryon number violating decays of the proton and neutron for decades now without success. Theorists have evolved deep understanding of the relationship between the natural forces in the development of various Grand Unified Theories (GUTs) that nearly universally predict baryon number violating proton decay, or related phenomena like n-{bar n} oscillations. With this in mind, the Proton Decay Working Group reviewed the current experimental and theoretical status of the search for baryon number violation with an eye to the advancement in the next decade.
Date: December 1994
Creator: Haines, T.; Kaneyuki, K.; McGrew, C.; Mohapatra, R.; Peterson, E. & Cline, D. 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

Search for anomalous WW and WZ production at D0

Description: We present a preliminary result from a search for anomalous WW and WZ production in p{bar p} collisions at {radical}s = 1.8 TeV using p{bar p} {yields} e{nu}jj events observed during the 1992-1993 run of the Fermilab Tevatron collider. A fit to the p{sub T} spectrum of W(e{nu}) yields direct limits on the CP-conserving anomalous WW{gamma} and WWZ coupling parameters of -0.89 < {Delta}{kappa} < 1.07 ({lambda} = 0) and -0.66 < {lambda} < 0.67 ({Delta}{kappa} = 0) at the 95% confidence level, assuming that the WWZ coupling parameters are equal to the WW{gamma} coupling parameters, and a form factor scale {Lambda} = 1.5 TeV.
Date: July 1, 1995
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

Search for first and second generation leptoquarks at D0

Description: A search for first and second generation pair produced scalar leptoquarks has been done with the DO detector at Fermilab`s p{bar p} machine with {radical}s = 1.8 TeV. Leptoquarks are assumed to be strictly generational; for example, a first generation leptoquark couples only to the electron, its neutrino, and the u and d quarks. 95% C.L. mass limits of 133 GeV/c{sup 2} and 120 GeV/c{sup 2} for respective 100% and 50% decay branching ratios to electron plus quark for first generation scalar leptoquarks have been published. The preliminary results of a search for second generation scalar leptoquarks in the absence of a signal are mass limits of 111 GeV/c{sup 2} and 89 GeV/c{sup 2} for 100% and 50% decay branching ratios to muon plus quark. A feature of these mass limits is that they are independent of the unknown coupling of the leptoquark to leptons and quarks. The detection for e{sup +}e{sup {minus}} and e-p machines depends on the strength of this coupling.
Date: July 1, 1995
Creator: Abachi, S.; Abbott, B. & Abolins, M.
Partner: UNT Libraries Government Documents Department

Preliminary results from IMB3 muon/electron identification tests at KEK

Description: A test has been conducted at KEK, Japan using beams of electrons and muons in a 1 kiloton water Cherenkov detector instrumented with IMB3 phototubes and electronics to evaluate IMB`s algorithms for identifying electrons and muons. This identification is important because the IMB3 detector`s results on the atmospheric neutrino anomaly depend on the proper identification of the electrons and muons produced in neutrino charged-current interactions. Preliminary results are presented.
Date: September 1, 1995
Creator: Bratton, C.B.; Breault, J. & Conner, Z.
Partner: UNT Libraries Government Documents Department

Duke University High Energy Physics; Progress report, December 1, 1990--March 15, 1993

Description: The research program of the Duke High Energy Physics Group is described in this Progress Report and a separate Proposal containing their plans for 1994. These two documents are supplemented by compilations of selected publications, thesis abstracts, and the curriculum vitae of the eleven Ph.D. physicists who are carrying out this research program. This Progress Report contains a review of the research which has been done over the first half (1992 and 1993 to date) of the current three-year DOE grant, plus some earlier research to establish a broader perspective of the research interests. High energy physics research at Duke has three components. The first, Task A, is based upon experiments carried out at Fermilab`s Tevatron Collider. The group is finishing the analysis of data from their first collider experiment (E735), a study of inclusive particle production from {bar p} p collisions at {radical}{bar s} = 1.8 TeV. The second component of the research, Task B, deals primarily with heavy flavor physics. The third part of the research program, Task D, deals with preparation for research at the SSC. The authors have been active in the development of tracking detectors for the SSC since 1989, and are now concentrating on the design and construction of straw tube drift chambers for the solenoid detector.
Date: March 1, 1993
Creator: Fortney, L.R.; Goshaw, A.T. & Walker, W.D.
Partner: UNT Libraries Government Documents Department

Structural and phonon transmission study of Ge-Au-Ge eutectically bonded interfaces

Description: This thesis presents a structural analysis and phonon transparency investigation of the Ge-Au-Ge eutectic bond interface. Interface development was intended to maximize the interfacial ballistic phonon transparency to enhance the detection of the dark matter candidate WIMPs. The process which was developed provides an interface which produces minimal stress, low amounts of impurities, and insures Ge lattice continuity through the interface. For initial Au thicknesses of greater than 1,000 {angstrom} Au per substrate side, eutectic epitaxial growth resulted in a Au dendritic structure with 95% cross sectional and 90% planar Au interfacial area coverages. In sections in which Ge bridged the interface, lattice continuity across the interface was apparent. Epitaxial solidification of the eutectic interface with initial Au thicknesses < 500 A per substrate side produced Au agglomerations thereby reducing the Au planar interfacial area coverage to as little as 30%. The mechanism for Au coalescence was attributed to lateral diffusion of Ge and Au in the liquid phase during solidification. Phonon transmission studies were performed on eutectic interfaces with initial Au thicknesses of 1,000 {angstrom}, 500 {angstrom}, and 300 {angstrom} per substrate side. Phonon imaging of eutectically bonded samples with initial Au thicknesses of 300 {angstrom}/side revealed reproducible interfacial percent phonon transmissions from 60% to 70%. Line scan phonon imaging verified the results. Phonon propagation TOF spectra distinctly showed the predominant phonon propagation mode was ballistic. This was substantiated by phonon focusing effects apparent in the phonon imaging data. The degree of interface transparency to phonons and resulting phonon propagation modes correlate with the structure of the interface following eutectic solidification. Structural studies of samples with initial Au thickness of 1,000 {angstrom}/side appear to correspond with the phonon transmission study.
Date: July 1, 1995
Creator: Knowlton, W.B.
Partner: UNT Libraries Government Documents Department

B Decay Studies at SLD

Description: We present three preliminary results from SLD on B decays: an inclusive search for the process b {r_arrow} s gluon, a measurement of the branching ratio for the process B {r_arrow} D{bar D}X, and measurements of the charged and neutral B lifetimes. All three measurements make use of the excellent vertexing efficiency and resolution of the CCD Vertex Detector and the first two make use of the excellent particle identification capability of the Cherenkov Ring Imaging Detector. The b {r_arrow} sg analysis searches for an enhancement of high momentum charged kaons produced in B decays. Within the context of a simple, Jetset-inspired model of b {r_arrow} sg, a limit of B(b {r_arrow} sg) &lt; 7.6% is obtained. The B(B {r_arrow} D{bar D}X) analysis reconstructs two secondary vertices and uses identified charged kaons to determine which of these came from charm decays. The result of the analysis is B(B {r_arrow} D{bar D}X) = (16.2 {+-} 1.9 {+-} 4.2)%. The results of the lifetime analysis are: {tau}{sub B{sup +}} = 1.686 {+-} 0.025 {+-} 0.042 ps, {tau}{sub B{sup 0}} = 1.589 {+-} 0.026 {+-} 0.055 ps and {tau}{sub B{sup +}}/{tau}{sub B{sup 0}} = 1.061 {+-} 0.031/0.029 {+-} 0.027.
Date: March 19, 1999
Creator: Convery, Mark R
Partner: UNT Libraries Government Documents Department

Fast Drift CRID with GEM

Description: The only available technique at the present time, to perform particle identification up to 40-50 GeV/c in a 4{pi} solenoidal geometry using the Cherenkov ring imaging method is the use of gaseous detectors tilled with either TMAE or TEA photocathodes, and a combination of the gaseous, and solid or liquid radiators. If one would consider building such a device, one may want to investigate alternative methods of building a single-electron detector. This paper investigates the feasibility of using the GEM together with a simple MWPC detector employing 33 {micro}m diameter carbon wires to obtain a second coordinate. The results are compared to the CRID single-electron detector.
Date: May 20, 1999
Creator: Va'Vra, Jaroslav
Partner: UNT Libraries Government Documents Department

Search for light top squarks with the D{O} detector

Description: We present preliminary results of a search for pair produced top squarks, the supersymmetric partners to the top quark, under the assumption that the two-body decay {bar t}{sub 1} {yields} b{bar W}{sub 1} and three-body decay {bar t}{sub 1} {yields} bW{bar Z}{sub 1} are kinematically forbidden. This scenario is realized if {bar t}{sub 1} is considerably lighter than all other squarks as well as {bar W}{sub 1}, all {bar v}s, and the top quark. Such light top squarks will dominantly decay via {bar t}{sub 1} {yields} c{bar Z}{sub 1} yielding a signal of two acollinear jets with (E){sub T}. The data reported here were taken during the 1992-1993 run of the D0 detector at the Fermilab Tevatron p{bar p} collider operating at {radical}s = 1.8 TeV.
Date: July 1, 1995
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

Proceedings of the workshop on triggering and data acquisition for experiments at the Supercollider

Description: This meeting covered the following subjects: triggering requirements for SSC physics; CDF level 3 trigger; D0 trigger design; AMY trigger systems; Zeus calorimeter first level trigger; data acquisition for the Zeus Central Tracking Detector; trigger and data acquisition aspects for SSC tracking; data acquisition systems for the SSC; validating triggers in CDF level 3; optical data transmission at SSC; time measurement system at SSC; SSC/BCD data acquisition system; microprocessors and other processors for triggering and filtering at the SSC; data acquisition, event building, and on-line processing; LAA real-time benchmarks; object-oriented system building at SSC; and software and project management. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.
Date: April 1, 1989
Creator: Donaldson, R.
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

New particle searches at CDF

Description: One of the fundamental roles of a general purpose detector exploring, by means of increasing luminosity, higher and higher mass reach, is to search for new particles and exotic phenomena. This is a continuing effort for the CDF collaboration, and will report on several searches using about 20 pb{sup -1} from the 1992/93 run labelled {open_quotes}run 1a{close_quotes} and {approximately}50 of the 90 pb{sup -1} so far from the current {open_quotes}run 1b.{close_quotes} These are mostly preliminary analyses, typically using a total of 70 pb{sup -1}. Our limits on SUSY using missing E{sub T} with jets as well as three leptons are discussed elsewhere; results from the D0 collaboration are similar. I will discuss searches for additional vector bosons Z{prime} and W{prime}, second generation scalar leptoquarks, as well as a broad search for objects decaying into jet pairs, including b-tagged jet pairs. I will also describe two events which do not fit in comfortably with either the standard model or a phenomenologically motivated search.
Date: September 1, 1995
Creator: Nodulman, L.J.
Partner: UNT Libraries Government Documents Department

A limit on {sigma} {center_dot} BR (B{sub c}{sup {+-}} {yields} J/{psi} + {pi}{sup {+-}})/{sigma} {center_dot} BR(B{sub u}{sup {+-}} {yields} J/{psi} + K{sup {+-}}) in {radical}s = 1.8 TeV proton-antiproton collisions

Description: We report on the results of a search for the B{sub c} (b{bar c}) meson in the decay B{sub c}{sup +-} {yields} J/{psi} + {pi}{sup +-}. This search is guided by a control sample of decays of B{sub u} mesons to J/{psi} + K and uses {approx_equal} 75pb{sup -1} of data collected at the Collider Detector Facility (CDF) at Fermilab. The lifetime of the B{sub c} meson is unknown, so the 95% confidence level limit on {sigma} {center_dot} BR(B{sub c} {yields} {psi} + {pi})/{sigma} {center_dot} BR(B{sub u} {yields} {psi} + K) is obtained as a function of the B{sub c} lifetime.
Date: July 15, 1995
Creator: Abe, F.
Partner: UNT Libraries Government Documents Department