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Search for neutrino oscillations at LAMPF

Description: The decays of stopped pions in the LAMPF beam stop present a unique opportunity to probe neutrino oscillations in the mass region of deltam/sup 2/ approx.0.1eV/sup 2/ and mixing parameters as low was sin/sup 2/2THETA approx.10/sup -3/. The appearance of anti nu/sub e/ will be measured with high sensitivity by Experiment 645 during the run cycle that begins in the summer of 1986.
Date: January 1, 1986
Creator: Harper, R.W.; Ling, T.Y.; Mitchell, J.W.; Romanowski, T.A.; Smith, E.S.; Timko, M. et al.
Partner: UNT Libraries Government Documents Department

Search for neutrino oscillations at the AGS with the narrow band beam

Description: We have taken neutrino data with the Narrow Band Beam (NBB) at Brookhaven National Laboratory (BNL) in the summer and fall of 1985. We are in the process of completing the analysis of the NBB data. In this paper we present preliminary results of this analysis. We observe an anomalous appearance of electron neutrinos above the expected background. 3 refs., 16 figs., 3 tabs.
Date: January 1, 1987
Creator: Chi, C.; Kondakis, N.; Lee, W.; O'Brien, E.; O'Halloran, T.; Reardon, K. et al.
Partner: UNT Libraries Government Documents Department

Progress report on recent rare muon decay experiments at the Los Alamos Meson Physics Facility

Description: A search has been performed for the decays ..mu.. ..-->.. eee, ..mu.. ..-->.. e..gamma.., and ..mu.. ..-->.. e..gamma gamma.. with a sensitivity in the branching ratios at the level of 10/sup -10/. The experiment used a separated, 26 MeV/c ..mu../sup +/ beam with an average intensity of 300kHz. A total of 2.2 x 10/sup 11/ muon decays were examined for the present result. The detector for the experiment is the Crystal Box, which consists of a cylindrical drift chamber surrounded by 396 NaI(T1) crystals. A layer of scintillation counters in front of the crystals provided timing for electrons and veto for photons. The energy resolution for electrons and photons is approx. 6% (FWHM). The position resolution of the drift chamber is 350 ..mu..m leading to a vertex cut with a rejection of 10/sup 3/ for ..mu.. ..-->.. eee. The timing resolution is approx. 300 ps the scintillators and approx. 1 ns from the crystals. No candidate for ..mu.. ..-->.. eee has been found, yielding an upper limit for the branching ratio of B/sub ..mu..3e/ < 1.3 x 10/sup -10/ (90% C.L.). 21 references.
Date: January 1, 1984
Creator: Hogan, G.E.; Bolton, R.D.; Bowman, J.D.; Carlini, R.; Cooper, M.D.; Duong-van, M. et al.
Partner: UNT Libraries Government Documents Department

Soudan 2 data acquisition and trigger electronics

Description: The 1.1 kton Soudan 2 detector is read out by 16K anode wires and 3 2K cathode strips. Preamps from each wire or strip are bussed together in groups of 8 to reduce the number of ADC channels. The resulting 6144 channels of ionization signal are flash-digitized every 150 ns and stored in RAM. The raw data hit patterns are continually compared with programmable trigger multiplicity and adjacency conditions. The data acquisition process is managed in a system of 24 parallel crates each containing an Intel 8086 microprocessors, which supervises a pipe-lined data compactors, and allows transfer of the compacted data via CAMAC to the host computer. The 8086's also manage the local trigger conditions and can perform some parallel processing of the data. Due to the scale of the system and multiplicity of identical channels, semi-custom gate array chips are used for much of the logic, utilizing 2.5 micron CMOS technology.
Date: January 1, 1985
Creator: Dawson, J.; Laird, R.; May, E.; Mondal, N.; Schlereth, J.; Solomey, N. et al.
Partner: UNT Libraries Government Documents Department

Search for neutrino oscillations

Description: The present paper reports on preliminary results from the E 816 experiment at Brookhaven National Laboratory. E 816 is the continuation of a 1984 experiment (PS 191) which was devoted to a neutrino decay search in the CERN PS neutrino beam. No candidate was seen, but a study of neutrino interactions in the calorimeter indicated an anomalous electron production. The statistics was too low and the experiment has been rerun in spring 86 at BNL to look specifically, with an improved detector for nu/sub e/ arising from a low energy nu/sub ..mu../ beam. The results presented here are preliminary for at least two reasons: first the collaboration is presently running a calibration test which results are not included here; second, only 1/3 of the neutrino data is used, and no mention will be made to antineutrino data for which the analysis is still going on. This report will directly start with a description of our apparatus, followed by the data analysis.
Date: January 1, 1987
Creator: Astier, P.
Partner: UNT Libraries Government Documents Department

Results from FNAL E745 on neutrino-nucleus interactions (EMC effect and hadron formation)

Description: The dark tracks (stubs) in high energy neutrino-nucleus interactions in the Tohoku High Resolution Freon Bubble Chamber are investigated. Classifying events into groups by using the dark tracks, correlations between the dark track production and neutrino interactions are studied. Events without dark tracks comprise a reasonable sample of events which occurred on quasi-free nucleons inside nucleus. By comparing the groups using the no dark track group as a comparison sample instead of neutrino-deuterium events, the EMC effect and hadron formation are investigated. This method provides new results which differ somewhat from the conventional data for the EMC effect and formation-rescattering. 10 refs., 17 figs.
Date: January 1, 1989
Creator: Kitagaki, T. (Tohoku Univ., Sendai (Japan). Bubble Chamber Physics Lab.)
Partner: UNT Libraries Government Documents Department

The future of tau physics and tau-charm detector and factory design

Description: Future research on the tau lepton requires large statistics, thorough investigation of systematic errors, and direct experimental knowledge of backgrounds. Only a tau-charm factory with a specially designed detector can provide all the experimental conditions to meet these requirements. This paper is a summary of three lectures delivered at the 1991 Lake Louise Winter Institute.
Date: February 1, 1991
Creator: Perl, M.L.
Partner: UNT Libraries Government Documents Department

New results for rare muon decays

Description: Branching-ratio limits obtained with the Crystal Box detector are presented for the rare muon decays ..mu.. ..-->.. eee, ..mu.. ..-->.. e..gamma.., and ..mu.. ..-->.. e..gamma gamma... These decays, which violate the conservation of separate lepton-family numbers, are expected to occur in many extensions to the standard model. We found no candidates for the decay ..mu.. ..-->.. eee, yielding an upper limit for the branching ratio of B/sub ..mu..3e/ < 3.1 x 10/sup -11/ (90% C.L.). A maximum-likelihood analysis of the ..mu.. ..-->.. e..gamma.. candidates yields an upper limit of B/sub ..mu..e..gamma../ < 4.9 x 10/sup -11/ and an analogous analysis of ..mu.. ..-->.. e..gamma gamma.. candidates gives an upper limit of B/sub ..mu..e..gamma gamma../ < 7.2 x 10/sup -11/. These results strengthen the constraints on models that allow transitions between lepton families.
Date: January 1, 1986
Creator: Mischke, R.E.; Bolton, R.D.; Bowman, J.D.; Cooper, M.D.; Frank, J.S.; Hallin, A.L. et al.
Partner: UNT Libraries Government Documents Department

Z degree yields hadrons in SDC

Description: We report on a study of hadronic Z{degrees} decays at high P{sub t}(P{sub t}>500 GeV/c), at 40 TeV CM energy. Our goal here is to understand the effects of the kinematics of Z{degrees} decay, especially the Lorentz boost, on detection issues. We used an ISAJET sample of Drell Yan events, requiring the Z{degrees} to have pseudorapidity ({eta}) in (-1.5,1.5) and P{sub t}>500 GeV/c. ISAJET forces the Z{degrees} to decay to two primary partons, which then cascade by gluon and quark emission to stable hadrons. We excluded Z{degrees} {yields} {nu}{bar {nu}} decays. In about 10% of the hadronic decays, significant energy is lost due to neutrino emission from heavy quarks, so that the hadronic mass is significantly less than the Z{degrees} mass generated; these events were not explicitly removed. We treated muons like other hadrons, assuming that high P{sub t} muons could be identified and corrected for. For this study we retained only the stable daughter particles in Z{degrees} decay, labelled according to their parton parentage ( Jet 1 or 2''). We ignored the particles from the underlying event and from other final state jets. (These contributions, along with other non-Z{degrees} noise'', can be explicitly added back for relevant studies.) Finally, we note that the Z{degrees} decay angular distribution is approximately flat for these events, not peaked at 90 deg. as in Higgs {yields} Z{degrees}Z{degrees}; this will have little effect on our conclusions. To avoid very asymmetric decays, we required each of the two jets to satisfy P{sub t}> 100 GeV/c.
Date: August 30, 1991
Creator: Wicklund, A.B.
Partner: UNT Libraries Government Documents Department

Lifetimes of heavy leptons and hadrons

Description: Recent measurements of the lifetimes of the tau lepton and charm and beauty particles are reviewed, with emphasis on the experimental techniques used for vertex detection. 32 refs., 10 figs.
Date: February 1, 1987
Creator: Lueth, V.
Partner: UNT Libraries Government Documents Department

Possible deviations from (V-A) charged currents: precise measurement of muon decay parameters

Description: This short review examines the experimental limits on possible deviations from (V-A) charged weak currents, as would occur at some mass scale, for example, in manifestly left-right-symmetric electro-weak theories. Both present and anticipated limits are considered, emphasizing muon-decay experiments but including other experimental input where convenient.
Date: February 1, 1981
Creator: Strovink, M.
Partner: UNT Libraries Government Documents Department

Properties of hadronic decays of the Z boson

Description: The decays of the Z{sup 0} boson to quarks and subsequently to hadrons were first directly observed in 1989 with the Mark II detector. This report studies the general properties of the hadronic events in the initial data sample recorded at center-of-mass energies near the Z{sup 0} resonance (91.2 GeV). The preliminary chapters introduce the theoretical framework and the apparatus. A brief review is given of some features of Quantum Chromodynamics (QCD) that are relevant to the study. Two QCD-based models that are used to help correct the data distributions for detector effects and also for comparisons with the corrected distributions are described. For each of the detector systems used in the analysis, the design, operation and performance is discussed. The next chapter describes the event selection which is designed to provide a sample of well-measured hadronic events. The following three chapters contain the measured data distributions. The QCD-based models with parameters tuned at E{sub cm} = 29 GeV describe the 91 GeV data distributions well. Each of these chapters also shows the variation of the observables as the center-of-mass energy changes. 43 figs., 12 tabs.
Date: June 1, 1990
Creator: O'Shaughnessy, K.F.
Partner: UNT Libraries Government Documents Department

B-jet tagging using electrons at SDC

Description: This note examines b-jet tagging at SDC, using semileptonic b {r arrow} e{upsilon} X electron decays. The main application for this tagging capability would be in the study of Top decays. Thus, we consider Top decays in a reasonable'' mass range (e.g. 110 < Mtop < 170). For completeness, we also consider inclusive QCD production of b-quarks. We are mainly interested in the effects of hadron calorimeter segmentation on the electron efficiency, assuming that similar algorithms are used for electron ID at SDC as at CDF. We review the following topics: kinematics of top decay; kinematics of semileptonic b-decay; effects of Had/EM cuts on electron ID, as a function of b-decay kinematics and calorimeter segmentation; overall efficiency for b-tagging from Top decay and inclusive b-production. We consider only the barrel region in our simulation, e.g. {eta} < 1.4. 19 figs.
Date: August 14, 1991
Creator: Wicklund, A.B.
Partner: UNT Libraries Government Documents Department

Measurement of the B hadron lifetime from Mark II at PEP

Description: Using data taken by the Mark II detector at PEP, the decays of B hadrons are tagged by identifying leptons at high transverse momentum. By means of a precision inner drift chamber, the impact parameters of these leptons are measured with respect to the B production point. From this impact parameter distribution, the B hadron lifetime is found to be 0.98 +- 0.12 +- 0.13 ps. This measurement can be used to place constraints models of quark mixing. 11 refs., 2 figs., 2 tabs.
Date: January 1, 1988
Creator: Ong, R.A.
Partner: UNT Libraries Government Documents Department

Current and target jets produced in high energy neutrino-deuterium interactions

Description: In an analysis of approx. 7000 charged-current ..nu..-deuterium interactions from an exposure of the Fermilab 15-foot bubble chamber to a wide band neutrino beam, the single quark jet (current fragments) was observed to have a wider spread in P/sub t/ than that from the recoiling diquark jet (target fragments) for W > 9 GeV. This result suggests an effect of gluon emission from the single quark. 6 figures, 1 table.
Date: January 1, 1980
Creator: Kitagaki, T.; Tanaka, S. & Yuta, H.
Partner: UNT Libraries Government Documents Department