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Search for W prime and Z prime at CDF

Description: We have searched for heavy charged and neutral vector bosons via the decays W{prime} {yields} ev, W{prime} {yields} {mu}v, Z{prime} {yields} {mu}{mu} in p{bar p} collisions at {radical}s = 1.8 TeV, using data taken with the collider Detector at Fermilab. The nonobservation of these processes leads to a lower limit (95% confidence level) of 520 GeV/c{sup 2} on the mass of the W{prime} and of 412 GeV/C{sup 2} on the mass of the Z{prime}, assuming standard model coupling to fermions. 12 refs., 6 figs., 1 tab.
Date: September 1, 1991
Creator: Fuess, T.
Partner: UNT Libraries Government Documents Department

A search for neutrino oscillations at LAMPF (Los Alamos Meson Physics Facility)

Description: Experiment E645 is a search for neutrino oscillations, employing the LAMPF beam stop as a neutrino source. Data collection is now underway, and we describe the experiment, the quality of the preliminary data, and the sensitivity to neutrino oscillations that we expect to reach by the end of the 1987 running cycle.
Date: January 1, 1987
Creator: Freedman, S.J.
Partner: UNT Libraries Government Documents Department

LAMPF E645/current status

Description: Experiment E645 at LAMPF is a search for /bar /nu///sub ..nu../ ..-->.. /bar /nu///sub e/ oscillations using the proton beamstop as a neutrino source. The apparatus is a 20-ton neutrino detector and a cosmic-ray anticoincidence shield approx. =26 m from the beamstop. No evidence for neutrino oscillations was found in the first year of data taking. The experiment is described and the limits on neutrino oscillation parameters from the data collected during 1987 are presented. 6 refs., 3 figs.
Date: January 1, 1988
Creator: Freedman, S.J.
Partner: UNT Libraries Government Documents Department

Search for right-handed currents in muon decay

Description: We report new limits on right-handed currents, based on precise measurement of the endpoint of the e/sup +/ spectrum from ..mu../sup +/ decay. Highly polarized ..mu../sup +/ from the TRIUMF surface beam were stopped in pure metal foils within either an 1.1-T spin-holding longitudinal field, or a 70-gauss spin-precessing transverse field. Decay e/sup +/ emitted within 200 mrad of the beam direction were momentum-analyzed to +-0.2%. For the spin-held data, decay via (V-A) currents requires the e/sup +/ rate to approach zero in the beam direction at the endpoint. Measurement of this rate sets the 90% confidence limits xi P/sub ..mu../delta/rho > 0.9959 and M(W/sub R/) > 380 GeV, where W/sub R/ is the possible right-handed gauge boson. For the spin-precessed data we independently determine a 90% confidence limit xi P/sub ..mu../delta/rho > 0.9918. 18 references.
Date: April 1, 1983
Creator: Carr, J.; Gidal, G.; Gobbi, B.; Jodidio, A.; Oram, C.J.; Shinsky, K.A. et al.
Partner: UNT Libraries Government Documents Department

Study of rare muon decay modes with the crystal box

Description: We report on a search for the lepton family-number-nonconserving decays ..mu../sup +/..-->..e/sup +/e/sup -/e/sup +/, ..mu../sup +/..-->..e/sup +/..gamma.., and ..mu../sup +/..-->..e/sup +/..gamma gamma.., using the Crystal Box detector at LAMPF. The experiment was run in the stopped muon channel at LAMPF during the winter and summer of 1984. Muons were stopped in the middle of a detector system consisting of a cylindrical drift chamber, a plastic scintillator hodoscope, and a segmented array of sodium iodide crystals. The sodium iodide surrounded the hodoscope and drift chamber. Events consistent with any of the above decays were recorded. The off-line data analysis imposed requirements on the timing, vertex location, and energy and momentum conservation for each event. Radioactive sources, conventional muon decay spectra, and photons from the process ..pi../sup -/p..-->..n..gamma.. and ..pi../sup -/p..-->..n..pi../sup 0/ were used to provide energy calibration and resolution estimates. The inner bremsstrahlung processes ..mu../sup +/..-->.. e/sup +/..gamma nu..anti..nu.. and ..mu../sup +/..-->..e/sup +/e/sup -/e/sup +/..nu..anti..nu.. were observed at the expected rates. Details of the detector, the data analysis, and our latest bounds for the branching ratios will be presented. 33 figs.
Date: January 1, 1985
Creator: Sandberg, V.; Bolton, R.D.; Bowman, J.D.; Carlini, R.D.; Copper, M.D.; Doung-Van, M. et al.
Partner: UNT Libraries Government Documents Department

Search for rare muon and pion decay modes with the crystal box detector

Description: New experiental upper limits for the branching ratios of the lepton-family-number nonconserving decays ..mu../sup +/ ..-->.. e/sup +/..gamma.. and ..mu../sup +/ ..-->.. e/sup +/..gamma gamma.. are presented. A new determination of ..gamma.., the ratio of pion axial vector to vector form factors, from radiative pion decay is also reported. These results are from data taken with the Crystal Box detector at LAMPF. 11 refs., 7 figs.
Date: January 1, 1986
Creator: Piilonen, L.E.; Bolton, R.D.; Bowman, J.D.; Cooper, M.D; Frank, J.S.; Hallin, A.L. et al.
Partner: UNT Libraries Government Documents Department

Limits on neutrino oscillations in the Fermilab narrow band beam

Description: A search for neutrino oscillations was made using the Fermilab narrow-band neutrino beam and the 15 ft. bubble chamber. No positive signal for neutrino oscillations was observed. Limits were obtained for mixing angles and neutrino mass differences for nu/sub ..mu../ ..-->.. nu/sub e/, nu/sub ..mu../ ..-->.. nu/sub tau/, nu/sub e/ ..-->.. nu/sub e/. 5 refs.
Date: January 1, 1986
Creator: Brucker, E.B.; Jacques, P.F.; Kalelkar, M.; Koller, E.L.; Plano, R.J.; Stamer, P.E. et al.
Partner: UNT Libraries Government Documents Department

Recent results on weak decays of charmed mesons from the Mark III experiment

Description: Recent results from the Mark III experiment on weak decays of charmed mesons are presented. Measurements of the resonant substructure of D{sup 0} {yields} K{sup {minus}}{pi}{sup +}{pi}{sup {minus}}{pi}{sup +} decays, the first model independent result on D{sub s} {yields} {phi}{pi}{sup +}, as well as limits on D{sub s} {yields} {eta}{pi}{sup +} and D{sub s} {yields} {eta}{prime}{pi}{sup +} are described. The implications of these new results are also discussed. 37 refs., 7 figs., 4 tabs.
Date: October 20, 1989
Creator: Browder, T.E.
Partner: UNT Libraries Government Documents Department

An upper limit on the decay D/sup 0/. -->. mu. e

Description: A search for the lepton family number violating decay D/sup 0/ ..-->.. ..mu..e is reported. No signal is observed in a data sample of 9.3 pb/sup -1/ collected at the psi(3770) resonance with the Mark III detector, where 0.18 +- 0.06 +- 0.05 background events are expected. A 90% confidence level upper limit on the branching fraction B(D/sup 0/ ..-->.. ..mu..e) of 1.5 x 10/sup -4/ is obtained.
Date: April 1, 1987
Creator: Stockhausen, W.
Partner: UNT Libraries Government Documents Department

Measurements of the Z boson resonance parameters at SLC (SLAC Linear Collider)

Description: This paper presents the measurement by the Mark II experiment at the SLAC Linear Collider of the parameters of the Z boson resonance. The results are updated from those presented at the SLAC Summer Institute to include all data presented in the most recent Mark II publication, consisting of 19 nb{sup {minus}1} of data at ten different center-of-mass energies between 89.2 and 93.0 GeV. The resonance parameters are extracted by measuring the Z production cross section at a series of center-of-mass energies (scan points) near the Z peak, then fitting these data with the theoretical cross section. The four major aspects of the analysis are the determination at each scan point of the center-of-mass energy (E), the integrated luminosity, the number of Z decays and the expected cross section as a function of the resonance parameters, such as mass and width. I will discuss each of these steps in turn, after a brief description of the Mark II detector, then conclude with the results of the analysis. 7 refs., 9 figs., 3 tabs.
Date: July 1, 1989
Creator: Hearty, C.
Partner: UNT Libraries Government Documents Department

Direct lepton production in hadronic and nuclear collisions at low p/sub t/ and low pair mass

Description: A brief review of the direct production of single leptons and dileptons in hadronic collisions at low p/sub t/ and low pair mass is given. Several open questions are pointed out and the universality of lepton production is briefly discussed. The Bevalac Di-Lepton Spectrometer project is presented. 25 refs., 5 figs.
Date: June 1, 1986
Creator: Roche, G.
Partner: UNT Libraries Government Documents Department

Second class current effects in tau lepton decay

Description: Experiments to see the effects of second class currents in neutrino interactions are described. Evidence from tau lepton decay is discussed, including the ''one-prong anomaly'' and direct observation of eta meson production in tau decay. (LEW)
Date: January 1, 1987
Creator: Derrick, M.
Partner: UNT Libraries Government Documents Department

Inclusive. eta. production in. tau. decays

Description: We have searched for inclusive eta production in tau decays using a sample of 2553 events of e{sup +}e{sup minus} {yields} {tau}{sup +}{tau}{sup minus} in the one-three topology. The data were taken with the High Resolution Spectrometer at {radical}s = 29 GeV. Our results are based on an analysis of the {pi}{sup +}{pi}{sup minus} invariant mass spectrum to find the narrow peak resulting from the decay sequence {tau} {yields} {eta}x and {eta} {yields} {pi}{sup +}{pi}{sup minus}{pi}{degree}. No clear peak is observed and a 90% confidence upper limit on the process {tau} {yields} {eta}x of 2.1% is found. For decays {tau} {yields} {eta}{eta}x the 90% confidence upper limit is 1.3%. Our best limit on {tau} {yields} {eta}{eta}x is obtained from tau decay to five charged particles with a 90% confidence level upper limit of 0.5%.
Date: January 1, 1987
Creator: Abachi, S.; Akerlof, C.; Baringer, P.; Blockus, D.; Brabson, B.; Brom, J.M. et al.
Partner: UNT Libraries Government Documents Department

The decay tau. -->. rho nu (and rho. -->. pi. eta nu. )

Description: Motivated by the question of missing exclusive branching fractions in tau decays, mostly suspected to be in one prong decays with neutrals, we have studied the decay tau ..-->.. rho nu in tau pair production by e/sup +/e/sup -/ annihilation at ..sqrt..s = 3.77 GeV. The branching fraction is measured to be B(tau ..-->.. rho nu) = (23.0 +- 1.3 +- 1.7)% consistent with known measurements and not offering a solution to the branching ratio question. No eta signal in the ..gamma gamma.. mass spectrum pointing to a decay tau ..-->.. eta ..pi.. nu is obvious. An upper limit on this branching fraction is given.
Date: April 1, 1987
Creator: Stockhausen, W.
Partner: UNT Libraries Government Documents Department

Multiple-neutral-meson decays of the /tau/ lepton and electromagnetic calorimeter requirements at Tau-Charm Factory

Description: This is a study of the physics sensitivity to the multiple-neutral-meson decays of the /tau/ lepton at the Tau-Charm Factory. The sensitivity is compared for a moderate and an ultimate electromagnetic calorimeter. With the high luminosity of the Tau- Charm Factory, a very large sample of the decays /tau//sup /minus// /yields/ /pi//sup /minus//2/pi//sup 0//nu//sub /tau// and /tau//sup /minus// /yields/ /pi//sup /minus//3/pi//sup 0//nu//sub /tau// can be collected with both detectors. However, with the ultimate detector, 2/pi//sup 0/ and 3/pi//sup 0/ can be unambiguously reconstructed with very little background. For the suppressed decay /tau//sup /minus// /yields/ /pi//sup /minus///eta//pi//sup 0//nu//sub /tau//, only the ultimate detector has the sensitivity. The ultimate detector is also sensitive to the more suppressed decay /tau//sup /minus// /yields/ K/sup /minus///eta//nu//sub /tau// and the moderate detector may have the sensitivity if the hadronic background is not significantly larger than that predicted by Lund. In the case of the highly suppressed second-class-current decay /tau//sup /minus// /yields/ /pi//sup /minus///eta//nu//sub /tau//, only the ultimate detector has sensitivity. The sensitivity can be greatly enhanced with a small-angle photon veto. 16 refs., 9 figs., 2 tabs.
Date: August 1, 1989
Creator: Gan, K.K.
Partner: UNT Libraries Government Documents Department

Neutrino-oscillation search with cosmic-ray neutrinos

Description: It is shown that a sensitive search for neutrino oscillations involving more flavors than just nu/sub e/ and nu/sub ..mu../ is provided by measurement of the ratio of the total interaction rates of upward- and downward-going cosmic-ray neutrinos within a massive (approx. 10 kiloton) detector. Assuming mixing between all pairs of nu/sub e/, nu/sub ..mu../ and nu/sub tau/, the experiment is capable of observing time-averaging probabilities < P/sub e tau/>/sub t/ of magnitude set by mixing strengths corresponding to, e.g., the d- to s-quark mixing strength, and of reaching the limit ..delta..m/sub ij//sup 2/ identical with vertical bar m/sub i//sup 2/-m/sub j//sup 2/ vertical bar approx. = 10/sup -4/ eV/sup 2/, where m/sub i/, m/sub j/ are neutrino mass eigenstates, and P/sub e tau/ and p/sub ..mu.. tau/ are the probabilities for nu/sub e/ and nu/sub ..mu../, respectively, to oscillate into nu/sub tau/ after traversing a distance L approx. = diameter of the earth.
Date: October 1, 1982
Creator: Ayres, D.S.; Gaisser, T.K.; Mann, A.K. & Shrock, R.E.
Partner: UNT Libraries Government Documents Department

Neutrino production of charm at FNAL E744

Description: We present data on opposite-sign dimuon production in Fermilab neutrino experiment E744. Opposite-sign dimuons are a clean signature of charm production and provide unique information on the strange component of the nucleon. 12 refs., 11 figs.
Date: October 1, 1988
Creator: Foudas, C.; Bachmann, K.T.; Bernstein, R.H.; Blair, R.E.; Lefmann, W.C.; Leung, W.C. et al.
Partner: UNT Libraries Government Documents Department

Dilepton (e sup + e sup minus ) production recent pp and pd studies with DLS at Berkeley

Description: The use of dileptons as probes of hot, dense hadronic matter is described. Preliminary results on dileptons produced in p-p and p-d interactions at the Bevalac are presented along with potential ramifications for existing model calculations of dileptons at these energies. Future directions of the dilepton program at Berkeley are outlined. 14 refs., 3 figs.
Date: September 1, 1991
Creator: Schroeder, L.S.
Partner: UNT Libraries Government Documents Department

Measuring the mass and width of the Z sup 0 : The status of the energy spectrometers

Description: The Stanford Linear Collider (SLC) located at the Stanford Linear Accelerator Center (SLAC) collides electrons and positrons produced in the linear accelerator pulse by pulse. The object is to produce collisions energetic enough to produce the heavy intermediate vector boson, the Z{sup 0}. An essential component of the SLC physics program is the precise knowledge of the center-of-mass energy of each interaction. We measure the energy of each collision by using two energy spectrometers. The spectrometers are located in extraction lines of each beam. We will measure the energy of each beam to 20 MeV or 5 parts in 10{sup 4}. We report here on the status of the energy spectrometer system. 13 refs., 7 figs., 3 tabs.
Date: May 1, 1989
Creator: Rouse, F.; Levi, M. (Lawrence Berkeley Lab., CA (United States)); Kent, J.; King, M.; Von Zanthier, C.; Watson, S. (California Univ., Santa Cruz, CA (United States)) et al.
Partner: UNT Libraries Government Documents Department

Probing nuclear currents with dilepton production in ultrarelativistic heavy-ion collisions

Description: In this paper we discuss the coherent production of ..mu.. and /tau/ pairs perturbatively in the two-photon limit. Previous calculations of cross sections have been reported using the Weizsaecker-Williams method; however, serious objections have been raised to the use of such methods. Approaches which do not impose the constraint that the photons are ''on-shell'' usually give different results due to the breakdown of the equivalent photon approximation. The breakdown of the equivalent photon approximation usually occurs at the same level as the coupling to the nuclear currents. For example, nucleons in nuclei can ''carry'' a large momentum. Form factors controlling the coupling of protons to photons regulate the magnitude of the pair vertex. In the Weizsaecker-Williams method, these form factors cannot be treated properly. Even though the pair production is nonperturbative at the highest energies, the introduction of nucleon form factors tends to regularize perturbation theory, and Feynman theory can be used to address details of the hadron-photon couplings and their effect on the dilepton cross sections. Calculations of this type have been used to study anomalous electron pair production in ..pi../sup /minus//p collisions. In the present work we shall use perturbation theory to study ..mu.. and /tau/ lepton production and to explore the sensitivity of the cross sections to a range of plausible models for the nuclear form factors. 13 refs., 6 figs.
Date: January 1, 1989
Creator: Bottcher, C.; Strayer, M.R.; Albert, C. & Ernst, D.J.
Partner: UNT Libraries Government Documents Department

W mass and W asymmetry at CDF

Description: The lepton charge asymmetry from W decaying into a lepton and a neutrino is discussed (preliminary result). This measurement gives information on parton distribution functions at low x values. The derivation of the recently published W mass value of 79.91 {plus minus} 0.39 GeV/c{sup 2} is also presented. M{sub W} is used to set an upper limit on the top quark mass. 13 refs., 4 figs., 1 tab.
Date: May 1, 1991
Creator: Leone, S. (Pisa Univ. (Italy) Istituto Nazionale di Fisica Nucleare, Pisa (Italy))
Partner: UNT Libraries Government Documents Department

New particle searches at CDF

Description: We present results from searches for the top quark, supersymmetric particles, and new gauge bosons at the Collider Detector at Fermilab (CDF). 8 refs., 6 figs.
Date: January 1, 1991
Creator: Kuhlmann, S.E.
Partner: UNT Libraries Government Documents Department

Experimental limits on massive neutrinos from e/sup +/e/sup /minus// annihilations at 29 GeV

Description: A search was made in 29 GeV e/sup +/e/sup /minus// annihilations for massive neutrinos decaying to e/sup +-/X/sup /minus plus//(..nu..) where X is a muon or meson. A 300 pb/sup /minus/1/ data sample yielded just one candidate event with a mass m/sub ex/ > 1.8 GeV. Significant limits are found for new neutrinos with masses from 1.8 to 6.7 GeV and with mixing parameters in the range 10/sup /minus/6/ < chemically bondUchemically bond/sup 2/ < 1. 12 refs., 4 figs.
Date: January 1, 1989
Creator: Akerlof, C.; Chapman, J.; Errede, D.; Ken, M.T.; Meyer, D.I.; Neal, H. et al.
Partner: UNT Libraries Government Documents Department