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Search for charged Higgs bosons in CDF

Description: We present results of a direct search for charged Higgs production from {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV at Fermilab`s Tevatron collider using the CDF detector. An expanded Higgs sector containing charged Higgs bosons is a persistent feature of candidate theories to replace the Standard Model. The minimal supersymmetric extension of the Standard Model, for example predicts that the dominant decay mode of the top quark is {ital t} {r_arrow} H{sup +}{ital b} {r_arrow} {tau}{sup +} {ital vb} for large values of tan {Beta}. We use the hadronic decays of the tau lepton in this channel to exclude charged Higgs bosons with M{sub H{sup {+-}}} {lt} 140 GeV/c{sup 2} for large tan{Beta}.
Date: August 1, 1996
Creator: Loomis, C.
Partner: UNT Libraries Government Documents Department

Search for charginos and neutralinos using trileptons

Description: We search for supersymmetry (SUSY) using trilepton events in {ital p{anti p}} collisions at {radical}s = 1.8 TeV. In the Minimal Supersymmetric Standard Model (MSSM), trilepton events are expected from chargino-neutralino ({anti {chi}}{sub 1}{sup {+-}}{anti {chi}}{sub 2}{sup 0}) pair production, with subsequent decay into leptons. In all possible combinations of electron and muon channels in 100 pb{sup -1} of data, we observe no events which pass our trilepton selection criteria. Assuming the GUT hypothesis within the framework of the MSSM, our preliminary analysis excludes M({anti {chi}}{sub 1}{sup {+-}}) < 68 GeV/c{sup 2}.
Date: October 1, 1996
Creator: Done, J. P.
Partner: UNT Libraries Government Documents Department

Refrigerated hydrogen gas jet for the Fermilab antiproton accumulator

Description: A hydrogen gas jet has been built for use at Fermilab for the study of charmonium spectroscopy in proton-antiproton annihilations. The hydrogen gas jet is part of an upgrade to a previous experiment which ran in the Fermilab 1990-1991 fixed target program utilizing a jet cooled to 80 K with liquid nitrogen. The jet delivers a defined stream of hydrogen gas which travels through a series of vacuum chambers and then intersects the circulating antiproton beam. The goal of the upgrade is to provide a hydrogen gas stream at least twice as dense as used for the earlier experiment to increase the interaction rate and allow an improved study of rare processes. This is achieved by cooling the stream to below 30 K using a Gifford-McMahon refrigerator. The jet apparatus is designed to allow motion in the plane perpendicular to the gas stream as well as angular positioning at the jet nozzle to provide a means of optimizing the interaction rate. Two skimmers located in the vacuum chambers are used to define the gas stream dimensions. The jet target vacuum chambers require constant pumping with turbomolecular pumps. The vacuum space around the jet is designed to have a large system pumping speed so that the chamber pressure can be maintained below an absolute pressure of 1 Pa. The jet will operate in the next fixed target run at Fermilab. Details of the design and test results are discussed.
Date: July 1, 1995
Creator: Allspach, D.H.; Kendziora, C.L. & Marinelli, M.
Partner: UNT Libraries Government Documents Department

Production and decays of top quark pairs in the single lepton and dilepton channels at CDF

Description: We present the results from {ital t}{ital {anti t}} production in {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV, with decays into one or two leptons plus multiple jets. The full data set accumulated by the CDF collaboration at the Fermilab Tevatron from 1992 through 1995, corresponding to a total integrated luminosity of 109.4 {+-} 7.2 pb{sup -1}, is used.
Date: August 1, 1996
Creator: Kruse, M. C.
Partner: UNT Libraries Government Documents Department

Remote data monitoring for CDF

Description: Remote data monitoring from the physicists` home institutions has become an important issue in large international experiments to ensure high performance of the detectors and high quality of data and scientific results. The CDF experiment is a collaboration of 450 physicists from 36 institutions in the U.S., Japan, Canada, Italy and Taiwan. Future experiments at Fermilab, CERN and elsewhere will be even larger, and will be performed over a period of order 10 years. The ability of collaborators at remote sites to monitor the increasingly complex detectors and feed the results back into the data acquisition process will be of great importance We report on the status and performance of remote monitoring from Japan of the CDF experiment in Batavia Illinois. We also discuss feasibilities for modest Remote Control Rooms.
Date: November 1, 1995
Creator: Kippenhan, H. A., Jr.; Lidinsky, W. & Roediger, G.
Partner: UNT Libraries Government Documents Department