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Searches for exotic particles at the Tevatron

Description: This paper reports on recent searches for exotic particles by the CDF and D#31; Collaborations. The results are derived from the data collected during the 1992-95 Run I at the Fermilab Tevatron. Limits are presented on new heavy gauge bosons, leptoquarks, monopoles and technicolor particles.
Date: October 1, 1998
Creator: Grosso-Pilcher, C.
Partner: UNT Libraries Government Documents Department

2 x 2 TeV mu(superscript +) mu (superscript) collider

Description: The scenarios for high-luminosity 2 x 2 TeV and 250 x 250 GeV {mu}{sup +}{mu}{sup -} colliders are presented. Having a high physics potential, such a machine has specific physics and technical advantages and disadvantages when compared with an e{sup +}e{sup -} collider. Parameters for the candidate designs and the basic components - proton source, pion production and decay channel, cooling, acceleration and collider storage ring - are considered. Attention is paid to the areas mostly affecting the collider performance: targetry, energy spread, superconducting magnet survival, detector backgrounds, polarization, environmental issues. 13 refs., 9 figs., 4 tabs.
Date: October 1, 1996
Creator: Mokhov, N.V. & Noble, R.J.
Partner: UNT Libraries Government Documents Department

Scaling linear colliders to 5 TeV and above

Description: Detailed designs exist at present for linear colliders in the 0.5-1.0 TeV center-of-mass energy range. For linear colliders driven by discrete rf sources (klystrons), the rf operating frequencies range from 1.3 GHz to 14 GHz, and the unloaded accelerating gradients from 21 MV/m to 100 MV/m. Except for the collider design at 1.3 GHz (TESLA) which uses superconducting accelerating structures, the accelerating gradients vary roughly linearly with the rf frequency. This correlation between gradient and frequency follows from the necessity to keep the ac {open_quotes}wall plug{close_quotes} power within reasonable bounds. For linear colliders at energies of 5 TeV and above, even higher accelerating gradients and rf operating frequencies will be required if both the total machine length and ac power are to be kept within reasonable limits. An rf system for a 5 TeV collider operating at 34 GHz is outlined, and it is shown that there are reasonable candidates for microwave tube sources which, together with rf pulse compression, are capable of supplying the required rf power. Some possibilities for a 15 TeV collider at 91 GHz are briefly discussed.
Date: April 1, 1997
Creator: Wilson, P.B.
Partner: UNT Libraries Government Documents Department

Measurement of the mass of the B{sub s}{sup 0} meson in {bar p}p collisions at {radical}s = 1.8 TeV

Description: We measure the mass of the B{sub s}{sup 0} meson by fully reconstructing the decay B{sub s}{sup 0} {yields} J/{psi} {phi} with the subsequent decays J/{psi} {yields} {mu}{sup +} {mu}{sup {minus}} and {phi} {yields} K{sup +} K{sup {minus}}. The data was obtained from 19.3 pb{sup {minus}1} of integrated luminosity of {bar p}p collisions at {radical}s = 1.8 TeV using the Collider Detector at Fermilab (CDF). A sample of 80,000 inclusive J/{psi} {yields} {mu}{sup +}{mu}{sup {minus}} events is used to study systematic biases in track reconstruction and is used to calibrate the momentum scale. We reconstruct the kinematically similar decays B{sup {minus}} {yields} J/{psi} K{sup {minus}} and B{sup 0} {yields} J/{psi} K* to study the mass measurement technique used for the B{sup 0} meson. Based on the observation of 32 {plus_minus} 6 candidates, the mass of the B{sub s}{sup 0} meson is measured to be 5369.9 {plus_minus} 2.3 {plus_minus} 1.3 MeV/c{sup 2}.
Date: July 1995
Creator: Abe, F.
Partner: UNT Libraries Government Documents Department

Top quark physics at the D0 experiment

Description: In this paper I present the latest results on top quark physics from the D0 collaboration since the discovery of the top quark in March 1995. I summarize the discovery results, discuss progress since the discovery, and show how we can measure the top quark mass using three separate techniques. The measurements were made at the Fermilab Tevatron, a p{bar p} collider with {radical}s = TeV, using {approximately}50 pb{sup {minus}1} data collected from 1992 to early 1995.
Date: January 1, 1996
Creator: Heinson, A.P.
Partner: UNT Libraries Government Documents Department

Studies of the top quark with the D0 detector

Description: The observation of the top quark by the D0 experiment, at Fermilab`s Tevatron proton-antiproton collider, is briefly reviewed. The analysis of the top quark mass in the lepton plus jets decay channels, resulting in m{sub t} {approx} 200 GeV/c{sup 2} is reviewed; and a preliminary mass analysis from the dilepton decay channels resulting in m{sub t} = 145 {plus_minus} 25 (statistical) {plus_minus} 20 (systematic) GeV/c{sup 2} is presented. These mass measurements are compared with Standard Model limits from CERN`s LEP experiments and the published CDF measurement. Preliminary observation of top quark-W boson correlation is shown.
Date: January 1, 1996
Creator: Stephens, R.W.
Partner: UNT Libraries Government Documents Department

Studies of topological distributions of the three- and four-jet events in {bar p}p collisions at {radical}s = 1800 GeV with the D0 detector

Description: The global topologies of three- and four-jet events produced in {bar p}p interactions are described. the three- and four-jet events are selected from data recorded by the D0 detector at the Tevatron Collider operating at a center-of-mass energy of {radical}s = 1800 GeV. the measured normalized distributions of various topological variables are compared with parton-level predictions of the tree- level QCD calculations. The parton-level QCD calculations are found to be in good agreement with the data. The studies also show that the topological distributions of the different subprocesses involving different numbers of quarks are very similar and reproduce the measured distributions well.
Date: July 1, 1995
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

Comparison of the total cross sections measurements of CDF and E811

Description: The total cross section at {radical}s = 1.8 TeV has been measured by three groups (CDF, E710, and E811). We think that CDF should quote results based only on our own measurement. We also indicate how to compare cross sections measured by both CDF and D0.
Date: March 3, 1999
Creator: Albrow, M.; Beretvas, A.; Nodulman, L. & Giromini, P.
Partner: UNT Libraries Government Documents Department

Search for new exotic particles at CDF

Description: We present recent results of searches for new particles beyond the Standard Model at the Collider Detector at Fermilab (CDF). These include searches for heavy gauge bosons (Z{prime}, W{prime}), leptoquarks and stable massive charged particles. For most of these particles we set the currently most stringent limits. 15 refs., 7 figs.
Date: July 1, 1996
Creator: Wensel, H.
Partner: UNT Libraries Government Documents Department

RF power sources for 5--15 TeV linear colliders

Description: After outlining the design of the NLC rf system at 1 TeV, the possibility of a leap in linear collider energy into the 5--15 TeV energy range is considered. To keep the active accelerator length and ac wall-plug power within reasonable bounds, higher accelerating gradients at higher rf frequencies will be necessary. Scaling relations are developed for basic rf system parameters as a function of frequency, and some specific parameter examples are given for colliders at 34 Ghz and 91 Ghz. Concepts for rf pulse compression system design and for high power microwave sources at 34 Ghz (for example sheet-beam and multiple-beam klystrons) are briefly discussed.
Date: September 1, 1996
Creator: Wilson, P.B.
Partner: UNT Libraries Government Documents Department

Preliminary measurement of the inclusive jet and dijet cross section in {bar p}p collisions at {radical} s = 1.8 TeV

Description: We report on preliminary measurements of the central, |{eta}| {le} 0.5, inclusive jet and dijet cross sections at {radical}s = 1.8 TeV. Two data sets with integrated luminosities of 91 pb{sup {minus}1} and 14 pb{sup {minus}1} were collected at the Fermilab Tevatron p{ovr p} Collider with the D0 detector. The inclusive jet cross section measured with both data sets and reported as a function of transverse jet energy (35 GeV {le} E{sub T} {le} 470 GeV) and the dijet cross section measured with the 91 pb{sup {minus}1} data set and reported as a function of dijet mass (200 GeV {le} M{sub JJ} {le} 1 TeV) are in excellent agreement with next-to-leading order QCD. 11 refs., 5 figs.
Date: June 1, 1996
Creator: Blazey, G.C.
Partner: UNT Libraries Government Documents Department

Top mass measurement at CDF

Description: We present the measurement of the top quark mass using L = 110 pb{sup -1} data sample of p{ovr p} collisions at {radical}s = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). We show the results for the different channels and discuss with some emphasis the determination of the systematic uncertainties. 7 refs., 10 figs., 5 tabs.
Date: June 1, 1996
Creator: Rolli, S.
Partner: UNT Libraries Government Documents Department

Subjet structure of jets at D0

Description: The authors present a preliminary study of jet structure in {anti p}p collisions at {radical}s = 1.8 TeV using data taken with the D0 detector during the 1994--95 Tevatron run. They measure the average number <N{sub sub}> and radial distributions of subjects within a jet, and compare to the predictions of HERWIG 5.8, a parton-shower Monte Carlo event generator.
Date: September 1996
Creator: Snihur, R.
Partner: UNT Libraries Government Documents Department

A study of multi-jet production ratios in p{anti p} collisions at D0

Description: The authors study inclusive jet multiplicity ratios in multi-jet events from p{anti p} collisions at {radical}s = 1.8 TeV recorded using the D0 detector at the Fermilab Tevatron collider. Preliminary average multi-jet production ratios are presented as a function of the scalar jet transverse energy and compared to NLO calculations.
Date: September 1, 1996
Creator: Gallas, E.
Partner: UNT Libraries Government Documents Department

Particle production measurements by E802/E859/E866 and recent results from NMA in {sup 196}Au + {sup 196}Au collisions at 11.6 A{center_dot}GeV/c

Description: A summary of the particle production measurements in relativistic nucleus-nucleus collisions by the E802/E859/E866 Collaboration at the Brookhaven National Laboratory AGS-Tandem accelerator complex is presented. These results have been collected since 1986 through a series of experiments using the E802/E859/E866 spectrometer/calorimeter system. Also included are the latest results from the E866 collaboration using the New Multiplicity Array (NMA) detector for pion multiplicity measurements and for global event characterization of large entropy production in central Au + Au collisions. The detector consists of 346 lucite Cerenkov modulus surrounding the target, covering the pseudorapidity interval between {minus}0.4 and 2.8.
Date: December 31, 1995
Creator: Fung, Sun-yiu
Partner: UNT Libraries Government Documents Department

Electromagnetic dissociation of Au targets by Au beams in E862

Description: E862 is an experiment to measure Electromagnetic Dissociation (ED) of Au and Co targets by 9.89 GeV/nucleon beams from the AGS. ED occurs at impact parameters large enough so that no strong interaction occurs, but virtual photons are exchanged, resulting in the excitation of a giant resonance. The authors report the first observation of an ED cross section {sigma}{sub ED} larger than the total hadronic cross section for Au+Au of 6.1 barns. Results are given for both the single- and double-neutron removal processes and compared to calculations using both semiclassical and quantum methods, including effects from both E1 and E2 giant resonances. Predictions are extended to RHIC and LHC collider energies where ED will be a significant determinant of the quality of the stored beams.
Date: September 1, 1997
Creator: Hill, J.C.; Ewell, L.A. & Libby, B.
Partner: UNT Libraries Government Documents Department

The b{bar b} production cross section and correlations in p{bar p} collisions at {radical}s = 1.8 TeV

Description: The authors present measurements of the b{bar b} production cross section and angular correlations between the b and {bar b}-quarks in p{bar p} collisions using the D0 detector at the Fermilab Tevatron operating at {radical}s = 1.8 TeV. The b-quark production cross section for {vert_bar}y{sup b}{vert_bar} < 1.0 and {rho}{sub {tau}}{sup b} > 8 GeV/c is extracted and found to be consistent with next-to-leading order QCD predictions. In addition, the angular correlations between the b and {bar b}-quarks are found to agree in shape with next-to-leading order QCD predictions.
Date: August 1, 1996
Creator: Gomez, B.; Hoeneisen, B. & Negret, J.P.
Partner: UNT Libraries Government Documents Department

Tevatron results on b-quark cross sections and correlations

Description: We report on recent results obtained by the D0 and CDF collaborations on the properties of b-quark production and correlations in p{bar p} collisions at {radical}s = 1.8 TeV. The D0 experiment has measured the angular correlations between the b- and {bar b}-quarks using the azimuthal opening angle between their decay muons. This measurement is also used to extract the inclusive b-quark production cross section for |y{sub b}| < 1.0 and is combined with previous Tevatron results. The CDF experiment has made the first direct measurement of b{bar b} rapidity correlations at a hadron collider, measuring the ratio of cross sections obtained in two different rapidity bins. D0 has also measured the inclusive production cross section for muons originating from b-quark decays in the forward region. These results are combined with previous measurements in the central region to obtain a rapidity dependence of the b-quark production cross section.
Date: April 8, 1999
Creator: Fein, David K.
Partner: UNT Libraries Government Documents Department

Inclusive jet cross section in p{bar p} collisions with the D0 detector

Description: The authors report on two preliminary measurements of the central inclusive jet cross section at {radical}s = 1.8 TeV. The two data sets with integrated luminosities of 91 pb{sup {minus}1} and 14 pb{sup {minus}1} were collected at the Fermilab Tevatron p{bar p} Collider with the D0 detector. The cross section, reported as a function of transverse jet energy 35 GeV {le} E{sub {tau}} {le} 470 GeV and in the pseudorapidity interval {vert_bar}{eta}{vert_bar} {le} 0.5, is in excellent agreement with next-to-leading order QCD.
Date: July 1, 1996
Creator: Gomez, B.; Hoeneisen, B. & Negret, J.P.
Partner: UNT Libraries Government Documents Department

Estimates of Hadronic Backgrounds in Future e+e- LinearColliders

Description: We have estimated hadronic backgrounds for an e+e- linear collider at a center- of-mass energy of 5 TeV. In order to achieve a required luminosity in TeV e+ e- colliders, the high beamstrahlung parameter {Upsilon}, such as several thousands, is caused. In the high {Upsilon} regime, the {gamma}{gamma} luminosities due to the collision of beamstrahlung photons are calculated by using the CAIN code. According to the {gamma}{gamma} luminosity distribution, we have estimated the hadronic backgrounds of {gamma}{gamma} {yields} minijets based on the parton distributions of the Drees and Grassie model by the PYTHIA 5.7 code. The Japan Linear Collider (J LC-1) detector simulator is applied for selection performances in the detector.
Date: May 1, 1998
Creator: Ohgaki, Tomomi
Partner: UNT Libraries Government Documents Department

Discussion on muon collider parameters at center of mass energies from 0.1 TeV to 100 TeV

Description: The main motivation for research and development efforts on muon collider technology is the assertion that affordably priced muon colliders might provide lepton-lepton collisions at much higher center of mass (CoM) energies than is feasible for electron colliders, and perhaps eventually explore the spectrum of elementary particles at mass scales inaccessible even to hadron colliders. This paper attempts to present some justification for these assertions through discussion and evaluation of the self-consistent muon collider parameter sets given in table 1 at CoM energies ranging from 0.1 to 100 TeV. The parameter set at 0.1 TeV CoM energy was included as a lower energy reference point and was constrained to essentially reproduce one of the sets of parameters currently under study by the Muon Collider Collaboration (MCC). In contrast, the other parameter sets represent speculation by the author on how the parameters might evolve with CoM energy and they have not been studied or discussed in detail within the MCC.
Date: June 1, 1998
Creator: King, B.J.
Partner: UNT Libraries Government Documents Department