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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

High-energy high luminosity mu{sup +}mu{sup {minus}} collider design

Description: The authors discuss the design of a high luminosity (10{sup 35} cm{sup {minus}2}s{sup {minus}1}), high energy (2+2 TeV) mu{sup +}mu{sup {minus}} collider, starting from the proton accelerator needed to generate the muon beams and proceeding through the muon storage ring.
Date: May 1, 1995
Creator: Palmer, Robert B.; Fernow, Richard; Gallardo, Juan C.; Lee, Y.Y.; Torun, Yagmur; Neuffer, David et al.
Partner: UNT Libraries Government Documents Department

Determination and study of the cosmic-ray composition above 100 TeV

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to develop a new technique using ground-based measurements to determine the cosmic-ray composition at energies around 10{sup 15} eV (the knee in the cosmic-ray spectrum). Cosmic rays are high-energy nuclei that continuously bombard the earth. Though cosmic rays were first detected in the 1870s it wasn`t until 1915 that their cosmic origin was established. At present, the authors still do not know the source of cosmic rays. At energies above 50 TeV (1 TeV = 1 trillion electron-volts) they do not know the composition of the cosmic rays. At about 5 PeV (1PeV = 10{sup 15} eV) the cosmic ray spectrum steepens. Knowledge of the composition above and below this point can help determine the origin of cosmic rays.
Date: November 1, 1998
Creator: Sinnis, G.; Haines, T.J. & Hoffman, C.M.
Partner: UNT Libraries Government Documents Department

CP violation and flavor-changing-currents at {mu}{sup +}{mu}{sup minus} colliders

Description: Production and decay (CP) asymmetries at {mu}{sup +}{mu}{sup {minus}} collider, in extensions of the Standard Model (SM) are reported. Production asymmetries appear to be very promising for a large range of parameters, decays are less effective. Importance of flavor- changing scalar currents involving the top are emphasized. At lepton colliders, the top-anticharm final state is uniquely suited for such searches. At a muon collider there is the novel possibility of tree level {mu}{sup +}{mu}{sup {minus}} {r_arrow} t{ovr c}. This talk is based on works done in collaboration with David Atwood and Laura Reina. 10 refs., 8 figs.
Date: April 2, 1996
Creator: Soni, A.
Partner: UNT Libraries Government Documents Department

Measurement of the W boson mass from CDF

Description: The CDF collaboration has measured the mass of the W boson to be M{sub W} = 80.41 {plus_minus} 0.18 GeV/c{sup 2} using 5718 W {yields} e{nu} events and 3268 W {yields} {mu}{nu} events collected in {approximately} 19 pb{sup {minus}1} from the 1992--93 collider run at the Fermilab Tevatron. This measurement has an uncertainty half that of the best previously published measurements.
Date: July 1995
Creator: Kim, Young-Kee
Partner: UNT Libraries Government Documents Department

Muon collider design

Description: The possibility of muon colliders was introduced by Skrinsky et al., Neuffer, and others. More recently, several workshops and collaboration meetings have greatly increased the level of discussion. In this paper we present scenarios for 4 TeV and 0.5 TeV colliders based on an optimally designed proton source, and for a lower luminosity 0.5 TeV demonstration based on an upgraded version of the AGS. It is assumed that a demonstration version based on upgrades of the FERMILAB machines would also be possible. 53 refs., 25 figs., 8 tabs.
Date: March 1, 1996
Creator: Palmer, R.; Sessler, A. & Skrinsky, A.
Partner: UNT Libraries Government Documents Department

Production of heavy quark states at CDF

Description: In this paper the author presents results on quarkonia production, B-meson production and b{bar b} correlations in p{bar p} collisions at {radical}s = 1.8 TeV. These results were obtained from data taken with the CDF detector at Fermilab. The author covers recently completed analyses of the 1992-95 collider run. Prospects for the near and more distant future are also discussed.
Date: July 1, 1995
Creator: Papadimitriou, V.
Partner: UNT Libraries Government Documents Department

Diphoton production in p{bar p} collisions at {radical}s = 1.8 TeV

Description: We present measurements of the inclusive {gamma}{gamma} cross section (as a function of invariant mass and photon {epsilon}{sub {tau}}), in p{bar p} collisions at {radical}s = 1.8 TeV, made using the D0 detector at the Fermilab Tevatron collider. The next is leading order (NLO) QCD prediction is found to be in good agreement with the data. The effects of invariant mass and diphoton balance cuts, which test the next-to-leading order contributions to the cross section, are investigated. We also compare the distribution of {kappa}{sub {tau}} between samples of diphotons and highly electromagnetic jets, and find that the NLO QCD prediction models the shape of the {gamma}{gamma} {kappa}{sub {tau}} distribution quite well.
Date: July 1, 1995
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

Inclusive jet cross sections in pbar p collisions at 630 and 1800 GeV

Description: We have made a precise measurement of the inclusive jet cross section at {radical}s=1800 GeV. The result is based on an integrated luminosity of 92 pb<sup>-1</sup> collected at the Fermilab Tevatron {anti p}p Collider with the D0 detector. The measurement is reported as a function of jet transverse energy (60 GeV {<=} E<sub>T</sub> {<=} 500 GeV ), and in the pseudo- rapidity intervals |{eta}| {<=} 0.5 and 0.1 {<=} |{eta}| {<=} 0.7. A preliminary measurement of the pseudorapidity dependence of inclusive jet production ( |{eta}| {<=} 1.5 ) is also discussed. The results are in good agreement with predictions from next-to-leading order (NLO) quantum chromodynamics (QCD). D0 has also determined the ratio of jet cross sections at {radical}s=630 GeV and {radical}s=1800 GeV ( |{eta}| {<=} 0.5). This preliminary measurement differs from NLO QCD predictions.
Date: September 8, 1999
Creator: Elvira, V.Daniel
Partner: UNT Libraries Government Documents Department

Multijet events at the Tevatron proton-antiproton collider

Description: The characteristics of three-jet, four-jet, and five-jet events observed by the CDF and D0 experiments at the Fermilab Tevatron {bar p}p collider are compared with leading order QCD matrix element predictions, and with the predictions from a parton shower Monte Carlo program.
Date: July 1, 1995
Creator: Geer, S.
Partner: UNT Libraries Government Documents Department

High-energy high-luminosity {mu}{sup +}{mu}{sup {minus}} collider design

Description: We discuss the design of a high luminosity (l0{sup 35} cm-{sup {minus}2} s{sup {minus}1}), high energy (2 + 2 TeV) {mu}{sup +}{mu}{sup {minus}} collider, starting from the proton accelerator needed to generate the muon beams and proceeding through the muon storage ring.
Date: July 1, 1995
Creator: Palmer, R.B.; Fernow, R.; Gallardo, J.C.; Lee, Y.Y.; Torun, Y.; Neuffer, D. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the triple differential jet cross section at {square root} s = 1800 GeV

Description: We present a measurement of the triple differential cross section for dijet production in proton-antiproton scattering at a center of mass energy of 1800 GeV. The data were taken with the D0 detector at the Fermilab Tevatron and are compared to next to leading order QCD theoretical predictions with differing parton distribution functions. The data are of sufficient accuracy to rule out or favor parton distribution functions over a wide range in x .
Date: July 7, 1999
Creator: Schellman, H.
Partner: UNT Libraries Government Documents Department

A search for di-lepton signatures from minimal low energy supergravity in {bar p}p collisions at {radical}s 1.8 = TeV

Description: We report on a search for supersymmetry using the DO detector. The 1994-96 data sample of {radical}s = 1:8 TeV {bar p}p collisions was analyzed for events containing two leptons (e or {mu}), two or more jets, and missing transverse energy. Assuming minimal supergravity, with free parameters m{sub 0}, m{sub 1/2} and tan {beta}, various thresholds were employed to optimize the search. No excess of events was observed. We present exclusion contours in the (m{sub 0}, m{sub 1/2}) plane for tan {beta} = 2-6.
Date: August 5, 1999
Creator: II, Richard J. Genik
Partner: UNT Libraries Government Documents Department

Observation of B{sup +} {yields} J/{psi}{pi}{sup +}

Description: We report on the observation of the Cabibbo-suppresed mode B{sup +} J/{psi}{pi}{sup +}, with J/{psi} {yields} {mu}{sup +}{mu}{sup {minus}}. Further, we calculate the relative branching ratio. BR(B{sup +} - J/{psi}{pi}{sup +})/BR(B{sup +} {yields} J/{psi}K{sup +}) and find a value of (4.9{sub {minus}1.7}{sup +}{plus_minus}1.1)%.
Date: July 1, 1995
Creator: Abe, F.
Partner: UNT Libraries Government Documents Department

Search for AGN neutrinos with the soudan 2 detector.

Description: Several authors have presented models for neutrino production from Active Galactic Nuclei (AGN) that allow for the possibility of AGN neutrinos outnumbering the atmospheric neutrino flux for energies in excess of 30 TeV. The authors present preliminary results from a search for high energy neutrinos from AGN using the underground Soudan 2 Detector.
Date: October 15, 1997
Creator: DeMuth, D. M.
Partner: UNT Libraries Government Documents Department

A search for rapidity gap events in p{bar p} collisions at D0

Description: Preliminary results from a search for jet events with rapidity gaps are presented. These events were produced in p{bar p} interactions at {radical}s = 1.8 TeV and measured with the D{O} detector at Fermilab. The fraction of events with a rapidity gap is measured as a function of the pseudo-rapidity difference between the cone edges of the two leading jets ({Delta}{eta}{sub c}). An upper limit on the fraction of events with no particles between jets is measured at 0.0093 at a 90% confidence level for events with {Delta}{eta}{sub c} > 3 and jet transverse energies greater than 30 GeV.
Date: November 1, 1993
Creator: Streets, K. T. & Collaboration, D0
Partner: UNT Libraries Government Documents Department

A search for first generation scalar leptoquarks at {radical}s = 1.8 TeV with the D0 detector

Description: A search for first generation scalar leptoquarks was done at the DO detector at Fermi National Accelerator Laboratory from 15 pb{minus}1 of data taken during the 1992--1993 colder run. At Fermilab`s p{bar p} collider with a center-of-mass energy of 1.8 TeV, leptoquarks are produced mostly by the strong force in pairs. Leptoquarks carry fractional charge, color, and also lepton and baryon quantum numbers. First generation leptoquarks couple exclusively to the electron, electron neutrino, and the u and d quarks; such a leptoquark would decay into, for example, an electron plus a quark. Signatures for leptoquarks at p{bar p} colliders that have been investigated at DO are two electrons plus two jets and one electron plus missing energy (from an electron neutrino) plus two jets.
Date: December 31, 1993
Creator: Norman, D. M.
Partner: UNT Libraries Government Documents Department

Direct {anti b}b production in {anti p}p collisions at {radical}s = 1.8 TeV

Description: The first measurement of bottom quark production in the forward detector at CDF is presented in this thesis. Events from the 1988/89 Fermilab collider run were selected with forward muons with nearby jets to form a bottom quark tag. The efficiency and acceptance of the detector are then taken into account and the number of events is turned into a cross section: {sigma}(p{sub t}{sup b} > 20 GeV, 1.9 < {vert_bar}{eta}{sup b}{vert_bar} < 2.5) = (124. {+-} 35. {+-} 76.) nb. The contribution from direct bottom quarks is {sigma}(p{sub t}{sup b} > 20 GeV, p{sub t}{sup {anti b}} > 15 GeV, 1.9 < {vert_bar}{eta}{sup b}{vert_bar} < 2.5) = (100. {+-} 30.{sub {minus}31.}{sup +30.}) nb.
Date: December 31, 1993
Creator: Lamoureux, J.
Partner: UNT Libraries Government Documents Department

Analysis of forward and near-forward elastic-scattering amplitudes for pp and anti pp collisions

Description: We will present the results of two recently published (1983) papers by M.M. Block and R.N. Cahn, which analyze for anti pp and pp elastic scattering the rho values (ratios of the real to the imaginary parts of the forward nuclear scattering amplitudes), the total (hadronic) cross sections sigma, and the b values, the nuclear slope parameters. The predictions of the analyses, from ..sqrt.. s bar > 5 GeV, is compared with the recently measured values of sigma and b at the SPS Collider. The analysis has also been redone to include new ISR data available from R211 at ..sqrt.. s bar = 62.5 GeV, in order to estimate odderon contributions, i.e., contributions from odd amplitudes with unconventional (non-Reggeon) energy dependence. Limits of approx. 1% are placed on these amplitudes. Our analysis has been extrapolated up to 100 TeV, to give sigma, rho and b predictions for cosmic ray and future collider energies.
Date: April 1, 1983
Creator: Block, M.B. & Cahn, R.N.
Partner: UNT Libraries Government Documents Department