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Jet production at CDF

Description: In this talk I present the results from the measurement of the inclusive jet cross section and strong coupling constant based on the CDF Run 1B data, and discuss prospects for Run 2.
Date: April 22, 2002
Creator: Mesropian, Christina
Partner: UNT Libraries Government Documents Department

Results of active well coincidence counter cross-calibration measurements at Argonne National Laboratory-West.

Description: Nondestructive Assay (NDA) of Nuclear Materials (NM) is a common tool used by inspectors involved in Material Protection, Control and Accounting (MPC&A) programs, both domestically and internationally. NDA is generally used to quantify the properties of NM, usually by determining the mass or enrichment of materials such as U-235 or Pu-240. For the NDA of Highly Enriched Uranium (HEU) metal, powder or scrap samples, Active Well Coincidence Counter (AWCC) NDA systems are routinely used. These systems bombard samples with neutrons, inducing fission events. The fissile mass of the sample is determined based upon the number of coincidence neutrons detected. To obtain accurate quantitative measurements using AWCC systems it is necessary to calibrate the instruments using physical standards representative of the unknown sample to be measured. During international inspections it is both expensive and difficult to obtain the large number of physical standards necessary to accurately assay the wide range of NM present at multiple sites. To address this issue, a cross-calibration method has been developed by Los Alamos National Laboratory (LANL) allowing the transfer of calibration parameters measured to field inspection systems without the need for physical standards. Argonne National Laboratory-West (ANLW) routinely uses AWCC systems as part of its MPC&A program to verify the fissile mass of HEU items of various enrichments. In addition, ANLW is involved in a MPC&A program initiated by the U.S. Department of Energy (DOE) to provide AWCC system support to Russia. Approximately 25 AWCCs have been delivered to Russia through this program. Before shipment to Russia, the AWCC systems measured reference standards at LANL. The results of these measurements are included in Appendix II and III. Using this data, a study of the cross calibration technique using low enriched uranium was performed by the Moscow State Engineering Physics Institute (MEPhI) with encouraging results. The ...
Date: October 22, 2002
Creator: Jensen, B. A.; Sanders, J.; Wenz, T. & R., Buchheit.
Partner: UNT Libraries Government Documents Department

Search for Neutron to Anti-Neutron Transitions at HFIR/ORNL

Description: The transition of neutron to anti-neutron might be the first observed signal of the baryon instability long-awaited in Grand Unification models and required for the explanation of baryon asymmetry in the universe. A newly-proposed experiment to search for neutron-antineutron transitions at High Flux Isotope Reactor at Oak Ridge National Laboratory can improve the discovery potential by factor of {approximately} 1,000 relative to the existing limits. Further prospects of n -> n(overbar) search are also discussed in this paper.
Date: October 22, 1998
Creator: Kamyshkov, Y.
Partner: UNT Libraries Government Documents Department

Signals from flavor changing scalar currents at the future colliders

Description: We present a general phenomenological analysis of a class of Two Higgs Doublet Models with Flavor Changing Neutral Currents arising at the tree level. The existing constraints mainly affect the couplings of the first two generations of quarks, leaving the possibility for non negligible Flavor Changing couplings of the top quark open. The next generation of lepton and hadron colliders will offer the right environment to study the physics of the top quark and to unravel the presence of new physics beyond the Standard Model. In this context we discuss some interesting signals from Flavor Changing Scalar Neutral Currents.
Date: November 22, 1996
Creator: Atwood, D.; Reina, L. & Soni, A.
Partner: UNT Libraries Government Documents Department

DSE hadron phenomenology.

Description: A perspective on the contemporary application of Dyson-Schwinger equations, focusing on some recent phenomenological applications: a description and unification of light-meson observable using a one-parameter model of the effective quark-quark interaction, and studies of leptonic and nonleptonic nucleon form factors. The theory and phenomenological application of Dyson-Schwinger equations (DSEs) have seen something of a renaissance. For example, they have been applied simultaneously to phenomena as apparently unconnected as low-energy {pi}{pi} scattering, B {r_arrow} D{sup *} decays and the equation of state for a quark gluon plasma, and there are renewed attempts to understand the origin of the infrared enhancement necessary in the kernel of the quark DSE (QCD gap equation) to generate dynamical chiral symmetry breaking (DCSB). Also significant is the appreciation that in this approach current algebra's anomalies remain a feature of the global aspects of DCSB.
Date: May 22, 2000
Creator: Hecht, M. B.; Roberts, C. D. & Schmidt, S. M.
Partner: UNT Libraries Government Documents Department

The Propagation and Backscattering of Soliton-Like Pulses in a Chain of Quartz Beads and Related Problems. (I). Propagation

Description: We confirm that for vanishingly small loading and large impact condition, it may be possible to generate solitons in a chain of grains that are characterized by Herkian contacts. For uniform or progressive loading conditions throughout the chain, one generates soft-solitons which are weakly dispersive in space and time. Under conditions of weak impact one generates acoustic pulses through the chain. We describe the displacements, velocities and accelerations suffered by the individual grains when subjected to solitons, soft-solitons and acoustic pulses and describe the effects of restitution on the propagating pulse.
Date: January 22, 2000
Partner: UNT Libraries Government Documents Department

Chamber, Target and Final Focus Integrated Design

Description: Liquid wall protection, which challenges chamber clearing, has such advantages it's Heavy Ion Fusion's (HIF) main line chamber design. Thin liquid protection from x rays is necessary to avoid erosion of structural surfaces and thick liquid makes structures behind 0.5 m of Flibe (7 mean free paths for 14 MeV neutrons), last the life of the plant. Liquid wall protection holds the promise of greatly increased economic competitiveness. Driver designers require {approx}200 beams to illuminate recent target designs from two sides. The illumination must be compatible with liquid wall protection. The ''best'' values for driver energy, gain, yield and pulse rate comes out of well-known trade-off studies. An integrated chamber design, yet to be made, depends on several key assumptions, which are to be proven before HIF can be shown to be feasible. The chamber R&D needed to reduce the unknowns and risks depend on resolving a few technical issues such as jet surface smoothness and rapid chamber clearing.
Date: March 22, 2000
Creator: Moir, R.W
Partner: UNT Libraries Government Documents Department

Transversely Polarized L Production.

Description: Transversely polarized {Lambda} production in hard scattering processes is discussed in terms of a leading twist T-odd fragmentation function which describes the fragmentation of an unpolarized quark into a transversely polarized {Lambda}. We focus on the properties of this function and its relevance for the RHIC and HERMES experiments.
Date: May 22, 2000
Creator: BORER, D.
Partner: UNT Libraries Government Documents Department

Prospect for discovering a light higgs at the Tevatron in Run II

Description: The present upgrades of the CDF and DO detectors as well as of the Fermilab Tevatron have dramatically improved their sensitivity for Standard Model and minimal supersymmetry Higgs bosons searches in Run II. This paper reviews the recent estimates of this sensitivity in terms of Higgs discovery and exclusion reach based on a total expected Run II Tevatron luminosity of 15 fb{sup {minus}1} delivered to each experiment.
Date: June 22, 2001
Creator: Velev, G.
Partner: UNT Libraries Government Documents Department

Signatures of Quark-Gluon Plasma Phase Transition in High-Energy Nuclear Collisions

Description: In high-energy nuclear collisions, the new phase of the quark-gluon plasma is indicated by an anomalous increase in pressure, an excess of direct photon production, an excess of strangeness production, and an anomalous J/{psi} suppression. We review these signatures and discuss how recent high-energy heavy-ion experiments at CERN are consistent with the production of the quark-gluon plasma in high-energy Pb+Pb collisions.
Date: May 22, 2000
Creator: Wong, C.-Y.
Partner: UNT Libraries Government Documents Department

Centrality Dependent Strange Baryon Production in P-A and its Implications for Heavy Ion Collisions

Description: BNL E910 has measured strange baryon production as a function of collision centrality for 17.5 GeV/c p-Au collisions. Collision centrality is defined by v{sub 1} the mean number projectile-nucleon interactions estimated from the ''grey'' track multiplicity. The measured {Lambda} yield increases faster than the participant scaling expectation for v {le} 3 and then saturates. A simple parameterization of this dependence applied to nucleus-nucleus collisions reproduces the measured E866 km. and WA97 {Lambda} centrality dependent yields. The increase in {Lambda} production to v {le} 3 is also evident for {Lambda}s which are leading baryons, in disagreement with predictions from RQMD.
Date: September 22, 2000
Creator: Soltz, R.
Partner: UNT Libraries Government Documents Department

Higgs searches at the Tevatron

Description: This paper describes the searches for the Higgs boson performed by the CDF and DO collaborations at the Tevatron p{bar p} Collider using the data collected in the 1992-95 run. Searches for standard model Higgs and as well for neutral and charged minimal SUSY Higgs bosons are also presented. No signal has been observed and limits are set for production cross sections.
Date: June 22, 2001
Creator: Moneta, L.
Partner: UNT Libraries Government Documents Department

LOTIS: GRB follow-up observations at early times

Description: LOTIS is an automated wide field-of-view telescope system capable of responding to GRB events as early as 10s after a trigger from the GCN which rapidly distributes coordinates from the Beppo/SAX, BATSE and RXTE instruments. Measurements of optical activity at these early times will provide important clues to the GRB production mechanism. In over two year's of operation, LOTIS has responded to 40 GCN triggers including GRB971217 with l10s and GRB980703 within 5 hours. We report results from these events and constraints on simultaneous optical signals during these GRB's.
Date: February 22, 1999
Creator: Park, H S
Partner: UNT Libraries Government Documents Department

The triangle anomaly in the tripple-regge limit

Description: The U(l) triangle anomaly is present, as an infra-red divergence, in the six-reggeon triple-regge interaction vertex obtained from a maximally non-planar Feynman diagram in the full triple-regge limit of three-to-three quark scattering.
Date: November 22, 1999
Creator: White, A. R.
Partner: UNT Libraries Government Documents Department

Coarsening in Multicomponent Multiphase Systems [Final Report, November 1, 1995--October 31, 1998]

Description: The goal of the project was to extend the theory of particle coarsening, which is well established for binary systems, to the case of multicomponent and multiphase alloys. The theoretical approach involved three stages: (1) a mean field description based on the Lifshitz-Slyozov-Wagner (LSW) [1,2] formulation (recently published in Acta Mater. [3]), (2) an analytical description of coarsening valid at small volume fractions where the Marqusee and Ross [4] model was employed and (3) a numerical simulation of three phase coarsening where the boundary integral method of Akaiwa and Voorhees [5] was implemented. The main result of the mean field analysis can be stated as follows. The growth rate of a particle from a particular phase in a multiphase system is precisely the same as that derived for a single phase, multicomponent system. Also, it was found that the scaled particle size distribution for each phase in the system has exactly the same form as that originally derived by LSW. Since it neglects particle interactions, the mean field theory is clearly unrealistic and as such the formulation of coarsening in low volume fraction multiphase systems was undertaken.
Date: October 22, 1999
Creator: Hoyt, J.J.
Partner: UNT Libraries Government Documents Department

Energy-Momentum Tensor and Particle Creation in the De Sitter Universe

Description: Particle creation in a conformally flat spacetime (e.g., FRW universe) requires a non-conformal field. The choice of state is crucial, as one may misunderstand the physics of particle creation by choosing a too restrictive vacuum for the quantum field. The authors exhibit a vacuum state in which the expectation values of the energy and pressure allow an intuitive physical interpretation. They apply this general result to the de Sitter universe.
Date: June 22, 1998
Creator: Molina-Paris, C.
Partner: UNT Libraries Government Documents Department

Searches for exotics at the Tevatron

Description: The Fermilab Tevatron collider experiments CDF and D0 collected more than 100 pb{sup -1} of data at {radical}(s) = 1.8 TeV during Run I (1992-1995). Results of searches for new phenomena (exotics) are presented, covering supersymmetry, leptoquarks, technicolor, and quark compositeness. In each case, no discrepancy with the Standard Model is observed, and stringent limits on new physics predicted by these models are extracted. Parameters for Run II of the Tevatron are given along with projections of search reaches for this upcoming run.
Date: June 22, 2000
Creator: Chertok, Maxwell
Partner: UNT Libraries Government Documents Department

The Propagation and Backscattering of Soliton-Like Pulses in a Chain of Quartz Beads and Related Problems. (II). Backscattering

Description: We demonstrate that the propagation of solitons, soliton-like excitations and acoustic pulses discussed in the preceding article can be used to detect buried impurities in a chain of elastic grains with Hertzkur contacts. We also present preliminary data for 3D granular beds, where soliton-like objects can form and can be used to probe for buried impurities, thus suggesting that soliton-pulse spectroscopy has the potential to become a valuable tool for probing the structural properties of granular assemblies. The effects of restitution are briefly discussed. We refer to available experiments which support our contention.
Date: January 22, 2000
Partner: UNT Libraries Government Documents Department


Description: The Relativistic Heavy Ion Collider (RHIC) at the BNL requires the AGS to provide Gold beam with the intensity of 10{sup 9} ions per bunch. Over the years, the Tandem Van de Graaff has provided steadily increasing intensity of gold ion beams to the AGS Booster. However, the gold beam injection efficiency at the Booster has been found to decrease with the rising intensity of injected beams. As the result, for Tandem beams of the highest intensity, the Booster late intensity is lower than with slightly lower intensity Tandem beam. In this article, the authors present two experiments associated with the Booster injection efficiency and beam intensity. One experiment looks at the Booster injection efficiency by adjusting the Tandem beam intensity, and another looks at the beam life time while scraping the beam in the Booster. The studies suggest that the gold beam injection efficiency at the AGS Booster is related to the beam loss in the ring, rather than the intensity of injected beam or circulating beam. A close look at the effect of the lost gold ion at the Booster injection leads to the prediction that the lost gold ion creates large number of positive ions, and even larger number of electrons. The lost gold beam is also expected to create large numbers of neutral particles. In 1998 heavy ion run, the production of positive ions and electrons due to the lost gold beam has been observed. Also the high vacuum pressure due to the beam loss, presumably because of the neutral particles it created, has been measured. These results will be reported elsewhere.
Date: June 22, 1998
Creator: ZHANG,S.Y. & AHRENS,L.A.
Partner: UNT Libraries Government Documents Department

Photon structure and the production of jets, hadrons, and prompt photons.

Description: We give a pedagogical introduction to hard photoproduction processes at HERA, including the production of jets, hadrons, and prompt photons. Recent theoretical developments in the three areas are reviewed. In summary, hard photoproduction processes can provide very useful information on the hadronic structure of the photon, in particular on the gluon density, which is complimentary to the information coming from deep inelastic photon-photon scattering at electron-positron colliders. Among the different hadronic final states, jets are most easily accessible experimentally and phenomenologically. On the other hand, inclusive hadron production offers the possibility to test the universality of hadron fragmentation functions and measure the photon structure down to very low values of p{sub T} and x{sub {gamma}}. Prompt photon production suffers from a reduced cross section and limited data, but allows for the additional testing of photon fragmentation functions.
Date: July 22, 1999
Creator: Klasen, M.
Partner: UNT Libraries Government Documents Department

Observation of the moon shadow in deep underground muon flux.

Description: A shadow of the moon, with a statistical significance of 5{sigma}, has been observed in the underground muon flux at a depth of 2090 mwe using the Soudan 2 detector. The angular resolution of the detector is well described by a Gaussian with {sigma} {le}0.3{degree}. The position of the shadow confirms the alignment of the detector to better than 0.15{degree}. This alignment has remained stable during 10 years of data taking from 1989 through 1998.
Date: June 22, 1999
Creator: Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Cobb, J. H.; Fields, T. H.; Goodman, M. C. et al.
Partner: UNT Libraries Government Documents Department

Rare B decays, mixing and cp violation at the Fermilab Tevatron

Description: Over two decades since its discovery at Fermilab in 1977, the b quark has become an important laboratory for the exploration of the Standard Model as well as a potential window beyond it. Its kinematic properties, its large mass and long lifetime, and its large production cross section in hadron collisions, make it an excellent subject of study at the Tevatron {bar p}p collider. In this article, we will review recent results from CDF and D0 in two categories of tests of the Standard Model: the search for rare b decays, and the measurement of asymmetry parameters related to B{sup 0} meson mixing and CP violation. The detectors have been described elsewhere. The data for the results presented here are from the 1992-96 collider run, representing at each experiment, approximately 100 pb{sup -1} of integrated luminosity at {radical}s = 1.8 TeV.
Date: December 22, 1999
Creator: Tseng, J.
Partner: UNT Libraries Government Documents Department