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Questions of Identity

Description: As an introduction to {nu}Fact '99, the ICFA/ECFA Workshop on Neutrino Factories Based on Muon Storage Rings, I place the issues of neutrino properties and neutrino oscillations in the broader context of fermion flavor.
Date: August 25, 1999
Creator: Quigg, Chris
Partner: UNT Libraries Government Documents Department

Valence quark spin distribution functions

Description: The hyperfine interactions of the constituent quark model provide a natural explanation for many nucleon properties, including the {Delta} - N splitting, the charge radius of the neutron, and the observation that the proton's quark distribution function ratio d(x)/u(x) {r_arrow} 0 as x {r_arrow} 1. The hyperfine-perturbed quark model also makes predictions for the nucleon spin-dependent distribution functions. Precision measurements of the resulting asymmetries A{sub 1}{sup p}(x) and A{sub 1}{sup n}(x) in the valence region can test this model and thereby the hypothesis that the valence quark spin distributions are ''normal''.
Date: September 1, 1998
Creator: Isgur, Nathan
Partner: UNT Libraries Government Documents Department

D-Zero results on W boson properties

Description: The D0 experiment collected {approx} 15 pb{sup -1} in run 1A (1992- 1993) and {approx} 89 pb{sup -1} in run 1B (1994-1995) of the Fermilab Tevatron Collider using p{anti p} collisions at {radical}s = 1.8 TeV. Results from analyses of events with W and Z bosons are presented for the run 1B data samples. From W {yields} e{nu}, {mu}{nu} and Z {yields} ee, {mu}{mu} decays, the W and Z production cross sections and the W width are determined. Events with W {yields} {tau}{nu} decays are used to determine the ratio of the electroweak gauge coupling constants as a measure of lepton universality. Using W {yields} e{nu} and Z {yields} ee decays, the W boson mass is measured.
Date: October 1, 1997
Creator: Abbott, B.
Partner: UNT Libraries Government Documents Department

Hyperon static properties

Description: The static properties of the hyperons include masses, lifetimes, magnetic moments and CPT test from the asymmetries of these quantities for hyperon and anti-hyperon. The author reviews the present status of these measurements with an eye toward identifying places where new or improved measurements can have a significant physics impact. Most of these measurements are from the PDG where there have been only two new measurements quoted since 1995. He also reports two new measurements not yet published.
Date: March 24, 2000
Creator: Cooper, P.S.
Partner: UNT Libraries Government Documents Department

Dyson-Schwinger equations: connecting small and large length-scales.

Description: The phenomenological application of Dyson-Schwinger equations to the calculation of meson properties observable at TJNAF is illustrated. Particular emphasis is given to the ability of this framework to unify long-range effects constrained by chiral symmetry with short-range effects prescribed by perturbation theory, and interpolate between them.
Date: February 8, 1999
Creator: Roberts, C.
Partner: UNT Libraries Government Documents Department

Rheological Behavior of Dense Assemblies of Granular Materials

Description: Assemblies of granular materials behave differently when they are owing rapidly, from when they are slowly deforming. The behavior of rapidly owing granular materials, where the particle-particle interactions occur largely through binary collisions, is commonly related to the properties of the constituent particles through the kinetic theory of granular materials. The same cannot be said for slowly moving or static assemblies of granular materials, where enduring contacts between particles are prevalent. For instance, a continuum description of the yield characteristics of dense assemblies of particles in the quasistatic ow regime cannot be written explicitly on the basis of particle properties, even for cohesionless particles. Continuum models for this regime have been proposed and applied, but these models typically assume that the assembly is at incipient yield and they are expressed in terms of the yield function, which we do not yet know how to express in terms of particle-level properties. The description of the continuum rheology in the intermediate regime is even less understood. Yet, many practically important flows in nature and in a wide range of technological applications occur in the dense flow regime and at the transition between dilute and dense regimes; the lack of validated continuum rheological models for particle assemblies in these regimes limits predictive modeling of such flows. This research project is aimed at developing such rheological models.
Date: March 31, 2011
Creator: Sundaresan, Sankaran; Tardos, Gabriel I & Subramaniam, Shankar
Partner: UNT Libraries Government Documents Department

Status of the new muon (g - 2) experiment.

Description: The new muon (g - 2) experiment is now fully operational The goal of the experiment is to obtain a relative error on (g - 2) of {+-}O.35 ppm to measure the electroweak contribution for the first time, and to observe, or place stringent limits on physics beyond the standard model which can contribute to (g - 2). A brief status report is presented.
Date: May 3, 1999
Creator: Carey, R. M.; Earle, W.; Efstathiadis, E.; Hare, M. F.; Collaboration, MUON (g - 2); Nodulman, L. et al.
Partner: UNT Libraries Government Documents Department

Single top production and top properties at the Tevatron

Description: We summarize recent measurements made at the Tevatron Collider using top event candidates. Cross section and mass measurements are discussed in a separate contribution to these Proceedings. Here we report on studies of the top P<sub>T</sub> distribution in t{anti t} production and studies of single top production. Properties of top decays examined are: BF(t {yields} Wb)/BF(t {yields} Wq), helicity amplitudes of W's from top decays and correlations of t{anti t} decay products. Searches for new physics in rare top decays and a search for a state X {yields} t{anti t} are also reported.
Date: November 5, 1999
Creator: Barbaro-Galtieri, Angela
Partner: UNT Libraries Government Documents Department

Effective Supergravity from the Weakly Coupled HeteroticString

Description: The motivation for Calabi-Yau-like compactifications of the weakly coupled E{sub 8} {circle_times} E{sub 8} heterotic string theory, its particle spectrum and the issue of dilaton stabilization are briefly reviewed. Modular invariant models for hidden sector condensation and supersymmetry breaking are described at the quantum level of the effective field theory. Their phenomenological and cosmological implications, including a possible origin for R-parity, are discussed.
Date: May 1, 2005
Creator: Gaillard, Mary K.
Partner: UNT Libraries Government Documents Department


Description: We discuss lattice results on the properties of finite momentum cliarmonium states in a gluonic plasma. We also present preliminary results for bottomonium correlators and spectral functions in the plasma. Significant modifications of {chi}{sub b{sub 0.1}} states are seen at temperatures of 1.5 T{sub c}.
Date: October 24, 2005
Creator: Datta, S.; Jakovac, A.; Karsch, F. & Petreczky, P.
Partner: UNT Libraries Government Documents Department

Solar neutrino oscillations

Description: The special properties of solar neutrinos that render this flux so uniquely important in searches for neutrino masses and flavor mixing are reviewed. The effects of matter, including density fluctuations and turbulence, on solar neutrino oscillations are explained through analogies with more familiar atomic physics phenomena.
Date: December 31, 1993
Creator: Haxton, W. C.
Partner: UNT Libraries Government Documents Department

Determining properties of baryon resonances in nuclei

Description: Meson-nucleus and photon-nucleus interactions are important sources of information about the medium modifications of baryon resonances in nuclei. Indications of how large the medium effects are for resonances above the {Delta}{sub 33}(1232) are provided by it combined analysis of photonuclear and pion cross sections in the GeV range of energies. Tile existing data indicate a possible 10-20% renormalization of the pion coupling to higher-lying resonances in nuclei.
Date: October 1, 1996
Creator: Johnson, M.B.; Chen, C.M.; Ernst, D.J. & Jiang, M.F.
Partner: UNT Libraries Government Documents Department

Theoretical predictions for exotic hadrons

Description: In this contribution the authors discuss current theoretical expectations for the properties of light meson exotica, which are meson resonances outside the q{anti q} quark model. Specifically they discuss expectations for gluonic hadrons (glueballs and hybrids) and multiquark systems (molecules). Experimental candidates for these states are summarized, and the relevance of a TCF to these studies is stressed.
Date: December 1996
Creator: Barnes, T.
Partner: UNT Libraries Government Documents Department

Tau physics results from SLD

Description: Results on {tau} physics at SLD are presented. They are based on 4,316 {tau}-pair events selected from a 150 k Z{sup 0} data sample collected at the SLC. These results include measurements of the {tau} lifetime ({tau}{sub r} = 288.1 {+-} 6.1 {+-} 3.3 fs), the {tau} Michel parameters ({rho} = 0.71 {+-} 0.09 {+-} 0.04, {zeta} = 1.03 {+-} 0.36 {+-} 0.05, and {zeta}{delta} = 0.84 {+-} 0.27 {+-} 0.05), and the {tau} neutrino helicity (h{sub {nu}} = {minus}0.81 {+-} 0.18 {+-} 0.03).
Date: August 10, 1996
Creator: Daoudi, M. & Collaboration, SLD
Partner: UNT Libraries Government Documents Department

Top quark physics

Description: The top quark, when it was finally discovered at Fermilab in 1995 completed the three-generation structure of the Standard Model (SM) and opened up the new field of top quark physics. Viewed as just another SM quark, the top quark appears to be a rather uninteresting species. Produced predominantly, in hadron-hadron collisions, through strong interactions, it decays rapidly without forming hadrons, and almost exclusively through the single mode t {r_arrow} Wb. The relevant CKM coupling V{sub tb} is already determined by the (three-generation) unitarity of the CKM matrix. Rare decays and CP violation are unmeasurable small in the SM. Yet the top quark is distinguished by its large mass, about 35 times larger than the mass of the next heavy quark, and intriguingly close to the scale of electroweak (EW) symmetry breaking. This unique property raises a number of interesting questions. Is the top quark mass generated by the Higgs mechanism as the SM predicts and is its mass related to the top-Higgs-Yukawa coupling? Or does it play an even more fundamental role in the EW symmetry breaking mechanism? If there are new particles lighter than the top quark, does the top quark decay into them? Could non-SM physics first manifest itself in non-standard couplings of the top quark which show up as anomalies in top quark production and decays? Top quark physics tries to answer these questions. Several properties of the top quark have already been examined at the Tevatron. These include studies of the kinematical properties of top production, the measurements of the top mass, of the top production cross-section, the reconstruction of t{bar t}pairs in the fully hadronic final states, the study of {tau} decays of the top quark, the reconstruction of hadronic decays of the W boson from top decays, the search for flavor changing neutral ...
Date: March 24, 2000
Creator: Ahmadov, A.; Azuelos, G.; Bauer, U.; Belyaev, A.; Berger, E. L.; Sullivan, Z. et al.
Partner: UNT Libraries Government Documents Department

Color transparency and pion valence quark distributions from di-jet events in Fermilab E791

Description: Diffractive, exclusive di-jet events produced by 500 GeV/c {pi}{sup {minus}} scattered off nuclei were used to measure their A-dependence, and to make the first direct measurement of the valence-quark momentum distribution in pions. Data on the latter are compared to two limiting predictions for the pion light-cone wave-function. The results show that the asymptotic wave-function of perturbative QCD describes the data well for Q{sup 2} of 10 GeV{sup 2} and above. The measured A-dependence is consistent with observation of point-like configurations in the pion and color-transparency calculations.
Date: October 10, 2000
Creator: Appel, Jeffrey A.
Partner: UNT Libraries Government Documents Department

Dark matter distribution in the universe and ultra-high energy cosmic rays

Description: Two of the greatest mysteries of modern physics are the origin of the dark matter in the universe and the nature of the highest energy particles in the cosmic ray spectrum. The authors discuss here possible direct and indirect connections between these two problems, with particular attention to two cases: in the first they study the local clustering of possible sources of ultra-high energy cosmic rays (UHECRs) driven by the local dark matter overdensity. In the second case they study the possibility that UHECRs are directly generated by the decay of weakly unstable super heavy dark matter.
Date: October 10, 2000
Creator: Blasi, Pasquale
Partner: UNT Libraries Government Documents Department

Kaon Condensation in Neutron Stars.

Description: We discuss the kaon-nucleon interaction and its consequences for the change of the properties of the kaon in the medium. The onset of kaon condensation in neutron stars under various scenarios as well its effects for neutron star properties are reviewed.
Date: April 24, 2001
Creator: Ramos, A.; Schaffner-Bielich, J. & Wambach, J.
Partner: UNT Libraries Government Documents Department