6,211 research outputs found

    Spectroscopy of doubly charmed baryons: Ξcc+\Xi_{cc}^{+} and Ξcc++\Xi_{cc}^{++}

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    Using the quark-diquark approximation in the framework of Buchm\" uller-Tye potential model, we investigate the spectroscopy of doubly charmed baryons: Ξcc++\Xi_{cc}^{++} and Ξcc+\Xi_{cc}^{+}. Our results include the masses, parameters of radial wave functions of states with the different excitations of both diquark and light quark-diquark system. We calculate the values of fine and hyperfine splittings of these levels and discuss some new features, connected to the identity of heavy quarks, in the dynamics of hadronic and radiative transitions between the states of these baryons.Comment: 10 pages, Latex file, 1 fig, corrected some typo

    Heavy Quark Fragmentation to Baryons Containing Two Heavy Quarks

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    We discuss the fragmentation of a heavy quark to a baryon containing two heavy quarks of mass mQ≫ΛQCDm_Q\gg\Lambda_{\rm QCD}. In this limit the heavy quarks first combine perturbatively into a compact diquark with a radius small compared to 1/ΛQCD1/\Lambda_{\rm QCD}, which interacts with the light hadronic degrees of freedom exactly as does a heavy antiquark. The subsequent evolution of this QQQQ diquark to a QQqQQq baryon is identical to the fragmentation of a heavy antiquark to a meson. We apply this analysis to the production of baryons of the form ccqccq, bbqbbq, and bcqbcq.Comment: 9 pages, 1 figure included, uses harvmac.tex and epsf.tex, UCSD/PTH 93-11, CALT-68-1868, SLAC-PUB-622

    Assessment of the Mankato Area\u27s young Adult Population\u27s Knowledge of Mall Video Mining for Marketing Research

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    The most modern form of gathering marketing information is not as new as many people believe. The trepidation of Big Brother’s cameras watching down on us puts a chill down most peoples’ backs. In numerous mall stores, cameras are located in each store and are examining you. Most believe that the cameras are positioned for the purpose of shoplifting and crime, but the truth is many are also used for the purpose of marketing. Video mining as it is known has emerged as the latest method of conducting market research. The stores that are participating in this study are diligently watching an assortment of things. Marketing analysts watch what a customer has picked up, what they have looked at, the amount purchased, colors that attract them, their facial expressions, and many other forms of movement. This information is gathered and recorded, then shot across the nation via computer to a company such as Shopper Trak that views and analyzes clips of customers shopping. Shopper Trak presently has 40,000 cameras in various stores across the nation. Most customers have little knowledge of this marketing tactic or that there are no laws prohibiting this action. Do stores and business’s have an ethical duty to reveal their practices to their customers? Is it legal for them to use the personal information or preferences of their customers to exploit them without their knowledge or consent? Finally, where is the line drawn on what is considered personal, private information

    Ground-state phase diagram of the spin-1/2 square-lattice J1-J2 model with plaquette structure

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    Using the coupled cluster method for high orders of approximation and Lanczos exact diagonalization we study the ground-state phase diagram of a quantum spin-1/2 J1-J2 model on the square lattice with plaquette structure. We consider antiferromagnetic (J1>0) as well as ferromagnetic (J1<0) nearest-neighbor interactions together with frustrating antiferromagnetic next-nearest-neighbor interaction J2>0. The strength of inter-plaquette interaction lambda varies between lambda=1 (that corresponds to the uniform J1-J2 model) and lambda=0 (that corresponds to isolated frustrated 4-spin plaquettes). While on the classical level (s \to \infty) both versions of models (i.e., with ferro- and antiferromagnetic J1) exhibit the same ground-state behavior, the ground-state phase diagram differs basically for the quantum case s=1/2. For the antiferromagnetic case (J1 > 0) Neel antiferromagnetic long-range order at small J2/J1 and lambda \gtrsim 0.47 as well as collinear striped antiferromagnetic long-range order at large J2/J1 and lambda \gtrsim 0.30 appear which correspond to their classical counterparts. Both semi-classical magnetic phases are separated by a nonmagnetic quantum paramagnetic phase. The parameter region, where this nonmagnetic phase exists, increases with decreasing of lambda. For the ferromagnetic case (J1 < 0) we have the trivial ferromagnetic ground state at small J2/|J1|. By increasing of J2 this classical phase gives way for a semi-classical plaquette phase, where the plaquette block spins of length s=2 are antiferromagnetically long-range ordered. Further increasing of J2 then yields collinear striped antiferromagnetic long-range order for lambda \gtrsim 0.38, but a nonmagnetic quantum paramagnetic phase lambda \lesssim 0.38.Comment: 10 pages, 15 figure

    Analysis of hydrogen diffusion in the three stage electro-permeation test

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    The presence of hydrogen traps within a metallic alloy influences the rate of hydrogen diffusion. The electro-permeation (EP) test can be used to assess this: the permeation of hydrogen through a thin metallic sheet is measured by suitable control of hydrogen concentration on the front face and by recording the flux of hydrogen that exits the rear face. Additional insight is achieved by the more sophisticated three stage EP test: the concentration of free lattice hydrogen on the front face is set to an initial level, is then dropped to a lower intermediate value and is then restored to the initial level. The flux of hydrogen exiting the rear face is measured in all three stages of the test. In the present study, a transient analysis is performed of hydrogen permeation in a three stage EP test, assuming that lattice diffusion is accompanied by trapping and de-trapping. The sensitivity of the three stage EP response to the depth and density of hydrogen traps is quantified. A significant difference in permeation response can exist between the first and third stages of the EP test when the alloy contains a high number density of deep traps

    Charmed Strange Pentaquarks in the Large NcN_c Limit

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    The properties of pentaquarks containing a heavy anti-quark and strange quarks are studied in the bound state picture. In the flavor SU(3) limit, there are many pentaquark states with the same binding energy. When the SU(3) symmetry breaking effects are included, however, three states become particularly stable due to a ``Gell-Mann--Okubo mechanism''. They are the Qˉsuud\bar Qsuud and Qˉsudd\bar Qsudd states discussed by Lipkin, and a a previously unstudied Qˉssud\bar Qssud state. These states will have JP=12+J^P={1\over2}^+ and their masses are estimated. These states, if exist, may be seen in experiments in the near future.Comment: 12 pages in REVTeX, no figure

    From Tetraquark to Hexaquark: A Systematic Study of Heavy Exotics in the Large NcN_c Limit

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    A systematic study of multiquark exotics with one or Nc−1N_c-1 heavy quarks in the large NcN_c limit is presented. By binding a chiral soliton to a heavy meson, either a normal NcN_c-quark baryon or an exotic (Nc+2)(N_c+2)-quark baryon is obtained. By replacing the heavy quark with Nc−1N_c-1 heavy antiquarks, exotic (2Nc−2)(2N_c-2)-quark and 2Nc2N_c-quark mesons are obtained. When Nc=3N_c = 3, they are just the normal triquark baryon QqqQqq, the exotic pentaquark baryon QqˉqˉqˉqˉQ\bar q\bar q\bar q\bar q, tetraquark di-meson QˉQˉqq\bar Q \bar Q qq and the hexaquark di-baryon QˉQˉqˉqˉ barqqˉ\bar Q \bar Q \bar q \bar q\ bar q \bar q respectively. Their stabilities and decays are also discussed. In particular, it is shown that the ``heavy to heavy'' semileptonic decays are described by the Isgur--Wise form factors of the normal baryons.Comment: 14 pages in REVTeX, no Figure

    Utilizing qualitative data from nominal groups: Exploring the influences on treatment outcome prioritization with rheumatoid arthritis patients

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    The nominal group technique generates quantitative data through a process of experts ranking items of interest. This article focuses on the additional collection of qualitative data from nominal groups with rheumatoid arthritis (RA) patients, used to explore the influences on prioritizing treatment outcomes. Across all groups, the top five outcomes with the highest importance scores were identified as: pain; joint damage; fatigue; activities of daily living; and mobility. Qualitative findings showed that the personal impact of RA influenced decisions on how to rank specific outcomes through four domains: disease impact; adaptation to illness; external resources and stressors; and social expectations. © The Author(s) 2011

    Fluxtube model atmospheres and Stokes V zero-crossing wavelengths

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    First results of the inversion of Stokes I and V profiles from plage regions near disk center are presented. Both low and high spatial resolution spectra of FeI 6301.5 and FeI 6302.5 A obtained with the Advanced Stokes Polarimeter (ASP) have been considered for analysis. The thin flux tube approximation, implemented in an LTE inversion code based on response functions, is used to describe unresolved magnetic elements. The code allows the simultaneous and consistent inference of all atmospheric quantities determining the radiative transfer with the sole assumption of hydrostatic equilibrium. By considering velocity gradients within the tubes we are able to match the full ASP Stokes profiles. The magnetic atmospheres derived from the inversion are characterized by the absence of significant motions in high layers and strong velocity gradients in deeper layers. These are essential to reproduce the asymmetries of the observed profiles. Our scenario predicts a shift of the Stokes V zero-crossing wavelengths which is indeed present in observations made with the Fourier Transform Spectrometer.Comment: To appear in ApJ Letters (1997) (in press

    Hadrons with Charm and Beauty

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    By combining potential models and QCD spectral sum rules (QSSR), we discuss the spectroscopy of the (bcˉ)(b\bar c) mesons and of the (bcq)(bcq), (ccq)(ccq) and (bbq)(bbq) baryons (q≡d{q}\equiv {d} or ss), the decay constant and the (semi)leptonic decay modes of the BcB_c meson. For the masses, the best predictions come from potential models and read: MBc=(6255±20)M_{B_c} = (6255 \pm 20)~MeV, MBc∗=(6330±20)M_{B^*_c} = (6330 \pm 20)~MeV, MΛ(bcu)=(6.93±0.05)M_{\Lambda(bcu)} = (6.93\pm 0.05)~GeV, MΩ(bcs)=(7.00±0.05)M_{\Omega(bcs)} = (7.00\pm 0.05)~GeV, MΞ∗(ccu)=(3.63±0.05)M_{\Xi^*(ccu)} =(3.63\pm 0.05)~GeV and MΞ∗(bbu)=(10.21±0.05)M_{\Xi^*(bbu)} = (10.21\pm 0.05)~GeV. The decay constant fBc=(2.94±0.21)fπf_{B_c} = (2.94 \pm 0.21) f_\pi is well determined from QSSR and leads to: Γ(Bc→νττ)=(3.0±0.4)(Vcb/0.037)2\Gamma(B_c \rightarrow \nu_\tau \tau) = (3.0 \pm 0.4)( V_{cb}/0.037 )^2 ×1010\times 10^{10} s−1^{-1}.The uses of the vertex sum rules for the semileptonic decays of the BcB_c show that the tt-dependence of the form factors is much stronger than predicted by vector meson dominance. It also predicts the almost equal strength of about 0.30 ×1010\times 10^{10} sec−1^{-1} for the semileptonic rates BcB_c into Bs,Bs∗,ηcB_s, B^*_s,\eta_c and J/ψ\psi. Besides these phenomenological results, we also show explicitly how the Wilson coefficients of the ⟨αsG2⟩\langle\alpha_s G^2\rangle and ⟨G3⟩\langle G^3\rangle gluon condensates already contain the full heavy quark- (⟨QˉQ⟩\langle\bar QQ\rangle) and mixed- (⟨QˉGQ⟩\langle\bar QGQ\rangle) condensate contributions in the OPE.}Comment: 32 pages, LaTeX, no changes in the 1994 paper, latex errors corrected in 201
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