1,249 research outputs found

    New results for hadronic collisions in the framework of the Parton-Based Gribov-Regge Theory

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    We recently proposed a new approach to high energy nuclear scattering, which treats hadronic collisions in a sophisticated way. Demanding theoretical consistency as a minimal requirement for a realistic model, we provide a solution for the energy conservation, screening problems and identical elementary interactions, the so-called "Parton-Based Gribov-Regge Theory" including enhanced diagrams. We can now present some of our results for SPS and RHIC energies.Comment: 4 pages, 3 figures, To appear in the proceedings of Quark Matter 2002 (QM 2002), Nantes, France, 18-24 Jul 200

    Effective String Theory of Vortices and Regge Trajectories

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    Starting from a field theory containing classical vortex solutions, we obtain an effective string theory of these vortices as a path integral over the two transverse degrees of freedom of the string. We carry out a semiclassical expansion of this effective theory, and use it to obtain corrections to Regge trajectories due to string fluctuations.Comment: 27 pages, revtex, 3 figures, corrected an error with the cutoff in appendix E (was previously D), added more discussion of Fig. 3, moved some material in section 9 to a new appendi

    Relativistic Quark Spin Coupling Effects in the Correlations Between Nucleon Electroweak Properties

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    We investigate the effect of different relativistic spin couplings of constituent quarks on nucleon electroweak properties. Within each quark spin coupling scheme the correlations between static electroweak observables are found to be independent of the particular shape of the momentum part of the nucleon light-front wave function. The neutron charge form factor is very sensitive to different choices of spin coupling schemes once the magnetic moment is fitted to the experimental value. However, it is found rather insensitive to the details of the momentum part of the three-quark wave function model.Comment: 23 pages, 13 figures, requires axodraw.sty 1 figure corrected, 1 refs. added, some changes in tex

    Weight suppression and weight elevation are associated with eating disorder symptomatology in women age 50 and older: Results of the gender and body image study

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    Objective: Weight suppression (WS), the difference between highest past non-pregnancy weight and current weight, predicts negative outcomes in eating disorders, but the impact of WS and related weight constructs are understudied in nonclinical, midlife populations. We examined WS (current weight < highest weight) and weight elevation (WE), the opposite of WS (current weight > lowest weight) and their associations with eating psychopathology in women aged 50+. Method: Participants were a community-based sample (N = 1,776, M age = 59) who completed demographic and eating psychopathology questions via online survey. WS, WE, and WS × WE were tested as predictors of outcome variables; BMI and medical conditions that affect weight were controlled for. Results: Individuals that were higher on WS and WE were most likely to engage in current weight loss attempts, dieting in the past 5 years, and extreme lifetime restriction. Individuals with higher WS were more likely to experience binge eating, greater frequency of weight checking, overvaluation of shape and weight, and lifetime fasting. Individuals with higher WE were more likely to report negative life impacts of eating and dieting. Higher WS and WE each predicted higher levels of skipping meals over the lifetime. Discussion: This novel study investigated WS in midlife women and introduced a new conceptualization of weight change (WE) that may be more relevant for aging populations given that women tend to gain weight with age. The findings implicate the utility of investigating both WS and WE as factors associated with eating psychopathology in midlife women

    An integral method for solving nonlinear eigenvalue problems

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    We propose a numerical method for computing all eigenvalues (and the corresponding eigenvectors) of a nonlinear holomorphic eigenvalue problem that lie within a given contour in the complex plane. The method uses complex integrals of the resolvent operator, applied to at least kk column vectors, where kk is the number of eigenvalues inside the contour. The theorem of Keldysh is employed to show that the original nonlinear eigenvalue problem reduces to a linear eigenvalue problem of dimension kk. No initial approximations of eigenvalues and eigenvectors are needed. The method is particularly suitable for moderately large eigenvalue problems where kk is much smaller than the matrix dimension. We also give an extension of the method to the case where kk is larger than the matrix dimension. The quadrature errors caused by the trapezoid sum are discussed for the case of analytic closed contours. Using well known techniques it is shown that the error decays exponentially with an exponent given by the product of the number of quadrature points and the minimal distance of the eigenvalues to the contour

    Strong Decays of Strange Quarkonia

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    In this paper we evaluate strong decay amplitudes and partial widths of strange mesons (strangeonia and kaonia) in the 3P0 decay model. We give numerical results for all energetically allowed open-flavor two-body decay modes of all nsbar and ssbar strange mesons in the 1S, 2S, 3S, 1P, 2P, 1D and 1F multiplets, comprising strong decays of a total of 43 resonances into 525 two-body modes, with 891 numerically evaluated amplitudes. This set of resonances includes all strange qqbar states with allowed strong decays expected in the quark model up to ca. 2.2 GeV. We use standard nonrelativistic quark model SHO wavefunctions to evaluate these amplitudes, and quote numerical results for all amplitudes present in each decay mode. We also discuss the status of the associated experimental candidates, and note which states and decay modes would be especially interesting for future experimental study at hadronic, e+e- and photoproduction facilities. These results should also be useful in distinguishing conventional quark model mesons from exotica such as glueballs and hybrids through their strong decays.Comment: 69 pages, 5 figures, 39 table

    Muon production in extensive air showers and its relation to hadronic interactions

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    In this work, the relation between muon production in extensive air showers and features of hadronic multiparticle production at low energies is studied. Using CORSIKA, we determine typical energies and phase space regions of secondary particles which are important for muon production in extensive air showers and confront the results with existing fixed target measurements. Furthermore possibilities to measure relevant quantities of hadron production in existing and planned accelerator experiments are discussed.Comment: To appear in the proceedings of international conference on interconnection between high energy physics and astroparticle physics "From Colliders to Cosmic Rays" (C2CR 2005), Prague, Czech Republic, 7-13 September 200

    Confining QCD Strings, Casimir Scaling, and a Euclidean Approach to High-Energy Scattering

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    We compute the chromo-field distributions of static color-dipoles in the fundamental and adjoint representation of SU(Nc) in the loop-loop correlation model and find Casimir scaling in agreement with recent lattice results. Our model combines perturbative gluon exchange with the non-perturbative stochastic vacuum model which leads to confinement of the color-charges in the dipole via a string of color-fields. We compute the energy stored in the confining string and use low-energy theorems to show consistency with the static quark-antiquark potential. We generalize Meggiolaro's analytic continuation from parton-parton to gauge-invariant dipole-dipole scattering and obtain a Euclidean approach to high-energy scattering that allows us in principle to calculate S-matrix elements directly in lattice simulations of QCD. We apply this approach and compute the S-matrix element for high-energy dipole-dipole scattering with the presented Euclidean loop-loop correlation model. The result confirms the analytic continuation of the gluon field strength correlator used in all earlier applications of the stochastic vacuum model to high-energy scattering.Comment: 65 pages, 13 figures, extended and revised version to be published in Phys. Rev. D (results unchanged, 2 new figures, 1 new table, additional discussions in Sec.2.3 and Sec.5, new appendix on the non-Abelian Stokes theorem, old Appendix A -> Sec.3, several references added

    Sweet taste preference in binge-eating disorder: A preliminary investigation

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    Research suggests that individuals with high liking for sweets are at increased risk for binge eating, which has been minimally investigated in individuals with binge-eating disorder (BED). Forty-one adults (85% female, 83% white) with binge eating concerns completed a sweet taste test and measures of eating disorder behaviors and food cravings. A subset of participants with BED completed an oral glucose tolerance test (OGTT; N = 21) and a 24-hour dietary recall (N = 26). Regression models were used to compare highest sweet preferers (HSP [N = 18]) to other sweet preferers (OSP [N = 23]) and were used to assess associations between sweet taste preference and outcome variables. Effect sizes (ηp2) for differences between HSP and OSP ranged from small (≀ 0.01) to large (≄ 0.24); group differences were statistically nonsignificant except for 24-hour caloric intake (ηp2 = 0.16, p = 0.04), protein intake (ηp2 = 0.16, p = 0.04), and insulin sensitivity index (ηp2 = 0.24, p = 0.04), which were higher in HSP, and postprandial insulin, which was smaller in HSP (ηp2 = 0.27, p = 0.03). Continuous analyses replicated postprandial insulin response. Compared with OSP, HSP reported numerically higher binge-eating frequency (ηp2 = 0.04), over-eating frequency (ηp2 = 0.06), and carbohydrate intake (ηp2 = 0.14), and they exhibited numerically smaller postprandial glucose AUC (ηp2 = 0.16). Sweet taste preference may have implications for glucose regulation, binge-eating frequency, and nutrient intake in BED
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