253 research outputs found

    Heavy Hadrons and QCD Instantons

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    Heavy hadrons are analyzed in a random and dilute gas of instantons. We derive the instanton-induced interactions between heavy and light quarks at next to leading order in the heavy quark mass and in the planar approximation, and discuss their effects on the hadronic spectrum. The role of these interactions in the formation of exotic hadrons is also discussed.Comment: 26 pages, REVTeX, 2 tables, 5 figures, uses FEYNMAN.st

    Anomalous Chiral Fermi Surface

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    We provide a geometrical argument for the emergence of a Wess-Zumino-Witten (WZW) term for a Fermi surface threaded by a Berry curvature. In the presence of external fields, the gauged WZW term yields a chiral (triangle) anomaly for the fermionic current at the edge of the Fermi surface. Fermion number is conserved though since the Berry curvatures occur always in pairs with opposite (monopole) charge. The anomalous vector and axial currents for a a fermionic fluid at low temperature threaded by pairs of Berry curvatures are discussed. The leading temperature correction to the chiral vortical effect in a slowly rotating Fermi surface threaded by a Berry curvature maybe tied to the gravitational anomaly.Comment: 4 pages; version to appear in PR

    Strongly Coupled Quark Gluon Plasma (SCQGP)

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    We propose that the reason for the non-ideal behavior seen in lattice simulation of quark gluon plasma (QGP) and relativistic heavy ion collisions (URHICs) experiments is that the QGP near T_c and above is strongly coupled plasma (SCP), i.e., strongly coupled quark gluon plasma (SCQGP). It is remarkable that the widely used equation of state (EoS) of SCP in QED (quantum electrodynamics) very nicely fits lattice results on all QGP systems, with proper modifications to include color degrees of freedom and running coupling constant. Results on pressure in pure gauge, 2-flavors and 3-flavors QGP, are all can be explained by treating QGP as SCQGP as demonstated here.Energy density and speed of sound are also presented for all three systems. We further extend the model to systems with finite quark mass and a reasonably good fit to lattice results are obtained for (2+1)-flavors and 4-flavors QGP. Hence it is the first unified model, namely SCQGP, to explain the non-ideal QGP seen in lattice simulations with just two system dependent parameters.Comment: Revised with corrections and new results, Latex file (11 pages), postscript file of 7 figure

    Gluonic Correlations in Matter

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    We derive the analogue of the QCD low energy theorems for the scalar and pseudoscalar gluonic correlators in nuclear matter. We find that the scalar correlations are depleted while the pseudoscalar correlations are enhanced to leading order in the nuclear matter density. We briefly discuss the consequences of these findings on the QCD spectrum.Comment: 9 pages, LaTe

    Level Crossing Analysis of Growing surfaces

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    We investigate the average frequency of positive slope να+\nu_{\alpha}^{+} , crossing the height α=hhˉ\alpha = h- \bar h in the surface growing processes. The exact level crossing analysis of the random deposition model and the Kardar-Parisi-Zhang equation in the strong coupling limit before creation of singularities are given.Comment: 5 pages, two column, latex, three figure

    Confined two-dimensional fermions at finite density

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    We introduce the chemical potential in a system of two-dimensional massless fermions, confined to a finite region, by imposing twisted boundary conditions in the Euclidean time direction. We explore in this simple model the application of functional techniques which could be used in more complicated situations.Comment: 15 pages, LaTe

    Real Time Correlators in Hot (2+1)d QCD

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    We use dimensional reduction techniques to relate real time finite T correlation functions in (2+1) dimensional QCD to bound state parameters in a generalized 't Hooft model with an infinite number of heavy quark and adjoint scalar fields. While static susceptibilities and correlation functions of the DeTar type can be calculated using only the light (static) gluonic modes, the dynamical correlators require the inclusion of the heavy modes. In particular we demonstrate that the leading T perturbative result can be understood in terms of the bound states of the 2d model and that consistency requires bound state trajectories composed of both quarks and adjoint scalars. We also propose a non-perturbative expression for the dynamical DeTar correlators at small spatial momenta.Comment: 21 pages, Latex, uses axodra

    Presenting a Model Regarding the Effect of Ethical Sensitivity and Its Associated Components on the Quality of Research among Academic Personnel

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    Background and Objective: Ethical sensitivity is one of the criteria regarding the professional competence of researchers, which affects the ethical performance of the researcher. Since compliance with the principles and rules of ethics is an effective factor in providing high quality research results, the present study was conducted to investigate the ethical sensitivity and its associated components on the quality of research among academic personnel of universities of medical sciences in metropolitan area No. 1 in Iran. Methods: This cross-sectional study was conducted on 320 academic personnel of universities of medical sciences in metropolitan area No. 1 (Guilan, Mazandaran, Golestan, Babol, Shahrud, and Semnan) who were selected by stratified random sampling. Data were collected using ethical sensitivity and research quality questionnaires. The ethical sensitivity questionnaire includes 50 questions and two dimensions of "functional and individual", each of which includes 4 fields. The researcher-made questionnaire of research quality includes 31 questions and 4 fields. The questionnaires were rated from 1 to 5 according to Likert scale. Ethical sensitivity was compared between researchers based on work experience, academic degree and gender. Then, the effect of each component of ethical sensitivity on the quality of the research was evaluated. Findings: Out of 320 studied samples, 223 were male (69.7%) and 97 were female (30.3%). In people with experience of less than 10 years, the mean score of honesty was 15.74±3.21, ethical behavior was 30.50±5.74, accountability was 33.81±5.64, decision-making was 23.62±4.28, and interpersonal communication was 18.66±3.56, indicating higher values compared to people with an experience of more than 10 years (p<0.01). Among the dimensions of ethical sensitivity, the dimensions of honesty and discipline showed positive and significant effects on the quality of research. However, the effect of respect for the client, ethical behavior, professional knowledge, accountability, decision-making and interpersonal communication was not statistically significant despite the effect on the quality of the research. Discipline had the greatest effect on research quality (β=0.293). The R2 value (0.489) shows that about 49% of the variance of the research quality score is explained by the dimensions of ethical sensitivity. Ethical sensitivity with a standard coefficient of 7.758 had an effect on the quality of research. Conclusion: The results of the present study showed that ethical sensitivity, especially the dimensions of honesty and discipline, has an effect on the quality of research

    Topology of the gauge-invariant gauge field in two-color QCD

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    We investigate solutions to a nonlinear integral equation which has a central role in implementing the non-Abelian Gauss's Law and in constructing gauge-invariant quark and gluon fields. Here we concern ourselves with solutions to this same equation that are not operator-valued, but are functions of spatial variables and carry spatial and SU(2) indices. We obtain an expression for the gauge-invariant gauge field in two-color QCD, define an index that we will refer to as the ``winding number'' that characterizes it, and show that this winding number is invariant to a small gauge transformation of the gauge field on which our construction of the gauge-invariant gauge field is based. We discuss the role of this gauge field in determining the winding number of the gauge-invariant gauge field. We also show that when the winding number of the gauge field is an integer 0\ell{\neq}0, the gauge-invariant gauge field manifests winding numbers that are not integers, and are half-integers only when =0\ell=0.Comment: 26 pages including 6 encapsulated postscript figures. Numerical errors have been correcte
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