Relations Among Correlation Functions in the High Temperature Phase of QCD with Broken SU(3)

Group-theoretic arguments are used to determine the dependence of two-point correlators of quark bilinears on the current quark masses. The leading difference between $\pi$ and $\delta$ correlators is found to be of order $m_s$ times a U(1)$_{\scriptscriptstyle A}$-violating correlator. These general arguments are consistent with Schaefer's observation that if U(1)$_{\scriptscriptstyle A}$ violation persists to high enough temperatures then the strange $\eta$ can be lighter than the non-strange one.Comment: 8 page

How strange a non-strange heavy baryon?

We give some general arguments in favor of the large magnitude of matrix elements of an operator associated with nonvalence quarks in heavy hadrons. We estimate a strange matrix element for \Lambda_b baryon whose valence content is b, u, d quarks. We find a noticeable contribution of the strange quark into the heavy baryon mass on the level 200-300 MeV. The arguments are based on the QCD sum rules and low energy theorems. The physical picture behind of the phenomenon is somewhat similar to the one associated with the large strange content of the nucleon where matrix element. We discuss some possible applications of the obtained result.Comment: A final version to appear in Phys. Lett. B. New section on the violation of the Zweig's rule is adde

Parameter exclusions in Henon-like systems

This survey is a presentation of the arguments in the proof that Henon-like maps f_a(x,y)=(1-a x^2,0) + R(a,x,y) with |R(a,x,y)|< b have a "strange attractor", with positive Lebesgue probability in the parameter "a", if the perturbation size "b" is small enough. We first sketch a "geometric model" of the strange attractor in this context, emphasising some of its key geometrical properties, and then focus on the construction and estimates required to show that this geometric model does indeed occur for many parameter values. Our ambitious aim is to provide an exposition at one and the same time intuitive, synthetic, and rigorous. We think of this text as an introduction and study guide to the original papers in which the results were first proved. We shall concentrate on describing in detail the overall structure of the argument and the way it breaks down into its (numerous) constituent sub-arguments, while referring the reader to the original sources for detailed technical arguments.Comment: 40 pages, 3 figure

Identifying the Charge Carriers of the Quark-Gluon Plasma

Charge correlations in lattice gauge calculations suggest that up, down and strange charges move independently in the QGP (quark-gluon plasma), and that the density of such charges is similar to what is expected from simple thermal arguments. Here, we show how specific elements of the charge-charge correlation matrix in the QGP survive hadronization and become manifest in final-state charge-charge correlation measurements.Comment: 4 pages, 4 figure

Importance of reaction volume in hadronic collisions: Canonical enhancement

We study the canonical flavor enhancement arising from exact conservation of strangeness, and charm flavor. Both the theoretical motivation, and the practical consequences are explored. We argue using qualitative theoretical arguments and quantitative evaluation, that this proposal to reevaluate strangeness signature of quark--gluon plasma is not able to explain the majority of available experimental results.Comment: 14 pages including 6 figures, submitted to Journal of Physics G Presented at: Strange Quark Matter, September 2001, Frankfur

Structure and Production of Lambda Baryons

We discuss the quark parton structure of the $\Lambda$ baryon and the fragmentation of quarks into $\Lambda$ baryons. We show that the hyperfine interaction, responsible for the $\Delta$-$N$ and $\Sigma^0$-$\Lambda$ mass splittings, leads not only to sizeable SU(3) and SU(6) symmetry breaking in the quark distributions of the $\Lambda$, but also to significant polarized non-strange quark distributions. The same arguments suggest flavor asymmetric quark fragmentation functions and non-zero polarized non-strange quark fragmentation functions. The calculated fragmentation functions give a good description of all measured observables. We predict significant positive $\Lambda$ polarization in semi-inclusive DIS experiments while models based on SU(3) flavor symmetry predict zero or negative $\Lambda$ polarization. Our approach also provides a natural explanation for the dependence of the maximum of the $\xi=\ln(1/z)$ spectrum on the mass of the particles produced in $e^+e^-$ annihilation.Comment: 24 pages, 9 figures, minor change