Spin Alignment of Heavy Meson Revisited

Using heavy quark effective theory a factorized form for inclusive production rate of a heavy meson can be obtained, in which the nonperturbative effect related to the heavy meson can be characterized by matrix elements defined in the heavy quark effective theory. Using this factorization, predictions for the full spin density matrix of a spin-1 and spin-2 meson can be obtained and they are characterized only by one coefficient representing the nonperturbative effect. Predictions for spin-1 heavy meson are compared with experiment performed at $e^+e^-$ colliders in the energy range from $\sqrt{s}=10.5$GeV to $\sqrt{s}=91$GeV, a complete agreement is found for $D^*$- and $B^*$-meson. There are distinct differences from the existing approach and they are discussed.Comment: 6 pages, Talk given at 3rd Circum-Pan-Pacific Symposium on "High Energy Spin Physics", Beijing, China, 8-13, 200

A QCD-Analysis for Radiative Decays of Υ\Upsilon into f2(1270)f_2(1270)

We perform a QCD analysis for the radiative decay of a heavy $^3S_1$ quarkonium into the tensor meson $f_2(1270)$. We make an attempt to separate the nonperturbative effect related to the quarkonium and that related to the tensor meson, the former is represented by NRQCD matrix elements, while the later is parameterized by distribution amplitudes of gluons in the tensor meson at twist-2 level and at twist-3 level. We find that at twist-2 level the helicity $\lambda$ of the tensor meson can be 0 and 2 and the amplitude with $\lambda =2$ is suppressed. At twist-3 level the tensor meson can have $\lambda =1$. A comparison with experiment is made, an agreement of our results with experiment can be found. We also briefly discuss the radiative decay into $\eta$ and obtain a prediction for $\Upsilon\to\gamma+\eta$.Comment: Corrections of two type-errors and a numerical error in the published version in Nucl.Phys. B605 (2001) 625, conclusions remain the sam

Measuring an entropy in heavy ion collisions

We propose to use the coincidence method of Ma to measure an entropy of the system created in heavy ion collisions. Moreover we estimate, in a simple model, the values of parameters for which the thermodynamical behaviour sets in.Comment: LATTICE98(hightemp), 3 pages, LaTeX with two eps figure

Global U(1) Invariance and Mass Scales in Supersymmetry

In a supersymmetric theory with global U(1) invariance, the spontaneous breaking of the latter without the breaking of supersymmetry is revisited in the case of the most general superpotential of 3 singlet superfields. The interesting possibility of having 2 hierarchical mass scales is pointed out, together with its consequences as applied to the axionic solution of the strong CP problem.Comment: 9 pages, including 1 figur

Characteristics of WAP traffic

This paper considers the characteristics of Wireless Application Protocol (WAP) traffic. We start by constructing a WAP traffic model by analysing the behaviour of users accessing public WAP sites via a monitoring system. A wide range of different traffic scenarios were considered, but most of these scenarios resolve to one of two basic types. The paper then uses this traffic model to consider the effects of large quantities of WAP traffic on the core network. One traffic characteristic which is of particular interest in network dimensioning is the degree of self-similarity, so the paper looks at the characteristics of aggregated traffic with WAP, Web and packet speech components to estimate its self-similarity. The results indicate that, while WAP traffic alone does not exhibit a significant degree of self-similarity, a combined load from various traffic sources retains almost the same degree of self-similarity as the most self-similar individual source

Ignore These At Your Peril: Ten principles for trust design

Online trust has been discussed for more than 10 years, yet little practical guidance has emerged that has proven to be applicable across contexts or useful in the long run. 'Trustworthy UI design guidelines' created in the late 90ies to address the then big question of online trust: how to get shoppers online, are now happily employed by people preparing phishing scams. In this paper we summarize, in practical terms, a conceptual framework for online trust we've established in 2005. Because of its abstract nature it is still useful as a lens through which to view the current big questions of the online trust debate - large focused on usable security and phishing attacks. We then deduct practical 10 rules for providing effective trust support to help practitioners and researchers of usable security

High--Resolution 3D Simulations of Relativistic Jets

We have performed high-resolution 3D simulations of relativistic jets with beam flow Lorentz factors up to 7, a spatial resolution of 8 cells per beam radius, and for up to 75 normalized time units to study the morphology and dynamics of 3D relativistic jets. Our simulations show that the coherent fast backflows found in axisymmetric models are not present in 3D models. We further find that when the jet is exposed to non-axisymmetric perturbations, (i) it does not display the strong perturbations found for 3D classical hydrodynamic and MHD jets (at least during the period of time covered by our simulations), and (ii) it does propagate according to the 1D estimate. Small 3D effects in the relativistic beam give rise to a lumpy distribution of apparent speeds like that observed in M87. The beam is surrounded by a boundary layer of high specific internal energy. The properties of this layer are briefly discussed.Comment: 15 pages, 4 figures. Accepted to be publish in the ApJ Letters. Tar+gzip documen