1,690 research outputs found
Local thermalization in d + Au collisions
The extent of a locally equilibrated parton plasma in d + Au collisions at
sqrt(s_NN) = 200 GeV is investigated as a function of centrality in a
nonequilibrium-statistical framework. Based on a three-sources model,
analytical solutions of a relativistic diffusion equation are in precise
agreement with recent data for charged-particle pseudorapidity distributions.
The moving midrapidity source indicates the size of the local thermal
equilibrium region after hadronization. In central d + Au collisions it
contains 19% of the produced particles.Comment: 4 pages, 1 figure, Proc. QM2005 Budapes
Closed strings in Ramond-Ramond backgrounds
We write the IIB Green-Schwarz action in certain general classes of curved
backgrounds threaded with Ramond-Ramond fluxes. The fixing of the kappa
symmetry in the light-cone gauge and the use of supergravity Bianchi identities
simplify the task. We find an expression that truncates to quartic order in the
spacetime spinors and relays interesting information about the vacuum structure
of the worldsheet theory. The results are particularly useful in exploring
integrable string dynamics in the context of the holographic duality.Comment: 24 pages; this is a significant revision to hep-th/0112063 with new
results added, and including comparison with recent literature; v2: minor
typos corrected, citations adde
Non-critical Heterotic Superstrings in Various Dimensions
We construct heterotic string theories on spacetimes of the form R^{d-1,1}
times N=2 linear dilaton, where d=6,4,2,0. There are two lines of
supersymmetric theories descending from the two supersymmetric ten-dimensional
heterotic theories. These have gauge groups which are lower rank subgroups of
E_{8} times E_{8} and SO(32). On turning on a (2,2) deformation which makes the
two dimensional part a smooth SL_{2}(R)/U(1) supercoset, the gauge groups get
broken further. In the deformed theories, there are non-trivial moduli which
are charged under the surviving gauge group in the case of d=6. We construct
the marginal operators on the worldsheet corresponding to these moduli.Comment: 27 pages, harvmac. v2 reference adde
How network-based and set-based visualizations aid consistency checking in ontologies
© 2017 ACM. Ontologies describe complex world knowledge in that they consist of hierarchical relations, such as is-a, which can be expressed by quantifiers or sets, and various binary relations, which can be expressed by links or networks. Should hierarchical relations be distinguished from other binary relations as essentially different ones in building cognitively accessible systems of ontologies? In this study, two kinds of ontology visualizations, a network-based visualization (SOVA) and a set-based visualization (concept diagrams), are empirically compared in the case of consistency checking. Participants were presented with one diagram and then asked to answer the question of whether the meaning of the diagram was contradictory. Our results showed that SOVA is more effective than concept diagrams, suggesting that to represent hierarchical and binary relations of ontologies in a way based on networks suits human cognition when checking ontologies' consistencies
- …