7,539 research outputs found

    Recent Results on Strangeness Production from CERN Experiment NA49

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    New results from NA49 on the production of strangeness in elementary and nuclear reactions are presented. New measurements of charged kaon and pion production have been obtained from 40 AGeV Pb+Pb collisions. The evolution of strange meson yields in nucleus-nucleus interactions is studied as a function of collision energy and system size. Cascade baryon yields are presented for a wide range of hadronic interactions including first measurements in p+p and centrality controlled p+Pb collisions.Comment: 4 pages, 4 figures, to be published in the Proceedings of XXXVIth Rencontre de Moriond, QCD and High Energy Hadronic Interactions, March 200

    Baryon Number Transfer in Hadron+Nucleus and Nucleus+Nucleus Collisions: A Link between Elementary and Complex Interactions

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    The baryon number transfer is studied in elementary and complex hadronic interactions at the CERN experiment NA49 at the SPS, at 158 AGeV beam energy (\sqrt{s}=17.2 GeV). A two component picture is proposed, which builds up the net proton distribution from a target and a projectile component. Using pion beam, the projectile component is experimentally determined for p+p and p+A interactions. A similar stopping behaviour of the projectile component is found for p+A and A+A interactions. Based on these observations, the baryon transfer is assumed to provide a common scale of inelasticity in p+p, p+A and A+A interactions. A model-independent way is proposed to predict the pion multiplicity in A+A.Comment: 10 pages, 12 figures. To appear in the proceedings of International Workshop on Quark and Hadron Dynamics in Relativistic Heavy Ion Collisions (BP 2002), Budapest, Hungary, 3-7 Mar 200

    Creating temperature dependent Ni-MH battery models for low power mobile devices

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    In this paper the methodology and the results of creating temperature dependent battery models for ambient intelligence applications is presented. First the measurement technology and the model generation process is presented in details, and then the characteristic features of the models are discussed.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

    On Renyi entropies characterizing the shape and the extension of the phase space representation of quantum wave functions in disordered systems

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    We discuss some properties of the generalized entropies, called Renyi entropies and their application to the case of continuous distributions. In particular it is shown that these measures of complexity can be divergent, however, their differences are free from these divergences thus enabling them to be good candidates for the description of the extension and the shape of continuous distributions. We apply this formalism to the projection of wave functions onto the coherent state basis, i.e. to the Husimi representation. We also show how the localization properties of the Husimi distribution on average can be reconstructed from its marginal distributions that are calculated in position and momentum space in the case when the phase space has no structure, i.e. no classical limit can be defined. Numerical simulations on a one dimensional disordered system corroborate our expectations.Comment: 8 pages with 2 embedded eps figures, RevTex4, AmsMath included, submitted to PR

    Comments concerning the paper "Measurement of negatively charged pion spectra in inelastic p+p interactions at 20, 31, 40, 80 and 158 GeV/c" by the NA61 collaboration

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    New data from the NA61 collaboration on the production of negative pions in p+p interactions at beam momenta between 20 and 158 GeV/c are critically compared to available results in the same energy range. It is concluded that the NA61 data show some discrepancies with the previous results. This concerns in particular the total yields, the pTp_T integrated rapidity distributions and the double differential cross sections.Comment: 16 pages, 13 figure

    Information Length and Localization in One Dimension

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    The scaling properties of the wave functions in finite samples of the one dimensional Anderson model are analyzed. The states have been characterized using a new form of the information or entropic length, and compared with analytical results obtained by assuming an exponential envelope function. A perfect agreement is obtained already for systems of 10310^3--10410^4 sites over a very wide range of disorder parameter 10−4<W<10410^{-4}<W<10^4. Implications for higher dimensions are also presented.Comment: 11 pages (+3 Figures upon request), Plain TE

    Occupation probability of harmonic-oscillator quanta for microscopic cluster-model wave functions

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    We present a new and simple method of calculating the occupation probability of the number of total harmonic-oscillator quanta for a microscopic cluster-model wave function. Examples of applications are given to the recent calculations including α+n+n\alpha+n+n-model for 6^6He, α+t+n+n\alpha+t+n+n-model for 9^9Li, and α+α+n\alpha+\alpha+n-model for 9^9Be as well as the classical calculations of α+p+n\alpha+p+n-model for 6^6Li and α+α+α\alpha+\alpha+\alpha-model for 12^{12}C. The analysis is found to be useful for quantifying the amount of excitations across the major shell as well as the degree of clustering. The origin of the antistretching effect is discussed.Comment: 9 page

    Positron scattering and annihilation from the hydrogen molecule at zero energy

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    The confined variational method is used to generate a basis of correlated gaussians to describe the interaction region wave function for positron scattering from the H2_2 molecule. The scattering length was ≈−2.7\approx -2.7 a0a_0 while the zero energy ZeffZ_{\rm eff} of 15.7 is compatible with experimental values. The variation of the scattering length and ZeffZ_{\rm eff} with inter-nuclear distance was surprisingly rapid due to virtual state formation at R≈3.4R \approx 3.4 a0a_0

    Nematic order of model goethite nanorods in a magnetic field

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    We explore the nematic order of model goethite nanorods in an external magnetic field within Onsager-Parsons density functional theory. The goethite rods are represented by monodisperse, charged spherocylinders with a permanent magnetic moment along the rod main axis, forcing the particles to align parallel to the magnetic field at low field strength. The intrinsic diamagnetic susceptibility anisometry of the rods is negative which leads to a preferred perpendicular orientation at higher field strength. It is shown that these counteracting effects may give rise to intricate phase behavior, including a pronounced stability of biaxial nematic order and the presence of reentrant phase transitions and demixing phenomena. The effect of the applied field on the nematic-to-smectic transition will also be addressed.Comment: 12 pages, 5 figures, submitted to Phys. Rev.

    Shell model on a random gaussian basis

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    Pauli-projected random gaussians are used as a representation to solve the shell model equations. The elements of the representation are chosen by a variational procedure. This scheme is particularly suited to describe cluster formation and cluster decay in nuclei. It overcomes the basis-size problem of the ordinary shell model and the technical difficulties of the cluster-configuration shell model. The model reproduces the α\alpha-decay width of 212^{212}Po satisfactorily.Comment: Latex, Submitted to Phys. Lett. B, 7 pages, 2 figures available upon request, ATOMKI-1994-
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