21,458 research outputs found

    Heavy Ion Physics at LHC

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    The study of heavy ion interactions constitutes an important part of the experimental program outlined for the Large Hadron Collider under construction at CERN and expected to be operational by 2006. ALICE is the single detector having the capabilities to explore at the same time most of the characteristics of high energy heavy ion interactions. Specific studies of jet quenching and quarkonia production, essentially related to μ\mu detection are also planned by CMS.Comment: 5 pages, 1 figure (in eps) talk given at XXXI International Symposium on Multiparticle Dynamics, Sep. 1-7, 2001, Datong China URL http://ismd31.ccnu.edu.cn

    Should We Be Concerned about the Distribution of Literacy across Households? An Axiomatic Investigation

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    This paper proposes a class of literacymeasures that takes into account the externality generated by the presence of literates in the household. It is claimed that such externality is increasing in the number of literates in the household, has characteristics of rivalry in consumption, and therefore is a function of the distribution of literates and illiterates in the household. The measure is given a full axiomatic characterization, and it is shown that its use may reverse the ranking of geographical areas obtained by using other literacy measures.

    Ab-initio Phonon Calculations for the layered compound TiOCl

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    We present first-principles frozen-phonon calculations for the three Raman-active AgA_g modes in the spin-1/2 layered TiOCl system within two different well-known approaches: the local density approximation (LDA) and the so-called LDA+U approximation. We observe that the inclusion of electron correlation in a mean-field level as implemented in the LDA+U leads to a better overall agreement with experimental results. We also discuss the implications of the two approaches on the physics of TiOCl.Comment: Phys. Rev. B (Rapid Comm.) (in Press

    Magnon splitting induced by charge ordering in NaV_2O_5

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    We consider the effects of charge ordering in NaV_2O_5 (below T_SP) on the exchange constants and on the magnon dispersion. We show that the experimentally observed splitting of the magnon branches along the a direction is induced by charge ordering. We find that one can distinguish between the proposed 'zig-zag' and 'in-line' patterns of charge ordering. Only the zig-zag ordering is consistent with the experimental results regarding (i) the unusual intensity modulation observed in magnetic neutron scattering, (ii) the reduction in the intra-ladder exchange constant below T_SP, and (iii) the magnon dispersion along a. We estimate the inter-ladder exchange constant to be 1.01meV=11.7K for T>T_SP.Comment: final version for PR

    An Accurate and Efficient Analysis of a MBSFN Network

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    A new accurate analysis is presented for an OFDM-based multicast-broadcast single-frequency network (MBSFN). The topology of the network is modeled by a constrained random spatial model involving a fixed number of base stations placed over a finite area with a minimum separation. The analysis is driven by a new closed-form expression for the conditional outage probability at each location of the network, where the conditioning is with respect to the network realization. The analysis accounts for the diversity combining of signals transmitted by different base stations of a given MBSFN area, and also accounts for the interference caused by the base stations of other MBSFN areas. The analysis features a flexible channel model, accounting for path loss, Nakagami fading, and correlated shadowing. The analysis is used to investigate the influence of the minimum base-station separation and provides insight regarding the optimal size of the MBSFN areas. In order to highlight the percentage of the network that will fail to successfully receive the broadcast, the area below an outage threshold (ABOT) is here used and defined as the fraction of the network that provides an outage probability (averaged over the fading) that meets a threshold.Comment: 5 pages, 4 figures, IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2014, to appea

    Comparative study between two quantum spin systems KCuCl3_{3} and TlCuCl3_{3}

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    We have performed an {\it ab initio} study of the electronic structure of two isostructural quantum spin systems, KCuCl3_{3} and TlCuCl3_{3}, which have recently attracted much attention due to their unconventional magnetic properties. Our first-principles analysis shows unambiguously the role of Tl, as opposed to structural differences between the two compounds, in making TlCuCl3_{3} a {\it strongly} coupled s=1/2 dimer system compared to KCuCl3_{3} which shows a {\it weakly} coupled s=1/2 dimer behavior. Good agreement with the existing analysis of inelastic neutron scattering results has been observed.Comment: minor changes in text with additional references; in EPL forma