19,972 research outputs found

    The maximization of Tsallis entropy with complete deformed functions and the problem of constraints

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    We first observe that the (co)domains of the q-deformed functions are some subsets of the (co)domains of their ordinary counterparts, thereby deeming the deformed functions to be incomplete. In order to obtain a complete definition of qq-generalized functions, we calculate the dual mapping function, which is found equal to the otherwise \textit{ad hoc} duality relation between the ordinary and escort stationary distributions. Motivated by this fact, we show that the maximization of the Tsallis entropy with the complete qq-logarithm and qq-exponential implies the use of the ordinary probability distributions instead of escort distributions. Moreover, we demonstrate that even the escort stationary distributions can be obtained through the use of the ordinary averaging procedure if the argument of the qq-exponential lies in (-∞\infty, 0].Comment: 7 page

    Rapidity Gaps from Colour String Topologies

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    Diffractive deep inelastic scattering at HERA and diffractive W and jet production at the Tevatron are well described by soft colour exchange models. Their essence is the variation of colour string-field topologies giving both gap and no-gap events, with a smooth transition and thereby a unified description of all final states.Comment: 3 pages, 6 eps figures, contribution to the DIS 99 workshop proceedings, uses npb.st

    The Rare Top Decays t→bW+Zt \to b W^+ Z and t→cW+W−t \to c W^+ W^-

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    The large value of the top quark mass implies that the rare top decays t→bW+Z,sW+Zt \rightarrow b W^+ Z, s W^+ Z and dW+Zd W^+ Z, and t→cW+W−t \rightarrow c W^+ W^- and uW+W−u W^+ W^-, are kinematically allowed decays so long as mt≥mW+mZ+mdi≈171.5GeV+mdim_t \ge m_W + m_Z + m_{d_i} \approx 171.5 GeV + m_{d_i} or mt≥2mW+mu,c≈160.6GeV+mu,cm_t \ge 2m_W + m_{u,c} \approx 160.6 GeV + m_{u,c}, respectively. The partial decay widths for these decay modes are calculated in the standard model. The partial widths depend sensitively on the precise value of the top quark mass. The branching ratio for t→bW+Zt\rightarrow b W^+ Z is as much as 2×10−52 \times 10^{-5} for mt=200GeVm_t = 200 GeV, and could be observable at LHC. The rare decay modes t→cW+W−t \rightarrow c W^+ W^- and uW+W−u W^+ W^- are highly GIM-suppressed, and thus provide a means for testing the GIM mechanism for three generations of quarks in the u, c, t sector.Comment: 19 pages, latex, t->bWZ corrected, previous literature on t->bWZ cited, t->cWW unchange

    Stabilities of generalized entropies

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    The generalized entropic measure, which is optimized by a given arbitrary distribution under the constraints on normalization of the distribution and the finite ordinary expectation value of a physical random quantity, is considered and its Lesche stability property (that is different from thermodynamic stability) is examined. A general condition, under which the generalized entropy becomes stable, is derived. Examples known in the literature, including the entropy for the stretched-exponential distribution, the quantum-group entropy, and the kappa-entropy are discussed.Comment: 16 pages, no figure

    Negative s and Light New Physics

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    Motivated by the difference between SLD's recent measurement of ALR and the corresponding LEP results, we explore which kinds of new particles can (1) contribute dominantly to new physics through oblique corrections, (2) produce negative values for S and T, and (3) not be in conflict with any other experiments, on or off the Z resonance. We are typically led to models which involve new particles which are not much heavier than MZ/2, and so which may also have implications for other experiments in the near future. For such light particles, we show how the oblique-parameter analysis of purely Z-pole data requires the interpretation of the data in terms of modified parameters, S' and T', whose difference from S and T improves the available parameter space of the models.Comment: plain TeX, 16 pages, 6 figures attached as a uuencoded file, McGill-94/27, NEIP-94-00

    Evaluation representations of quantum affine algebras at roots of unity

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    The purpose of this paper is to compute the Drinfel'd polynomials for two types of evaluation representations of quantum affine algebras at roots of unity and construct those representations as the submodules of evaluation Schnizer modules. Moreover, we obtain the necessary and sufficient condition for that the two types of evaluation representations are isomorphic to each other

    The Internal Control System of Russian Corporations

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    corporate form, organizational behavior, institutional complementarity, stock ownership, corporate governance, separation of ownership and management, ownership structure, corporate performance, managerial turnover, Russia
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