424 research outputs found

    Extensive Renyi Statistics from Non-Extensive Entropy

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    We show that starting with either the non-extensive Tsallis entropy in Wang's formalism or the extensive Renyi entropy, it is possible to construct the equilibrium statistical mechanics with non-Gibbs canonical distribution functions. The transformation formulas between Tsallis statistics and Renyi statistics are presented. The one-particle distribution function in Renyi statistics with extensive entropy for the classical ideal gas at finite particle number develops a power-law tail for high momenta.Comment: 14 pages, 2 figures, LaTe

    Equilibrium statistical mechanics for incomplete nonextensive statistics

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    The incomplete nonextensive statistics in the canonical and microcanonical ensembles is explored in the general case and in a particular case for the ideal gas. By exact analytical results for the ideal gas it is shown that taking the thermodynamic limit, with z=q/(1q)z=q/(1-q) being an extensive variable of state, the incomplete nonextensive statistics satisfies the requirements of equilibrium thermodynamics. The thermodynamical potential of the statistical ensemble is a homogeneous function of the first degree of the extensive variables of state. In this case, the incomplete nonextensive statistics is equivalent to the usual Tsallis statistics. If zz is an intensive variable of state, i.e. the entropic index qq is a universal constant, the requirements of the equilibrium thermodynamics are violated.Comment: 7 page

    A precise determination of the Bc mass from dynamical lattice QCD

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    We perform a precise calculation of the mass of the B_c meson using unquenched configurations from the MILC collaboration including 2+1 flavours of improved staggered quarks. Lattice NRQCD and the Fermilab formalism are used to describe the b and c quarks respectively. We find the mass of the B_c meson to be 6.304(16) GeVComment: Talk presented at Lattice2004(heavy), Fermilab, June 21-26. 3 pages, 2 figure

    Helicity conservation in inclusive nonleptonic decay B to VX: Test of long-distance final state interaction

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    The polarization measurement in the inclusive B decay provides us with a simple test of how much the long-distance final-state interaction takes place as the energy of the observed meson varies in the final state. We give the expectation of the perturbative QCD for the energy dependence of the helicity fractions in a semiquantitative form. Experiment will tell us for which decay processes the perturbative calculation should be applicable.Comment: 15 pages in Revtex with 3 figures embedde

    Measurement of K^+ \to \pi^0 \mu^+ \nu \gamma decay using stopped kaons

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    The K^+ \to \pi^0 \mu^+ \nu \gamma (Kμ3γK_{\mu 3 \gamma}) decay has been measured with stopped positive kaons at the KEK 12 GeV proton synchrotron. A Kμ3γK_{\mu 3 \gamma} sample containing 125 events was obtained. The partial branching ratio Br(Kμ3γ,Eγ>30MeV,θμ+γ>20)Br(K_{\mu 3 \gamma}, E_{\gamma}>30 {\rm MeV}, \theta_{\mu^+ \gamma}>20^{\circ}) was found to be [2.4±0.5(stat)±0.6(syst)]×105[2.4 \pm 0.5(stat) \pm 0.6(syst)]\times 10^{-5}, which is in good agreement with theoretical predictions.Comment: 12 pages, 3 figures, to be published in Physics Letters

    Low-Mass Baryon-Antibaryon Enhancements in B Decays

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    The nature of low-mass baryon-antibaryon enhancements seen in B decays is explored. Three possibilities include (i) states near threshold as found in a model by Nambu and Jona-Lasinio, (ii) isoscalar states with JPC=0±+J^{PC} = 0^{\pm +} coupled to a pair of gluons, and (iii) low-mass enhancements favored by the fragmentation process. Ways of distinguishing these mechanisms using angular distributions and flavor symmetry are proposed.Comment: 8 pages, LaTeX, no figures, to be submitted to Phys. Rev. D. One reference adde

    Semileptonic D->pi/K and B->pi/D decays in 2+1 flavor lattice QCD

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    We present results for form factors of semileptonic decays of DD and BB mesons in 2+1 flavor lattice QCD using the MILC gauge configurations. With an improved staggered action for light quarks, we successfully reduce the systematic error from the chiral extrapolation. The results for DD decays are in agreement with experimental ones. The results for B decays are preliminary. Combining our results with experimental branching ratios, we then obtain the CKM matrix elements Vcd|V_{cd}|, Vcs|V_{cs}|, Vcb|V_{cb}| and Vub|V_{ub}|. We also check CKM unitarity, for the first time, using only lattice QCD as the theoretical input.Comment: Talk presented at Lattice2004(heavy); 3 pages, 3 figure

    Bη(η)K(π)B \to \eta(\eta') K(\pi) in the Standard Model with Flavor Symmetry

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    The observed branching ratios for BKηB\to K \eta' decays are much larger than factorization predictions in the Standard Model (SM). Many proposals have been made to reconcile the data and theoretical predictions. In this paper we study these decays within the SM using flavor U(3) symmetry. If small annihilation amplitudes are neglected, one needs 11 hadronic parameters to describe BPPB\to PP decays where PP can be one of the π\pi, KK, η\eta and η\eta' nonet mesons. We find that existing data are consistent with SM with flavor U(3) symmetry. We also predict several measurable branching ratios and CP asymmetries for BK(π)η(η)B \to K (\pi) \eta(\eta'), η(η)η(η)\eta(\eta')\eta(\eta') decays. Near future experiments can provide important tests for the Standard Model with flavor U(3) symmetry.Comment: 13 pages, 4 table

    SU(3) Relations and the CP Asymmetries in B Decays to ηKS\eta' K_S, ϕKS\phi K_S and K+KKSK^+ K^- K_S

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    We consider CP asymmetries in neutral BB meson decays to ηKS\eta' K_S, ϕKS\phi K_S, and K+KKSK^+ K^- K_S. We use SU(3) relations to estimate or bound the contributions to these amplitudes proportional to VubVusV_{ub}^*V_{us}. Such contributions induce a deviation of the SfS_f terms measured in these time dependent CP asymmetries from that measured for ψKS\psi K_S. For the K+KKSK^+ K^- K_S mode, we estimate the deviation to be of order 0.1. For the ηKS\eta' K_S mode, we obtain an upper bound on this deviation of order 0.3. For the ϕKS\phi K_S mode, we have to add a mild dynamical assumption to the SU(3) analysis due to insufficient available data, yielding an upper bound of order 0.25. These bounds may improve significantly with future data. While they are large at present compared to the usually assumed Standard Model contribution, they are obtained with minimal assumptions and hence provide more rigorous tests for new physics. If measurements yield SfSψK|S_f-S_{\psi K}| that are much larger than our bounds, it would make a convincing case for new physics.Comment: 24 pages; corrections in Sec. III.A and V, results hardly affected, to appear in Phys Rev

    A Possibility of large electro-weak penguin contribution in B -> K pi modes

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    We discuss about a possibility of large electro-weak penguin contribution in B -> K pi from recent experimental data. The several relations among the branching ratios which realize when the contributions from tree type and electro-weak penguin are small compared with the gluon penguin and can be treated as the expansion parameters do not satisfy the data. The difference comes from the r^2 terms which is the square of the ratio with the gluon penguin and the main contribution comes from electro-weak penguin. We find that the contribution from electro-weak penguin may be large to explain the experimental data. If the magnitude estimated from experiment is quite large compared with the theoretical estimation, then it may be including some new physics effects.Comment: 11 pages, 1 figure, Typos correcte
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