424 research outputs found
Extensive Renyi Statistics from Non-Extensive Entropy
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
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 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 is an intensive variable of
state, i.e. the entropic index 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
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
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
The K^+ \to \pi^0 \mu^+ \nu \gamma () decay has been
measured with stopped positive kaons at the KEK 12 GeV proton synchrotron. A
sample containing 125 events was obtained. The partial
branching ratio was found to be , 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
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 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
We present results for form factors of semileptonic decays of and
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 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 , , and . 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
in the Standard Model with Flavor Symmetry
The observed branching ratios for 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 decays where can be one of the , , and 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 , 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 , and
We consider CP asymmetries in neutral meson decays to , , and . We use SU(3) relations to estimate or bound the
contributions to these amplitudes proportional to . Such
contributions induce a deviation of the terms measured in these time
dependent CP asymmetries from that measured for . For the mode, we estimate the deviation to be of order 0.1. For the
mode, we obtain an upper bound on this deviation of order 0.3. For the 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 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
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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