Periodic Orbits and Spectral Statistics of Pseudointegrable Billiards

We demonstrate for a generic pseudointegrable billiard that the number of periodic orbit families with length less than $l$ increases as $\pi b_0l^2/\langle a(l) \rangle$, where $b_0$ is a constant and $\langle a(l) \rangle$ is the average area occupied by these families. We also find that $\langle a(l) \rangle$ increases with $l$ before saturating. Finally, we show that periodic orbits provide a good estimate of spectral correlations in the corresponding quantum spectrum and thus conclude that diffraction effects are not as significant in such studies.Comment: 13 pages in RevTex including 5 figure

The Supersymmetric Standard Models with Decay and Stable Dark Matters

We propose two supersymmetric Standard Models (SMs) with decaying and stable dark matter (DM) particles. To explain the SM fermion masses and mixings and have a heavy decay DM particle S, we consider the Froggatt-Nielsen mechanism by introducing an anomalous U(1)_X gauge symmetry. Around the string scale, the U(1)_X gauge symmetry is broken down to a Z_2 symmetry under which S is odd while all the SM particles are even. S obtains a vacuum expectation value around the TeV scale, and then it can three-body decay dominantly to the second/third family of the SM leptons in Model I and to the first family of the SM leptons in Model II. Choosing a benchmark point in the constrained minimal supersymmetric SM with exact R parity, we show that the lightest neutralino DM is consistent with the CDMS II experiment. Considering S three-body decay and choosing suitable parameters, we show that the PAMELA and Fermi-LAT experiments and the PAMELA and ATIC experiments can be explained in Model I and Model II, respectively.Comment: RevTex4, 26 pages, 6 figures, references added, version to appear in EPJ

Measurement of K^+K^- production in two-photon collisions in the resonant-mass region

K^+K^- production in two-photon collisions has been studied using a large data sample of 67 fb^{-1} accumulated with the Belle detector at the KEKB asymmetric e^+e^- collider. We have measured the cross section for the process gamma gamma -> K^+ K^- for center-of-mass energies between 1.4 and 2.4 GeV, and found three new resonant structures in the energy region between 1.6 and 2.4 GeV. The angular differential cross sections have also been measured.Comment: 24 pages, 8 figures, to appear in Euro. Phys. Jour.

Observation of the ϕ(1680)\phi(1680) and the Y(2175) in e+e−→ϕπ+π−e^+ e^- \to \phi\pi^+\pi^-

The cross sections for $e^+ e^- \to \phi\pi^+\pi^-$ and e^+ e^- \to \phi \fzero are measured from threshold to $\sqrt{s}=3.0$ $\hbox{GeV}$ using initial state radiation. The analysis is based on a data sample of 673 fb$^{-1}$ collected on and below the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. First measurements are reported for the resonance parameters of the $\phi(1680)$ in the $\phi\pi^+\pi^-$ mode: $m=(1689\pm 7\pm 10)$ MeV/$c^2$ and $\Gamma=(211\pm 14\pm 19)$ MeV/$c^2$. A structure at $\sqrt{s}=2.1 \hbox{GeV}/c^2$, corresponding to the so called Y(2175), is observed; its mass and width are determined to be $2079\pm13^{+79}_{-28}$ MeV/$c^2$ and $192\pm23^{+25}_{-61} \hbox{MeV}/c^2$, respectively.Comment: 11 pages, 6 figures. Add one plot. Accepted by Phys.Rev.D(RC

Search for the Electric Dipole Moment of the tau Lepton

We have searched for a CP violation signature arising from an electric dipole moment (d_tau) of the tau lepton in the e+e- -> tau+tau- reaction. Using an optimal observable method and 29.5 fb^{-1} of data collected with the Belle detector at the KEKB collider at sqrt{s} = 10.58 GeV, we find Re(d_tau) = (1.15 +- 1.70) x 10^{-17} ecm and Im(d_tau) = (-0.83 +- 0.86) x 10^{-17} ecm and set the 95% confidence level limits -2.2 < Re(d_tau) < 4.5 (10^{-17}ecm) and -2.5 < Im(d_tau) < 0.8 (10^{-17}ecm).Comment: 15 pages, LaTeX, 21 figures, submitted to Phys. Lett.

Search for tau -> e gamma decay at Belle

We have searched for the lepton-flavor-violating decay tau -> e gamma using a data sample of 86.7/fb collected with the Belle detector at the KEKB asymmetric e^+ e^- collider. No evidence for a signal is obtained, and we set an upper limit for the branching fraction Br(tau -> e gamma) < 3.9 x 10^-7 at the 90% C.L.Comment: 11 pages, 10 figures, ReVTeX4, eps

Measurement of the gamma gamma -> pi+ pi- and gamma gamma -> K+ K- processes at energies of 2.4 - 4.1 GeV

We have measured pi+pi- and K+K- production in two-photon collisions using 87.7 /fb of data collected with the Belle detector at the asymmetric energy e+e- collider KEKB. The cross sections are measured to high precision in the two-photon center-of-mass energy (W) range between 2.4 GeV < W < 4.1 GeV and angular region |cos theta^{*}| < 0.6. The cross section ratio sigma(gammagamma->K+K-)/sigma(gammagamma->pi+pi-) is measured to be 0.89 +- 0.04(stat) +- 0.15(syst) in the range of 3.0 GeV < W < 4.1 GeV, where the ratio is energy independent. We observe a sin^{-4} theta^{*} behavior of the cross section in the same W range. Production of chi_{c0} and chi_{c2} mesons is observed in both gammagamma -> pi+pi- and gammagamma -> K+K- modes.Comment: 17 pages, 5 figures, submitted to Phys. Lett. B, errors relative to the two-photon decay width correcte

General Ad Hoc Encryption from Exponent Inversion IBE

Abstract. Among the three broad classes of Identity-Based Encryption schemes built from pairings, the exponent inversion paradigm tends to be the most efficient, but also the least extensible: currently there are no hierarchical or other known extension of IBE based on those schemes. In this work, we show that such extensions can be realized from IBE systems that conform to a certain abstraction of the exponent inversion paradigm. Our method requires no random oracles, and is simple and efficient.

Spectra of prompt electrons from decays of B+ and B0 mesons and ratio of inclusive semielectronic branching fractions

We present spectra of prompt electrons from decays of neutral and charged B mesons. The results are based on 140 /fb of data collected by the Belle detector on the Upsilon(4S) resonance at the KEKB e+e- asymmetric collider. We tag Upsilon(4S) -> B \bar{B} events by reconstructing a B meson in one of several hadronic decay modes; the semileptonic decay of the other B meson is inferred from the presence of an identified electron. We obtain for charged and neutral B mesons the partial rates of semileptonic decay, to electrons with momentum greater than 0.6 GeV/c in the B rest frame, and their ratio b_+/b_0 = 1.08 +- 0.05 +- 0.02, where the first and second errors are statistical and systematic, respectively.Comment: 16 pages, 2 figure files, submitted to Phys. Lett.