46 research outputs found

    Reconstructing the Equation of State for Dark Energy In the Double Complex Symmetric Gravitational Theory

    Full text link
    We propose to study the accelerating expansion of the universe in the double complex symmetric gravitational theory (DCSGT). The universe we live in is taken as the real part of the whole spacetime MC4(J){\cal M}^4_C(J) which is double complex. By introducing the spatially flat FRW metric, not only the double Friedmann Equations but also the two constraint conditions pJ=0p_J=0 and J2=1J^2=1 are obtained. Furthermore, using parametric DL(z)D_L(z) ansatz, we reconstruct the ω(z)\omega^{'}(z) and V(ϕ)V(\phi) for dark energy from real observational data. We find that in the two cases of J=i,pJ=0J=i,p_J=0 and J=ϵ,pJ0J=\epsilon,p_J\neq 0, the corresponding equations of state ω(z)\omega^{'}(z) remain close to -1 at present (z=0z=0) and change from below -1 to above -1. The results illustrate that the whole spacetime, i.e. the double complex spacetime MC4(J){\cal M}^4_C(J), may be either ordinary complex (J=i,pJ=0J=i,p_J=0) or hyperbolic complex (J=ϵ,pJ0J=\epsilon,p_J\neq 0). And the fate of the universe would be Big Rip in the future.Comment: 5 pages, 5 figures, accepted by Commun. Theor. Phy

    Competing orders in a magnetic field: spin and charge order in the cuprate superconductors

    Full text link
    We describe two-dimensional quantum spin fluctuations in a superconducting Abrikosov flux lattice induced by a magnetic field applied to a doped Mott insulator. Complete numerical solutions of a self-consistent large N theory provide detailed information on the phase diagram and on the spatial structure of the dynamic spin spectrum. Our results apply to phases with and without long-range spin density wave order and to the magnetic quantum critical point separating these phases. We discuss the relationship of our results to a number of recent neutron scattering measurements on the cuprate superconductors in the presence of an applied field. We compute the pinning of static charge order by the vortex cores in the `spin gap' phase where the spin order remains dynamically fluctuating, and argue that these results apply to recent scanning tunnelling microscopy (STM) measurements. We show that with a single typical set of values for the coupling constants, our model describes the field dependence of the elastic neutron scattering intensities, the absence of satellite Bragg peaks associated with the vortex lattice in existing neutron scattering observations, and the spatial extent of charge order in STM observations. We mention implications of our theory for NMR experiments. We also present a theoretical discussion of more exotic states that can be built out of the spin and charge order parameters, including spin nematics and phases with `exciton fractionalization'.Comment: 36 pages, 33 figures; for a popular introduction, see http://onsager.physics.yale.edu/superflow.html; (v2) Added reference to new work of Chen and Ting; (v3) reorganized presentation for improved clarity, and added new appendix on microscopic origin; (v4) final published version with minor change

    A Measurement of Psi(2S) Resonance Parameters

    Full text link
    Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been measured in the vicinity of the Psi(2S) resonance using the BESII detector operated at the BEPC. The Psi(2S) total width; partial widths to hadrons, pi+pi- J/Psi, muons; and corresponding branching fractions have been determined to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)= (2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)= (97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%, respectively.Comment: 8 pages, 6 figure

    Measurements of the Mass and Full-Width of the ηc\eta_c Meson

    Get PDF
    In a sample of 58 million J/ψJ/\psi events collected with the BES II detector, the process J/ψγηc\psi\to\gamma\eta_c is observed in five different decay channels: γK+Kπ+π\gamma K^+K^-\pi^+\pi^-, γπ+ππ+π\gamma\pi^+\pi^-\pi^+\pi^-, γK±KS0π\gamma K^\pm K^0_S \pi^\mp (with KS0π+πK^0_S\to\pi^+\pi^-), γϕϕ\gamma \phi\phi (with ϕK+K\phi\to K^+K^-) and γppˉ\gamma p\bar{p}. From a combined fit of all five channels, we determine the mass and full-width of ηc\eta_c to be mηc=2977.5±1.0(stat.)±1.2(syst.)m_{\eta_c}=2977.5\pm1.0 ({stat.})\pm1.2 ({syst.}) MeV/c2c^2 and Γηc=17.0±3.7(stat.)±7.4(syst.)\Gamma_{\eta_c} = 17.0\pm3.7 ({stat.})\pm7.4 ({syst.}) MeV/c2c^2.Comment: 9 pages, 2 figures and 4 table. Submitted to Phys. Lett.

    Rare Decays of \Lambda_b->\Lambda + \gamma and \Lambda_b ->\Lambda + l^{+} l^{-} in the Light-cone Sum Rules

    Full text link
    Within the Standard Model, we investigate the weak decays of ΛbΛ+γ\Lambda_b \to \Lambda + \gamma and ΛbΛ+l+l\Lambda_b \to \Lambda + l^{+} l^{-} with the light-cone sum rules approach. The higher twist distribution amplitudes of Λ\Lambda baryon to the leading conformal spin are included in the sum rules for transition form factors. Our results indicate that the higher twist distribution amplitudes almost have no influences on the transition form factors retaining the heavy quark spin symmetry, while such corrections can result in significant impacts on the form factors breaking the heavy quark spin symmetry. Two phenomenological models (COZ and FZOZ) for the wave function of Λ\Lambda baryon are also employed in the sum rules for a comparison, which can give rise to the form factors approximately 5 times larger than that in terms of conformal expansion. Utilizing the form factors calculated in LCSR, we then perform a careful study on the decay rate, polarization asymmetry and forward-backward asymmetry, with respect to the decays of ΛbΛγ\Lambda_b \to \Lambda \gamma, Λl+l\Lambda l^{+}l^{-}.Comment: 38 pages, 15 figures, some typos are corrected and more references are adde

    Observation of the Decays B0->K+pi-pi0 and B0->rho-K+

    Get PDF
    We report the observation of B^0 decays to the K^+pi^-pi^0 final state using a data sample of 78 fb^-1 collected by the Belle detector at the KEKB e^+e^- collider. With no assumptions about intermediate states in the decay, the branching fraction is measured to be (36.6^{+4.2}_{-4.3}+- 3.0)*10^-6.We also search for B decays to intermediate two-body states with the same K^+pi^-pi^0 final state. Significant B signals are observed in the rho(770)^- K^+ and K^*(892)^+pi^- channels, with branching fractions of (15.1^{+3.4+1.4+2.0}_{-3.3-1.5-2.1})* 10^-6 and (14.8^{+4.6+1.5+2.4}_{-4.4-1.0-0.9})* 10^-6, respectively. The first error is statistical, the second is systematic and the third is due to the largest possible interference. Contributions from other possible two-body states will be discussed. No CP asymmetry is found in the inclusive K^+pi^-pi^0 or rho^-K^+ modes, and we set 90% confidence level bounds on the asymmetry of -0.12<A_{CP}<0.26 and -0.18<A_{CP}<0.64, respectively.Comment: 18 pages, 7 figure

    Measurement of Branching Ratios for ηc\eta_c Hadronic Decays

    Get PDF
    In a sample of 58 million J/ψJ/\psi events collected with the BES II detector, the process J/ψγηc\psi\to\gamma\eta_c is observed in five decay channels: ηcK+Kπ+π\eta_c \to K^+K^-\pi^+\pi^-, π+ππ+π\pi^+\pi^-\pi^+\pi^-, K±KS0πK^\pm K^0_S \pi^\mp (with KS0π+πK^0_S\to\pi^+\pi^-), ϕϕ\phi\phi (with ϕK+K\phi\to K^+K^-) and ppˉp\bar{p}. From these signals, we determine Br(J/ψγηc)×Br(ηcK+Kπ+π)Br(J/\psi\to\gamma\eta_c)\times Br(\eta_c\to K^+K^-\pi^+\pi^-) =(1.5±0.2±0.2)×104=(1.5\pm0.2\pm0.2)\times10^{-4}, Br(J/ψγηc)×Br(ηcπ+ππ+π)Br(J/\psi\to\gamma\eta_c)\times Br(\eta_c\to \pi^+\pi^-\pi^+\pi^-) =(1.3±0.2±0.4)×104=(1.3\pm0.2\pm0.4)\times10^{-4}, Br(J/ψγηc)×Br(ηcK±KS0π)Br(J/\psi\to\gamma\eta_c)\times Br(\eta_c\to K^\pm K_{S}^{0}\pi^\mp) =(2.2±0.3±0.5)×104=(2.2\pm0.3\pm0.5)\times10^{-4}, Br(J/ψγηc)×Br(ηcϕϕ)Br(J/\psi\to\gamma\eta_c)\times Br(\eta_c\to \phi\phi) =(3.3±0.6±0.6)×105=(3.3\pm0.6\pm0.6)\times10^{-5} and Br(J/ψγηc)×Br(ηcppˉ)Br(J/\psi\to\gamma\eta_c)\times Br(\eta_c\to p\bar{p}) =(1.9±0.3±0.3)×105=(1.9\pm0.3\pm0.3)\times10^{-5}.Comment: 8 pages, 1 figures and 4 table. Submitted to Phys. Lett.

    Evidence of psi(3770) non-DD-bar Decay to J/psi pi+pi-

    Full text link
    Evidence of ψ(3770)\psi(3770) decays to a non-DDˉ{D \bar D} final state is observed. A total of 11.8±4.8±1.311.8 \pm 4.8 \pm 1.3 \psi(3770) \to \PPJP events are obtained from a data sample of 27.7 pb1\rm {pb^{-1}} taken at center-of-mass energies around 3.773 GeV using the BES-II detector at the BEPC. The branching fraction is determined to be BF(\psi(3770) \to \PPJP)=(0.34\pm 0.14 \pm 0.09)%, corresponding to the partial width of \Gamma(\psi(3770) \to \PPJP) = (80 \pm 33 \pm 23) keV.Comment: 8 pages, 7 figures, Submitted to Physics Letters

    Prunella vulgaris: A comprehensive review of chemical constituents, pharmacological effects and clinical applications.

    Get PDF
    Prunella vulgaris (PV) is a perennial herb belonging to the Labiate family and is widely distributed in northeastern Asian countries such as Korea, Japan, and China. It is reported to display diverse biological activities including anti-microbial, anti-cancer, and anti-inflammation as determined by in vitro or in vivo studies. So far, about 200 compounds have been isolated from PV plant and majority of these have been characterized mainly as triterpenoids, sterols and flavonoids, followed by coumarins, phenylpropanoids, polysaccharides and volatile oils. This review summarizes and analyzes the current knowledge on the chemical constituents, pharmacological activities, mechanisms of action and clinical applications of the PV plant including its potential as a future medicinal plant. Although some of the chemical constituents of the PV plant and their mechanism of action have been investigated the biological activities of many of these remain unknown and further clinical trials are required to further enhance its reputation as a medicinal plant
    corecore