806 research outputs found

    Canonical Charmonium Interpretation for Y(4360) and Y(4660)

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    In this work, we consider the canonical charmonium assignments for Y(4360) and Y(4660). Y(4660) is good candidate of 53S1\rm 5 ^3S_1 ccˉc\bar{c} state, the possibility of Y(4360) as a 33D1\rm 3 ^3D_1 ccˉc\bar{c} state is studied, and the charmonium hybrid interpretation of Y(4360) can not be excluded completely. We evaluate the e+ee^{+}e^{-} leptonic widths, E1 transitions, M1 transitions and the open flavor strong decays of Y(4360) and Y(4660). Experimental tests for the charmonium assignments are suggested.Comment: 32 pages, 4 figure

    Strange-Beauty Meson Production at ppˉp\bar p Colliders

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    The production rates and transverse momentum distributions of the strange-beauty mesons BsB_s and BsB_s^* at ppˉp\bar p colliders are calculated assuming fragmentation is the dominant process. Results are given for the Tevatron in the large transverse momentum region, where fragmentation is expected to be most important.Comment: Minor changes in the discussion section. Also available at http://www.ph.utexas.edu/~cheung/paper.htm

    Ratios of BB and DD Meson Decay Constants in Relativistic Quark Model

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    We calculate the ratios of BB and DD meson decay constants by applying the variational method to the relativistic hamiltonian of the heavy meson. We adopt the Gaussian and hydrogen-type trial wave functions, and use six different potentials of the potential model. We obtain reliable results for the ratios, which are similar for different trial wave functions and different potentials. The obtained ratios show the deviation from the nonrelativistic scaling law, and they are in a pretty good agreement with the results of the Lattice calculations.Comment: 13 pages, 1 Postscript figur

    Narratives of Industry Responses to Cyberbullying: Perspectives on Self-regulation From and About the Industry

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    In this chapter, we provide an overview of narratives about online inter- mediaries’ responses to cyberbullying from the perspectives of policy makers and the companies, as well as children and parents. Relevant self-regulatory and self- organisational efforts are discussed aswell as the rationales for their adoption; includ- ing how the effectiveness of these efforts is seen from the perspectives of various stakeholders. We draw attention to the relative paucity of data on effectiveness of companies’ mechanisms, particularly from the perspective of any benefits received by children as a result of these interventions and support

    Effect of integrated care for sick listed patients with chronic low back pain: economic evaluation alongside a randomised controlled trial

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    Objective To evaluate the cost effectiveness, cost utility, and cost-benefit of an integrated care programme compared with usual care for sick listed patients with chronic low back pain

    Identifying the quark content of the isoscalar scalar mesons f_0(980), f_0(1370), and f_0(1500) from weak and electromagnetic processes

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    The assignments of the isoscalar scalar mesons f0(980), f0(1370), and f0(1500) in terms of their qqbar substructure is still a matter of heated dispute. Here we employ the weak and electromagnetic decays D(s)(+) to f0+pi(+) and f0 two-photon decays, respectively, to identify the f0(980) and f0(1500) as mostly ssbar, and the f0(1370) as dominantly nonstrange, in agreement with previous work. The two-photon decays can be satisfactorily described with quark as well as with meson loops, though the latter ones provide a less model-dependent and more quantitative description.Comment: v1, 15 pages, plain LaTeX, 1 eps figure. v2, 18 pages, plain LaTeX (figure included). More discussion, especially on the f0(1370) and its empirical two-photon widt

    The decay constants of pseudoscalar mesons in a relativistic quark model

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    The decay constants of pseudoscalar mesons are calculated in a relativistic quark model which assumes that mesons are made of a valence quark antiquark pair and of an effective vacuum like component. The results are given in terms of quark masses and of some free parameters entering the expression of the internal wave functions of the mesons. By using the pion and kaon decay constants Fπ+=130.7 MeV, FK+=159.8 MeVF_{\pi^+}=130.7~MeV,~F_{K^+}=159.8~MeV to fix the parameters of the model one gets 60 MeVFD+185 MeV, 95 MeVFDs230 MeV, 80 MeVFB+205 MeV60~MeV\leq F_{D^+}\leq 185~MeV,~95~MeV\leq F_{D_s}\leq230~MeV,~80~MeV\leq F_{B^+}\leq205~MeV for the light quark masses mu=5.1 MeV, md=9.3 MeV, ms=175 MeVm_u=5.1~MeV,~m_d=9.3~MeV,~m_s=175~MeV and the heavy quark masses in the range: 1. GeVmc1.6 GeV, 4.1 GeVmb4.5 GeV1.~GeV\leq m_c\leq1.6~GeV,~4.1~GeV\leq m_b\leq4.5~GeV. In the case of light neutral mesons one obtains with the same set of parameters Fπ0138 MeV, Fη 130 MeV,Fη 78 MeVF_{\pi^0}\approx 138~MeV,~F_\eta\approx~130~MeV,F_{\eta'} \approx~78~MeV. The values are in agreement with the experimental data and other theoretical results.Comment: 11 pages, LaTe

    A Brief Etymology of the Collateral Circulation

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    It is well known that the protective capacity of the collateral circulation falls short in many individuals with ischemic disease of the heart, brain and lower extremities. In the past fifteen years, opportunities created by molecular and genetic tools, together with disappointing outcomes in many “angiogenic” trials, has led to a significant increase in the number of studies that focus on: 1) understanding the basic biology of the collateral circulation; 2) identifying the mechanisms that limit the collateral circulation’s capacity in many individuals; 3) devising methods to measure collateral extent, which has been found to vary widely among individuals; and 4) developing treatments to increase collateral blood flow in obstructive disease. Unfortunately, accompanying this increase in reports has been a proliferation of vague terms used to describe the disposition and behavior of this unique circulation, as well as the increasing miss-use of well-ensconced ones by new (and old) students of the collateral circulation. With this in mind, we provide a brief glossary of readily understandable terms to denote the formation, adaptive growth, and mal-adaptive rarefaction of the collateral circulation. We also propose terminology for several newly discovered processes that occur in the collateral circulation. Finally, we include terms used to describe vessels that are sometimes confused with collaterals, as well as terms describing processes active in the general arterial-venous circulation when ischemic conditions engage the collateral circulation. We hope this brief review will help unify the terminology used in collateral research

    Leptonic widths of high excitations in heavy quarkonia

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    Agreement with the measured electronic widths of the ψ(4040)\psi(4040), ψ(4415)\psi(4415), and Υ(11019)\Upsilon (11019) resonances is shown to be reached if two effects are taken into account: a flattening of the confining potential at large distances and a total screening of the gluon-exchange interaction at r\ga 1.2 fm. The leptonic widths of the unobserved Υ(7S)\Upsilon(7S) and ψ(5S)\psi(5S) resonances: Γe+e(Υ(7S))=0.11\Gamma_{e^+e^-}(\Upsilon (7S))=0.11 keV and Γ(ψ(5S))0.54\Gamma(\psi(5S))\approx 0.54 keV are predicted.Comment: 11 pages revtex
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