5,740 research outputs found

    Supersymmetric Intersecting Branes in Time-dependent Backgrounds

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    We construct a family of supersymmetric solutions in time-dependent backgrounds in supergravity theories. One class of the solutions are intersecting brane solutions and another class are brane solutions in pp-wave backgrounds, and their intersection rules are also given. The relation to existing literature is also discussed. An example of D1-D5 with linear null dilaton together with its possible dual theory is briefly discussed.Comment: 12 pages, corrected typo, added reference, to appear in Phys. Rev.

    A Comprehensive Study of the Radiative Decays of J/ψJ/\psi and ψ(2S)\psi(2S) to Pseudoscalar Meson Pairs, and Search for Glueballs

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    Using 53 pb−1^{-1} of e+e−e^+e^- annihilation data taken at s=3.686\sqrt{s}=3.686 GeV, a comprehensive study has been made of the radiative decays of samples of 5.1 million J/ψJ/\psi and 24.5 million ψ(2S)\psi(2S) into pairs of pseudoscalar mesons, π+π−\pi^+\pi^-, π0π0\pi^0\pi^0, K+K−K^+K^-, KS0KS0K_S^0K_S^0, and ηη\eta\eta. Product branching fractions for the radiative decays of J/ψJ/\psi and ψ(2S)\psi(2S) to scalar resonances f0(1370,1500,1710,2100,and2200)f_0(1370,1500,1710,2100, \text{and} 2200), and tensor resonances f2(1270,1525,and2230)f_2(1270,1525, \text{and} 2230) have been determined, and are discussed in relation to predicted glueballs. For ψ(2S)\psi(2S) radiative decays the search for glueballs has been extended to masses between 2.5 GeV and 3.3 GeV.Comment: 21 pages, 14 figures, published in PR

    First Measurement of the Electromagnetic Form Factor of the Neutral Kaon at a Large Momentum Transfer and the Effect of SU(3)SU(3) Breaking

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    At large momentum transfers the photon interacts with the charges and spins of the constituent partons in a hadron. It is expected that the neutral kaon can acquire finite electromagnetic form factors because its wave function is affected by the order of magnitude difference between the mass of the strange quark and that of the down quark, or flavor SU(3)SU(3) breaking. We report on the first measurement of the form factor of neutral kaons at the large timelike momentum transfer of ∣Q2∣=17.4|Q^2|=17.4 GeV2^2 by measuring the cross section for e+e−→KSKLe^+e^-\to K_SK_L at s=4.17\sqrt{s}=4.17 GeV using CLEO-c data with an integrated luminosity of 586 pb−1^{-1}. We obtain FKSKL(17.4 GeV2)=5.3×10−3F_{K_SK_L}(17.4~\textrm{GeV}^2)=5.3\times10^{-3}, with a 90% C.L. interval of (2.9−8.2)×10−3(2.9-8.2)\times10^{-3}. This is nearly an order of magnitude smaller than FK+K−(17.4 GeV2)=(44±1)×10−3F_{K^+K^-}(17.4~\textrm{GeV}^2)=(44\pm1)\times10^{-3}, and indicates that the effect of SU(3)SU(3) breaking is small. In turn, this makes it unlikely that the recently observed strong violation of the pQCD prediction, Fπ+π−(∣Q2∣)/FK+K−(∣Q2∣)=fπ2/fK2F_{\pi^+\pi^-}(|Q^2|)/F_{K^+K^-}(|Q^2|)=f_\pi^2/f_K^2, which is based on the assumption of similar wave functions for the pions and kaons, can be attributed to SU(3)SU(3) breaking alone.Comment: 4 pages, 2 figures, accepted to PL
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