231 research outputs found

    Characterization of Epstein-Barr viral strains in parotid gland saliva and peripheral blood of patients with primary Sjogren's syndrome and healthy EBV carriers

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    Increased Epstein-Barr virus (EBV) replication has been reported in the salivary and lacrimal glands in Sjögren's syndrome (SS). We studied whether or not certain EBV strains would occur preferentially in the peripheral blood and parotid gland saliva of 18 EBV-seropositive patients with primary Sjögren's syndrome (pSS) and 12 EBV-seropositive control persons. Transforming EBV was detected in the blood of 11 of 18 (61%) pSS patients and 9 of 12 controls (75%). Unexpectedly, neither transforming nor Raji-superinfecting EBV strains were detected in SS parotid saliva, whereas these EBV types were detected in control saliva in 7 and 8 cases, respectively (P <0.001). Transforming EBV strains were further characterized by ‘Ebnotyping,’ i.e., analysis of the size spectrum of the viral antigens EBNA 1, 2, 3, and 6 in immunoblots of lymphoblastoid cell lines (LCL). Previous work has shown that a single EBV strain (Ebnotype) dominates the blood and oropharynx of healthy carriers and that unrelated individuals carry different EBV strains, reflecting the vast polymorphism of Ebnotypes in the general population. Two unexpected observations were made. First, an identical Ebnotype was detected in 4 unrelated individuals, i.e., in the blood of 1 pSS patient and in the saliva of 3 control persons. Second, carriage of 2 to 4 different Ebnotypes by a single individual was observed in 4 cases, i.e., in the blood of 1 pSS patient, and in the blood and saliva of 3 control persons. As only 1 control person had received a blood transfusion, it is suggested that (super)infection with exogenous EBV strains via salivary transmission and/or recombination of endogenous virions may have contributed to this situation

    Final State Interactions in D0K0K0ˉD^0 \to K^0 \bar{K^0}

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    It is believed that the production rate of D0K0Kˉ0D^0\to K^0\bar K^0 is almost solely determined by final state interactions (FSI) and hence provides an ideal place to test FSI models. Here we examine model calculations of the contributions from s-channel resonance fJ(1710)f_J(1710) and t-channel exchange to the FSI effects in D0K0Kˉ0D^0\to K^0\bar K^0. The contribution from s-channel f0(1710)f_0(1710) is smaForthetchannelFSIevaluation,weemploytheoneparticleexchange(OPE)modelandReggemodelrespecti For the t-channel FSI evaluation, we employ the one-particle-exchange (OPE) model and Regge model respecti The results from two methods are roughly consistent with each other and can reproduce the large rate of D0K0Kˉ0D^0\to K^0\bar K^0 reasonably well$Comment: Latex, 16 pages, with 2 figure

    Some properties of the newly observed X(1835) state at BES

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    Recently the BES collaboration has announced observation of a resonant state in the π+πη\pi^+\pi^- \eta' spectrum in J/ψγπ+πηJ/\psi \to \gamma \pi^+\pi^-\eta' decay. Fitting the data with a 0+0^{-+} state, the mass is determined to be 1833.7 MeV with 7.7σ7.7\sigma statistic significance. This state is consistent with the one extracted from previously reported ppˉp \bar p threshold enhancement data in J/ψγppˉJ/\psi \to \gamma p \bar p. We study the properties of this state using QCD anomaly and QCD sum rules assuming X(1835) to be a pseudoscalar and show that it is consistent with data. We find that this state has a sizeable matrix element leading to branching ratios of (2.617.37)×103(2.61\sim 7.37)\times 10^{-3} and (2.2110.61)×102(2.21\sim 10.61)\times 10^{-2} for J/ψγGpJ/\psi \to \gamma G_p and for Gpπ+πηG_p \to \pi^+\pi^- \eta', respectively. Combining the calculated branching ratio of J/ψγGpJ/\psi \to \gamma G_p and data on threshold enhancement in J/ψγppˉJ/\psi \to \gamma p \bar p, we determine the coupling for GpppˉG_p- p-\bar p interaction. We finally study branching ratios of other J/ψγ+threemesonsJ/\psi \to \gamma + {three mesons} decay modes. We find that J/ψγGpγ(π+πη,KKπ0)J/\psi \to \gamma G_p \to \gamma (\pi^+\pi^- \eta, K K \pi^0) can provide useful tests for the mechanism proposed.Comment: 13 pages, 3 figures. The final version to appear at EPJ

    \psi(2S) Decays into \J plus Two Photons

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    Using \gamma \gamma J/\psi, J/\psi \ra e^+ e^- and μ+μ\mu^+ \mu^- events from a sample of 14.0×10614.0\times 10^6 \psip decays collected with the BESII detector, the branching fractions for \psip\ra \pi^0\J, \eta\J, and \psi(2S)\ar\gamma\chi_{c1},\gamma\chi_{c2}\ar\gamma\gamma\jpsi are measured to be B(\psip\ra \pi^0\J) = (1.43\pm0.14\pm0.13)\times 10^{-3}, B(\psip\ra \eta\J) = (2.98\pm0.09\pm0.23)%, B(\psi(2S)\ar\gamma\chi_{c1}\ar\gamma\gamma\jpsi) = (2.81\pm0.05\pm 0.23)%, and B(\psi(2S)\ar\gamma\chi_{c2}\ar\gamma\gamma\jpsi) = (1.62\pm0.04\pm 0.12)%.Comment: 7 pages, 6 figures. submitted to Phys. Rev.

    Measurements of ψ(2S)\psi(2S) decays into Vector- Tensor final states

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    Decays of the ψ(2S)\psi(2S) into vector plus tensor meson final states have been studied with 14 million ψ(2S)\psi(2S) events collected with the BESII detector. Branching fractions of \psi(2S) \rt \omega f_{2}(1270), ρa2(1320)\rho a_2(1320), K(892)0Kˉ2(1430)0+c.c.K^*(892)^0\bar{K}^*_2(1430)^0+c.c. and ϕf2(1525)\phi f_2^{\prime}(1525) are determined. They improve upon previous BESI results and confirm the violation of the "12%" rule for ψ(2S)\psi(2S) decays to VT channels with higher precision.Comment: 7 pages, 7 figures and 2 table

    Baryonium, tetra-quark state and glue-ball in large N_c QCD

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    From the large-N_c QCD point of view, baryonia, tetra-quark states, hybrids, and glueballs are studied. The existence of these states is argued for. They are constructed from baryons. In N_f=1 large N_c QCD, a baryonium is always identical to a glueball with N_c valence gluons. The ground state 0^{-+} glueball has a mass about 2450 MeV. f_0(1710) is identified as the lowest 0^{++} glueball. The lowest four-quark nonet should be f_0(1370), a_0(1450), K^*_0(1430) and f_0(1500). Combining with the heavy quark effective theory, spectra of heavy baryonia and heavy tetra-quark states are predicted. 1/N_c corrections are discussed.Comment: 16 pages, 3 figure

    The σ\sigma pole in J/ψωπ+πJ/\psi \to \omega \pi^+ \pi^-

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    Using a sample of 58 million J/ψJ/\psi events recorded in the BESII detector, the decay J/ψωπ+πJ/\psi \to \omega \pi^+ \pi^- is studied. There are conspicuous ωf2(1270)\omega f_2(1270) and b1(1235)πb_1(1235)\pi signals. At low ππ\pi \pi mass, a large broad peak due to the σ\sigma is observed, and its pole position is determined to be (541±39)(541 \pm 39) - ii (252±42)(252 \pm 42) MeV from the mean of six analyses. The errors are dominated by the systematic errors.Comment: 15 pages, 6 figures, submitted to PL

    A Measurement of Psi(2S) Resonance Parameters

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    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

    Study of J/ψωK+KJ/\psi \to \omega K^+K^-

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    New data are presented on J/ψωK+KJ/\psi \to \omega K^+K^- from a sample of 58M J/ψJ/\psi events in the upgraded BES II detector at the BEPC. There is a conspicuous signal for f0(1710)K+Kf_0(1710) \to K^+K^- and a peak at higher mass which may be fitted with f2(2150)KKˉf_2(2150) \to K\bar K. From a combined analysis with ωπ+π\omega \pi ^+ \pi ^- data, the branching ratio BR(f0(1710)ππ)/BR(f0(1710)KKˉ)BR(f_0(1710)\to\pi\pi)/BR(f_0(1710) \to K\bar K) is <0.11< 0.11 at the 95% confidence level.Comment: 11 pages, 5 figures. Submitted to Phys. Lett.
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