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
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
It is believed that the production rate of 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 and t-channel exchange to
the FSI effects in . The contribution from s-channel
is sma The results from
two methods are roughly consistent with each other and can reproduce the large
rate of reasonably well$Comment: Latex, 16 pages, with 2 figure
Some properties of the newly observed X(1835) state at BES
Recently the BES collaboration has announced observation of a resonant state
in the spectrum in
decay. Fitting the data with a state, the mass is determined to be
1833.7 MeV with statistic significance. This state is consistent
with the one extracted from previously reported threshold
enhancement data in . 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 and for
and for , respectively.
Combining the calculated branching ratio of and data on
threshold enhancement in , we determine the
coupling for interaction. We finally study branching ratios of
other decay modes. We find that 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
Using \gamma \gamma J/\psi, J/\psi \ra e^+ e^- and events
from a sample of \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 decays into Vector- Tensor final states
Decays of the into vector plus tensor meson final states have been
studied with 14 million events collected with the BESII detector.
Branching fractions of \psi(2S) \rt \omega f_{2}(1270), ,
and are
determined. They improve upon previous BESI results and confirm the violation
of the "12%" rule for 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
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 pole in
Using a sample of 58 million events recorded in the BESII detector,
the decay is studied. There are conspicuous
and signals. At low mass, a large
broad peak due to the is observed, and its pole position is determined
to be - 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
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
New data are presented on from a sample of 58M
events in the upgraded BES II detector at the BEPC. There is a
conspicuous signal for and a peak at higher mass which
may be fitted with . From a combined analysis with
data, the branching ratio
is at the 95%
confidence level.Comment: 11 pages, 5 figures. Submitted to Phys. Lett.
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