19 research outputs found
Radiative decays of light vector mesons
The new data on radiative decays into
from SND experiment at VEPP-2M
collider are presented.Comment: 5 pages, 2 figures, talk given at 8th International Conference on
Hadron Spectroscopy (HADRON 99), Beijing, China, 24-28 Aug 199
Search for direct production of a2(1320) and f2(1270) mesons in e+e- annihilation
A search for direct production of C-even resonances a2(1320) and f2(1270) in
e+e- annihilation was performed with SND detector at VEPP-2M e+e- collider. The
upper limits of electronic widths of these mesons were obtained at 90%
confidence level:
Gamma(a2(1320) \to e+e-) < 0.56 eV,
Gamma(f2(1270) \to e+e-) < 0.11 eV.Comment: 6 pages, 5 figures, 1 table. Submitted to Phys. Lett.
Experimental study of the e+e- -> pi0 gamma process in the energy region sqrt(s)=0.60-0.97 GeV
Results of the study of the e+e-->pi0 gamma process with SND detector at
VEPP-2M collider in the c.m.s. energy range sqrt(s)=0.60-0.97 GeV are
presented. Using 36513 selected events corresponding to a total integrated
luminosity of 3.4 pb^-1 the e+e-->pi0 gamma cross section was measured. The
energy dependence of the cross section was analyzed in the framework of the
vector meson dominance model. The data are well described by a sum of
phi,omega,rho0->pi0 gamma decay contributions with measured decay
probabilities: Br(omega->pi0 gamma)=(9.34+-0.15+-0.31)% and Br(rho0->pi0
gamma)=(5.15+-1.16+-0.73)*10^-4 . The rho-omega relative interference phase is
phi(rho,omega}=(-10.2+-6.5+-2.5) degree
Study of the Process in the C.M.Energy Range 1.05-1.38 GeV with CMD-2
The process has been studied with the CMD-2 detector
using about 950 events detected in the center-of-mass energy range from 1.05 to
1.38 GeV. The cross section exceeds the expectation based on the contributions
of the rho(770), omega(782) and phi(1020) mesons only.Comment: 12 pages, 3 figures, uses elsart.cls, submitted to Physics Letters
Study of the Process e+ e- --> omega pi0 --> pi0 pi0 gamma in c.m. Energy Range 920--1380 MeV at CMD-2
The cross section of the process e+ e- --> omega pi0 --> pi0 pi0 gamma has
been measured in the c.m. energy range 920-1380 MeV with the CMD-2 detector.
Its energy dependence is well described by the interference of the rho(770) and
rho'(1450) mesons decaying to omega pi0. Upper limits for the cross sections of
the direct processes e+ e- --> pi0 pi0 gamma, eta pi0 gamma have been set.Comment: Accepted for publication in PL
Study of the Process e+ e- --> pi0 pi0 gamma in c.m. Energy Range 600--970 MeV at CMD-2
The cross section of the process e+ e- --> pi0 pi0 gamma has been measured in
the c.m. energy range 600--970 MeV with the CMD-2 detector. The following
branching ratios have been determined: B(rho --> pi0 pi0 gamma)
=(5.2^{+1.5}_{-1.3} +- 0.6)x10^{-5} and B(omega --> pi0 pi0 gamma)
=(6.4^{+2.4}_{-2.0} +- 0.8)x10^{-5}. Evidence for the rho --> f0(600) gamma
decay has been obtained: B(rho --> f0(600) gamma) = (6.0^{+3.3}_{-2.7}\pm
0.9)x10^{-5}. From a search for the process e+ e- --> eta pi0 gamma the
following upper limit has been obtained: B(omega --> eta pi0 gamma) < 3.3
10^{-5} at 90% CL.Comment: 15 pages, 4 figure
Measurement of e+e- -> pi+pi- cross section with CMD-2 around rho-meson
The cross section of the process e+e- -> pi+pi- has been measured using about
114000 events collected by the CMD-2 detector at the VEPP-2M e+e- collider in
the center-of-mass energy range from 0.61 to 0.96 GeV. Results of the pion form
factor determination with a 0.6% systematic uncertainty are presented.
Implications for the hadronic contribution to the muon anomalous magnetic
moment are discussed.Comment: 17 pages, 4 figures, submitted to PL
Sustainable reference points for multispecies coral reef fisheries
Sustainably managing fisheries requires regular and reliable evaluation of stock status. However, most multispecies reef fisheries around the globe tend to lack research and monitoring capacity, preventing the estimation of sustainable reference points against which stocks can be assessed. Here, combining fish biomass data for >2000 coral reefs, we estimate site-specific sustainable reference points for coral reef fisheries and use these and available catch estimates to assess the status of global coral reef fish stocks. We reveal that >50% of sites and jurisdictions with available information have stocks of conservation concern, having failed at least one fisheries sustainability benchmark. We quantify the trade-offs between biodiversity, fish length, and ecosystem functions relative to key benchmarks and highlight the ecological benefits of increasing sustainability. Our approach yields multispecies sustainable reference points for coral reef fisheries using environmental conditions, a promising means for enhancing the sustainability of the world's coral reef fisheries
THE EFFECT OF IODIZED OIL ON GOITRE SIZE, THYROID FUNCTION AND THE DEVELOPMENT OF THE JOD BASEDOW PHENOMENON
Recent results of the study of hadronic production with the CMD-2 and SND detectors at the VEPP-2M collider
The Cryogenic Magnetic Detector (CMD-2) and Spherical Neutral Detector (SND) operated at the VEPP-2M electron-positron collider in the c.m. energy range 360-1380 MeV. The total integrated luminosity above 60 pb–1 has been collected by both detectors. The cross sections of hadronic production have been measured with high precision. New results for the light vector meson parameters and rare decay mode were obtained.
PACS: 13.66.Bc Hadron production in e
–
e
+ interactions – 13.66.Jn Precision measurements in e
–
e
+ interaction