389 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.
New experimental data for the decays and from SND detector
The processes and have been
studied with SND detector at VEPP-2M collider in the vicinity of
resonance. The branching ratios and were obtained.Comment: 5 pages, 4 figures, talk given at 8th International Conference on
Hadron Spectroscopy (HADRON 99), Beijing, China, 24-28 Aug 199
The process in the energy range 2E_0=1.04 - 1.38 GeV
In the experiment with the SND detector at VEPP-2M e^+e^- collider the
process was studied in the energy range 2E_0 from
1.04 to 1.38 GeV. A broad peak was observed with the visible mass
MeV and cross section in the maximum
nb. The peak can be interpreted as a -like resonance .Comment: 10 pages LATEX and 5 figure
Experimental Study of rho -> pi0 pi0 gamma and omega -> pi0 pi0 gamma Decays
The e+e- -> pi0 pi0 gamma process was studied in the SND experiment at
VEPP-2M e+e- collider in the energy region 0.60-0.97 GeV. From the analysis of
the energy dependence of measured cross section the branching ratios B(omega ->
pi0 pi0 gamma)= (6.6 +1.4-0.8(stat) +-0.6(syst))x10^-5 and B(rho -> pi0 pi0
gamma)=(4.1 +1.0-0.9(stat) +-0.3(syst))x10^-5 were obtained.Comment: 16 pages, 7 figures, submitted to Phys. Lett.
New Data from SND Detector in Novosibirsk
The current status of experiments with SND detector at VEPP-2M e^+e^-
collider in the energy range 2E_0=400-1400 MeV and recent results of data
analysis for , and decays and e^+e^- annihilation into
hadrons are presented.Comment: 7 pages, 8 figures, Latex2e, uses espcrc1.sty. Talk given at 8th
International Conference on Hadron Spectroscopy (HADRON 99), Beijing, China,
24-28 Aug 199
Search for the radiative decay in the SND experiment at VEPP-2M
The decay was investigated by the SND detector
at VEPP-2M collider in the reaction .
Here we present the results and some details of this study. We report an upper
limit (90% c.l.) as our
final result. Our upper limit does not contradict the earlier measurement by
GAMS spectrometer. To facilitate future studies a rather detailed review of the
problem is also given.Comment: 24 pages, 6 figures, LaTex. To be published in Nucl. Phys.
First Observation of PHI(1020)--->PI0+PI0+GAMMA Decay
In the SND experiment at the VEPP-2M electron-positron collider the
PHI(1020)--->PI0+PI0+GAMMA decay was studied. The branching ratio
B(PHI--->PI0+PI0+GAMMA)=(1.14+-0.10+-0.12)x10^{-4} was measured. It was shown,
that the F0(980)GAMMA mechanism dominates in this decay and the 4-quark model
of F0(980) describes our data most consistently.Comment: 6 pages, 6 figures, 1 table, Will be published in Phys.Lett.
Correlation gap in the heavy-fermion antiferromagnet UPd_2Al_3
The optical properties of the heavy-fermion compound UPdAl have been
measured in the frequency range from 0.04 meV to 5 meV (0.3 to 40 cm) at
temperatures K. Below the coherence temperature K, the hybridization gap opens around 10 meV. As the temperature decreases
further ( K), a well pronounced pseudogap of approximately 0.2 meV
develops in the optical response; we relate this to the antiferromagnetic
ordering which occurs below K. The frequency dependent mass and
scattering rate give evidence that the enhancement of the effective mass mainly
occurs below the energy which is associated to the magnetic correlations
between the itinerant and localized 5f electrons. In addition to this
correlation gap, we observe a narrow zero-frequency conductivity peak which at
2 K is less than 0.1 meV wide, and which contains only a fraction of the
delocalized carriers. The analysis of the spectral weight infers a loss of
kinetic energy associated with the superconducting transition.Comment: RevTex, 15 pages, 7 figure
Investigation of the reaction in the energy domain near the -meson
The process was investigated
in the SND experiment at the VEPP-2M collider. A narrow energy interval near
the -meson was scanned. The observed cross-section reveals, at the level
of three standard deviation, the interference effect caused by decay. The cross-section parameters, as well as the real and
imaginary parts of the -meson related amplitude, were measured.Comment: 34 pages, 7 figures, LaTeX, uses FEYNMAN package. Erroneously
reported C_{12} coefficient corrected (an error discovered in
hep-ph/0603241). in the published version Nucl. Phys. B569(2000), 158 this
coefficient is reported incorrectl
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