155 research outputs found
Energy calibration of the NaI(Tl) calorimeter of the SND detector using cosmic muons
The general purpose spherical nonmagnetic detector (SND) is now taking data
at VEPP-2M collider in BINP (Novosibirsk) in the centre of mass energy
range of GeV. The energy calibration of the NaI(Tl) calorimeter
of the SND detector with cosmic muons is described. Using this method, the
energy resolution of for 500 MeV photons was achieved.Comment: 15 pages, Latex, 11 figures (.EPS
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
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 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
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
Pion Form Factor at SND (new edition)
The update of the e^+e^-\to\pi^+\pi^- process cross section, measured in the
energy region \sqrt{s}<1 GeV with SND detector at VEPP-2M collider is
presented.Comment: Talk given at Int. Workshop e+e- Collisions from phi to psi, February
27 - March 2, 200
Study of the process in the energy region below 0.98 GeV
The cross section of the process was measured in
the Spherical Neutral Detector (SND) experiment at the VEPP-2M collider in the
energy region below 980 MeV. This measurement was based on about
selected events. The obtained cross section was analyzed
together with the SND and DM2 data in the energy region up to 2
GeV. The -meson parameters: MeV,
MeV and nb were obtained. It was found that the experimental data cannot be
described by a sum of only , , and
resonances contributions. This can be interpreted as a
manifestation of decay, suppressed by -parity, with relative
probability .Comment: 41 pages REVTEX and 34 figure
High Precision Mass Measurements in and Families Revisited
High precision mass measurements in and families performed
in 1980-1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited.
The corrections for the new value of the electron mass are presented. The
effect of the updated radiative corrections has been calculated for the
and mass measurements.Comment: 5 pages, 1 table, submitted to Phys. Lett.
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.
Extracting Br(omega->pi^+ pi^-) from the Time-like Pion Form-factor
We extract the G-parity-violating branching ratio Br(omega->pi^+ pi^-) from
the effective rho-omega mixing matrix element Pi_{rho omega}(s), determined
from e^+e^- -> pi^+ pi^- data. The omega->pi^+ pi^- partial width can be
determined either from the time-like pion form factor or through the constraint
that the mixed physical propagator D_{rho omega}^{mu nu}(s) possesses no poles.
The two procedures are inequivalent in practice, and we show why the first is
preferred, to find finally Br(omega->pi^+ pi^-) = 1.9 +/- 0.3%.Comment: 12 pages (published version
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