33 research outputs found
Erhic – electron-proton collider with polarized beams
The layout and main parameters of the e-ring for eRHIC project are presented. The optics properties to fulfill the
so-called spin-transparency condition to obtain sufficient polarization degree at IP are given. The possibility of using
super-bends for the polarization time in a wide energy range be decreased is also discussed.Представлені основні параметри і розташування e-кільця в проекті eRHIC. Дані оптичні властивості для
виконання так званої умови спінової прозорості для одержання достатнього ступеня поляризації в IP. Також
обговорюється можливість використання надвигинів для зменшення часу поляризації в широкому
енергетичному діапазоні.Представлены основные параметры и расположение e-кольца в проекте eRHIC. Даны оптические свойства для выполнения так называемого условия спиновой прозрачности для получения достаточной степени
поляризации в IP. Также обсуждается возможность использования сверхизгибов для уменьшения времени
поляризации в широком энергетическом диапазоне
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
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.
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.
Project of VEPP-2000 electron-positron collider
The status of VEPP-2M collider is presented. Implementation of Round Colliding Beams (RCB) concept in the new collider VEPP-2M is outlined, potential advantages of RCB over the flat colliding beams are discussed. The main desing parameters and features of this VEPP-2000 collider are reported
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
High-statistics measurement of the pion form factor in the rho-meson energy range with the CMD-2 detector
We present a measurement of the pion form factor based on e+e- annihilation
data from the CMD-2 detector in the energy range 0.6<sqrt(s)<1.0 GeV with a
systematic uncertainty of 0.8%. A data sample is five times larger than that
used in our previous measurement.Comment: 18 pages, 10 figures. Added comparison with KLOE measurement, minor
updates. Accepted by PL
Cross section of the reaction below 1 GeV at CMD-2
Using 3.07 of data collected in the energy range 0.60-0.97 GeV by
CMD-2, about 150 events of the process \epm \to \pch have been selected. The
energy dependence of the cross section agrees with the assumption of the
intermediate state which is dominant above 1 GeV. For the first
time \fourpi events are observed at the meson energy. Under the
assumption that all these events come from the meson decay, the value of
the cross section at the meson peak corresponds to the following decay
width:
\Gamma(\rho^0 \to \fourpi) = (2.8 \pm 1.4 \pm 0.5) {keV} or to the branching
ratio
B(\rho^0 \to \fourpi) = (1.8 \pm 0.9 \pm 0.3) \cdot 10 ^{-5}.Comment: 15 pages, 5 figure
Observation of the conversion decay at CMD-2
Using 15.1^{-1} of data collected by CMD-2 in the -meson energy range,
the branching ratio of the conversion decay has been
measured for the first time: B(\phi\to\pi^0e^+e^-) = (1.22 \pm 0.34 \pm 0.21)
\cdot 10 ^{-5}.Comment: 13 pages, 6 PostScript figures, uses refmerge.sty. To be published in
Phys. Lett.
Study of the Process e+ e- ---> eta gamma in c.m. Energy Range 600-1380 MeV at CMD-2
The cross section of the process e+ e- ---> eta gamma has been measured in
the 600-1380 MeV c.m. energy range with the CMD-2 detector. The following
branching ratios have been determined:
B(rho ---> eta gamma) = (3.28 +- 0.37 +- 0.23) 10^{-4},
B(omega ---> eta gamma) = (5.10 +- 0.72 +- 0.34) 10^{-4},
B(phi --> eta gamma) = (1.287 +- 0.013 +- 0.063) 10^{-2}.
Evidence for the rho'(1450) ---> eta gamma decay has been obtained for the
first time.Comment: 17pages, 4 figures, submited to Phys.Lett.