52 research outputs found
Measurement of the cross section with the CMD-3 detector at the VEPP-2000 collider
The process has been studied in the
center-of-mass energy range from 1500 to 2000\,MeV using a data sample of 23
pb collected with the CMD-3 detector at the VEPP-2000 collider.
Using about 24000 selected events, the cross
section has been measured with a systematic uncertainty decreasing from 11.7\%
at 1500-1600\,MeV to 6.1\% above 1800\,MeV. A preliminary study of
production dynamics has been performed
Measurement of the neutron timelike electromagnetic form factor with the SND detector
The results of the measurement of the cross section
and effective neutron timelike form factor are presented. The data taking was
carried out in 2020-2021 at the VEPP-2000 collider in the
center-of-mass energy range from 1891 to 2007 MeV. The general purpose
nonmagnetic detector SND is used to detect neutron-antineutron events. The
event selection is performed using the time-of-flight technique. The measured
cross section is 0.4-0.6 nb. The neutron form factor in the energy range under
study varies from 0.3 to 0.2.Comment: 13 pages, 8 figure
Study of the process in the energy range GeV with SND
The process is studied in
the center-of-mass energy region GeV using data with an integral
luminosity of about 35 pb collected with the SND detector at the
VEPP-2000 collider. In the energy range under study, the value of the
measured Born cross section varies from 0.7 to 18 nb. The statistical
uncertainty of the cross section is %, while the systematic uncertainty
is in the range of %. The results are consistent with previous
measurements but have better accuracy.Comment: 13 pages, 11 figure
Measurement of the cross section from threshold to 1.2 GeV with the CMD-3 detector
The cross section of the process has been measured in
the center of mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at
the electron-positron collider VEPP-2000. The measurement is based on a full
dataset collected below 1 GeV during three data taking seasons, corresponding
to an integrated luminosity of about 62 pb. In the dominant
-resonance region, a systematic uncertainty of 0.7% has been reached. At
energies around -resonance the production cross section was
measured for the first time with high energy resolution. The forward-backward
charge asymmetry in the production has also been measured. It
shows the strong deviation from the theoretical prediction based on
conventional sQED framework and is in good agreement with GVDM and
dispersive-based predictions. The impact of presented results on the evaluation
of the hadronic contribution to the anomalous magnetic moment of muon is
discussed.Comment: 52 pages, 36 figures; cosmetic changes of the text, fix fig.2 , fix
comment on used selection cuts in the attached radiative correction tabl
Measurement of the pion formfactor with CMD-3 detector and its implication to the hadronic contribution to muon (g-2)
The cross section of the process has been measured in
the center of mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at
the electron-positron collider VEPP-2000. The measurement is based on an
integrated luminosity of about 88 pb out of which 62 pb
constitutes a full dataset collected by CMD-3 at center-of-mass energies below
1 GeV. In the dominant region near -resonance a systematic uncertainty of
0.7% has been reached. The impact of presented results on the evaluation of the
hadronic contribution to the anomalous magnetic moment of muon is discussed.Comment: 6 pages, 3 figure
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