31 research outputs found
Study of the process in the c.m. energy range from threshold to 2 GeV with the CMD-3 detector
Using a data sample of 6.8 pb collected with the CMD-3 detector at the
VEPP-2000 collider we select about 2700 events of the process and measure its cross section at 12 energy ponts with about
6\% systematic uncertainty. From the angular distribution of produced nucleons
we obtain the ratio
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 \sqrt{s} = \mbox{1.05-2.00} GeV with the SND detector
The process is studied in the center-of-mass
energy range 1.05-2.00 GeV using data with an integrated luminosity of 94.5
pb collected by the SND detector at the VEPP-2000 collider. The
cross section is measured for the first time. It is
shown that the dominant mechanism of this reaction is the transition through
the intermediate state. The measured cross section of the
subprocess is consistent with previous
measurements in the mode. It is found, with a
significance of 5.6, that the process is not
completely described by hadronic vector-pseudoscalar intermediate states. The
cross section of this missing contribution, which can originate from radiation
processes, e. g. , is measured. It is found to be
15-20 pb in the wide energy range from 1.3 to 1.9 GeV.Comment: 10 pages, 6 figures, to be submitted to European Physical Journal