Recent results from the CMD-3 detector Lukin, P.A.; Akhmetshin, R.R.; Amirkhanov, A.N. ...
Nuclear and particle physics proceedings,
January-March 2020, 2020-01-00, Volume:
309-311
Journal Article
Peer reviewed
This paper reports a current status of the measurements of the hadronic cross sections in the c.m. energy range from 0.32 to 2.0 GeV with the CMD-3 detector at the VEPP-2000 electron-positron ...collider. The overall size of the data, acquired by the CMD-3 in the runs of 2010–2013 and 2017–2018 years, is about 160 pb−1. The results of data analysis for various exclusive modes of e+e−→hadrons are described.
The cross section of the process e+e−→ωη is measured in the center-of-mass energy range 1.34–2.00 GeV. The analysis is based on data collected with the SND detector at the VEPP-2000 e+e− collider. ...The measured e+e−→ωη cross section is the most accurate to date. A significant discrepancy is observed between our data and previous BABAR measurements.
The VEPP-2000 electron–positron collider has been operating at the Budker Institute of Nuclear Physics (BINP) since 2010. Applying the concept of round colliding beams allowed the record value of the ...beam–beam parameter ξ ∼ 0.12 to be reached. The upgrading of the VEPP-2000 complex, including the connection to the new BINP Injection Complex and modification of the electron–position booster and the BEP–VEPP-2000 transfer channels to work at 1 GeV, resulted in a significant increase in luminosity. Work on statistical data collection using detectors is in progress.
Since December 2010, the CMD-3 detector has collected data at the electronpositron collider VEPP-2000. The sample of the accumulated data corresponds to about 60 pb−1 of integrated luminosity in the ...c.m. energy from 0.32 up to 2 GeV. Preliminary results of the analysis of various processes e+e− annihilation to hadrons are presented. It is shown the processes with multihadron events have several intermediate states which must be taken into account to correctly describe the angular and invariant mass distributions as well as cross section dependence versus energy.
Recent results on
e
+
e
−
annihilation to hadrons from SND experiment at VEPP-2000 collider are presented. Corresponding data set is about 200 pb
−1
of integrated luminosity collected at the energy ...region below 2 GeV. The processes
e
+
e
−
→ π
+
π
−
, π
0
γ, ωπ
0
, π
+
π
−
π
0
, ηπ
+
π
−
π
0
,
η
, π
+
π
−
4π
0
have been studied. Searches for
e
+
e
−
annihilation to
C
-even resonances η and
f
1(1285) were done.
Abstract
The process
$$e^+e^-\rightarrow n{\bar{n}}$$
e
+
e
-
→
n
n
¯
is studied in the experiment at the VEPP-2000
$$e^+e^-$$
e
+
e
-
collider with the SND detector. The technique of the time ...measurements in the multichannel NaI(Tl) electromagnetic calorimeter is used to select
$$n{\bar{n}}$$
n
n
¯
events. The value of the measured cross section in the center-of-mass energy range from 1.894 to 2 GeV varies from 0.5 to 0.35 nb. The effective neutron timelike form factor is derived from the measured cross section and compared with the proton form factor. The ratio of the neutron electric and magnetic form factors is obtained from the analysis of the antineutron polar angle distribution and found to be consistent with unity.
Abstract
The process
$$e^+e^-\rightarrow \eta \eta \gamma $$
e
+
e
-
→
η
η
γ
is studied in the center-of-mass energy range 1.17–2.00 GeV using data with an integrated luminosity of 201 pb
$$^{-1}$$
-
...1
collected by the SND detector at the VEPP-2000
$$e^+e^-$$
e
+
e
-
collider. The
$$e^+e^-\rightarrow \eta \eta \gamma $$
e
+
e
-
→
η
η
γ
cross section is measured for the first time. It is shown that the dominant mechanism of this reaction is the transition through the
$$\phi \eta $$
ϕ
η
intermediate state. Our result on the
$$e^+e^-\rightarrow \eta \eta \gamma $$
e
+
e
-
→
η
η
γ
cross section is consistent with the
$$e^+e^-\rightarrow \phi \eta $$
e
+
e
-
→
ϕ
η
measurement in the
$$\phi \rightarrow K^+ K^-$$
ϕ
→
K
+
K
-
mode. The search for radiative processes contributing to the
$$e^+e^-\rightarrow \eta \eta \gamma $$
e
+
e
-
→
η
η
γ
cross section is performed, and no significant signal is observed.
Abstract The process $$e^+e^-\rightarrow \eta \eta \gamma $$ e + e - → η η γ is studied in the center-of-mass energy range 1.17–2.00 GeV using data with an integrated luminosity of 201 pb $$^{-1}$$ - ...1 collected by the SND detector at the VEPP-2000 $$e^+e^-$$ e + e - collider. The $$e^+e^-\rightarrow \eta \eta \gamma $$ e + e - → η η γ cross section is measured for the first time. It is shown that the dominant mechanism of this reaction is the transition through the $$\phi \eta $$ ϕ η intermediate state. Our result on the $$e^+e^-\rightarrow \eta \eta \gamma $$ e + e - → η η γ cross section is consistent with the $$e^+e^-\rightarrow \phi \eta $$ e + e - → ϕ η measurement in the $$\phi \rightarrow K^+ K^-$$ ϕ → K + K - mode. The search for radiative processes contributing to the $$e^+e^-\rightarrow \eta \eta \gamma $$ e + e - → η η γ cross section is performed, and no significant signal is observed.
This paper reports measurements of the hadronic cross sections with the CMD-3 detector at the VEPP-2000 electron-positron collider. The overall size of the data sample analyzed is about 60 pb-1, ...collected by the CMD- 3 running since December 2010 up to June 2013 in the c.m. energy range from 0.32 to 2.0 GeV. The preliminary results of data analysis for various modes of e+e−→hadrons are discussed.
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