Belle II distributing computing Krokovny, P
Journal of physics. Conference series,
05/2015, Letnik:
608, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The next generation B factory experiment Belle II will collect huge data samples which are a challenge for the computing system. To cope with the high data volume and rate, Belle II is setting up a ...distributed computing system based on existing technologies and infrastructure, plus Belle II specific extensions for workflow abstraction. This paper describes the highlights of the Belle II computing and the current status. We will also present the experience of the latest MC production campaign in 2014.
A
bstract
The cross section of the process
e
+
e
−
→ ηπ
+
π
−
is measured using the data collected with the CMD-3 detector at the VEPP-2000 collider in the center-of-mass energy range from 1
.
1 to 2
....
0 GeV. The decay mode
η → γγ
is used for
η
meson reconstruction in the data sample corresponding to an integrated luminosity of 78
.
3 pb
−
1
. The energy dependence of the
e
+
e
−
→ ηπ
+
π
−
cross section is fitted within the framework of vector meson dominance in order to extract the Γ(
ρ
(1450)
→ e
+
e
−
)
B
(
ρ
(1450)
→ ηπ
+
π
−
) and the Γ(
ρ
(1700)
→ e
+
e
−
)
B
(
ρ
(1700)
→ ηπ
+
π
−
) products. Based on conservation of vector current, the analyzed data are used to test the relationship between the
e
+
e
−
→ ηπ
+
π
−
cross section and the spectral function in
τ
−
→ ηπ
−
π
0
ντ
decay. The
e
+
e
−
→ ηπ
+
π
−
cross section obtained with the CMD-3 detector is in good agreement with the previous measurements.
A brief review of the recent results on the hadronic cross section measurements with the CMD-3 detector at the
e
+
e
−
collider VEPP-2000 is given. Focus is made on the processes with charged kaons ...in multihadron events, which have a strong impact on strange meson spectroscopy and form factors that are important ingredients in the Dalitz plot analysis. Experimental data relevant to the topic are presented from the broad energy range covered by VEPP-2000 and compared to earlier measurements by the different collaborations. The analysis is based on the integrated luminosity of about 100 pb
−1
collected in 2011, 2012 and 2017.
The cross section of the process
e
+
e
−
→ π
+
π
−
π
+
π
−
has been measured using an integrated luminosity of 17 pb
−1
collected with the CMD-3 detector in the center-of-mass energy range 650-1000 ...MeV. High-precision measurements of various hadronic cross sections are of great interest in relation with the problem of the muon anomalous magnetic moment g-2. This measurement can be also used to test the relation between the cross section of
e
+
e
−
→ π
+
π
−
π
+
π
−
and the spectral function for the τ
−
→ π
−
π
0
π
0
π
0
decay predicted by the conservation of vector current (CVC).
A search for the process
e
+
e
−
→
D
*0
(2007) has been performed with the CMD-3 detector at the VEPP-2000
e
+
e
−
-collider. Two main decay modes of the
D
*0
(2007) decay,
D
0
π
0
and
D
0
γ, ...followed by
D
0
→
K
+
π
−
π
+
π
−
are used in this analysis. With an integrated luminosity of 3.7 pb
−1
collected at the center-of-mass energy E
c.m.
=2006.62 MeV our preliminary upper limit is B
D*
0
→
e
+
e
−
<1.6× 10
−6
at 90%C.L.
Existing Monte-Carlo generators with radiative corrections to the
e
+
e
-
→π
+
π
-
process are usually developed under the assumption that pions can be treated as pointlike particles. We study the
e
...+
e
-
→π
+
π
-
γ
process with final-state radiation and test this assumption using simulated events from the MCGPJ generator based on the scalar QED hypothesis. In order to increase a fraction of events with FSR, the analysis was performed in the energy region to the left from the
ρ
-meson peak (660÷785 MeV) that is based on the integrated luminosity of about 8.4 pb
-1
. The experimental data for the photon energy spectrum agree with the simulation results at 1% level.
A large data sample of
e
+
e
-
→ 4π collected by the CMD-3 experiment at the VEPP-2000
e
+
e
−
collider allowed for an amplitude analysis of the process
e
+
e
−
→ 4π in the center-of-mass energy ...range 900–2000 MeV. Various intermediate components were distinguished and dominance of the ωπ
0
and a
1
π amplitudes has been proved.
A study of hadron production at the nucleon-antinucleon threshold has been performed with the CMD-3 detector at the VEPP-2000
e
+
e
−
collider. A very fast rise with an about 1 MeV width has been ...observed in the
e
+
e
−
→
pp
̅ cross section. A sharp drop in the
e
+
e
−
→ 3(π
+
π
−
) cross section has been con?rmed and found to have a width of less than 2 MeV, in agreement with the observed fast rise of the
e
+
e
−
→
pp
̅ cross section. For the ?rst time a similar sharp drop is demonstrated in the
e
+
e
−
→
K
+
K
−
π
+
π
−
cross section. The behavior of the
e
+
e
−
→ 3(π
+
π
−
),
K
+
K
−
π
+
π
−
cross sections cannot be explained by an interference of any resonance amplitude with continuum, therefore this phenomenon cannot be due to a narrow near-threshold resonance. No such structure has been observed in the
e
+
e
−
→ 2(π
+
π
−
) cross section.
The results of the experiment on the measurement of the e+e− → π+π− cross section in a cm energy range of 370–520 MeV are presented. The systematic measurement error is equal to 0.7%. In the vector ...dominance model, the pion electromagnetic radius is calculated using all the CMD-2 data on the pion form factor. The cross section for the production of a muon pair is measured in the energy range of the experiment.
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