The VEPP-4 facility is an
e
+
e
–
collider with a beam energy up to 2 GeV. The scientific program includes topics in high-energy and nuclear physics, as well as various investigations using ...synchrotron radiation and polarized or unpolarized charged-particle beams. An energy upgrade to 5 GeV is planned, and reliable and efficient operation of the storage-ring complex upon increased energy must be provided. We discuss the recent experimental results and the opportunities to be created by the energy upgrade.
To obtain a harder energy spectrum and increase the photon flux and brightness of synchrotron radiation of the Synchrotron Radiation Facility—Siberian Circular Photon Source “SKlF” synchrotron light ...source, it is planned to use multipole superconducting insertion devices—radiation generators (wigglers and undulators). Having a short period and large amplitude of the magnetic field, such devices have a serious impact on the optics and dynamics of the electron beam. In the proposed work, we consider various aspects of this influence (changes in radiation parameters, distortion of optical functions, and a reduction in dynamic aperture) and discuss possible options for correcting the undesirable consequences of installing wigglers and undulators in the SKIF storage ring.
A
bstract
We present the study of the decay
J/ψ
→
ρπ
. The results are based on of 5.2 million
J/ψ
events collected by the KEDR detector at the VEPP-4M collider. The branching fractions are measured ...to be
B
(
J/ψ
→
ρπ
) = (2
.
072 ± 0
.
017 ± 0
.
062) ∙ 10
−
2
and
B
(
J/ψ
→
π
+
π
−
π
0
) = (1
.
878 ± 0
.
013 ± 0
.
051) ∙ 10
−
2
, where the first uncertainties are statistical and the second systematic. Our results are more precise than the previous relative measurements.
Using the 1.32
pb
-
1
statistics collected at the
J
/
ψ
peak with the KEDR detector at the VEPP-4M
e
+
e
-
collider, we measured the branching fractions of
J
/
ψ
meson decays to the final states 2(
π
...+
π
-
)
π
0
,
K
+
K
-
π
+
π
-
π
0
, 2(
π
+
π
-
)
and
K
+
K
-
π
+
π
-
. The results obtained for the decays
J
/
ψ
→
2(
π
+
π
-
)
π
0
,
J
/
ψ
→
K
+
K
-
π
+
π
-
π
0
contradict the measurements performed by other groups in the last century, but agree well with recent results of BABAR and BESIII collaborations.
Using the MADX options, the stages of orbit correction and then optics correction were simulated, taking into account the specified tolerances for the positioning of magnetic elements and girders in ...the Siberian Circular Photon Source (SKIF, the Russian acronym). Numerical modeling of hte effect of residual perturbations of the guide field on the vertical emittance and vertical size of the beam has been carried out. A generalized method of skew-quadrupole coupling correction in SKIF has been developed and verified by simulation, which allows simulteneously minimizing the vertical dispersion and compensating for the linear difference coupling resonance.
A method proposed to preserve the electron beam polarization at the VEPP-4M collider during acceleration with crossing the integer (imperfection) spin resonance at energyE=1763MeVhas been ...successfully applied. It is based on full decompensation of the0.6×3.3Tesla×meterintegral of the KEDR detector longitudinal magnetic field due to the antisolenoid being “switched off.”
VEPP-4 is a multipurpose storage ring facility at Budker Institute of Nuclear Physics (Novosibirsk, Russia) with several research programs including high energy physics in colliding beam mode, ...nuclear physics, synchrotron radiation, accelerator physics study, etc. The paper discusses VEPP-4 activities relating to generation and application of synchrotron radiation not only for SR user community but for beam diagnostics in storage ring as well.
The main technical solutions chosen to implement the project of fourth-generation synchrotron radiation (SR) source Synchrotron Radiation Facility “Siberian Circular Photon Source” (SRF SKIF), which ...is currently being built in Novosibirsk, are presented. The choice of the configuration and parameters of the synchrotron radiation source is described; the principles of the scientific program compilation are considered; and the radiation generation devices, the frontend design, and the engineering infrastructure are discussed.
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