Using the KEDR detector at the VEPP-4M e+e− collider, we have determined the values of R at thirteen points of the center-of-mass energy between 1.84 and 3.05 GeV. The achieved accuracy is about or ...better than 3.9% at most of the energy points with a systematic uncertainty less than 2.4%.
Using the KEDR detector at the VEPP-4M e+e− collider, we have measured the values of Ruds and R at seven points of the center-of-mass energy between 3.12 and 3.72 GeV. The total achieved accuracy is ...about or better than 3.3% at most of energy points with a systematic uncertainty of about 2.1%. At the moment it is the most accurate measurement of R(s) in this energy range.
We present the analysis of all KEDR data on the determination of J/ψ and ψ(2S) masses. The data comprise six scans of J/ψ and seven scans of ψ(2S) which were performed at the VEPP-4M e+e− collider in ...2002–2008. The beam energy was determined using the resonance depolarization method. The detector and accelerator conditions during scans were very different that increases the reliability of the averaged results. The analysis accounts for partial correlations of systematic uncertainties on the masses. The following mass values were obtained:MJ/ψ=3096.900±0.002±0.006 MeV,Mψ(2S)=3686.099±0.004±0.009 MeV. These results supersede our previous measurements published in 2003 and 2012.
This paper describes an approach enabling the continuous monitoring of all devices on the Synchrotron Radiation Facility Siberian Circular Photon Source (SRF SKIF) accelerator complex units ...synchronically with the measurements of beam parameters. The operation of devices is monitored in distributed controllers with a frequency of 10 kHz. After detecting any deviations from specified parameters above the tolerance value in the operation of a device, the controller of this device sets a corresponding signal. When a beam exhibits an abnormal behavior, the comparative analysis of synchronous data from the distributed controllers and the beam diagnosing electronics is performed to reveal the device resulting in such a behavior.
The present work continues a series of the KEDR measurements of the R value that started in 2010 at the VEPP-4M e+e− collider. By combining new data with our previous results in this energy range we ...measured the values of Ruds and R at nine center-of-mass energies between 3.08 and 3.72 GeV. The total accuracy is about or better than 2.6% at most of energy points with a systematic uncertainty of about 1.9%. Together with the previous precise R measurement at KEDR in the energy range 1.84–3.05 GeV, it constitutes the most detailed high-precision R measurement near the charmonium production threshold.
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.
Using the inclusive photon spectrum based on a data sample collected at the J/ψ peak with the KEDR detector at the VEPP-4M e+e− collider, we measured the rate of the radiative decay J/ψ→γηc as well ...as ηc mass and width. Taking into account an asymmetric photon lineshape we obtained Γγηc0=2.98±0.18−0.33+0.15keV, Mηc=2983.5±1.4−3.6+1.6MeV/c2, Γηc=27.2±3.1−2.6+5.4MeV.
Measurement of Γee(J/ψ) with KEDR detector Anashin, V. V; Aulchenko, V. M; Baldin, E. M ...
The journal of high energy physics,
05/2018, Letnik:
2018, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A
bstract
The product of the electronic width of the
J/ψ
meson and the branching fractions of its decay to hadrons and electrons has been measured using the KEDR detector at the VEPP-4M
e
+
e
−
...collider. The obtained values are
Γ
e
e
J
/
ψ
=
5.550
±
0.056
±
0.089
keV
,
Γ
e
e
J
/
ψ
·
ℬ
hadrons
J
/
ψ
=
4.884
±
0.048
±
0.078
keV
,
Γ
e
e
J
/
ψ
·
ℬ
e
e
J
/
ψ
=
0.3331
±
0.0066
±
0.0040
keV
.
The uncertainties shown are statistical and systematic, respectively. Using the result presented and the world-average value of the electronic branching fraction, one obtains the total width of the
J/ψ
meson:
Γ
=
92.94
±
1.83
keV
.
These results are consistent with the previous experiments.
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