In this paper, we describe the project of a photon source with energies up to 2500 MeV at the SKIF synchrotron radiation facility (under construction in Novosibirsk). It is intended for experiments ...on photonuclear reactions, nonlinear QED, EM detector calibration and other applications. A polarized photon beam with a flux of 10
6
–10
8
Hz (in full spectrum) is produced using Compton backscattering (or inverse scattering) of IR, visible, and UV laser radiation, as well as the UV band of its own synchrotron radiation, on the SKIF electron beam (15 kHz). Spectrum monochromatization with collimators or/and tagging system by recoil electrons is possible. The discrepancy between experimental and theoretical photofission cross sections of actinide nuclei in a photon energy range of hundreds of MeV has been known since the 1980s, so it is proposed to study these cross sections in the first series of experiments.
Study of the Process in the Energy Range GeV Achasov, M. N.; Barnyakov, A. Yu; Beloborodov, K. I. ...
Physics of atomic nuclei,
2023/12, Letnik:
86, Številka:
6
Journal Article
Recenzirano
The
cross section is measured in the center-of-mass energy range from 1.07 to 2.00 GeV in the decay channel
,
. The data set with an integrated luminosity of 242 pb
accumulated in the experiment with ...the SND detector at the VEPP-2000
collider is analyzed.
The Spherical Neutral Detector (SND) is an experiment for e+e− annihilation study at low energies 0.2−2 GeV. The light quark anti−quark bound states are the main subject of study at these energies. ...They express themselves as resonances in the e+e− hadronic cross sections. Hadronic cross sections could be recalculated to hadronic vacuum polarization (HVP). The Standard Model predictions today are limited by HVP which is not calculable with modern QCD theory. In this talk we present the review of the hadronic cross sections measurements at SND and new measurements: e+e− → π+π−, π0γ, π+π−π0, ωπ0, K+K−η, η, KsKLπ0, π+π−π0η, ωπ0η e.t.c.
The beam energy measurement system for the VEPP-2000 electron-positron collider is described. The method of Compton backscattering of CO laser photons on the electron beam is used. The relative ...systematic uncertainty of the beam energy determination is estimated as 610 super(-5). It was obtained through comparison of the results of the beam energy measurements using the Compton backscattering and resonance depolarization methods.
Laser backscattering was implemented as a tool for accurate beam energy measurement at three of the five existing electron-positron colliders. The present report summarizes the experience obtained ...during these experiments.
Energy deviation study of BEMS at BEPCII Zhang, J.Y.; Cai, X.; Mo, X.H. ...
Nuclear physics. B,
February 2019, 2019-02-00, 2019-02-01, Letnik:
939, Številka:
C
Journal Article
Recenzirano
Odprti dostop
The beam energy measurement system (BEMS) at the upgraded Beijing Electron-Positron Collider (BEPCII) is designed to provide beam energy value with the relative error at the level of 5×10−5. The ...obvious energy deviation found during J/ψ resonance scan in 2012 leads to great amount of investigations on both BEPCII and BEMS sides. The reasons causing such an unexpected difference are figured out, which include the neutron damage to HPGe detector, the leakage of RF cavity, and the background from Linac. Based on a series of measures, the ψ(3686) line shape scan is designed and performed, the experimental result indicates that BEMS can measure the beam energy with the claimed accuracy. The afterward performance of BEMS is smooth and stable, and BEMS will play a crucial role in the following high accurate experiments.
Search for the Process with the SND Detector Achasov, M. N.; Barnyakov, A. Yu; Beloborodov, K. I. ...
Physics of atomic nuclei,
09/2020, Letnik:
83, Številka:
5
Journal Article
Recenzirano
The results of searches for the process
in an experiment with the SND detector at the VEPP-2000 electron–positron collider are presented. The data used in these searches and based on an integrated ...luminosity of about 87 pb
were accumulated at c.m. energies
between 1.15 and 2 GeV. The upper limits of
pb for
GeV and
pb for
GeV were set at a 90
confidence level.
KEDR detector has the tagging system (TS) to study the gamma-gamma processes. To determine the two-photon invariant mass, the energies of the scattered at small angles electrons and positrons are ...measured by the magnetic spectrometer embedded into the lattice of the VEPP-4M collider. The energy resolution (scattered electron/positron energy resolution divided by the beam energy) of this spectrometer varies from 0.6% to 0.03% depending on the electron/positron energy. The Compton backscattering of laser radiation on the electron/positron beam is used for the accurate energy scale and resolution calibration of the tagging system. The report covers the design, recent results and current status of the KEDR TS calibration system.
The process
is studied in the range of center-of-mass (c.m.) collision energies between 1.05 and 2.00 GeV on the basis of data corresponding to an integrated luminosity of 94.5 pb
that were ...accumulated in an experiment with the SND detector at the VEPP-2000
collider. The cross section for this process was measured for the first time and was found to receive a dominant contribution from the mechanism of a transition through an
intermediate state. The cross section measured for the process
agrees with the results of earlier measurements in the channel
. At a level of 5.7 standard deviations (5.7
), it is established that the process
is not fully described by hadronic intermediate states of the
type. The cross section was measured for this missing contribution, which may be generated by radiative processes—for example,
. It ranges from 15 to 20 pb over a broad energy interval extending from 1.3 to 1.9 GeV.
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