S. G. Klimenko

Status of the KEDR detector

Abstract KEDR is a general-purpose detector for experiments at the VEPP-4M e + e − -collider in the energy range 2 E =2.0– 12 GeV . All detector subsystems (except the aerogel Cherenkov counters) have been installed into the detector at VEPP-4M. Some preliminary data have been taken in the energy region of the J/Ψ meson. The tuning of the detector and the VEPP-4M collider is in progress. Preliminary results on the detector performance are presented. The future experimental program for the KEDR detector is discussed.

Experimental investigation of high-energy photon splitting in atomic fields

Data analysis of an experiment in which photon splitting in atomic fields was observed is presented. The experiment was performed at the tagged photon beam of the ROKK-1M facility at the VEPP-4M collider. In the energy region of 120-450 MeV, statistics of 1.6x10(9) photons incident on the BGO target was collected. About 400 candidate photon-splitting events were reconstructed. Within the attained experimental accuracy, the experimental results are consistent with the calculated exact atomic-field cross section. The predictions obtained in the Born approximation differ significantly from the experimental results.

Delbrück scattering at energies of 140–450 MeV

The differential cross section of Delbr{u}ck scattering is measured on a bismuth germanate

Luminosity measurement with the MD-1 detector at VEPP-4

Bi_4Ge_3O_{12}

Investigation of an electromagnetic calorimeter based on liquid krypton

target at photon energies

A high precision measurement of the ϒ, ϒ′ and ϒ″-meson masses

140 - 450 MeV

Liquid krypton calorimeter for KEDR detector

and scattering angles

Experiments with the MD-1 detector at the e+e− collider VEPP-4 in the energy region of ϒ mesons

2.6 - 16.6 mrad

Measurement of particle polarization in e+e− storage rings by means of synchrotron radiation scattering on the colliding beam

. A good agreement with the theoretical results, obtained exactly in a Coulomb field, is found.

Liquid krypton calorimeter for KEDR detector and last prototype results

Abstract For the luminosity measurements with the MD-1 at VEPP-4, elastic Bhabha scattering at small angles and single bremsstrahlung were used. The relative errors of the luminosity measurements were 1.5% for a small angle monitor and about 3% for a single bremsstrahlung monitor. The absolute luminosity calibration was performed using the processes of double bremsstrahlung and large angle Bhabha scattering. The accuracy of the calibration was estimated to be 2.5%.