Measurement of RudsR_{\text{uds}} and RR between 3.12 and 3.72 GeV at the KEDR detector

Using the KEDR detector at the VEPP-4M $e^+e^-$ collider, we have measured the values of $R_{\text{uds}}$ 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

The Super C-

The Super C-τ (SCT) Factory at Novosibirsk is a project of new colliding beam experiment proposed in Budker Institute of Nuclear Physics. Electron-positron collider based on Crab-Waist technique for operation energy range 2–5 GeV in center of mass is suggested. The luminosity up to 1035cm−1s−1 (in 100 times higher than in operated today experiments in this energy region) is expected. To perform broad experimental program of the project successfully the excellent particle identification (PID) system is needed. A number of options are under consideration. Three of them are described in the paper: Focusing Aerogel RICH (FARICH) detector, threshold Cherenkov counters based on ASHIPH (Aerogel SHifter PHotomultiplier) technique with 6000 litres of aerogel of two refractive indexes and time-of-flight counters with TOP (Time of Propagation) approach with time resolution better than 30 ps. Comparison of PID capabilities with help of parametric simulation is given

Final analysis of KEDR data on J/ψ and ψ(2S) masses

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