Experiments with the SND detector at the e[sup +]e[sup −] collider VEPP-2M in Novosibirsk

Recent results from e+e− → hadrons

“…Below 1 GeV CMD-2 reliably selected about 200 events of the reaction e + e − → π + π − π + π − and measured the cross sections as low as about 50 pb near the ρ peak [29]. The measurement of the SND detector for which the data sample above the φ was about 80000 events and the systematic uncertainty ranged from 8 to 20%, confirmed the CMD-2 results on the production mechanisms [30].…”

“…SND described in detail elsewhere [16] is a nonmagnetic detector with drift chambers for tracking and a three layer NaI electromagnetic calorimeter. Outside it there are a muon streamer tube chamber and plastic scintillators.…”

Observation of the conversion decay φ→π0e+e− at CMD-2

“…A large data sample of the φ mesons collected by two detectors at VEPP-2M allowed reliable detection of the decay mode φ → ηe + e − by both CMD-2 [ 13] and SND [ 14] groups. CMD-2 has also reported on the first observation of the φ → π 0 e + e − decay [ 13].…”

Confronting spectral functions from e+e− annihilation and τ decays: Consequences for the muon magnetic moment

“…These are probably related to problems in the calculation of the detection efficiency, since the efficiencies are small in general (∼ 10 − 30%) and they are affected by uncertainties in the decay dynamics that is assumed in the Monte Carlo simulation. One could expect the more recent experiments (CMD-2 [40] and SND [41]) to be more reliable in this context because of specific studies performed in order to identify the major decay processes involved.…”