Mikhail N Achasov

Spherical neutral detector for VEPP-2M collider

Abstract The Spherical Neutral Detector (SND) operates at VEPP-2M collider in Novosibirsk studying e + e − annihilation in the energy range up to 1.4xa0GeV. Detector consists of a fine granulated spherical scintillation calorimeter with 1632 NaI(Tl) crystals, two cylindrical drift chambers with 10 layers of sense wires, and a muon system made of streamer tubes and plastic scintillation counters. The detector design, performance, data acquisition and processing are described.The Spherical Neutral Detector (SND) operates at VEPP-2M collider in Novosibirsk studying e^+e^- annihilation in the energy range up to 1.4 GeV. Detector consists of a fine granulated spherical scintillation calorimeter with 1632 NaI(Tl) crystals, two cylindrical drift chambers with 10 layers of sense wires, and a muon system made of streamer tubes and plastic scintillation counters. The detector design, performance, data acquisition and processing are described.

First observation of φ(1020)→π0π0γ decay

In the SND experiment at the VEPP-2M electron-positron collider the PHI(1020)--->PI0+PI0+GAMMA decay was studied. The branching ratio B(PHI--->PI0+PI0+GAMMA)=(1.14+-0.10+-0.12)x10^{-4} was measured. It was shown, that the F0(980)GAMMA mechanism dominates in this decay and the 4-quark model of F0(980) describes our data most consistently.Abstract In the SND experiment at VEPP-2M e + e − collider the φ (1020)→ π 0 π 0 γ decay was studied. Its branching ratio B ( φ → π 0 π 0 γ )=(1.14±0.10±0.12)·10 −4 was measured. It was shown, that f 0 (980) γ mechanism dominates in this decay. Corresponding branching ratio B ( φ → f 0 γ )=(3.42±0.30±0.36)·10 −4 was obtained.

The φ(1020) → π0π0γ decay

In the SND experiment at VEPP-2M

Evidence of the φ → ηπ0γ decay

e^+e^-

The φ→ηπ0γ decay

collider the

The process e+e−→ωπ0→π0π0γ up to 1.4 GeV

phi(1020)topi^0pi^0gamma

Dynamics of η → 3π0 decay

decay was studied and its branching ratio was measured:

Upper limit on the KS→3π0 decay

B(phitopi^0pi^0gamma)=(1.221pm 0.098pm0.061)cdot10^{-4}

The e+e−→π0π0γ process below 1.0 GeV

. It was shown, that

Observation of the decay φ→ωπ0

f_0(980)gamma