First Physical Results from SND Detector at VEPP-2M

TL;DR

This paper reports the initial experimental results from the SND detector at VEPP-2M, including measurements of meson production and rare decay processes, based on data collected between 1995 and 1997.

Contribution

First physical results from the SND detector at VEPP-2M, including measurements of meson production and rare decay branching ratios.

Findings

Collected 6.4 pb^{-1} of data in 1995-1997

Produced 4 million phi-mesons

Measured several rare decay branching ratios

Abstract

The paper describes experiments with the SND detector at VEPP-2M collider, carried out during the period from October 1995 until June 1997. The total integrated luminosity of 6.4 pb^{-1} was collected in the energy range 2E=0.4-1.4 GeV (MHAD97 experiment), corresponding to 4*10^5 mu^+ mu^- pairs produced. Preliminary results of the 1996 phi-meson experiment (FI96) are presented. The total number of phi-mesons produced is 4*10^6. New data on rare decays of phi and eta (550) mesons, in particular B(phi -> eta gamma) = (1.30+-0.06+-0.07)%, B(phi -> pi^0 pi^0 gamma) = (1.1+-0.2)*10^{-4}, (M_{pi^0 pi^0} > 800 MeV), B(phi -> f^0 gamma) = (4.7+-1.0)*10^{-4}, B(phi -> eta pi^0 gamma) = (1.3+-0.5)*10^{-4}, B(phi -> eta' gamma) < 1.7*10^{-4}, B(phi -> 2 pi^0 ) < 6*10^{-4} were obtained.