L.B. Epshteyn

Study of the process e+e−→pp¯ in the c.m. energy range from threshold to 2 GeV with the CMD-3 detector

Abstract Using a data sample of 7.7 pb − 1 collected with the CMD-3 detector at the VEPP-2000 e + e − collider we select about 2900 events of the process e + e − → p p ¯ and measure its cross section at 12 energy points with about 6% systematic uncertainty. From the angular distribution of produced nucleons we obtain the ratio G E / G M .

The CMD-3 TOMA DAQ infrastructure

An upgrade of the CMD-3 detector for the VEPP-2000 e+e− collider is now in progress at the Budker Institute of Nuclear Physics (BINP) in Novosibirsk. CMD-3 is equipped with a TOMA (Time Oriented Measurement and Acquire) DAQ system specially developed for the experiments at low energy e+e− colliders. The CMD-3 TOMA DAQ has a high grade of unification, which decreases the cost of ownership and production time of the whole system. Unification also makes it possible to reduce the variety, the price and the production time of the DAQ modules. Special attention is paid to the synchronization of the data transmission and on-line checks of electronics. The communication between DAQ elements is realized via a custom developed interface named C-Link. Several types of DAQ TOMA modules are briefly described.

Current status of luminosity measurement with the CMD-3 detector at the VEPP-2000

Since December 2010 the CMD-3 detector has taken data at the electron-positron collider VEPP-2000. The collected data sample corresponds to an integrated luminosity of 60 pb−1 in the c.m. energy from 0.32 up to 2 GeV. The preliminary results of the luminosity measurement are presented in various energy ranges. The current accuracy for integrated luminosity is estimated to be 1%.

e^+e^-

A cross section of the process

collider

e^+e^- \to \pipi\pipi

Study of the process

has been measured using 6798

e^+e^-\to \pi^+\pi^-\pi^+\pi^-

\pm

in the c.m. energy range 920–1060 MeV with the CMD-3 detector

93 signal events from a data sample corresponding to an integrated luminosity of 9.8 pb

MEASUREMENT OF THE

^{-1}

e^+e^- \to p \bar{p}

collected with the CMD-3 detector in the center-of-mass energy range 920--1060 MeV. The measured cross section exhibits an interference pattern of the