36 research outputs found
Study of the process e+eββ3(Ο+Οβ) in the c.m. energy range 1.5β2.0 GeV with the CMD-3 detector
AbstractThe cross section of the process e+eββ3(Ο+Οβ) has been measured using a data sample of 22Β pbβ1 collected with the CMD-3 detector at the VEPP-2000 e+eβ collider. 7956 signal events are selected in the center-of-mass energy range 1.5β2.0 GeV. The measured cross section exhibits a sharp drop near the ppΒ― threshold. A first study of dynamics of six-pion production has been performed
Study of the process e+eββK+Kβ in the center-of-mass energy range 1010β1060 MeV with the CMD-3 detector
The process e+eββK+Kβ has been studied using 1.7Γ106 events from a data sample corresponding to an integrated luminosity of 5.7 pbβ1 collected with the CMD-3 detector in the center-of-mass energy range 1010β1060 MeV. The cross section is measured with about 2% systematic uncertainty and is used to calculate the contribution to the anomalous magnetic moment of the muon aΞΌK+Kβ=(19.33Β±0.40)Γ10β10, and to obtain the Ο(1020) meson parameters. We consider the relationship between the e+eββK+Kβ and e+eββKS0KL0 cross sections and compare it to the theoretical prediction
Study of the process e+eβ β 2(Ο+ΟβΟ0) with the CMD-3 detector at VEPP-2000 collider
Since 2010 the CMD-3 detector has been collecting data at the VEPP-2000 e+eβ collider. CMD-3 is a general purpose detector designed to study e+eβ annihilation into hadrons in the center-of-mass (c.m.) energy range from 0.3 up to 2 GeV. Preliminary results for the e+eβ β 2(Ο+ΟβΟ0) cross section were obtained in the c.m. energy range from 1.5 up to 2 GeV. The analysis is based on a data sample of 22 pbβ1
Study of the processes
The data sample collected in 2011-2013 at the c.m.s. energies between 0.32-2 GeV with the CMD-3 detector operating at the VEPP-2000 e+eβ collider is analzed. The collected data corresponds to an integrated luminosity about βΌ 60pbβ1. The techniques for determination of the integrated luminosity for each energy setting is described. Some preliminary results of the study of the processes e+eββ K+ Kβ + nΟ (n = 1,2,3) with two charged kaons in the final state are presented. These processes have several intermediate states, which are important to correctly descript the angular distributions of final particles and the cross sections dependence on the energy
CMD-3 Overview
The CMD-3 detector is installed at the VEPP-2000 e+eβ collider at BINP (Novosibirsk, Russia). It is a general-purpose detector, equipped with a tracking system, two crystal (CSI and BGO) calorimeters, liquid Xe calorimeter, TOF and muon systems. The main goal of experiments at CMD-3 is a study of exclusive modes of e+eββ hadrons at energies GeV. In particular, these results provide an important input for calculation of the hadronic contribution to the muon anomalous magnetic moment.
The first round of data taking was performed in 2011β2013, when about 60 1/pb were taken in the center-of-mass (c.m.) energy range from 0.32 to 2.0 GeV. Here we present a survey of results of data analysis.
Between 2013 and 2016 the collider and the detector were upgraded. The data taking resumed by the end of 2016. In the first run after the upgrade about 50 1/pb were collected at the energy range between 1.28 and 2.007 GeV. We discuss the upgrade and the first preliminary results from the new data
Study of the process e+eββKS0KL0 in the center-of-mass energy range 1004β1060 MeV with the CMD-3 detector at the VEPP-2000 e+eβ collider
The e+eββKS0KL0 cross section has been measured in the center-of-mass energy range 1004β1060 MeV at 25 energy points using 6.1Γ105 events with KS0βΟ+Οβ decay. The analysis is based on 5.9Β pbβ1 of an integrated luminosity collected with the CMD-3 detector at the VEPP-2000 e+eβ collider. To obtain Ο(1020) meson parameters the measured cross section is approximated according to the Vector Meson Dominance model as a sum of the Ο,Ο,Ο-like amplitudes and their excitations. This is the most precise measurement of the e+eββKS0KL0 cross section with a 1.8% systematic uncertainty
Study of the process e+eββΟ+ΟβΟ+Οβ in the c.m. energy range 920β1060 MeV with the CMD-3 detector
A cross section of the process e+eββΟ+ΟβΟ+Οβ has been measured using 6798Β±93 signal events from a data sample corresponding to an integrated luminosity of 9.8 pbβ1 collected with the CMD-3 detector in the center-of-mass energy range 920β1060 MeV. The measured cross section exhibits a pattern of interference of the Ο(1020)βΟ+ΟβΟ+Οβ decay with a non-resonant process e+eββΟ+ΟβΟ+Οβ, from which we obtain the branching fraction of the doubly suppressed decays (by G-parity and OZI rule): B(ΟβΟ+ΟβΟ+Οβ)=(6.5Β±2.7Β±1.6)Γ10β6