The CMD-3 detector is taking data at the VEPP-2000 e + e − collider (Budker INP, Novosibirsk, Russia). The main goal of experiments with CMD-3 is the measurement of the cross-sections and dynamics of the exclusive modes of e + e − annihilation to hadrons. In particular, these results provide an important input for calculations of the hadronic contribution to the muon anomalous magnetic moment. The first round of data taking with the CMD-3 detector was performed in 2011-2013 with about 60 1/pb integrated luminosity in the center-of-mass (c.m.) energy range from 0.32 to 2.0 GeV. The collected data sample exceeds those in all previous experiments. Here we present the survey of results of data taken in 2011-2013, including a precise measurement of the e + e − → π + π − reaction as well as other hadron final states with up to six pions or states including two kaons. At the end of 2016 the VEPP-2000 collider resumed operation after upgrade of the injection system, and performance approaching the project luminosity of 10 32 cm −2 s −1 at 2 GeV has been demonstrated. Preliminary results of the new 2017 run are also presented.
The Muon g − 2 collaboration has measured the anomalous magnetic g value, a = (g − 2)/2, of the positive muon with an unprecedented uncertainty of 0.7 parts per million. The result a µ + (expt) = 11 659 204(7)(5) × 10 −10 , based on data collected in the year 2000 at Brookhaven National Laboratory, is in good agreement with the preceding data on a µ + and a µ − . The measurement tests standard model theory, which at the level of the current experimental uncertainty involves quantum electrodynamics, quantum chromodynamics, and electroweak interaction in a significant way.
This article discusses tests of CPT and Lorentz invariance with data from the muon g-2 experiment at Brookhaven National Laboratory. According to an extension of the Standard Model by Kostelecký et al., CPT/Lorentz violating terms in the Lagrangian induce a shift of the anomaly frequency ωa of muons in a magnetic field. This shift is predicted to be different for positive and negative muons and to oscillate with the Earth's sidereal frequency. We discuss the sensitivity of the g-2 experiment to different parameters of this Standard Model extension and propose an analysis method to search for sidereal variations of ωa.
We report preliminary results on the measurement of the e + e − → K + K − π + π − cross section in the c. m. energy range from 1.5 GeV to 2 GeV. It was found that the cross section is dominated by the contributions of the K
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