We present a measurement of the pion form factor based on e + e − annihilation data from the CMD-2 detector in the energy range 0.6 < √ s < 1.0 GeV with a systematic uncertainty of 0.8%. A data sample is five times larger than that used in our previous measurement.

The cross section of the process e + e − → π + π − has been measured using about 114000 events collected by the CMD-2 detector at the VEPP-2M e + e − collider in the center-of-mass energy range from 0.61 to 0.96 GeV. Results of the pion form factor determination with a 0.6% systematic uncertainty are presented. The following values of the ρ-and ω-meson parameters were found: M ρ = (776.09± 0.81) MeV, Γ ρ = (144.46 ± 1.55) MeV, Γ(ρ → e + e − ) = (6.86 ± 0.12) keV, Br(ω → π + π − ) = (1.33 ± 0.25)%. Implications for the hadronic contribution to the muon

The Technical Design for the COMET Phase-I experiment is presented in this paper. COMET is an experiment at J-PARC, Japan, which will search for neutrinoless conversion of muons into electrons in the field of an aluminum nucleus ($\mu$–$e$ conversion, $\mu^{-}N \rightarrow e^{-}N$); a lepton flavor-violating process. The experimental sensitivity goal for this process in the Phase-I experiment is $3.1\times10^{-15}$, or 90% upper limit of a branching ratio of $7\times 10^{-15}$, which is a factor of 100 improvement over the existing limit. The expected number of background events is 0.032. To achieve the target sensitivity and background level, the 3.2 kW 8 GeV proton beam from J-PARC will be used. Two types of detectors, CyDet and StrECAL, will be used for detecting the $\mu$–$e$ conversion events, and for measuring the beam-related background events in view of the Phase-II experiment, respectively. Results from simulation on signal and background estimations are also described.

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