# Study of the $e^+e^-\to K^+K^-$ reaction in the energy range from 2.6 to 8.0 GeV

Abstract : The $e^+e^-\to K^+K^-$ cross section and charged-kaon electromagnetic form factor are measured in the $e^+e^-$ center-of-mass energy range ($E$) from 2.6 to 8.0 GeV using the initial-state radiation technique with an undetected photon. The study is performed using 469 fb$^{-1}$ of data collected with the BABAR detector at the PEP-II $e^+e^-$ collider at center-of-mass energies near 10.6 GeV. The form factor is found to decrease with energy faster than $1/E^2$, and approaches the asymptotic QCD prediction. Production of the $K^+K^-$ final state through the $J/\psi$ and $\psi(2S)$ intermediate states is observed. The results for the kaon form factor are used together with data from other experiments to perform a model-independent determination of the relative phases between single-photon and strong amplitudes in $J/\psi$ and $\psi(2S)\to K^+K^-$ decays. The values of the branching fractions measured in the reaction $e^+e^- \to K^+K^-$ are shifted relative to their true values due to interference between resonant and nonresonant amplitudes. The values of these shifts are determined to be about $\pm5\%$ for the $J/\psi$ meson and $\pm15\%$ for the $\psi(2S)$ meson.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01177828
Contributor : Sabine Starita <>
Submitted on : Friday, July 17, 2015 - 11:08:04 AM
Last modification on : Friday, November 6, 2020 - 3:31:26 AM

### Citation

J. P. Lees, V. Poireau, V. Tisserand, N. Arnaud, M. Davier, et al.. Study of the $e^+e^-\to K^+K^-$ reaction in the energy range from 2.6 to 8.0 GeV. Physical Review D, American Physical Society, 2015, 92, pp.072008. ⟨10.1103/PhysRevD.92.072008⟩. ⟨in2p3-01177828⟩

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