Study of the e+e-→K+K- reaction in the energy range from 2.6 to 8.0 GeV
Abstract
The e+e-→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-II2 e+e- collider at center-of-mass energies near 10.6 GeV. The form factor is found to decrease with energy faster than 1 /E2 and approaches the asymptotic QCD prediction. Production of the K+K- final state through the J /ψ and ψ (2 S ) 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 electromagnetic (single-photon) and strong amplitudes in J /ψ and ψ (2 S )→K+K- decays. The values of the branching fractions measured in the reaction e+e-→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 ±5 % for the J /ψ meson and ±15 % for the ψ (2 S ) meson.
- Publication:
-
Physical Review D
- Pub Date:
- October 2015
- DOI:
- 10.1103/PhysRevD.92.072008
- Bibcode:
- 2015PhRvD..92g2008L
- Keywords:
-
- 13.66.Bc;
- 13.25.Gv;
- 13.40.Gp;
- 14.40.Df;
- Hadron production in e<sup>-</sup>e<sup>+</sup> interactions;
- Decays of J/psi Upsilon and other quarkonia;
- Electromagnetic form factors