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 469fb-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(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 electromagnetic (single-photon) and strong amplitudes in J/ψ and ψ(2S)→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(2S) meson.

Study of the e+e- →k+K- reaction in the energy range from 2.6 to 8.0 GeV

ANGELINI, CARLO;BATIGNANI, GIOVANNI;BETTARINI, STEFANO;CASAROSA, GIULIA;FORTI, FRANCESCO;PAOLONI, EUGENIO;RIZZO, GIULIANA;
2015-01-01

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 469fb-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(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 electromagnetic (single-photon) and strong amplitudes in J/ψ and ψ(2S)→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(2S) meson.
2015
Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Brown, D. N.; Kerth, L. T.; Kolomensky, Yu G.; Lee, M. J.; Lyn...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/782555
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