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arXiv · hep-ex/0102029

Direct measurement of the phi(1020) leptonic branching ratio

M. N. Achasov·K. I. Beloborodov·A. V. Berdyugin·A. G. Bogdanchikov·A. V. Bozhenok·A. D. Bukin·D. A. Bukin·S. V. Burdin·T. V. Dimova·A. A. Drozdetsky·V. P. Druzhinin·M. S. Dubrovin·I. A. Gaponenko·V. B. Golubev·V. N. Ivanchenko·P. M. Ivanov·A. A. Korol·S. V. Koshuba·A. P. Lysenko·I. N. Nesterenko·E. V. Pakhtusova·E. A. Perevedentsev·A. A. Salnikov·S. I. Serednyakov·V. V. Shary·Yu. M. Shatunov·V. A. Sidorov·Z. K. Silagadze·A. N. Skrinsky·Yu. V. Usov·A. V. Vasiljev
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Abstract

The process e+e-->mu+mu- has been studied by SND detector at VEPP-2M e+e- collider in the phi(1020)-resonance energy region. The measured effective phi meson leptonic branching ratio: B(phi->l+l-)=sqrt{B(phi->e+e-)*B(phi->mu+mu-)}=(2.89+-0.10+-0.06)*10^{-4} agrees well with the PDG value B(phi->e+e-)=(2.91+-0.07)*10^{-4} confirming mu-e universality. Without additional assumption of mu-e universality the branching ratio B(phi->mu+mu-)=(2.87+-0.20+-0.14)*10^{-4} was obtained.

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M. N. Achasov, K. I. Beloborodov, A. V. Berdyugin, A. G. Bogdanchikov, A. V. Bozhenok, A. D. Bukin, D. A. Bukin, S. V. Burdin, T. V. Dimova, A. A. Drozdetsky, V. P. Druzhinin, M. S. Dubrovin, I. A. Gaponenko, V. B. Golubev, V. N. Ivanchenko, P. M. Ivanov, A. A. Korol, S. V. Koshuba, A. P. Lysenko, I. N. Nesterenko, E. V. Pakhtusova, E. A. Perevedentsev, A. A. Salnikov, S. I. Serednyakov, V. V. Shary, Yu. M. Shatunov, V. A. Sidorov, Z. K. Silagadze, A. N. Skrinsky, Yu. V. Usov, A. V. Vasiljev. 2001-02-12. Direct measurement of the phi(1020) leptonic branching ratio. https://doi.org/10.1103/physrevlett.86.1698

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