Using 4.48 × 108 ψð3686Þ events collected with the BESIII detector, we search for the decays χcJ → μþμ−J=ψ through the radiative decays ψð3686Þ → γχcJ, where J 1⁄4 0, 1, 2. The decays χc1;2 → μþμ−J=ψ are observed, and the corresponding branching fractions are measured to be Bðχc1 → μþμ−J=ψÞ 1⁄4 ð2.51 ` 0.18 ` 0.20Þ × 10−4 and Bðχc2 → μþμ−J=ψÞ 1⁄4 ð2.33 ` 0.18 ` 0.29Þ × 10−4, where the first uncertainty is statistical and the second one systematic. No significant χc0 → μþμ−J=ψ decay is observed, and the upper limit on the branching fraction is determined to be 2.0 × 10−5 at 90% confidence level. Also, we present a study of dimuon invariant mass dependent transition form factor for the decays χc1;2 → μþμ−J=ψ.

Study of electromagnetic Dalitz decays χcJ→μ+μ−J/ψ

Cibinetto, G.;Farinelli, R.;Garzia, I.;Mezzadri, G.;Savrié, M.;
2019

Abstract

Using 4.48 × 108 ψð3686Þ events collected with the BESIII detector, we search for the decays χcJ → μþμ−J=ψ through the radiative decays ψð3686Þ → γχcJ, where J 1⁄4 0, 1, 2. The decays χc1;2 → μþμ−J=ψ are observed, and the corresponding branching fractions are measured to be Bðχc1 → μþμ−J=ψÞ 1⁄4 ð2.51 ` 0.18 ` 0.20Þ × 10−4 and Bðχc2 → μþμ−J=ψÞ 1⁄4 ð2.33 ` 0.18 ` 0.29Þ × 10−4, where the first uncertainty is statistical and the second one systematic. No significant χc0 → μþμ−J=ψ decay is observed, and the upper limit on the branching fraction is determined to be 2.0 × 10−5 at 90% confidence level. Also, we present a study of dimuon invariant mass dependent transition form factor for the decays χc1;2 → μþμ−J=ψ.
2019
Ablikim, M.; Achasov, M.  N.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Amoroso, A.; An, F.  F.; An, Q.; Bai, Y.; Bakina, O.; Baldini Ferroli, R.; Ban, Y...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/2403857
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