Observation of the Electromagnetic Dalitz Transition h_c → e⁺e^-η_c

2024/06/28 by BESIII Collaboration, Ablikim, M., Achasov, M. N. +504
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)

paper · doi:10.48550/arxiv.2407.00136

Abstract

Using (27.12± 0.14)×10⁸ ψ(3686) decays and data samples of e⁺e^- collisions with √(s) from 4.130 to 4.780~GeV collected with the BESIII detector, we report the first observation of the electromagnetic Dalitz transition h_c→ e⁺e^-η_c with a statistical significance of 5.4σ. We measure the ratio of the branching fractions (B(h_c→ e⁺e^-η_c))/(B(h_c→ γη_c)) separately for the h_c samples produced via ψ(3686)→π⁰h_c and e⁺e^-→π⁺π^-h_c. The average ratio is determined to be (0.59±0.10(stat.)±0.04(syst.))%, where the uncertainty includes both statistical and systematic components.

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