Using (10.087  0.044) × 10^9 J/ψ events collected with the BESIII detector at the e+e− BEPCII collider, we present the first amplitude analysis of J/ψ → γppbar with the ppbar invariant mass in the ηc mass region [2.70; 3.05] GeV/c2. The product branching fraction B(J/ψ → γηc) × B(ηc → ppbar) is determined to be (2.11  0.02stat  0.07syst) × 10−5 with precision improved by 1 order of magnitude. Combining with the product branching fractions B(ηc → ppbar) × B(ηc → γγ) and B(J/ψ → γηc) × B(ηc → γγ), the branch- ing fractions of B(J/ψ → γηc) and B(ηc → γγ) are calculated to be (2.29 pm 0.01stat pm 0.04syst pm 0.18)% and (2.28 pm 0.01stat pm 0.04syst  pm 0.18) × 10−4 , respectively, which are consistent with the latest lattice quantum chromodynamics calculations. Here, opbf is the uncertainty from the other product branching fractions used in the calculation.
Study of the Magnetic Dipole Transition of 𝐽/𝜓 →𝛾𝜂𝑐 via 𝜂𝑐 →𝑝pbar
Garzia, I.;Melendi, F. M.;
2026
Abstract
Using (10.087 0.044) × 10^9 J/ψ events collected with the BESIII detector at the e+e− BEPCII collider, we present the first amplitude analysis of J/ψ → γppbar with the ppbar invariant mass in the ηc mass region [2.70; 3.05] GeV/c2. The product branching fraction B(J/ψ → γηc) × B(ηc → ppbar) is determined to be (2.11 0.02stat 0.07syst) × 10−5 with precision improved by 1 order of magnitude. Combining with the product branching fractions B(ηc → ppbar) × B(ηc → γγ) and B(J/ψ → γηc) × B(ηc → γγ), the branch- ing fractions of B(J/ψ → γηc) and B(ηc → γγ) are calculated to be (2.29 pm 0.01stat pm 0.04syst pm 0.18)% and (2.28 pm 0.01stat pm 0.04syst pm 0.18) × 10−4 , respectively, which are consistent with the latest lattice quantum chromodynamics calculations. Here, opbf is the uncertainty from the other product branching fractions used in the calculation.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.


