We report on an analysis of the decay J/ψ→γπ0η′ using a sample of (1310.6±7.0)×106J/ψ events collected with the BESIII detector. We search for the CP-violating process ηc→π0η′ and a dark gauge boson U′ in J/ψ→U′η′,U′→γπ0,π0→γγ. No evidence of an ηc signal is observed in the π0η′ invariant-mass spectrum and the upper limit of the branching fraction is determined to be 5.6×10-5 at the 90% confidence level. We also find no evidence of U′ production and set upper limits at the 90% confidence level on the product branching fraction B(J/ψ→U′η′)×B(U′→π0γ) in the range between (0.8-6.5)×10-7 for 0.2≤mU′≤2.1 GeV/c2. In addition, we study the process J/ψ→ωη′ with ω→γπ0. The branching fraction of J/ψ→ωη′ is found to be (1.87±0.09±0.12)×10-4, where the first uncertainty is statistical and the second is systematic, with a precision that is improved by a factor of 1.4 over the previously published BESIII measurement.

Search for intermediate resonances and dark gauge bosons in J /ψ →γπ0η′

Alekseev M.;Amoroso A.;Bianchi F.;Destefanis M.;De Mori F.;Greco M.;Lavezzi L.;Maggiora M.;Marcello S.;Sosio S.;Spataro S.;
2020-01-01

Abstract

We report on an analysis of the decay J/ψ→γπ0η′ using a sample of (1310.6±7.0)×106J/ψ events collected with the BESIII detector. We search for the CP-violating process ηc→π0η′ and a dark gauge boson U′ in J/ψ→U′η′,U′→γπ0,π0→γγ. No evidence of an ηc signal is observed in the π0η′ invariant-mass spectrum and the upper limit of the branching fraction is determined to be 5.6×10-5 at the 90% confidence level. We also find no evidence of U′ production and set upper limits at the 90% confidence level on the product branching fraction B(J/ψ→U′η′)×B(U′→π0γ) in the range between (0.8-6.5)×10-7 for 0.2≤mU′≤2.1 GeV/c2. In addition, we study the process J/ψ→ωη′ with ω→γπ0. The branching fraction of J/ψ→ωη′ is found to be (1.87±0.09±0.12)×10-4, where the first uncertainty is statistical and the second is systematic, with a precision that is improved by a factor of 1.4 over the previously published BESIII measurement.
2020
102
5
052005-1
052005-13
Ablikim M.; Achasov M.N.; Adlarson P.; Ahmed S.; Albrecht M.; Alekseev M.; Amoroso A.; An F.F.; An Q.; Bai Y.; Bakina O.; Baldini Ferroli R.; Balossin...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1760496
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