Search NASA⌕ Search

SEARCH · Search NASA

Results for “ELECTROMAGNETIC”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Study of electromagnetic Dalitz decays χ c J → μ + μ - J / ψ

Using 4.48 × 10 8 ψ (3686) events collected with the BESIII detector, we search for the decays χ cJ → μ + μ – J/ψ through the radiative decays ψ(3686) → γχ cJ , where J = 0,1,2. The decays χ c1,2 → μ + μ – J/ψ are observed, and the corresponding branching fractions are measured to be B(χ c1 → μ + μ – J/ψ) = (2.51 ± 0.18 ± 0.20) × 10 –4 and B(χ c2 → μ + μ – J/ψ) = (2.33 ± 0.18 ± 0.29) × 10 –4 , where the first uncertainty is statistical and the second one systematic. No significant χ c0 → μ + μ – 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. Furthermore, we present a study of dimuon invariant mass dependent transition form factor for the decays χ c1,2 → μ + μ – J/ψ.

astronomy & astrophysics↗