Engineering topics

Coen, S. C.

Publications and source records attributed to Coen, S. C..

At least 55 records · Page 3

DOE OSTI2024

First Measurement of the Decay Asymmetry in the Pure W -Boson-Exchange Decay Λ c + → Ξ 0 K +

Based on 4.4 fb − 1 of e + e − annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with the BESIII detector at the BEPCII collider, the pure W -boson-exchange decay Λ c + → Ξ 0 K + is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be α Ξ 0 K + = 0.01 ± 0.16 ( stat ) ± 0.03 ( syst ) . This result reflects the noninterference effect between the S - and P -wave amplitudes. The phase shift between S - and P -wave amplitudes has two solutions, which are δ p − δ s = − 1.55 ± 0.25 ( stat ) ± 0.05 ( syst ) rad or 1.59 ± 0.25 ( stat ) ± 0.05 ( syst ) rad . Published by the American Physical Society 2024

Physics↗

DOE OSTI2024

Observation and branching fraction measurement of the decay J / ψ → p ¯ Σ + K S 0 + c . c .

The first observation of the decays J / ψ → p ¯ Σ + K S 0 and J / ψ → p Σ ¯ − K S 0 is reported using ( 10087 ± 44 ) × 10 6 J / ψ events recorded by the BESIII detector at the BEPCII storage ring. The branching fractions of each channel are determined to be B ( J / ψ → p ¯ Σ + K S 0 ) = ( 1.361 ± 0.006 ± 0.025 ) × 10 − 4 , and B ( J / ψ → p Σ ¯ − K S 0 ) = ( 1.352 ± 0.006 ± 0.025 ) × 10 − 4 . The combined result is B ( J / ψ → p ¯ Σ + K S 0 + c . c . ) = ( 2.725 ± 0.009 ± 0.050 ) × 10 − 4 , where the first uncertainty is statistical and the second systematic. The results presented are in good agreement with the branching fractions of the isospin partner decay J / ψ → p K − Σ ¯ 0 + c . c . Published by the American Physical Society 2024

Astronomy & Astrophysics↗

DOE OSTI2024

Observation of the decay J / ψ → e + e − η ( 1405 ) with η ( 1405 ) → π 0 f 0 ( 980 )

Using a data sample of ( 10087 ± 44 ) × 10 6 J / ψ events collected by the BESIII detector in 2009, 2012, 2018 and 2019, the electromagnetic Dalitz process J / ψ → e + e − η ( 1405 ) is observed via the decay η ( 1405 ) → π 0 f 0 ( 980 ) , f 0 ( 980 ) → π + π − , with a significance of about 9.8 σ . The branching fraction of this decay is measured to be B ( J / ψ → e + e − η ( 1405 ) → e + e − π 0 f 0 ( 980 ) → e + e − π 0 π + π − ) = ( 2.04 ± 0.20 ( stat ) ± 0.08 ( syst ) ) × 10 − 7 . The branching fraction ratio B ( J / ψ → e + e − η ( 1405 ) ) / B ( J / ψ → γ η ( 1405 ) ) is determined to be ( 1.36 ± 0.17 ( stat ) ± 0.06 ( syst ) ) × 10 − 2 . Furthermore, an e + e − invariant mass dependent transition form factor of J / ψ → e + e − η ( 1405 ) is presented for the first time. The obtained result provides input for different theoretical models and is valuable for the improved understanding the intrinsic structure of the η ( 1405 ) meson. Published by the American Physical Society 2024

Astronomy & Astrophysics↗

DOE OSTI2024

Measurement of the e + e − → Λ Σ ¯ 0 + c . c . cross sections at s from 2.3094 to 3.0800 GeV

The Born cross sections and effective form factors of the process e + e − → Λ Σ ¯ 0 + c . c . are measured at 14 center-of-mass energy points from 2.3094 to 3.0800 GeV, based on data corresponding to an integrated luminosity of ( 478.5 ± 4.8 ) pb − 1 collected with the BESIII detector. A nonzero Born cross section is observed at the center-of-mass energy of 2.3094 GeV with a statistical significance of more than five standard deviations, and the cross sections at other energies are obtained with improved precision compared to earlier measurements from the Collaboration. The Born cross-section line shape is described better by a shape considering the strong-interaction effects than by a pQCD motivated functional form. Published by the American Physical Society 2024

Astronomy & Astrophysics↗

DOE OSTI2023