Search NASA⌕ Search

Engineering topics

Chen, H. S.

Publications and source records attributed to Chen, H. S..

At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Study of the decay D s + → π + π + π - η and observation of the W -annihilation decay D s + → a 0 ( 980 ) + ρ 0

The decay $D^+_s$ → $π^+π^+π^-η$ is observed for the first time, using e + e - collision data corresponding to an integrated luminosity of 6.32 fb -1 collected by the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV. The absolute branching fraction for this decay is measured to be $\mathscr{B}$($D^+_s$ → $π^+π^+π^-η$) = (3.12 ± 0.13 stat ± 0.90 syst )%. The first amplitude analysis of this decay reveals the substructures in $D^+_s$ → $π^+π^+π^-η$ nd determines the relative fractions and the phases among these substructures. The dominant intermediate process is $D^+_s$ → $a_1$(1260) + $η,a_1$(1260) + → ρ(770) 0 $π^+$ with a branching fraction of (1.73 ± 0.14 stat ±0.08 syst )%. We also observe the W-annihilation process $D^+_s$ → $a_0$(980) + ρ(770) 0 , $a_0$(980) + → $π^+η$ with a branching fraction of (0.21 ± 0.08 stat ± 0.05 syst )%, which is larger than the branching fractions of other measured pure W-annihilation decays by 1 order of magnitude.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Observation of e + e - → ηψ(2S) at center-of-mass energies from 4.236 to 4.600 GeV

Using a total of 5 25 fb -1 of e + e - collision data with center-of-mass energies from 4.236 to 4.600 GeV, we report the first observation of the processe + e - → ηψ(2S) with a statistical significance of 4.9 standard deviations. The data sets were collected by the BESIII detector operating at the BEPCII storage ring. We measure the yield of events integrated over center-of-mass energies and also present the energy dependence of the measured cross section.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Measurements of the center-of-mass energies of $e^+e^-$ collisions at BESIII*

During the 2016-17 and 2018-19 running periods, the BESIII experiment collected 7.5 fb -1 of $e^+e^-$ collision data at center-of-mass energies ranging from 4.13 to 4.44 GeV. These data samples are primarily used for the study of excited charmonium and charmoniumlike states. By analyzing the di-muon process $e^+e^-$ → $e^+e^-$ →, we measure the center-of-mass energies of the data samples with a precision of 0.6 MeV. Through a run-by-run study, we find that the center-of-mass energies were stable throughout most of the data-collection period.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗