2021/08/31 by BESIII Collaboration, М. Н. Ачасов, M. Ablikim +514
Physics and Astronomy · #Algorithm #Astrophysics #Branching fraction #Collider #Computer science #Electron–positron annihilation #Hadron #High-Energy Particle Collisions Research #Lambda #Luminosity #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #hep-ex
paper · pdf · doi:10.1103/physrevd.104.l091104
published as Phys. Rev. D 104, L091104 (2021) · 8 pages, 4 Figures, 1 Supplemental Material with 2 pages, consistent with paper published in Phys. Rev. D 104, L091104 (2021)
openalex publication_date 2021/11/29 · arxiv created 2021/11/30 · arxiv updated 2021/12/01 · openalex created_date 2021/12/06 · openalex updated_date 2026/08/05
The Born cross section of the process e+e^\ensuremath-\ensuremath→\mathrm\ensuremathΛ\mathrm\ensuremathΛ is measured at 33 center-of-mass energies between 3.51 and 4.60 GeV using data corresponding to the total integrated luminosity of 20.0 fb^\ensuremath-1 collected with the BESIII detector at the BEPCII collider. Describing the energy dependence of the cross section requires a contribution from the \ensuremathψ(3770)\ensuremath→\mathrm\ensuremathΛ\mathrm\ensuremathΛ decay, which is fitted with a significance of 4.6\ensuremath-4.9\ensuremathσ including the systematic uncertainty. The lower bound on its branching fraction is 2.4\ifmmode×\else\texttimes\fi10^\ensuremath-6 at the 90% confidence level (C.L.), at least an order of magnitude larger than expected from predictions using a scaling based on observed electronic widths. This result indicates the importance of effects from vector charmonium(like) states when interpreting data in terms of e.g., electromagnetic structure observables. The data do not allow for definite conclusions on the interplay with other vector charmonium(like) states, and we set 90% C.L. upper limits for the products of their electronic widths and the branching fractions.