Measurements of the mass and width of the eta_c using psi' -> gamma eta_c
BESIII Collaboration: M. Ablikim, M. N. Achasov, D. Alberto, D. J., Ambrose, F. F. An, Q. An, Z. H. An, J. Z. Bai, R. B. Ferroli, Y. Ban, J., Becker, N. Berger, M. B. Bertani, J. M. Bian, E. Bogera, O. Bondarenko, I., Boyko, R. A. Briere, V. Bytev, X. Cai, A. C. Calcaterra
TL;DR
This paper precisely measures the mass and width of the eta_c meson using a large dataset of psi' decays, accounting for interference effects to improve accuracy.
Contribution
It introduces a model that includes interference effects between signal and background to accurately describe the eta_c line shape.
Findings
Eta_c mass measured as 2984.3 MeV/c^2
Eta_c width measured as 32.0 MeV
Interference effects are significant in line shape analysis
Abstract
The mass and width of the lowest lying S-wave spin singlet charmonium state, the eta_c, are measured using a data sample of 1.06x10^8 psi' decays collected with the BESIII detector at the BEPCII storage ring. We use a model that incorporates interference between the signal reaction, psi' -> gamma eta_c, and a non-resonant radiative background to successfully describe the line shape of the eta_c. We measure the eta_c mass to be 2984.3 +- 0.6 +- 0.6 MeV/c^2 and the total width to be 32.0 +- 1.2 +- 1.0 MeV, where the first errors are statistical and the second are systematic.
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.