Measurement of the eta'-meson mass using J/psi--> gamma eta'

TL;DR

This paper precisely measures the eta' meson mass using multiple decay channels in J/psi events, achieving higher accuracy than previous measurements with data from the CLEO-c detector.

Contribution

The study provides a more precise measurement of the eta' meson mass by analyzing various decay modes in J/psi events, improving upon the current world average.

Findings

Measured eta' mass as 957.793 MeV with uncertainties of 0.054 and 0.036 MeV.

Results are consistent with previous measurements but more precise.

Utilized three decay modes to enhance measurement accuracy.

Abstract

We measure the mass of the eta' meson using psi(2S)--> pi+ pi- J/psi, J/psi--> gamma eta' events acquired with the CLEO-c detector operating at the CESR e+e- collider. Using three decay modes, eta'--> rho0 gamma, eta'--> pi+ pi- eta with eta--> gamma gamma, and eta'--> pi+ pi- eta with eta--> pi+ pi- pi0, we find M(eta') = 957.793 +- 0.054 +- 0.036 MeV, in which the first uncertainty is statistical and the second is systematic. This result is consistent with but substantially more precise than the current world average.