Rare Decays of the $\eta^{'}$

TL;DR

This study searched for rare eta prime meson decays into various lepton and photon modes, found no signals, and established upper limits on their branching fractions, contributing to understanding meson decay processes.

Contribution

First to set experimental upper limits on several rare eta prime decay modes using CLEO II data, refining constraints on these processes.

Findings

No signal detected in any decay mode

Set upper limits on branching fractions

Analyzed Dalitz plot with PDG parameterization

Abstract

We have searched for the rare decays of the eta prime meson to e+ e- eta, e+ e- pizero, e+ e- gamma, and e mu in hadronic events at the CLEO II detector. The search is conducted on 4.80 fb^-1 of e+ e- collisions at the Cornell Electron Storage Ring. We find no signal in any of these modes, and set 90% confidence level upper limits on their branching fractions of 2.4 X 10^-3, 1.4 X 10^-3, 0.9 X 10^-3, and 4.7 X 10^-4, respectively. We also investigate the Dalitz plot of the common decay of the eta prime to pi+ pi- eta. We fit the matrix element with the Particle Data Group parameterization and find Re(alpha) = -0.021 +- 0.025, where alpha is a linear function of the kinetic energy of the eta.