Measurements of Branching Ratios for $\eta$ Decays into Charged Particles

Abstract

The WASA-at-COSY experiment has collected $3\times 10^7$ events with $\eta$-mesons produced via the reaction $pd\to {}^3\text{He}\eta$ at $\text{T}=1.0\text{GeV}$. Using this data set, we evaluate the branching ratios of the decays $\eta \to {\pi }^{+}{\pi }^{-}\gamma$, $\eta \to e^{+}{e}^{-}\gamma$, $\eta \to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$ and $\eta \to e^{+}{e}^{-}{e}^{+}{e}^{-}$. The branching ratios are normalized to the $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ decay. In addition an upper limit on a $CP$-violating asymmetry in $\eta \to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$ is extracted.

References in corpus (8)

• Study of the electromagnetic transition form-factors in η-> μ^+μ^-γand ω-> μ^+μ^-π^0 decays with NA60
• The WASA Detector Facility at CELSIUS
• Anomalous decay and scattering processes of the eta meson
• Precision study of the $\eta \to {\mu }^{+}{\mu }^{-}\gamma$ and $\omega \to {\mu }^{+}{\mu }^{-}{\pi }^0$ electromagnetic transition form-factors and of the $\rho \to {\mu }^{+}{\mu }^{-}$ line shape in NA60
• Measurement of Γ(η-> π^+π^-γ)/Γ(η-> π^+π^-π^0) with the KLOE Detector
• Precision study of the d+p->3He+eta reaction for excess energies between 20 and 60 MeV
• Measurement of the $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ Dalitz plot distribution
• Cross section ratio and angular distributions of the reaction p + d -> 3He + eta at 48.8 MeV and 59.8 MeV excess energy

Cited by in corpus (10)

• Precision tests of fundamental physics with $\eta$ and ${\eta }^{\prime }$ mesons
• Etaprime and Eta Mesons with Connection to Anomalous Glue
• Potential of the J-PET detector for studies of discrete symmetries in decays of positronium atom - a purely leptonic system
• A data-driven approach to ${\pi }^0,\eta$ and ${\eta }^{\prime }$ single and double Dalitz decays
• ${\eta }^{\prime }\to \eta \pi \pi$ decays in unitarized resonance chiral theory
• Search for $C$ violation in the decay $\eta \to {\pi }^0+e^{+}+e^{-}$ with WASA-at-COSY
• Measurement of the Branching Fraction of and Search for a CP-Violating Asymmetry in ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$ at BESIII
• The legacy of the experimental hadron physics programme at COSY
• The REDTOP experiment
• Spin dependence of η meson production in proton-proton collisions close to threshold