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\title{\boldmath{ $\eta_c$}\ \ \ \ \ \ \ $****$}
\maketitle
The $\eta_c$ is the lightest $c\bar{c}$ meson. It mass and width are measured, although the error on the width is large, but only a few decay modes are known. The mass  and width are taken from \cite{Yao:2006px}. The exclusive modes are taken from \cite{Yao:2006px} apart from some 6 charged pion and kaon modes which are omitted. The remaining modes are simulated using partonic decays. The $\eta_c$ is allowed to be off-shell by ten times the width.
The $\eta_c$ has mass $2980.4$~MeV and is unstable. The $\eta_c$ has spin $0$, charge $0$ and is colour neutral.
 The $\eta_c$ is a meson and is from the $1^1S_0$ multiplet.The $\eta_c$ has width $25.5$~MeV. The lower limit on the mass of the particle is $255$~MeV and the upper limit is $255$~MeV. These are the deviations from the on-shell value. The branching ratios are fixed.
The properties of the particle and its antiparticle are taken to be charge-conjugate to each other.
 The PDG code is 441.
\setlongtables
\begin{longtable}[t]{|c|c|c|p{1in}|p{2.5in}|c|}
\hline
Branching & Rating & On/ & Outgoing  & Description & Decayer  \\ 
Ratio     &                                 & Off & Particles &             &         \\ 
\hline
\endhead
\caption{The decay modes of the $\eta_c$ (continues).}
\endfoot
\caption{The decay modes of the $\eta_c$.}
\endlastfoot
\label{tab:441decaymodes}
0.720947 & $***$ & on & $ g, g $  & Partonic decay of $\eta_c$ which is included to ensure the branching ratios sum to unity.   & Herwig::Quarkonium::QDecayME0 \\ 
\hline
0.032667 & $****$ & on & $ \eta, \pi^+, \pi^- $  & Decay of the $\eta_c$ to an eta and two pions. The branching ratio is taken from \cite{Yao:2006px} together with the identical particle symmetry factor to give the ratio of neutral to the charge mode.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.027333 & $****$ & on & $ \eta', \pi^+, \pi^- $  & Decay of the $\eta_c$ to an $\eta'$ and two pions. The branching ratio is taken from \cite{Yao:2006px} together with the identical particle symmetry factor to give the ratio of neutral to the charge mode.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.023333 & $****$ & on & $ K^+, \bar{K}^0, \pi^- $  & Decay of $\eta_c$ to $K\pi\pi$ with branching ratio from \cite{Yao:2006px}. The relative rates for the difference modes is given by isospin conservation.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.023333 & $****$ & on & $ K^-, K^0, \pi^+ $  & Decay of $\eta_c$ to $K\pi\pi$ with branching ratio from \cite{Yao:2006px}. The relative rates for the difference modes is given by isospin conservation.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.016333 & $****$ & on & $ \eta, \pi^0, \pi^0 $  & Decay of the $\eta_c$ to an eta and two pions. The branching ratio is taken from \cite{Yao:2006px} together with the identical particle symmetry factor to give the ratio of neutral to the charge mode.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.015000 & $***$ & on & $ K^{*0}, \bar{K}^{*0}, \pi^+, \pi^- $  & Decay of $\eta_c$ with branching ratio from \cite{Yao:2006px}.   & Herwig::Mambo::Mambo \\ 
\hline
0.013667 & $****$ & on & $ \eta', \pi^0, \pi^0 $  & Decay of the $\eta_c$ to an $\eta'$ and two pions. The branching ratio is taken from \cite{Yao:2006px} together with the identical particle symmetry factor to give the ratio of neutral to the charge mode.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.013333 & $****$ & on & $ \rho^+, \rho^- $  & Decay of the $\eta_c$ to two rho mesons with branching ratio from \cite{Yao:2006px}. The relative rates of the two modes is given by the identical particle symmetry factor.   & Herwig::PScalarVectorVector::PVV \\ 
\hline
0.011667 & $****$ & on & $ K^+, K^-, \pi^0 $  & Decay of $\eta_c$ to $K\pi\pi$ with branching ratio from \cite{Yao:2006px}. The relative rates for the difference modes is given by isospin conservation.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.011667 & $****$ & on & $ K^0, \bar{K}^0, \pi^0 $  & Decay of $\eta_c$ to $K\pi\pi$ with branching ratio from \cite{Yao:2006px}. The relative rates for the difference modes is given by isospin conservation.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.010000 & $***$ & on & $ f_2(1270), f_2(1270) $  & Decay of $\eta_c$ with branching ratio taken from \cite{Yao:2006px}.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.008470 & $****$ & on & $ K^{*0}, K^-, \pi^+ $  & Decay of $\eta_c$ to $K^*K\pi$. The $K^{*0}K\pi$ mode has been observed and is included with branching ratio from \cite{Yao:2006px},  after the $K^*K^*$ mode has been subtracted, while the other modes are added as requested by isospin.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.008470 & $****$ & on & $ \bar{K}^{*0}, K^+, \pi^- $  & Decay of $\eta_c$ to $K^*K\pi$. The $K^{*0}K\pi$ mode has been observed and is included with branching ratio from \cite{Yao:2006px} ,  after the $K^*K^*$ mode has been subtracted, while the other modes are added as requested by isospin.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.008470 & $****$ & on & $ K^{*-}, K^0, \pi^+ $  & Decay of $\eta_c$ to $K^*K\pi$. The $K^{*0}K\pi$ mode has been observed and is included with branching ratio from \cite{Yao:2006px}, after the $K^*K^*$ mode has been subtracted, while the other modes are added as requested by isospin.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.008470 & $****$ & on & $ K^{*+}, \bar{K}^0, \pi^- $  & Decay of $\eta_c$ to $K^*K\pi$. The $K^{*0}K\pi$ mode has been observed and is included with branching ratio from \cite{Yao:2006px},  after the $K^*K^*$ mode has been subtracted, while the other modes are added as requested by isospin.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.006667 & $****$ & on & $ \rho^0, \rho^0 $  & Decay of the $\eta_c$ to two rho mesons with branching ratio from \cite{Yao:2006px}. The relative rates of the two modes is given by the identical particle symmetry factor.   & Herwig::PScalarVectorVector::PVV \\ 
\hline
0.005333 & $****$ & on & $ \pi^+, \pi^-, \pi^+, \pi^- $  & Decay of the $\eta_c$ to four pions with branching ratio from \cite{Yao:2006px} after the $\rho^0\rho^0$ mode has been subtracted.   & Herwig::Mambo::Mambo \\ 
\hline
0.004600 & $****$ & on & $ K^{*+}, K^{*-} $  & Decay of the $\eta_c$ to two $K^*$ mesons with branching ratio from \cite{Yao:2006px}. The relative rates of the two modes is given by isospin.   & Herwig::PScalarVectorVector::PVV \\ 
\hline
0.004600 & $****$ & on & $ K^{*0}, \bar{K}^{*0} $  & Decay of the $\eta_c$ to two $K^*$ mesons with branching ratio from \cite{Yao:2006px}. The relative rates of the two modes is given by isospin.   & Herwig::PScalarVectorVector::PVV \\ 
\hline
0.004230 & $****$ & on & $ \bar{K}^{*0}, K^0, \pi^0 $  & Decay of $\eta_c$ to $K^*K\pi$. The $K^{*0}K\pi$ mode has been observed and is included with branching ratio from \cite{Yao:2006px},  after the $K^*K^*$ mode has been subtracted, while the other modes are added as requested by isospin.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.004230 & $****$ & on & $ K^{*0}, \bar{K}^0, \pi^0 $  & Decay of $\eta_c$ to $K^*K\pi$. The $K^{*0}K\pi$ mode has been observed and is included with branching ratio from \cite{Yao:2006px},  after the $K^*K^*$ mode has been subtracted, while the other modes are added as requested by isospin.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.004230 & $****$ & on & $ K^{*+}, K^-, \pi^0 $  & Decay of $\eta_c$ to $K^*K\pi$. The $K^{*0}K\pi$ mode has been observed and is included with branching ratio from \cite{Yao:2006px},  after the $K^*K^*$ mode has been subtracted, while the other modes are added as requested by isospin.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.004230 & $****$ & on & $ K^{*-}, K^+, \pi^0 $  & Decay of $\eta_c$ to $K^*K\pi$. The $K^{*0}K\pi$ mode has been observed and is included with branching ratio from \cite{Yao:2006px},  after the $K^*K^*$ mode has been subtracted, while the other modes are added as requested by isospin.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.002700 & $****$ & on & $ \phi, \phi $  & Decay of the $\eta_c$ to two phi mesons with branching ratio from \cite{Yao:2006px}.   & Herwig::PScalarVectorVector::PVV \\ 
\hline
0.001570 & $***$ & on & $ \phi, K^+, K^- $  & Decay of $\eta_c$ with branching from \cite{Yao:2006px} after the resonant $\phi\phi$ mode is subtracted.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.001570 & $***$ & on & $ \phi, K^0, \bar{K}^0 $  & Decay added with same branching ratio as $\phi K^+K^-$ mode.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.001300 & $****$ & on & $ p^+, \bar{p}^- $  & Decay of the $\eta_c$ to a proton-antiproton pair with branching ratio from \cite{Yao:2006px}.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.001300 & $****$ & on & $ n^0, \bar{n}^0 $  & Decay of the $\eta_c$ to a neutron-antineutron pair. The branching ratio is inferred from the proton mode using isospin.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.000280 & $****$ & on & $ \gamma, \gamma $  & Decay of the $\eta_c$ to two photons with branching ratio from \cite{Yao:2006px}.   & Herwig::PScalarVectorVector::PVV \\ 
\hline
\end{longtable}The $\eta_c$ decay modes are given in Table~\ref{tab:441decaymodes} and the total branching ratio is $1$.


The mass generator is \verb|eta_cmass| for the $\eta_c$.
The width generator is \verb|eta_cwidth| for the $\eta_c$.

\bibliography{particles}


 The particle was checked by Peter Richardson at 16:20:50 on the 15th of May 2008. The most recently changed decay mode was modified at 19:14:56 on the 10th of May 2008. The particle data was last modified at 16:25:39 on the 3rd of November 2006.

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