% particle data information automatically produced from the herwig database
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\title{\boldmath{ $f_1(1420)$}\ \ \ \ \ \ \ $***$}
\maketitle
The $f_1(1420)$ is the heavier of the isospin singlets containing only light quarks from the lightest pseudovector multiplet. The mass and width are accurately measured but while a number of decay modes have been observed \cite{Yao:2006px} does not include the branching ratios. We therefore assumed that there are only $\phi\gamma$, $K\bar{K}\pi$, $a_0\pi$ and $KK^*$ modes. The ratios 
\begin{eqnarray}
\frac{\Gamma(\phi\gamma)}{\Gamma(K\bar{K}\pi)}&=&0.003\pm0.001\pm0.001\\
\frac{\Gamma(a_0\pi)}{\Gamma(KK^*)}&=&0.04\pm0.01\pm0.01
\end{eqnarray}
  from \cite{Yao:2006px} and the ratio 
\begin{eqnarray}
\frac{\Gamma(KK^*)}{\Gamma(K\bar{K}\pi)}&=&0.78\pm0.05
\end{eqnarray}
calculated by averaging the results in \cite{Yao:2006px} are used to obtain the branching ratios. The $f_1(1420)$ is allowed to be off-shell by five times the width below the central value to ensure the decays are kinematically possible and by ten times the width above the central value.
The $f_1(1420)$ has mass $1426.3$~MeV and is unstable. The $f_1(1420)$ has spin $1$, charge $0$ and is colour neutral.
 The $f_1(1420)$ is a meson and is from the $1^3P_1$ multiplet.The $f_1(1420)$ has width $54.9$~MeV. The lower limit on the mass of the particle is $274.5$~MeV and the upper limit is $549$~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 20333.
\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 $f_1(1420)$ (continues).}
\endfoot
\caption{The decay modes of the $f_1(1420)$.}
\endlastfoot
\label{tab:20333decaymodes}
0.188600 & $***$ & on & $ K^{*+}, K^- $  & The decay of the $f_1(1420)$ to a $K^*$ and a kaon. The calculation of the branching ratio is described above.   & Herwig::PVectorMesonVectorPScalar::PVectorVP \\ 
\hline
0.188600 & $***$ & on & $ K^{*-}, K^+ $  & The decay of the $f_1(1420)$ to a $K^*$ and a kaon. The calculation of the branching ratio is described above.   & Herwig::PVectorMesonVectorPScalar::PVectorVP \\ 
\hline
0.188600 & $***$ & on & $ \bar{K}^{*0}, K^0 $  & The decay of the $f_1(1420)$ to a $K^*$ and a kaon. The calculation of the branching ratio is described above.   & Herwig::PVectorMesonVectorPScalar::PVectorVP \\ 
\hline
0.188600 & $***$ & on & $ K^{*0}, \bar{K}^0 $  & The decay of the $f_1(1420)$ to a $K^*$ and a kaon. The calculation of the branching ratio is described above.   & Herwig::PVectorMesonVectorPScalar::PVectorVP \\ 
\hline
0.070900 & $***$ & on & $ K^+, \bar{K}^0, \pi^- $  & The decay of the $f_1(1420)$ to two kaons and a pion. This is the part of this mode which is not part of the $a_0\pi$ or $K^*K$ channels.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.070900 & $***$ & on & $ K^-, K^0, \pi^+ $  & The decay of the $f_1(1420)$ to two kaons and a pion. This is the part of this mode which is not part of the $a_0\pi$ or $K^*K$ channels.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.035500 & $***$ & on & $ K^0, \bar{K}^0, \pi^0 $  & The decay of the $f_1(1420)$ to two kaons and a pion. This is the part of this mode which is not part of the $a_0\pi$ or $K^*K$ channels.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.035500 & $***$ & on & $ K^+, K^-, \pi^0 $  & The decay of the $f_1(1420)$ to two kaons and a pion. This is the part of this mode which is not part of the $a_0\pi$ or $K^*K$ channels.   & Herwig::Hw64::DecayME0 \\ 
\hline
0.010000 & $***$ & on & $ a^+_0(980), \pi^- $  & The decay of the $f_1(1420)$ to the $a_0(980)$ and a pion. The calculation of the branching ratio is described above.   & Herwig::VectorMeson2Meson::Vector2Meson \\ 
\hline
0.010000 & $***$ & on & $ a^-_0(980), \pi^+ $  & The decay of the $f_1(1420)$ to the $a_0(980)$ and a pion. The calculation of the branching ratio is described above.   & Herwig::VectorMeson2Meson::Vector2Meson \\ 
\hline
0.010000 & $***$ & on & $ a^0_0(980), \pi^0 $  & The decay of the $f_1(1420)$ to the $a_0(980)$ and a pion. The calculation of the branching ratio is described above.   & Herwig::VectorMeson2Meson::Vector2Meson \\ 
\hline
0.002800 & $***$ & on & $ \phi, \gamma $  & The decay of the $f_1(1420)$ to a phi meson and a photon. The calculation of the branching ratio is described above.   & Herwig::Hw64::DecayME0 \\ 
\hline
\end{longtable}The $f_1(1420)$ decay modes are given in Table~\ref{tab:20333decaymodes} and the total branching ratio is $1$.


The mass generator is \verb|f'_1mass| for the $f_1(1420)$.
The width generator is \verb|f'_1width| for the $f_1(1420)$.

\bibliography{particles}


 The particle was checked by Peter Richardson at 21:29:16 on the 20th of October 2007. The most recently changed decay mode was modified at 10:26:46 on the 4th of August 2005. The particle data was last modified at 15:15:6 on the 2nd of August 2007.

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