An overall fit to total width, 8 combinations of particle width obtained from integrated cross section,19 branching ratios uses 93 measurements and one constraint to determine 13 parameters. The overall fit has a $\chi {}^{2}$ = 121.6 for 81 degrees of freedom.
The following off-diagonal array elements are the correlation coefficients <$\mathit \delta $x$_{i}$~$\delta $x$_{j}$> $/$ ($\mathit \delta $x$_{i}\cdot{}\delta $x$_{j}$), in percent, from the fit to parameters ${{\mathit p}_{{i}}}$, including the branching fractions, $\mathit x_{i}$ =$\Gamma _{i}$ $/$ $\Gamma _{total}$. The fit constrains the ${{\mathit x}_{{i}}}$ whose labels appear in this array to sum to one.
 x4  100
 x7   100
 x15    100
 x27     100
 x28      100
 x31       100
 x35        100
 x38         100
 x41          100
 x43           100
 x49            100
 Γ             100
 x999              100
   x4  x7  x15  x27  x28  x31  x35  x38  x41  x43  x49 Γ  x999
  Mode Rate (MeV)Scale factor

Γ4  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ ${{\mathit K}^{*}{(892)}}{{\overline{\mathit K}}^{*}{(892)}}$  $0.0070$ $\pm0.0013$ 
Γ7  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ ${{\mathit \phi}}{{\mathit \phi}}$  $0.00177$ $\pm0.00019$ 
Γ15  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ ${{\mathit f}_{{2}}{(1270)}}{{\mathit f}_{{2}}{(1270)}}$  $0.0098$ $\pm0.0025$ 
Γ27  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ ${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$  $0.073$ $\pm0.004$ 
Γ28  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ ${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \eta}}$  $0.0136$ $\pm0.0015$ 
Γ31  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$  $0.0069$ $\pm0.0010$ 
Γ35  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ 2( ${{\mathit K}^{+}}{{\mathit K}^{-}}$) $0.00146$ $\pm0.00030$ 
Γ38  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ 2( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$) $0.0097$ $\pm0.0012$ 
Γ41  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ ${{\mathit p}}{{\overline{\mathit p}}}$  $0.00145$ $\pm0.00014$ 
Γ43  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\overline{\mathit \Lambda}}}$  $0.00107$ $\pm0.00024$ 
Γ49  ${{\mathit \eta}_{{c}}{(1S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$  ($1.58$ $\pm0.11$) $ \times 10^{-4}$