fit of \[ {\cal M}_{3s}(E)=\frac{\Gamma}{E^2-M_r^2} \] with
\[ M_r= P[0]+iP[1]\\ \Gamma= P[2]+iP[3] \]
here we took \(k_{df}\) from the \(g=20\) fit
\[\begin{gather} \chi^2/d.o.f.=1.55976 \\ P[0]=3.02159\pm (0.00033) \\ P[1]=-6.77087e-06\pm (1e-06) \\ P[2]=-305.731\pm (32) \\ P[3]=13.6057\pm (1.4) \\ \end{gather}\] {\[\begin{gather} C=\begin{pmatrix} 1& -0.977& -0.291& 0.233\\ -0.977& 1& 0.404& -0.345\\ -0.291& 0.404& 1& -0.996\\ 0.233& -0.345& -0.996& 1\\ \end{pmatrix} \end{gather}\]}
fiting only the points close to the pole
\[\begin{gather} \chi^2/d.o.f.=0.40235 \\ P[0]=3.02135\pm (0.00031) \\ P[1]=-3.32718e-06\pm (3.9e-07) \\ P[2]=-278.789\pm (30) \\ P[3]=11.8617\pm (1.3) \\ \end{gather}\] {\[\begin{gather} C=\begin{pmatrix} 1& -0.979& -0.355& 0.298\\ -0.979& 1& 0.498& -0.447\\ -0.355& 0.498& 1& -0.997\\ 0.298& -0.447& -0.997& 1\\ \end{pmatrix} \end{gather}\]}
fit of \[ {\cal M}_{3s}(E)=\frac{\Gamma}{E^2-M_r^2}+a_0 \] with
\[ M_r= P[0]+iP[1]\\ \Gamma= P[2]+iP[3]\\ c=P[4]+iP[5] \]
\[\begin{gather} \chi^2/d.o.f.=0.00701599 \\ P[0]=3.02113\pm (0.0003) \\ P[1]=-1.18407e-06\pm (6.8e-07) \\ P[2]=-257.033\pm (35) \\ P[3]=10.9339\pm (1.5) \\ P[4]=-2985.59\pm (6.5e+02) \\ P[5]=162.329\pm (25) \\ \end{gather}\] {\[\begin{gather} C=\begin{pmatrix} 1& -0.249& -0.658& 0.671& 0.0389& 0.0831\\ -0.249& 1& -0.0839& 0.0198& 0.88& -0.796\\ -0.658& -0.0839& 1& -0.997& 0.0143& -0.267\\ 0.671& 0.0198& -0.997& 1& -0.0739& 0.323\\ 0.0389& 0.88& 0.0143& -0.0739& 1& -0.965\\ 0.0831& -0.796& -0.267& 0.323& -0.965& 1\\ \end{pmatrix} \end{gather}\]}
fit of \[ {\cal M}_{3s}(E)=\frac{\Gamma}{E^2-M_r^2} \] with
\[ M_r= P[0]+iP[1]\\ \Gamma= P[2]+iP[3] \]
here we took \(k_{df}\) from the \(g=20\) fit
\[\begin{gather} \chi^2/d.o.f.=1.24408 \\ P[0]=3.02112\pm (0.00032) \\ P[1]=6.01479e-06\pm (1.3e-06) \\ P[2]=-232.875\pm (25) \\ P[3]=-11.5752\pm (1.1) \\ \end{gather}\] {\[\begin{gather} C=\begin{pmatrix} 1& 0.995& -0.172& -0.119\\ 0.995& 1& -0.128& -0.0727\\ -0.172& -0.128& 1& 0.996\\ -0.119& -0.0727& 0.996& 1\\ \end{pmatrix} \end{gather}\]}
fiting only the points close to the pole
\[\begin{gather} \chi^2/d.o.f.=0.319426 \\ P[0]=3.02093\pm (0.00029) \\ P[1]=2.74916e-06\pm (6e-07) \\ P[2]=-215.056\pm (23) \\ P[3]=-10.2435\pm (1) \\ \end{gather}\] {\[\begin{gather} C=\begin{pmatrix} 1& 0.992& -0.238& -0.18\\ 0.992& 1& -0.119& -0.0612\\ -0.238& -0.119& 1& 0.996\\ -0.18& -0.0612& 0.996& 1\\ \end{pmatrix} \end{gather}\]}
fit of \[ {\cal M}_{3s}(E)=\frac{\Gamma}{E^2-M_r^2}+a_0 \] with
\[ M_r= P[0]+iP[1]\\ \Gamma= P[2]+iP[3]\\ c=P[4]+iP[5] \]
\[\begin{gather} \chi^2/d.o.f.=0.00761025 \\ P[0]=3.02077\pm (0.00027) \\ P[1]=2.62394e-07\pm (6.1e-07) \\ P[2]=-189.74\pm (26) \\ P[3]=-8.83004\pm (1.2) \\ P[4]=-2071.72\pm (4.9e+02) \\ P[5]=-129.52\pm (20) \\ \end{gather}\] {\[\begin{gather} C=\begin{pmatrix} 1& 0.215& -0.541& -0.587& 0.0623& -0.0239\\ 0.215& 1& 0.369& 0.291& -0.831& -0.734\\ -0.541& 0.369& 1& 0.995& -0.131& 0.0866\\ -0.587& 0.291& 0.995& 1& -0.0694& 0.147\\ 0.0623& -0.831& -0.131& -0.0694& 1& 0.975\\ -0.0239& -0.734& 0.0866& 0.147& 0.975& 1\\ \end{pmatrix} \end{gather}\]}