\label{r2_SU3_NLO}$$

  ------------------- ------------------ ---------------- ------------------------------------- ------------------ ---------------- ------------------------------------- -- --
   $M_\pi (\rm MeV)$                                                                                                                                                         
                       $l^r_6(\mu=1/a)$   $\chi^2/d.o.f$   $\left< r^2 \right>_{phys}$(fm$^2$)   $L^r_9(\mu=1/a)$   $\chi^2/d.o.f$   $\left< r^2 \right>_{phys}$(fm$^2$)     
          296            -0.00737(45)        0.29(10)                   0.366(14)                  0.00256(19)         0.29(10)                   0.380(14)                  
          411            -0.00728(26)        2.34(26)                   0.363(8)                   0.00260(11)         2.31(26)                   0.383(8)                   
  ------------------- ------------------ ---------------- ------------------------------------- ------------------ ---------------- ------------------------------------- -- --

  : NLO ChPT fit of $G_\pi(Q^2)$ at fixed pion mass $M_\pi$. LEC’s are calculated at $\mu=1/a=2.176$ GeV. The decay constants in the chiral limit are taken from the work of PACS-CS collaboration [@pacscs]: $f=124.8(5.1) {\rm \ MeV}, f_0=116.0(8.8) {\rm \ MeV}$. Those values are determined with pion masses up to 411 MeV. Physical value of the squared charge radius, $\left<r^2\right>_{phys}$, is calculated at the physical pion mass for the SU(2) case and at the physical pion and kaon masses for the SU(3) case.[]{data-label="table:PFF_ChPT_NLO-f"}

\

In Table \[table:PFF\_ChPT\_NLO-f\] we present results of NLO fits of the form factor for both SU(2) and SU(3) ChPT. Fits are made fixing the pion mass at each of the two lightest values, $M_\pi=411$ and $296$ MeV, available in our data set. Let us first look at the SU(3) results. In this case the measured kaon and pion masses are used in the fit, while the physical masses are substituted 