defined the integrals S(,Q\^2)&=&\_[k\_[min]{}]{}\^[k\_[max]{}]{}dkk(u\^2(p)+w\^2(p)),\
S\_(,Q\^2)&=&\_[k\_[min]{}]{}\^[k\_[max]{}]{}dkk(u\^2(p)+w\^2(p)) k\_\^2 The deuteron wave function is normalized as $\int k^2dk[u^2(p)+w^2(p)]=1$, $u,w(p)$ denote the $s,d$ radial wave function of the deuteron, respectively. The magnitude of the three-momentum of the bound nucleon is denoted by $k=|\vec k|$, and its component perpendicular to the direction of the virtual photon is $k_\perp^2=k^2\sin^2\theta_k$, the angle $\theta_k$ is defined below.

![Quasielastic scattering kinematics.[]{data-label="figQE"}](QEdiag.pdf){width="4.5cm"}

The on-shell condition for the external (knock-out) nucleons and 4-momentum conservation M\_d+&=&+, with the average nucleon mass $M\equiv\frac{1}{2}(M_p+M_n)\approx0.938919$ GeV, leads to a delta function for the angle between the three-momenta of the virtual photon and the active nucleon, \_k=. The integral over the Fermi momentum $k$ is constrained between two finite values due to the requirement $-1\leq\cos\theta_k\leq1$, k\_[min]{}&=&|-+|,\
k\_[max]{}&=&+, with $\nu_{min}=Q^2/(2M_d)+\epsilon+{\cal O}(\epsilon^2)$ and $\epsilon=2M-M_d\approx2.224$ MeV.

Experimental data on deuteron electrodesintegration feature a sharp peak just above the threshold, that is due to final state interactions between proton and neutron after the break-up [@Durand:1961zz]. We adopt an approximate formula (Eq. (48) of that Ref.) to obtain the following model for the transverse and longitudinal cross sections, \_T\^0&=&\
\_L\^0&=&, with the $n-p$ singlet and triplet scattering lengths entering the FSI part, $a_S=-23.74$ fm, $a_T=5.38$ fm, respectively. Above, we note that 