  Based on the standard model (SM) of particle physics, we study the decays
$\Lambda_b \to \Lambda \ell^+ \ell^-$ in light of the available inputs from
lattice and the data from LHCb. We fit the form-factors of this decay mode
using the available theory and experimental inputs after defining different fit
scenarios and checking their consistencies. The theory inputs include the
relations between the form-factors in heavy quark effective theory (HQET) and
soft collinear effective theory (SCET) at the endpoints of di-lepton invariant
mass squared $q^2$. Utilizing the fit results, we have predicted a few
observables related to this mode. We have also predicted the observable
$R_{\Lambda} = Br(\Lambda_b \to \Lambda \ell_i^+\ell_i^- )/Br(\Lambda_b \to
\Lambda \ell_j^+\ell_j^-)$ where $\ell_{i}$ and $\ell_j$ are charged leptons of
different generations ($i \ne j$). At the moment, we do not observe noticeable
differences in the extracted values of the observables in fully data-driven and
SM like fit scenarios.
