2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42917The Littlest Higgs Model is constrained using the tree-level perturbative arguments, similar to those employed to obtain the Higgs mass bound. It is found that the perturbative unitaity violations set in at energy scales $\sim 1.5χf$, where $f$ is the analog of pion decay constant and sets the scale for the masses in the theory and also the strong interaction scale and $χ$ is a dimensionless parameter which together with $f$ sets the mass scale of heavy scalars in the theory.7 page Revtex4 file, corrections made, results changed accordinglyHigh Energy Physics - Phenomenologytext