  We describe a new method to determine non-perturbatively the beta function of
a gauge theory using lattice simulations in the p-regime of the theory. This
complements alternative measurements of the beta function working directly at
zero fermion mass and bridges the gap between the weak coupling perturbative
regime and the strong coupling regime relevant to the mass spectrum of the
theory. We apply this method to ${\mathrm {SU(3)} }$ gauge theory with two
fermion flavors in the 2-index symmetric (sextet) representation. We find that
the beta function is small but non-zero at the renormalized coupling value $g^2
= 6.7$, consistent with our previous independent investigation using
simulations directly at zero fermion mass. The model continues to be a very
interesting explicit realization of the near-conformal composite Higgs paradigm
which could be relevant for Beyond Standard Model phenomenology.
