  We compute the Hall angle and the magnetoresistance of the spin-fermion
model, which is a successful phenomenological theory to describe the physics of
the cuprates and iron-based superconductors within a wide range of doping
regimes. We investigate both the role of the spin-fermion interaction that
couples the large-momentum antiferromagnetic fluctuations to the so-called
"hot-spots" at the Fermi surface and also of an effective higher-order
composite operator in the theory. The latter operator provides a scattering
mechanism such that the momentum transfer for the fermions close to the Fermi
surface can be small. We also include weak disorder that couples to both the
bosonic order-parameter field and the fermionic degrees of freedom. Since the
quasiparticle excitations were shown in recent works to be destroyed at the
"hot-spots" in the low-energy limit of the model, we employ the Mori-Zwanzig
memory-matrix approach that permits the evaluation of all transport
coefficients without assuming well-defined Landau quasiparticles in the system.
We then apply this transport theory to discuss universal metallic-state
properties as a function of temperature and magnetic field of the cuprates from
the perspective of their fermiology, which turn out to be in qualitative
agreement with key experiments in those materials.
