  Time reversal symmetry breaking Weyl semimetals are unique among Weyl
materials in allowing the minimal number of Weyl points thus offering the
clearest signatures of the associated physics. Here we present neutron
diffraction, density functional theory and transport measurement results which
indicate that EuCd$_2$As$_2$ , under ambient field, strain and pressure, is
such a material with a single pair of Weyl points. Our work reveals a magnetic
structure (magnetic space group $C2'/m'$) with Eu moments pointing along the
[210] direction in-plane and canted $\sim$ 30$^{\circ}$ out-of-plane. Density
functional theory calculations using this structure show that the observed
canting drastically alters the relevant electronic bands, relative to the
in-plane order, leading to a single set of well defined Weyl points.
Furthermore, we find the canting angle can tune the distance of the Weyl points
above the Fermi level, with the smallest distance at low canting angles.
Finally, transport measurements of the anomalous Hall Effect and longitudinal
magnetoresistance exhibit properties indicative of a chiral anomaly, thus
supporting the neutron scattering and DFT results suggesting EuCd$_2$As$_2$ is
close to the ideal situation of the Weyl "Hydrogen atom".
