  A polarized electronic Raman scattering study reveals the emergence of
symmetry dependence in the electronic Raman response of single crystalline
URu$_{2}$Si$_{2}$ below the Kondo crossover scale $T_K\sim100K$. In particular,
the development of a coherent Kondo pseudo-gap predominantly in the E$_g$
channel highlights strong anisotropy in the Kondo physics in URu$_{2}$Si$_{2}$
that has previously been neglected in theoretical models of this system. A
calculation of the Raman vertices demonstrates that the strongest Raman vertex
does indeed develop within the E$_g$ channel for interband transitions and
reaches a maximum along the diagonals of the Brillouin zone, implying a
d-wave-like geometry for the Kondo pseudo-gap. Below the hidden order phase
transition at $T_{HO}= 17.5K$, the magnitude of the pseudo-gap is found to be
enhanced. Moreover, the anisotropy of the pseudo-gap is similar in form to that
proposed for the chiral d-wave (E$_g$) superconducting state that appears below
$T_c=1.5K$.
