A Redefinition of the Halo Boundary Leads to a Simple yet Accurate Halo
  Model of Large Scale Structure
  We present a model for the halo--mass correlation function that explicitly
incorporates halo exclusion. We assume that halos trace mass in a way that can
be described using a single scale-independent bias parameter. However, our
model exhibits scale dependent biasing due to the impact of halo-exclusion, the
use of a ``soft'' (i.e. not infinitely sharp) halo boundary, and differences in
the one halo term contributions to $\xi_{\rm hm}$ and $\xi_{\rm mm}$. These
features naturally lead us to a redefinition of the halo boundary that lies at
the ``by eye'' transition radius from the one--halo to the two--halo term in
the halo--mass correlation function. When adopting our proposed definition, our
model succeeds in describing the halo--mass correlation function with $\approx
2\%$ residuals over the radial range $0.1\ h^{-1}{\rm Mpc} < r < 80\ h^{-1}{\rm
Mpc}$, and for halo masses in the range $10^{13}\ h^{-1}{\rm M}_{\odot} < M <
10^{15}\ h^{-1}{\rm M}_{\odot}$. Our proposed halo boundary is related to the
splashback radius by a roughly constant multiplicative factor. Taking the
87-percentile as reference we find $r_{\rm t}/R_{\rm sp} \approx 1.3$.
Surprisingly, our proposed definition results in halo abundances that are well
described by the Press-Schechter mass function with $\delta_{\rm sc}=1.449\pm
0.004$. The clustering bias parameter is offset from the standard
background-split prediction by $\approx 10\%-15\%$. This level of agreement is
comparable to that achieved with more standard halo definitions.
