  We calculate the angular two-point autocorrelation function (ACF) of the soft
X-ray background (SXRB) produced by the warm-hot intergalactic medium (WHIM)
associated with dark halos, motivated primarily by searching for missing
baryons and distinguishing different physical processes of the WHIM in dark
halos. We employ a purely analytic model for the halo population which is
completely determined by the universal density profile and the Press-Schechter
mass function. We then adopt a phenomenological approach to nongravitational
processes of the WHIM such as preheating and radiative cooling. It shows that
the power spectra of the SXRB predicted by three WHIM models, namely, the
self-similar model, preheating model and cooling model demonstrate remarkably
different signatures in both amplitude and shape, with the peak locations
moving from 4X10^4 for the self-similar model to a smaller value of (3-5)X10^3
when nongravitational processes are taken into account. The corresponding ACFs
for preheating and cooling models become shallower too as compared with the
prediction of the self-similar model. This may permit an effective probe of the
physical processes of the WHIM in massive halos in conjunction with the
observationally determined power spectrum or ACF of the SXRB from diffuse WHIM.
However, a direct comparison of our theoretical predictions with existing data
(e.g. the ACF determined from ROSAT observations) is still difficult because of
the dominant contribution of AGNs in the soft X-ray sky. We discuss briefly the
implication of our results for resolving the missing baryon problem in the
local universe.
