  We reexamine the two-point correlation of density maxima in Gaussian initial
conditions. Spatial derivatives of the linear density correlation, which were
ignored in the calculation of Bardeen, Bond, Kaiser & Szalay (1986), are
included in our analysis. These functions exhibit large oscillations around the
sound horizon scale for generic CDM power spectra. We derive the exact
leading-order expression for the correlation of density peaks and demonstrate
the contribution of those spatial derivatives. In particular, we show that
these functions can modify significantly the baryon acoustic signature of
density maxima relative to that of the linear density field. The effect depends
upon the exact value of the peak height, the filter shape and size, and the
small-scale behaviour of the transfer function. In the LambdaCDM cosmology, for
maxima identified in the density field smoothed at mass scale M\approx
10^{12}-10^{14}M_sun/h and with linear threshold height \nu=1.673/\sigma(M),
the contrast of the BAO can be a few tens of percent larger than in the linear
matter correlation. Overall, the BAO is amplified (damped) for threshold
heights larger (less) than unity. Density maxima thus behave quite differently
than linearly biased tracers of the density field, whose acoustic signature is
a simple scaled version of the linear baryon acoustic oscillation. We also
calculate the mean streaming of peak pairs in the quasi-linear regime. We show
that the leading-order 2-point correlation and pairwise velocity of density
peaks are consistent with a nonlinear, local biasing relation involving
gradients of the density field. Biasing will be an important issue in
ascertaining how much of the enhancement of the BAO in the primeval correlation
of density maxima propagates into the late-time clustering of galaxies.
