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The dark matter that appears to be gravitationally dominant on all scales larger than galactic cores may consist of axions, stable photinos, or other collisionless particles whose velocity dispersion in the early universe is so small that-fluctuations of galactic size or larger are not damp~ed by free streaming. An attractive feature of this cold dark matter hypothesis is its considerable predictive power: the post-recombination fluctuation spectrum is calculable, and it in turn governs the formation of galaxies and clusters. Good agreement with the data is obtained for a Zeldovich (j&l2 a: k;) spectrum of primordial fluctuations.

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We use N-body simulations combined with semi-analytic models to compute the clustering properties of modeled galaxies at z ∼ 3, and confront these predictions with the clustering properties of the observed population of Lyman-break galaxies (LBGs). Several scenarios for the nature of LBGs are explored, which may be broadly categorized into models in which high-redshift star formation is driven by collisional starbursts and those in which quiescent star formation dominates. For each model, we make predictions for the LBG overdensity distribution, the variance of counts-in-cells, the correlation length, and close pair statistics. Models which assume a one-to-one relationship between massive darkmatter halos and galaxies are disfavored by close pair statistics, as are models in which colliding halos are associated with galaxies in a simplified way. However, when modeling of gas consumption and star formation is included using a semi-analytic treatment, the quiescent and collisional starburst models predict similar clustering properties and none of these models can be ruled out based on the available clustering data. None of the "realistic" models predict a strong dependence of clustering amplitude on the luminosity threshold of the sample, in apparent conflict with some observational results.