  We present a physically motivated semi-analytic model to understand the
clustering of high redshift LBGs. We show that the model parameters constrained
by the observed luminosity function, can be used to predict large scale (\theta
> 80 arcsec) bias and angular correlation function of galaxies. These
predictions are shown to reproduce the observations remarkably well. We then
adopt these model parameters to calculate the halo occupation distribution
(HOD) using the conditional mass function. The halo model using this HOD is
shown to provide a reasonably good fit to the observed clustering of LBGs at
both large (\theta>80") and small (\theta < 10") angular scales for z=3-5 and
several limiting magnitudes. However, our models underpredict the clustering
amplitude at intermediate angular scales, where quasi-linear effects are
important. The average mass of halos contributing to the observed clustering is
found to be 6.2 x 10^{11} M_\odot and the characteristic mass of a parent halo
hosting satellite galaxies is 1.2 \times 10^{12} M_\odot for a limiting
absolute magnitude of -20.5 at z=4. For a given threshold luminosity these
masses decrease with increasing z and at any given z these are found to
increase with increasing value of threshold luminosity. We find that
approximately 40 % of the halos above a minimum mass M_{min}, can host
detectable central galaxies and about 5-10 % of these halos are likely to also
host a detectable satellite. The satellites form typically a dynamical
timescale prior to the formation of the parent halo. The small angular scale
clustering is due to central-satellite pairs and is quite sensitive to changes
in the duration of star formation in a halo. The present data favor star
formation in a halo lasting typically for a few dynamical time-scales. Our
models also reproduce different known trends between parameters related to star
formation.
