  The interpretation of globular cluster horizontal branch (HB) morphology is a
classical problem that can significantly blur our understanding of stellar
populations. In this paper, we present a new multivariate analysis connecting
the effective temperature extent of the HB with other cluster parameters. The
work is based on Hubble Space Telescope photometry of 54 Galactic globular
clusters. The present study reveals an important role of the total mass of the
globular cluster on its HB morphology. More massive clusters tend to have HBs
more extended to higher temperatures. For a set of three input variables
including the temperature extension of the HB, [Fe/H] and M_V, the first two
eigenvectors account for the 90% of the total sample variance. Possible effects
of cluster self-pollution on HB morphology, eventually stronger in more massive
clusters, could explain the results here derived.
