  Globular Cluster (GC) Color-Magnitude Diagrams (CMDs) are reasonably well
understood in terms of standard stellar-evolution. However, there are still
some open issues, such as fully accounting for the Horizontal Branch (HB)
morphology in terms of chemical and dynamical parameters. Mass-loss on the Red
Giant Branch (RGB) shapes the mass-distribution of the HB stars, and the color
distribution in turn. The physical mechanisms driving mass-loss are still
unclear, as direct observations fail to reveal a clear correlation between
mass-loss rate and stellar properties. The horizontal-branch mass-distribution
is further complicated by Helium-enhanced multiple stellar populations, because
of differences in the evolving mass along the HB. We present a simple
analytical mass-loss model, based on tidal stripping through Roche-Lobe
OverFlow (RLOF) during stellar encounters. Our model naturally results in a
non-gaussian mass-loss distribution, with high skewness, and contains only two
free parameters. We fit it to the HB mass distribution of four Galactic GCs, as
obtained from fitting the CMD with Zero Age HB (ZAHB) models. The best-fit
model accurately reproduces the observed mass-distribution. If confirmed on a
wider sample of GCs, our results would account for the effects of dynamics in
RGB mass-loss processes and provide a physically motivated procedure for
synthetic CMDs of GCs. Our physical modeling of mass-loss may result in the
ability to disentangle the effects of dynamics and helium-enhanced
multiple-populations on the HB morphology and is instrumental in making HB
morphology a probe of the dynamical state of GCs, leading to an improved
understanding of their evolution.
