Mass loss of different stellar populations in globular clusters
  Once fixed the age and metallicity; the colour distribution of horizontal
branch stars in a globular cluster depends on few parameters: the helium
abundance of the population and the mass lost during the pre-HB stages. These
parameters are usually derived from the HB itself, hence they are degenerate.
Breaking this degeneracy and understanding their role is a tricky and
challenging problem that no study has tried to solve yet. Combining the
information obtained from the chromosome maps and the analysis of multi-band
photometry with state of the art stellar evolution models, we can obtain a
solid estimate of Y for the various stellar populations in a GC. We will then
have, for the first time, the possibility to break the parameters degeneracy on
the HB, understand the role of the mass loss, and lay the foundation to build
another piece of the multiple populations mosaic.
