The Hubble Space Telescope UV Legacy Survey of Galactic Globular
  Clusters. XX. Ages of single and multiple stellar populations in seven bulge
  globular clusters
  In the present work we analyzed seven globular clusters selected from their
location in the Galactic bulge and with metallicity values in the range
$-1.30\lesssim\rm{[Fe/H]}\lesssim-0.50$. The aim of this work is first to
derive cluster ages assuming single stellar populations, and secondly, to
identify the stars from first (1G) and second generations (2G) from the main
sequence, subgiant and red giant branches, and to derive their age differences.
Based on a combination of UV and optical filters used in this project, we apply
the Gaussian mixture models to distinguish the multiple stellar populations.
Applying statistical isochrone fitting, we derive self-consistent ages,
distances, metallicities, and reddening values for the sample clusters. An
average of $12.3\pm0.4$ Gyr was obtained both using Dartmouth and BaSTI
(accounting atomic diffusion effects) isochrones, without a clear distinction
between the moderately metal-poor and the more metal-rich bulge clusters,
except for NGC 6717 and the inner halo NGC 6362 with $\sim 13.5$ Gyr. We
derived a weighted mean age difference between the multiple populations hosted
by each globular cluster of $41\pm170$ Myr adopting canonical He abundances;
whereas for higher He in 2G stars, this difference reduces to $17\pm170$ Myr,
but with individual uncertainties of $500$ Myr.
