Light mass galileons: Cosmological dynamics, mass screening and
  observational constraints
  In this paper, we examine the cosmological viability of a light mass galileon
field consistent with local gravity constraints. The minimal,
L_3=\Box\phi(\partial_\mu \phi)^2, massless galileon field requires an
additional term in order to give rise to a viable ghost free late time
acceleration of Universe. The desired cosmological dynamics can either be
achieved by incorporating an additional terms in the action such as (L_4,L_5) -
the higher order galileon Lagrangians or by considering a light mass field a la
galileon field potential. We analyse the second possibility and find that: (1)
The model produces a viable cosmology in the regime where the non-linear
galileon field is subdominant, (2) The Vainshtein mechanism operates at small
scales where the non-linear effects become important and contribution of the
field potential ceases to be significant. Also the small mass of the field
under consideration is protected against strong quantum corrections thereby
providing quantum stability to the system.
