Screening in perturbative approaches to LSS
(7 pages)

The linear and quasilinear regimes of Large Scale Structure formation are sensitive to the onset of any screening mechanisms which are in place (such as Vainshtein screening). If the Vainshtein scale is comparable to the scale at which nonlinearities enter the effective description of structure formation, then their can be 'residual screening' effects which are not captured by standard perturbation theory, which affect the equations of motion and modify observables. Here, a filter is proposed which can capture these effects on LSS observables, and this phenomenological modelling may be incorporated into broader EFT treatments of LSS.

Using new degrees of freedom in LCDM in order to resolve the cosmological constant often requires a screening mechanism to remove unwanted 'fifth forces' and match strict solar system requirements. These typically involve nonlinear terms becoming important, and balancing against contributions from the linear theory. When going beyond the linear regime in structure formation, it can therefore be necessary to take account of any screening mechanisms which exist in the theory. This is difficult to do exactly (because of the nonlinear nature of these corrections), but here a phenomenological ansatz is made which approximately captures the desired effects.
