Constraining Screened Massive Gravitons with Cosmic Explorer

Third generation gravitational wave (GW) detectors will soon initiate precision tests of GR at cosmological scales.  Currently LIGO's recent GW observations have put new constraints on the graviton mass.  Yet, in various viable massive graviton theories the massive carriers for gravitational interactions can be screened within galaxy distributions.  This is accomplished through the Vainshtein mechanism and could explain null results in local regions.  Screening can also hold for gravitational radiation, where beyond-GR effects are suppressed within matter distributions but accumulate in the phase outside such distributions.  Here detectors like Cosmic Explorer will allow accurate observations at vast scales to probe this screening effect.  This talk will discuss a framework for next generation detectors, i.e., Cosmic Explorer, to probe fundamental physics in GW propagation screened by multiple galaxy distributions.  Using realistic galaxy population models the constraint on the graviton mass and screening radius will also be discussed.