Dark Scattering: accelerated constraints from KiDS-1000 with $\tt{ReACT}$ and $\tt{CosmoPower}$

Abstract

We present constraints on the Dark Scattering model through cosmic shear measurements from the Kilo Degree Survey (KiDS-1000), using an accelerated pipeline with novel emulators produced with $\tt{CosmoPower}$. Our main emulator, for the Dark Scattering non-linear matter power spectrum, is trained on predictions from the halo model reaction framework, previously validated against simulations. Additionally, we include the effects of baryonic feedback from $\tt{HMcode2016}$, whose contribution is also emulated. We analyse the complete set of statistics of KiDS-1000, namely Band Powers, COSEBIs and Correlation Functions, for Dark Scattering in two distinct cases. In the first case, taking into account only KiDS cosmic shear data, we constrain the amplitude of the dark energy - dark matter interaction to be $\vert A_{\rm ds} \vert \lesssim 20$ $\rm b/GeV$ at 68% C.L. Furthermore, we add information from the cosmic microwave background (CMB) from Planck, along with baryon acoustic oscillations (BAO) from 6dFGS, SDSS and BOSS, approximating a combined weak lensing + CMB + BAO analysis. From this combination, we constrain $A_{\rm ds} = 10.6^{+4.5}_{-7.3}$ $\rm b/GeV$ at 68% C.L. We confirm that with this estimated value of $A_{\rm ds}$ the interacting model considered in this work offers a promising alternative to solve the $S_8$ tension.