Galaxy three-point correlation function in modified gravity

The next generation of galaxy surveys will provide highly accurate measurements the large-scale structure Universe, allowing for more stringent tests gravity on cosmological scales. Higher order statistics are a valuable tool to study non-Gaussianities in matter field and break degeneracies between modified other physical or nuisance parameters. However, understanding from first principles behaviour these correlations is essential characterise deviations General Relativity (GR), purpose this work. This work uses contemporary ideas Standard Perturbation Theory biased tracers characterize three point correlation function (3PCF) at tree level Modified Gravity models with scale-dependent gravitational strength, applies theory two specific ($f(R)$ DGP) that representative Chameleon Vainshtein screening mechanisms. Additionally, we use multipole decomposition, which apart speeding up algorithm extract signal data, also helps visualize GR deviations.