openNew dynamics from light and weakly-coupled sectors beyond the Standard Model may manifest as long-
range forces between visible matter particles. Such new forces can be searches for by means of a variety
of experimental approaches. In this thesis, we re-examine the calculation of non-relativistic potentials
mediated by new light particles coupled to the Standard Model, employing a general parametrization
of the new interactions and going beyond the leading order Born approximation. We correct and
integrate previous results, and point out as well the presence of new relevant contact terms arising at
next-to-leading order in the non-relativistic expansion.New dynamics from light and weakly-coupled sectors beyond the Standard Model may manifest as long-
range forces between visible matter particles. Such new forces can be searches for by means of a variety
of experimental approaches. In this thesis, we re-examine the calculation of non-relativistic potentials
mediated by new light particles coupled to the Standard Model, employing a general parametrization
of the new interactions and going beyond the leading order Born approximation. We correct and
integrate previous results, and point out as well the presence of new relevant contact terms arising at
next-to-leading order in the non-relativistic expansion
