Charged Loops at the Cosmological Collider with Chemical Potential

Cosmological collider physics allows the detection of heavy particles at inflationary scales through their imprints on primordial non-Gaussianities. We study the chemical potential mechanism applied to a pair of charged scalars. We analytically evaluate the resulting one-loop contribution to the bispectrum, using the spectral decomposition. In this way we are able to determine the parametric dependences for both the signal and the background. We show that a signal strength $f_{\mathrm{N}\mathrm{L}}\sim O(0.01)$ can be obtained within theoretical control, potentially reachable by 21cm tomography. As an application we consider the colored Higgs bosons in $\mathrm{S}\mathrm{U}(5)$ supersymmetric orbifold grand unification with masses $M\lesssim {10}^{15}\mathrm{G}\mathrm{e}\mathrm{V}$.