25354 2409.07524 10.1007/JHEP01(2025)115 115 115 Grand unification at the cosmological collider with chemical potential Regular Article - Theoretical Physics 1 31 2025 1 22 2024 10 2 2024 11 29 2025 1 22 2025 1 22 The Author(s) 2025 Open Access. This article is distributed under the terms of the Creative Commons Attribution License ( CC-BY 4.0 ), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited. 13130 2025 2025 1 1 Arushi Bodas arushib@uchicago.edu Edward Broadberry edbroad@umd.edu Raman Sundrum raman@umd.edu https://ror.org/024mw5h28 grid.170205.1 0000 0004 1936 7822 Enrico Fermi Institute, University of Chicago S Ellis Ave Chicago IL USA https://ror.org/020hgte69 grid.417851.e 0000 0001 0675 0679 Particle Theory Department, Fermilab Kirk and Pine St Batavia IL USA https://ror.org/047s2c258 grid.164295.d 0000 0001 0941 7177 Maryland Center for Fundamental Physics, Department of Physics University of Maryland Stadium Dr College Park MD USA Abstract We introduce a tree-level chemical potential mechanism for spin-1 particles within cosmological collider physics, allowing them to be detected in primordial non-Gaussianities for masses above the inflationary Hubble scale. We apply this mechanism to orbifold grand unification and the massive unification partners of the standard model gauge bosons. Our mechanism requires at least a pair of massive vector fields which are singlets of the standard model, a condition which is satisfied in the classic “trinification” scenario. Assuming that the gauge hierarchy problem is solved by supersymmetry, gauge coupling running points to unification partners at ~ 1015 GeV. We show that, within high-scale inflation, chemical potential enhancement can lead to observably strong signals for trinification partners in future cosmological surveys. Keywords Early Universe Particle Physics Grand Unification Cosmological models de Sitter space ArXiv ePrint: 2409.07524