Nucleosynthesis constraints on the faint vector portal

Abstract

New Abelian U(1)' gauge bosons $V_{\mu }$ can couple to the Standard Model through mixing of the associated field strength tensor $V_{\mu \nu }$ with the one from hypercharge, $F_{\mu \nu }^Y$. Here we consider early Universe sensitivity to this vector portal and show that the effective mixing parameter with the photon, $\kappa$, is being probed for vector masses in the GeV ballpark down to values $10^{-10}\lesssim \kappa \lesssim 10^{-14}$ where no terrestrial probes exist. The ensuing constraints are based on a detailed calculation of the vector relic abundance and an in-depth analysis of relevant nucleosynthesis processes.

Comments: 6 pages, 4 figures, contribution to the Dark Matter, Hadron Physics and Fusion Physics (DHF2014) conference, Messina, Italy, Sept. 24-26, 2014