Abstract
We show that gauge coupling unification is realized with a greater accuracy in the presence of a massless hidden photon which has a large kinetic mixing with hypercharge. We solve the renormalization group equations at two-loop level and find that the GUT unification scale is around 1016.5GeV which sufficiently suppresses the proton decay rate, and that the unification is essentially determined by the kinetic mixing only, and it is rather insensitive to the hidden gauge coupling or the presence of vector-like matter fields charged under U(1)H and/or SU(5). Matter fields charged under the unbroken hidden U(1)H are stable and they contribute to dark matter. Interestingly, they become minicharged dark matter which carries a small but non-zero electric charge, if the hidden gauge coupling is tiny. The minicharged dark matter is a natural outcome of the gauge coupling unification with a hidden photon.
Highlights
The Standard Model (SM) has been so successful that it explains almost all the existing experimental data with a very high accuracy
We find that the unification is almost determined by the kinetic mixing, but it is rather insensitive to the size of the hidden gauge coupling or the presence of vector-like matter fields charged under U(1)H and/or SU(5)
We have investigated the gauge coupling unification in the presence of an unbroken hidden U(1)H symmetry, which mixes with the U(1)Y of the SM gauge group
Summary
The Standard Model (SM) has been so successful that it explains almost all the existing experimental data with a very high accuracy. Recently studied the gauge coupling unification with unbroken hidden U(1)H by solving the RG equations at one-loop level, including the effect of extra matter fields charged under U(1)H, and discussed a possible origin of the required large kinetic mixing as well as phenomenological and cosmological implications of the extra matter fields. Those hidden matters are stable and contribute to dark matter. In this paper we study the GUT with a hidden photon in a greater detail and argue that minicharged dark matter is its natural outcome.
Sign-in/Register to view highlights & summary 
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call