Direct Detection of Vector Dark Matter

In this paper, we complete formulae for the elastic scattering cross section of general vector dark matter with nucleons in the direct detection at the leading order of the strong coupling constant alpha(s), assuming that the dark matter is composed of vector particles and interacts with heavy fermions with color charge as well as standard-model quark. As an application of our formulae, the direct detection of the first Kaluza-Klein photon in the minimal universal extra dimension model is discussed. It is found that the scattering cross section is larger than those in the previous works by up to a factor of ten.