Diffuse Gamma Rays
CALET, of necessity, will measure the diffuse gamma ray background and can make an important contribution by extending the Fermi gamma ray observations to energies above ~100 GeV. An example of what CALET can accomplish is illustrated in Figure 1 which shows diffuse gamma ray results from EGRET (top)  and Fermi compared to a particular model. The projected CALET results are indicated in red and demonstrate that CALET will be able to extend the Fermi data.
Figure 1. Diffuse gamma ray results anticipated for CALET compared
to previous data and to model predictions. Here the flux is multiplied by E2.
It should be noted that there are currently very many models for both annihilating and decaying dark matter particles. Each model must be analyzed for its prediction of electron spectrum or gamma ray enhancements, and these predictions must then be compared to the CALET capabilities to determine what might be observed and/or what type of limit the CALET data could impose on the model, assuming existing data have not already done so. This is an on-going process that will continue through CALET launch and data analysis -- especially considering the rate at which new theoretical models are produced. Yet again, this attests to the astrophysical promise for the CALET mission.