Diffusion of Cosmic Antiprotons Generated throughout the Dark Matter Halo—A Semianalytical Solution for a Linear Galactic Wind Model

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Abstract The public GALPROP code gives a fully numerical solution for the spectrum of cosmic rays propagating through a linear Galactic wind directed outward from the Galactic plane in the framework of a cylindrical diffusion model. Alternatively, for the linear Galactic wind case, we present a semianalytical solution of the two-zone cylindrical model that describes the spectrum of cosmic-ray antiprotons produced from the primary sources throughout the dark matter (DM) halo. While the secondary antiprotons can be generated by, e.g., the GALPROP WebRun, consistently using this semianalytical solution for the primary ones would be helpful to build a suited DM model, which may be sophisticated, and then to perform a statistical analysis when comparing it with data. As an example, using the obtained formula, we study the possible DM signal through the channel DM DM → b ¯ b and its constraint from the measurement of the AMS-02 antiproton-to-proton ratio. The indication of the DM signal is discussed. The advantages of the semianalytical approach and its comparison with the GALPROP model are presented.