Diffusion of Cosmic Antiprotons Generated throughout the Dark Matter Halo -- A Semi-Analytical Solution for a Linear Galactic Wind Model

TL;DR

This paper introduces a semi-analytical solution for modeling cosmic-ray antiprotons from dark matter in a galactic wind, facilitating more flexible dark matter analyses compared to fully numerical methods.

Contribution

It provides a new semi-analytical approach for calculating cosmic-ray antiprotons in a linear galactic wind model, complementing existing numerical solutions like GALPROP.

Findings

The semi-analytical solution matches GALPROP results for primary antiprotons.

Application to dark matter annihilation channels constrains DM models using AMS-02 data.

Discussion of potential dark matter signals in cosmic-ray antiproton measurements.

Abstract

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