PPPC 4 DM ID: A Poor Particle Physicist Cookbook for Dark Matter Indirect Detection

Abstract: We provide ingredients and recipes for computing signals of TeV-scale Dark Matter annihilations and decays in the Galaxy and beyond. For each DM channel, we present the energy spectra of electrons and positrons, antiprotons, antideuterons, gamma rays, neutrinos and antineutrinos e, mu, tau at production, computed by high-statistics simulations. We estimate the Monte Carlo uncertainty by comparing the results yielded by the Pythia and Herwig event generators. We then provide the propagation functions for charged particles in the Galaxy, for several DM distribution profiles and sets of propagation parameters. Propagation of electrons and positrons is performed with an improved semi-analytic method that takes into account position-dependent energy losses in the Milky Way. Using such propagation functions, we compute the energy spectra of electrons and positrons, antiprotons and antideuterons at the location of the Earth. We then present the gamma ray fluxes, both from prompt emission and from Inverse Compton scattering in the galactic halo. Finally, we provide the spectra of extragalactic gamma rays. All results are available in numerical form and ready to be consumed.

• The paper presents a comprehensive methodology to compute primary energy spectra of cosmic particles from dark matter annihilations and decays using PYTHIA and HERWIG.
• It implements detailed semi-analytic cosmic ray propagation models and gamma ray emission mechanisms, quantifying uncertainties across various halo profiles.
• The study offers freely available numerical tools, enabling robust, model-independent analyses for interpreting cosmic and gamma ray observations.

A Comprehensive Framework for Dark Matter Indirect Detection

The paper "PPPC 4 DM ID: A Poor Particle Physicist Cookbook for Dark Matter Indirect Detection" provides a detailed and systematic approach to calculating the signals of TeV-scale dark matter (DM) annihilations and decays in the galaxy and beyond. Authored by Marco Cirelli and collaborators, this comprehensive work presents a compilation of analytical tools and numerical results that aid in the analysis of dark matter indirect detection signals. It addresses particles such as electrons, positrons, antiprotons, antideuterons, gamma rays, and neutrinos. The cornerstone of this study is to furnish all the phenomenological ingredients required to perform analyses with maximum generality, without focusing on any specific dark matter model.

Main Contributions

1. Primary Spectra Calculation: The paper provides energy spectra for particles resulting from dark matter annihilations and decays, utilizing the well-known Monte Carlo event generators PYTHIA and HERWIG. These spectra are calculated for various dark matter particle masses (from a few GeV to 100 TeV) and final-state channels, including those for electrons and positrons, gamma rays, antiprotons, antideuterons, and neutrinos.
2. Propagation Models: Detailed treatment of the propagation of cosmic rays (including electrons, positrons, and antiprotons) through the galaxy is provided, using semi-analytic methods. These models incorporate spatial and energy-dependent factors, such as diffusion coefficients and energy loss, across varying galactic environments.
3. Gamma Ray Emission: The generation of prompt gamma rays and secondary emissions through Inverse Compton scattering is comprehensively covered. The work includes the calculation of halo functions specific to each emission mechanism.
4. Extragalactic Contributions: This manuscript considers gamma rays originating from extragalactic dark matter sources. It calculates their expected diffuse flux, accounting for various factors, such as cosmic-ray propagation, cosmological boost factors, and absorption of gamma rays by the intergalactic medium.
5. Availability of Numerical Results: All computational results are made available through the authors’ website in both numerical table format and as interpolation functions, making them readily useful for other researchers.

Strong Numerical Results and Methodological Advances

• Halo Profiles and Propagation Parameters: This work evaluates various dark matter halo profiles (e.g., NFW, Einasto) and propagation parameter sets (MIN, MED, MAX), ensuring robustness against astrophysical uncertainties. This contributes significantly to the consistency of dark matter signal predictions across different environments.
• Uncertainty Quantification: By comparing the outputs from PYTHIA and HERWIG, the authors provide insights into the uncertainties stemming from Monte Carlo methods. This comparison is crucial for assessing the reliability of the computed spectra used in dark matter indirect detection strategies.
• Innovative Toolkit: The provision of an extensive set of numerical tools for indirect detection of dark matter, accommodating theoretical models, makes this work particularly compelling. Researchers can leverage these resources to analyze and interpret data from cosmic observatories more effectively.

Implications and Speculations for Future Developments

The methods and results delineated in the paper have profound practical implications for dark matter searches using terrestrial and space-based observatories. They provide foundational support for interpreting excesses in cosmic ray and gamma ray data that may suggest dark matter activity. Furthermore, as data accumulation from various cosmic ray and gamma ray observatories, like Fermi-LAT or AMS-02, continues to grow, the methodologies and datasets provided by this framework could be pivotal in identifying or constraining theories regarding the nature of dark matter.

The study presents a forward-looking approach by speculating improvements in modeling consequences that baryonic matter may exert on dark matter distribution. The results and tools presented in this paper are anticipated to be benchmarks in future explorations towards a better understanding of dark matter properties and distribution.

Overall, the paper represents a substantial contribution to the field of astroparticle physics, setting the stage for ongoing and future investigations into the indirect signatures of dark matter and enabling a model-independent analysis aligned with experimental data.