A novel prediction for secondary positrons and electrons in the Galaxy

Abstract

The Galactic flux of cosmic-ray (CR) positrons in the GeV to TeV energy range is very likely due to different Galactic components. One of these is the inelastic scattering of CR nuclei with the atoms of the interstellar medium. The precise amount of this component determines the eventual contribution from other sources. We present here a new estimation of the secondary CR positron flux by incorporating the latest results for the production cross sections of $e^{\pm }$ from hadronic scatterings calibrated on collider data. All the reactions for CR nuclei up to silicon scattering on both hydrogen and helium are included. The propagation models are derived consistently by fits on primary and secondary CR nuclei data. Models with a small halo size ($L\le 2$ kpc) are disfavored by the nuclei data although the current uncertainties on the beryllium nuclear cross sections may impact this result. The resulting positron flux shows a strong dependence on the Galactic halo size, increasing up to factor 1.5 moving $L$ from 8 to 2 kpc. Within the most reliable propagation models, the positron flux matches the data for energies below 1 GeV. We verify that secondary positrons contribute less than $70\%$ of the data above a few GeV, corroborating that an excess of positrons is already present at very low energies. At larger energies, our predictions are below the data with the discrepancy becoming more and more pronounced. Our results are provided together with uncertainties due to propagation and hadronic cross sections. The former uncertainties are below 5\% at fixed $L$, while the latter are about 7\% almost independently of the propagation scheme. In addition to the predictions of positrons, we provide new predictions also for the secondary CR electron flux.

arXiv commentMatches published version. Few comments and clarifications added, results unchanged

References in corpus (68)

• An Introduction to PYTHIA 8.2
• MultiNest: an efficient and robust Bayesian inference tool for cosmology and particle physics
• Cosmic-ray propagation and interactions in the Galaxy
• The Interstellar Environment of our Galaxy
• Energy spectra of gamma-rays, electrons and neutrinos produced at proton-proton interactions in the very high energy regime
• Production and propagation of cosmic-ray positrons and electrons
• Measurement of separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope
• Pulsars as the Sources of High Energy Cosmic Ray Positrons
• Cosmic Rays below Z=30 in a diffusion model: new constraints on propagation parameters
• Parameterization of Gamma, e^+/- and Neutrino Spectra Produced by p-p Interaction in Astronomical Environment
• The cosmic-ray positron energy spectrum measured by PAMELA
• New limits on dark matter annihilation from AMS cosmic ray positron data
• Constraints on WIMP Dark Matter from the High Energy PAMELA $\bar{p}/p$ data
• Galactic secondary positron flux at the Earth
• Minimal Dark Matter predictions for galactic positrons, anti-protons, photons
• Extended Measurement of the Cosmic-Ray Electron and Positron Spectrum from 11 GeV to 4.8 TeV with the Calorimetric Electron Telescope on the International Space Station
• Interpretation of AMS-02 electrons and positrons data
• Solution of heliospheric propagation: unveiling the local interstellar spectra of cosmic ray species
• Astrophysical models for the origin of the positron "excess"
• On cosmic ray acceleration in supernova remnants and the FERMI/PAMELA data
• A Markov Chain Monte Carlo technique to sample transport and source parameters of Galactic cosmic rays: II. Results for the diffusion model combining B/C and radioactive nuclei
• Absorption of Very High Energy Gamma Rays in the Milky Way
• AMS-02 beryllium data and its implication for cosmic ray transport
• High-Energy Gamma Rays from the Milky Way: Three-Dimensional Spatial Models for the Cosmic-Ray and Radiation Field Densities in the Interstellar Medium
• Scrutinizing the evidence for dark matter in cosmic-ray antiprotons
• Current status and desired accuracy of the isotopic production cross sections relevant to astrophysics of cosmic rays I. Li, Be, B, C, N
• Constraints on the distribution of supernova remnants with Galactocentric radius
• Detection of a $\gamma$-ray halo around Geminga with the Fermi-LAT and implications for the positron flux
• Cosmic-ray transport from AMS-02 B/C data: benchmark models and interpretation
• Cosmic-ray protons, nuclei, electrons, and antiparticles under a two-halo scenario of diffusive propagation
• Multimessenger constraints on the dark matter interpretation of the Fermi-LAT Galactic center excess
• Production cross sections of cosmic antiprotons in the light of new data from the NA61 and LHCb experiments
• AMS-100: The Next Generation Magnetic Spectrometer in Space -- An International Science Platform for Physics and Astrophysics at Lagrange Point 2
• A new look at the cosmic ray positron fraction
• Cosmic-ray propagation with DRAGON2: II. Nuclear interactions with the interstellar gas
• New calculation of antiproton production by cosmic ray protons and nuclei
• $\beta$--Radioactive Cosmic Rays in a diffusion model: test for a local bubble?
• Galactic factories of cosmic-ray electrons and positrons
• The Three-Dimensional Spatial Distribution of Interstellar Gas in the Milky Way: Implications for Cosmic Rays and High-Energy Gamma-Ray Emissions
• Galactic halo size in the light of recent AMS-02 data
• Combined analysis of AMS-02 (Li,Be,B)/C, N/O, 3He, and 4He data
• Contribution of pulsars to cosmic-ray positrons in light of recent observation of inverse-Compton halos
• Parametrizations of Inclusive Cross Sections for Pion Production in Proton-Proton Collisions
• Dark matter vs. astrophysics in the interpretation of AMS-02 electron and positron data
• Dark matter or correlated errors: Systematics of the AMS-02 antiproton excess
• AMS-02 antiprotons' consistency with a secondary astrophysical origin
• Energy spectra of secondaries in proton-proton interactions
• Implications of Lithium to Oxygen AMS-02 spectra on our understanding of cosmic-ray diffusion
• AAfrag: Interpolation routines for Monte Carlo results on secondary production in proton-proton, proton-nucleus and nucleus-nucleus interactions
• SOLARPROP: Charge-sign Dependent Solar Modulation for Everyone
• Dipole anisotropy in cosmic electrons and positrons: inspection on local sources
• Secondary Cosmic Ray Nuclei from Supernova Remnants and Constraints to the Propagation Parameters
• The pinching method for Galactic cosmic ray positrons: implications in the light of precision measurements
• Breaks in interstellar spectra of positrons and electrons derived from time-dependent AMS data
• Stochastic Fluctuations of Low-Energy Cosmic Rays and the Interpretation of Voyager Data
• Features in cosmic-ray lepton data unveil the properties of nearby cosmic accelerators
• Studying the Milky Way Pulsar Population with Cosmic-Ray Leptons
• Constraining positron emission from pulsar populations with AMS-02 data
• New minimal, median, and maximal propagation models for dark matter searches with Galactic cosmic rays
• Time-dependent AMS-02 electron-positron fluxes in an extended force-field model
• Interpretations of the cosmic ray secondary-to-primary ratios measured by DAMPE
• A simple determination of the halo size $L$ from ${}^{10}$Be/${}^9$Be data
• Multi-messenger constraints to the local emission of cosmic-ray electrons
• Novel interpretation of the latest AMS-02 cosmic-ray electron spectrum
• Utilizing cosmic-ray positron and electron observations to probe the averaged properties of Milky Way pulsars
• Implications on Spatial Models of Interstellar Gamma-Ray Inverse-Compton Emission from Synchrotron Emission Studies in Radio and Microwaves
• Nonsecondary origin of cosmic ray positrons
• The rigidity dependence of galactic cosmic-ray fluxes and its connection with the diffusion coefficient

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