Cosmic-ray propagation with DRAGON2: I. numerical solver and astrophysical ingredients

Weakly interacting massive particles (WIMPs) have long reigned as one of the leading classes of dark matter candidates. The observed dark matter abundance can be naturally obtained by freezeout of weakscale dark matter annihilations in the early Universe. This "thermal WIMP" scenario makes direct predictions for the total annihilation cross section that can be tested in present-day experiments. While the dark matter mass constraint can be as high as m χ ≳ 100 GeV for particular annihilation channels, the constraint on the total cross section has not been determined. We construct the first model-independent limit on the WIMP total annihilation cross section, showing that allowed combinations of the annihilationchannel branching ratios considerably weaken the sensitivity. For thermal WIMPs with s-wave 2 → 2 annihilation to visible final states, we find the dark matter mass is only known to be m χ ≳ 20 GeV. This is the strongest largely model-independent lower limit on the mass of thermal-relic WIMPs; together with the upper limit on the mass from the unitarity bound (m χ ≲ 100 TeV), it defines what we call the "WIMP window." To probe the remaining mass range, we outline ways forward.

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“…To propagate our positron spectra generated with PYTHIA, we use the cosmic-ray propagation program DRAGON [90,91].…”

Section: A Cosmic-ray Propagationmentioning

confidence: 99%

GeV-scale thermal WIMPs: Not even slightly ruled out

et al. 2018

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“…Moskalenko et al 2015;Boschini et al 2017b;Evoli et al 2017;Kissmann et al 2015;Putze et al 2010) and to unprecedented precise CR measurements. Even though the main interaction processes are identified, details on CR propagation models, on injection spectra in the interstellar medium, and on the LIS are still uncertain.…”

Section: Introductionmentioning

confidence: 99%

“…Moskalenko et al 2002;Donato et al 2002;Maurin et al 2010;Donato & Serpico 2011;Aloisio & Blasi 2013;Tomassetti 2015) by using a well-established method based on comparing CR propagation models to CRs measurements (e.g. Jóhannesson et al 2016;Gaggero et al 2014;Boschini et al 2017b;Evoli et al 2017). CR all-electrons (electrons plus positrons), protons, and heavier nuclei interact with the gas in the interstellar medium and with the interstellar radiation field (ISRF) producing gamma rays via bremsstrahlung, inverse Compton (IC) scattering, and pion decay.…”

Section: Introductionmentioning

confidence: 99%

“…More precisely, CR direct measurements below several GeV are usually used to derive the propagation parameters that are then applied to the whole Galaxy (e.g. Jóhannesson et al 2016;Boschini et al 2017b;Evoli et al 2017). However, CR spectra below several GeV are affected by solar modulation (Parker 1958), which leads to unavoidable approximations in the modeling.…”

Section: Introductionmentioning

confidence: 99%

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Imprints of cosmic rays in multifrequency observations of the interstellar emission

Orlando

2017

Monthly Notices of the Royal Astronomical Society

102

147

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Ever since the discovery of Cosmic Rays (CRs), significant advancements have been made in modeling their propagation in the Galaxy and in the Heliosphere. However, propagation models suffer from degeneracy of many parameters. To complicate the picture the precision of recent data have started challenging existing models.To tackle these issues we use available multifrequency observations of the interstellar emission from radio to gamma rays, together with direct CR measurements, to study local interstellar spectra (LIS) and propagation models. As a result, the electron LIS is characterized without any assumption on solar modulation, and favorite propagation models are put forward. More precisely, our analysis leads to the following main conclusions: (1) the electron injection spectrum needs at least a break below a few GeV; (2) even though consistent with direct CR measurements, propagation models producing a LIS with large all-electron density from a few hundreds of MeV to a few GeV are disfavored by both radio and gamma-ray observations; (3) the usual assumption that direct CR measurements, after accounting for solar modulation, are representative of the proton LIS in our ∼1 kpc region is challenged by the observed local gamma-ray HI emissivity. We provide the resulting proton LIS, all-electron LIS, and propagation parameters, based on synchrotron, gamma-ray, and direct CR data. A plain diffusion model and a tentative diffusive-reacceleration model are put forward. The various models are investigated in the inner-Galaxy region in X-rays and gamma rays. Predictions of the interstellar emission for future gamma-ray instruments (e-ASTROGAM and AMEGO) are derived.

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“…(and references therein). Comparable results for the propagation of stable primary and secondary nuclei have been obtained in [5]. Recently, the PICARD code has been presented as well in [4].…”

Section: Pos(ifs2017)134mentioning

confidence: 85%

Cosmic rays and the diffuse gamma-ray emission

Donato¹

2017

Proceedings of 7th International Fermi Symposium — PoS(IFS2017)

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The diffuse γ-ray emission originated in the Galaxy is the main contributor to the photons observed by the Fermi-Large Area Telescope. It is a foreground or a background for the determination and the understanding of point sources and of diffuse processes. The diffuse galactic γ-ray emission is produced by the interactions of cosmic ray nuclei on the interstellar gas and of electrons on the interstellar radiation field. We discuss the impact that the charged cosmic rays (CRs) have on the determination of the gamma-ray diffuse galactic emission. We review the implications deriving from present data and outline some future prospects for data and models.

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Cosmic-ray propagation with DRAGON2: I. numerical solver and astrophysical ingredients

Cited by 229 publications

References 186 publications

GeV-scale thermal WIMPs: Not even slightly ruled out

GeV-scale thermal WIMPs: Not even slightly ruled out

Imprints of cosmic rays in multifrequency observations of the interstellar emission

Cosmic rays and the diffuse gamma-ray emission

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