Cosmic Rays below<i>Z</i> = 30 in a Diffusion Model: New Constraints on Propagation Parameters

Maurin, D.; Donato, Fiorenza; Taillet, R.; Salati, Pierre

doi:10.1086/321496

Cited by 387 publications

(726 citation statements)

References 64 publications

(80 reference statements)

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“…In Maurin et al (2001Maurin et al ( , 2002, the secondary-to-primary ratio B/C is used to place constraints on the parameter space, and in Donato et al (2002) the information provided by the cosmic ray radioactive species is studied. For the discussion below, it is convenient to isolate three sets of parameters labeled MIN, MED, and MAX, defined in Table 1.…”

Section: Propagation Parametersmentioning

confidence: 99%

“…The behavior of the proton and helium fluxes with radius r can be inferred readily from their measured values Φ (E) once the propagation parameters are selected. This so-called retro-propagation was implemented in the original B/C analysis by Maurin et al (2001). The radial variation in the proton flux is presented in Fig.…”

Section: Spatial Origin Of the Positronsmentioning

confidence: 99%

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Galactic secondary positron flux at the Earth

Delahaye

Lineros²,

Donato³

et al. 2009

A&A

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216

308

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Context. Secondary positrons are produced by spallation of cosmic rays within the interstellar gas. Measurements have been typically expressed in terms of the positron fraction, which exhibits an increase above 10 GeV. Many scenarios have been proposed to explain this feature, among them some additional primary positrons originating from dark matter annihilation in the Galaxy. Aims. The PAMELA satellite has provided high quality data that has enabled high accuracy statistical analyses to be made, showing that the increase in the positron fraction extends up to about 100 GeV. It is therefore of paramount importance to constrain theoretically the expected secondary positron flux to interpret the observations in an accurate way. Methods. We focus on calculating the secondary positron flux by using and comparing different up-to-date nuclear cross-sections and by considering an independent model of cosmic ray propagation. We carefully study the origins of the theoretical uncertainties in the positron flux. Results. We find the secondary positron flux to be reproduced well by the available observations, and to have theoretical uncertainties that we quantify to be as large as about one order of magnitude. We also discuss the positron fraction issue and find that our predictions may be consistent with the data taken before PAMELA. For PAMELA data, we find that an excess is probably present after considering uncertainties in the positron flux, although its amplitude depends strongly on the assumptions made in relation to the electron flux. By fitting the current electron data, we show that when considering a soft electron spectrum, the amplitude of the excess might be far lower than usually claimed. Conclusions. We provide fresh insights that may help to explain the positron data with or without new physical model ingredients. PAMELA observations and the forthcoming AMS-02 mission will allow stronger constraints to be aplaced on the cosmic-ray transport parameters, and are likely to reduce drastically the theoretical uncertainties.

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Section: Propagation Parametersmentioning

confidence: 99%

Section: Spatial Origin Of the Positronsmentioning

confidence: 99%

Galactic secondary positron flux at the Earth

Delahaye

Lineros²,

Donato³

et al. 2009

A&A

Self Cite

216

308

View full text Add to dashboard Cite

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“…As δ describes the spectrum of turbulent features in the bulk magnetic field, there has been a large industry devoted to theoretical and experimental considerations of what its value should be [68][69][70][71][72][73]. Particularly well-motivated theoretical values include δ = 0.33 (Kolmogorov turbulence) and δ = 0.5 (Kraichnan turbulence).…”

Section: Jhep01(2011)064mentioning

confidence: 99%

Cosmic ray anomalies from the MSSM?

Cotta

Conley

Gainer

et al. 2011

J. High Energ. Phys.

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Abstract:The recent positron excess in cosmic rays (CR) observed by the PAMELA satellite may be a signal for dark matter (DM) annihilation. When these measurements are combined with those from FERMI on the total (e + + e − ) flux and from PAMELA itself on thep/p ratio, these and other results are difficult to reconcile with traditional models of DM, including the conventional mSUGRA version of Supersymmetry even if boosts as large as 10 3−4 are allowed. In this paper, we combine the results of a previously obtained scan over a more general 19-parameter subspace of the MSSM with a corresponding scan over astrophysical parameters that describe the propagation of CR. We then ascertain whether or not a good fit to this CR data can be obtained with relatively small boost factors while simultaneously satisfying the additional constraints arising from gamma ray data. We find that a specific subclass of MSSM models where the LSP is mostly pure bino and annihilates almost exclusively into τ pairs comes very close to satisfying these requirements. The lightestτ in this set of models is found to be relatively close in mass to the LSP and is in some cases the nLSP. These models lead to a significant improvement in the overall fit to the data by an amount ∆χ 2 ∼ 1/dof in comparison to the best fit without Supersymmetry while employing boosts ∼ 100. The implications of these models for future experiments are discussed.

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“…In principle, it could be included in the calculations using an iterative approach. Table 1: Galactic propagation models [9,10]. All models set R = 20 kpc.…”

Section: Antiproton Flux: the Conventional Formalismmentioning

confidence: 99%

“…The parameters L, R, K 0 , V C and δ define the galactic propagation model. We list three commonly used models in Table 1; these values are obtained from the analysis of observed isotope ratios in cosmic rays, primarily boron to carbon (B/C) ratio [10]. An analytic solution can be obtained by expanding np as a Bessel series…”

Section: Modelmentioning

confidence: 99%

Antiprotons from dark matter: Effects of a position-dependent diffusion coefficient

Perelstein

Shakya

2011

Phys. Rev. D

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Energetic antiprotons in cosmic rays can serve as an important indirect signature of dark matter. Conventionally, the antiproton flux from dark matter decay or annihilation is calculated by solving the transport equation with a space-independent diffusion coefficient within the diffusion zone of the galaxy. Antiproton sources outside the diffusion zone are ignored under the assumption that they propagate freely and escape. In reality, it is far more likely that the diffusion coefficient increases smoothly with distance from the disk, and the outlying part of the dark matter halo ignored in the conventional approach can be significant, containing as much as 90% of the galactic dark matter by mass in some models. We extend the conventional approach to address these issues. We obtain analytic approximations and numerical solutions for antiproton flux for a diffusion coefficient that increases exponentially with the distance from the disk, thereby including contributions from dark matter annihilation/decay in essentially the full dark matter halo. We find that the antiproton flux predicted in this model deviates from the conventional calculation for the same dark matter parameters by up to about 25%.

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Cosmic Rays belowZ = 30 in a Diffusion Model: New Constraints on Propagation Parameters

Cited by 387 publications

References 64 publications

Galactic secondary positron flux at the Earth

Galactic secondary positron flux at the Earth

Cosmic ray anomalies from the MSSM?

Antiprotons from dark matter: Effects of a position-dependent diffusion coefficient

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