Diffuse gamma ray constraints on annihilating or decaying Dark Matter after Fermi

Cirelli, Marco; Panci, Paolo; Serpico, Pasquale Dario

doi:10.1016/j.nuclphysb.2010.07.010

Cited by 201 publications

(263 citation statements)

References 91 publications

(109 reference statements)

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“…For example, the limits derived by Abazajian & Harding (2012) from the HESS measurements of the Galactic centre (Abramowski et al 2011) vanish if the DM profile is taken to be isothermal. This is in agreement with the conclusions drawn by Cirelli et al (2010). Constraints from Ackermann et al (2014) based on observations of dwarf spheroidal satellites of the Milky Way (see also Geringer-Sameth & Koushiappas 2011;Ackermann et al 2011) depend on the DM profiles assumed for these objects.…”

Section: Introductionsupporting

confidence: 89%

A new look at the cosmic ray positron fraction

Boudaud

Aupetit

Caroff

et al. 2015

A&A

131

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Context. The positron fraction in cosmic rays has recently been measured with improved accuracy up to 500 GeV, and it was found to be a steadily increasing function of energy above ∼10 GeV. This behaviour contrasts with standard astrophysical mechanisms, in which positrons are secondary particles, produced in the interactions of primary cosmic rays during their propagation in the interstellar medium. The observed anomaly in the positron fraction triggered a lot of excitement, as it could be interpreted as an indirect signature of the presence of dark matter species in the Galaxy, the so-called weakly interacting massive particles (WIMPs). Alternatively, it could be produced by nearby sources, such as pulsars. Aims. These hypotheses are probed in light of the latest AMS-02 positron fraction measurements. As regards dark matter candidates, regions in the annihilation cross section to mass plane, which best fit the most recent data, are delineated and compared to previous measurements. The explanation of the anomaly in terms of a single nearby pulsar is also explored. Methods. The cosmic ray positron transport in the Galaxy is described using a semi-analytic two-zone model. Propagation is described with Green functions as well as with Bessel expansions. For consistency, the secondary and primary components of the positron flux are calculated together with the same propagation model. The above mentioned explanations of the positron anomaly are tested using χ 2 fits. The numerical package MicrOMEGAs is used to model the positron flux generated by dark matter species. The description of the positron fraction from conventional astrophysical sources is based on the pulsar observations included in the Australia Telescope National Facility (ATNF) catalogue. Results. The masses of the favoured dark matter candidates are always larger than 500 GeV, even though the results are very sensitive to the lepton flux. The Fermi measurements point systematically to much heavier candidates than the recently released AMS-02 observations. Since the latter are more precise, they are much more constraining. A scan through the various individual annihilation channels disfavours leptons as the final state. On the contrary, the agreement is excellent for quark, gauge boson, or Higgs boson pairs, with best-fit masses in the 10 to 40 TeV range. The combination of annihilation channels that best matches the positron fraction is then determined at fixed WIMP mass. A mixture of electron and tau lepton pairs is only acceptable around 500 GeV. Adding b-quark pairs significantly improves the fit up to a mass of 40 TeV. Alternatively, a combination of the four-lepton channels provides a good fit between 0.5 and 1 TeV, with no muons in the final state. Concerning the pulsar hypothesis, the region of the distance-to-age plane that best fits the positron fraction for a single source is determined. Conclusions. The only dark matter species that fulfils the stringent gamma ray and cosmic microwave background bounds is a particle annihilating into...

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Section: Introductionsupporting

confidence: 89%

A new look at the cosmic ray positron fraction

Boudaud

Aupetit

Caroff

et al. 2015

A&A

131

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“…This may seem contrary to the common intuition (see e.g., [7,106]) that large rates into the τ + τ − final state are easier to detect in γ's because of the relatively stiff π 0 decay spectrum. In figure 23 we display the continuum γ flux spectra from the models in our set that annihilate into the τ + τ − final state > ∼ 99% of the time (red) and from those that annihilate into the final state bb > ∼ 99% of the time (blue).…”

Section: Jhep01(2011)064contrasting

confidence: 66%

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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“…For the leptonic channels, we also show the regions that allow to fit the Fermi -LAT, PAMELA and H.E.S.S. cosmic-ray measurements [59], with 95% and 99.99% CL: our exclusion curves are factors ∼30 and ∼2 away from constraining those fits, for the µ + µ − and τ + τ − final states and masses m χ = 2.5 TeV and 5 TeV, respectively.…”

Section: Secondary Photons From Final State Standard Model Particlesmentioning

confidence: 98%

Optimized Dark Matter Searches in Deep Observations of Segue 1 with MAGIC

Aleksić

2016

Springer Theses

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Abstract. We present the results of stereoscopic observations of the satellite galaxy Segue 1 with the MAGIC Telescopes, carried out between 2011 and 2013. With almost 160 hours of good-quality data, this is the deepest observational campaign on any dwarf galaxy performed so far in the very high energy range of the electromagnetic spectrum. We search this large data sample for signals of dark matter particles in the mass range between 100 GeV and 20 TeV. For this we use the full likelihood analysis method, which provides optimal sensitivity to characteristic gamma-ray spectral features, like those expected from dark matter annihilation or decay. In particular, we focus our search on gamma-rays produced from different final state Standard Model particles, annihilation with internal bremsstrahlung, monochromatic lines and box-shaped signals. Our results represent the most stringent constraints to the annihilation cross-section or decay lifetime obtained from observations of satellite galaxies, for masses above few hundred GeV. In particular, our strongest limit (95% confidence level) corresponds to a ∼500 GeV dark matter particle annihilating into τ + τ − , and is of order σ ann v ≃ 1.2×10 −24 cm 3 s −1 -a factor ∼40 above the σ ann v thermal value.

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Diffuse gamma ray constraints on annihilating or decaying Dark Matter after Fermi

Cited by 201 publications

References 91 publications

A new look at the cosmic ray positron fraction

A new look at the cosmic ray positron fraction

Cosmic ray anomalies from the MSSM?

Optimized Dark Matter Searches in Deep Observations of Segue 1 with MAGIC

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