scholarly journals Upper limits on dark matter annihilation with the teraelectronvolt cosmic ray spectrum of electrons and positrons from DAMPE

2019 ◽  
Vol 1380 ◽  
pp. 012144 ◽  
Author(s):  
Maneenate Wechakama ◽  
Brandon Khan Cantlay
Keyword(s):  
Dark Matter ◽  
Cosmic Ray ◽  
Dark Matter Annihilation ◽  
Electrons And Positrons ◽  
Upper Limits

An excess radio signal in the Abell 4038 cluster

2020 ◽  
Vol 500 (4) ◽  
pp. 5583-5588
Author(s):  
Man Ho Chan ◽  
Chak Man Lee
Keyword(s):  
Dark Matter ◽  
Spectral Data ◽  
Cross Section ◽  
Radio Signal ◽  
Dark Matter Particle ◽  
Cosmic Ray ◽  
Annihilation Cross Section ◽  
Radio Continuum ◽  
Test Statistic ◽  
Dark Matter Annihilation

ABSTRACT In the past decade, various instruments, such as the Large Area Telescope (LAT) on the Fermi Gamma Ray Space Telescope, the Alpha Magnetic Spectrometer (AMS) and the Dark Matter Particle Explorer(DAMPE), have been used to detect the signals of annihilating dark matter in our Galaxy. Although some excesses of gamma rays, antiprotons and electrons/positrons have been reported and are claimed to be dark matter signals, the uncertainties of the contributions of Galactic pulsars are still too large to confirm the claims. In this paper, we report on a possible radio signal of annihilating dark matter manifested in the archival radio continuum spectral data of the Abell 4038 cluster. By assuming a thermal annihilation cross-section and comparing the dark matter annihilation model with the null hypothesis (cosmic ray emission without dark matter annihilation), we obtain very large test statistic (TS) values, TS > 45, for four popular annihilation channels, which correspond to more than 6σ statistical preference. This reveals a possible potential signal of annihilating dark matter. In particular, our results are also consistent with the recent claims of dark matter mass, m ≈ 30–50 GeV, annihilating via the $\rm b\bar{b}$ quark channel with the thermal annihilation cross-section. However, at this time, we cannot exclude the possibility that a better background cosmic ray model could explain the spectral data without recourse to dark matter annihilations.

scholarly journals A possible radio signal of annihilating dark matter in the Abell 4038 cluster

2019 ◽  
Vol 495 (1) ◽  
pp. L124-L128 ◽  
Author(s):  
Man Ho Chan ◽  
Chak Man Lee
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Radio Signal ◽  
Dark Matter Particle ◽  
Cosmic Ray ◽  
Annihilation Cross Section ◽  
Radio Continuum ◽  
Test Statistic ◽  
Large Area ◽  
Dark Matter Annihilation

ABSTRACT In the past decade, some telescopes [e.g. Fermi-Large Area Telescope (LAT), Alpha Magnetic Spectrometer(AMS), and Dark Matter Particle Explorer(DAMPE)] were launched to detect the signals of annihilating dark matter in our Galaxy. Although some excess of gamma-rays, antiprotons, and electrons/positrons have been reported and claimed as dark matter signals, the uncertainties of Galactic pulsars’ contributions are still too large to confirm the claims. In this Letter, we report a possible radio signal of annihilating dark matter manifested in the archival radio continuum spectral data of the Abell 4038 cluster. By assuming the thermal annihilation cross-section and comparing the dark matter annihilation model with the null hypothesis (cosmic ray emission without dark matter annihilation), we get very large test statistic values >45 for four popular annihilation channels, which correspond to more than 6.5σ statistical preference. This provides a very strong evidence for the existence of annihilating dark matter. In particular, our results also support the recent claims of dark matter mass m ≈ 30–50 GeV annihilating via the bb̄ quark channel with the thermal annihilation cross-section.

scholarly journals NEUTRINO EMISSION FROM DARK MATTER ANNIHILATION/DECAY IN LIGHT OF COSMIC e± AND $\bar{p}$ DATA

2012 ◽  
Vol 27 (06) ◽  
pp. 1250024 ◽  
Author(s):  
JIE LIU ◽  
QIANG YUAN ◽  
XIAOJUN BI ◽  
HONG LI ◽  
XINMIN ZHANG
Keyword(s):  
Dark Matter ◽  
Branching Ratio ◽  
Cosmic Ray ◽  
Current Data ◽  
Neutrino Emission ◽  
Dark Matter Annihilation ◽  
Text Data ◽  
Self Consistent ◽  
Γ Rays ◽  
Global Fitting

A self-consistent global fitting method based on the Markov Chain Monte Carlo technique to study the dark matter (DM) property associated with the cosmic ray electron/positron excesses was developed in our previous work. In this work we further improve the previous study to include the hadronic branching ratio of DM annihilation/decay. The PAMELA [Formula: see text] data are employed to constrain the hadronic branching ratio. We find that the 95% (2σ) upper limits of the quark branching ratio allowed by the PAMELA [Formula: see text] data is ~0.032 for DM annihilation and ~0.044 for DM decay, respectively. This result shows that the DM coupling to pure leptons is indeed favored by the current data. Based on the global fitting results, we further study the neutrino emission from DM in the galactic center. Our predicted neutrino flux is some smaller than previous works since the constraint from γ-rays is involved. However, it is still capable to be detected by the forthcoming neutrino detector such as IceCube. The improved points of the present study compared with previous works include: (1) the DM parameters, both the particle physical ones and astrophysical ones, are derived in a global fitting way, (2) constraints from various species of data sets, including γ-rays and antiprotons are included, and (3) the expectation of neutrino emission is fully self-consistent.

scholarly journals Perspectives for indirect dark matter search with AMS-2 using cosmic-ray electrons and positrons

2009 ◽  
Vol 11 (10) ◽  
pp. 105021 ◽  
Author(s):  
B Beischer ◽  
P von Doetinchem ◽  
H Gast ◽  
T Kirn ◽  
S Schael
Keyword(s):  
Dark Matter ◽  
Cosmic Ray ◽  
Dark Matter Search ◽  
Electrons And Positrons

scholarly journals Consistent explanation for the cosmic-ray positron excess in p-wave Sommerfeld-enhanced dark matter annihilation

2021 ◽  
Vol 2021 (09) ◽  
pp. 005
Author(s):  
Yu-Chen Ding ◽  
Yu-Lin Ku ◽  
Chun-Cheng Wei ◽  
Yu-Feng Zhou
Keyword(s):  
Dark Matter ◽  
Cosmic Ray ◽  
P Wave ◽  
Dark Matter Annihilation

scholarly journals Search for dark matter cosmic-ray electrons and positrons from the Sun with the Fermi Large Area Telescope

2020 ◽  
Vol 101 (2) ◽  
Author(s):  
A. Cuoco ◽  
P. De La Torre Luque ◽  
F. Gargano ◽  
M. Gustafsson ◽  
F. Loparco ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cosmic Ray ◽  
The Sun ◽  
Large Area ◽  
Electrons And Positrons

scholarly journals The pinching method for Galactic cosmic ray positrons: Implications in the light of precision measurements

2017 ◽  
Vol 605 ◽  
pp. A17 ◽  
Author(s):  
M. Boudaud ◽  
E. F. Bueno ◽  
S. Caroff ◽  
Y. Genolini ◽  
V. Poulin ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cosmic Ray ◽  
High Energy ◽  
Transport Processes ◽  
Secondary Component ◽  
Dark Matter Annihilation ◽  
Propagation Parameters ◽  
Positron Flux ◽  
Galactic Cosmic Ray ◽  
Best Fit

Context. Two years ago, the Ams-02 collaboration released the most precise measurement of the cosmic ray positron flux. In the conventional approach, in which positrons are considered as purely secondary particles, the theoretical predictions fall way below the data above 10 GeV. One suggested explanation for this anomaly is the annihilation of dark matter particles, the so-called weakly interactive massive particles (WIMPs), into standard model particles. Most analyses have focused on the high-energy part of the positron spectrum, where the anomaly lies, disregarding the complicated GeV low-energy region where Galactic cosmic ray transport is more difficult to model and solar modulation comes into play. Aims. Given the high quality of the latest measurements by Ams-02, it is now possible to systematically re-examine the positron anomaly over the entire energy range, this time taking into account transport processes so far neglected, such as Galactic convection or diffusive re-acceleration. These might impact somewhat on the high-energy positron flux so that a complete and systematic estimate of the secondary component must be performed and compared to the Ams-02 measurements. The flux yielded by WIMPs also needs to be re-calculated more accurately to explore how dark matter might source the positron excess. Methods. We devise a new semi-analytical method to take into account transport processes thus far neglected, but important below a few GeV. It is essentially based on the pinching of inverse Compton and synchrotron energy losses from the magnetic halo, where they take place, inside the Galactic disc. The corresponding energy loss rate is artificially enhanced by the so-called pinching factor, which needs to be calculated at each energy. We have checked that this approach reproduces the results of the Green function method at the per mille level. This new tool is fast and allows one to carry out extensive scans over the cosmic ray propagation parameters. Results. We derive the positron flux from sub-GeV to TeV energies for both gas spallation and dark matter annihilation. We carry out a scan over the cosmic ray propagation parameters, which we strongly constrain by requiring that the secondary component does not overshoot the Ams-02 measurements. We find that only models with large diffusion coefficients are selected by this test. We then add to the secondary component the positron flux yielded by dark matter annihilation. We carry out a scan over WIMP mass to fit the annihilation cross-section and branching ratios, successively exploring the cases of a typical beyond-the-standard-model WIMP and an annihilation through light mediators. In the former case, the best fit yields a p-value of 0.4% for a WIMP mass of 264 GeV, a value that does not allow to reproduce the highest energy data points. If we require the mass to be larger than 500 GeV, the best-fit χ2 per degree of freedom always exceeds a value of 3. The case of light mediators is even worse, with a best-fit χ2 per degree of freedom always larger than 15. Conclusions. We explicitly show that the cosmic ray positron flux is a powerful and independent probe of Galactic cosmic ray propagation. It should be used as a complementary observable to other tracers such as the boron-to-carbon ratio. This analysis shows also that the pure dark matter interpretation of the positron excess is strongly disfavoured. This conclusion is based solely on the positron data, and no other observation, such as the antiproton flux or the CMB anisotropies, needs to be invoked.

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