An anomalous positron abundance in cosmic rays with energies 1.5–100 GeV

Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, É. A.; Bonechi, L.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; Castellini, G.; Pascale, M. P. De; Rosa, G. De; Simone, N. De; Felice, V. Di; Galper, A. M.; Grishantseva, L.; Hofverberg, P.; Koldashov, S. V.; Krutkov, S. Y.; Kvashnin, A. N.; Leonov, A.; Malvezzi, V.; Marcelli, L.; Menn, W.; Mikhailov, V. V.; Mocchiutti, E.; Orsi, S.; Osteria, G.; Papini, P.; Pearce, Mark; Picozza, P.; Ricci, M.; Ricciarini, S.; Simon, M.; Sparvoli, R.; Спиллантини, П.; Stozhkov, Y. I.; Vacchi, A.; Vannuccini, E.; Vasilyev, G.; Voronov, S. A.; Yurkin, Y. T.; Zampa, G.; Zampa, N.; Zverev, V. G.

doi:10.1038/nature07942

Cited by 2,027 publications

(1,915 citation statements)

References 26 publications

Supporting

100

Mentioning

1,799

Contrasting

Unclassified

Order By: Relevance

“…The PAMELA satellite has reported a rise of the positron fraction e + /(e + + e − ) above the expected declining astrophysical background from ∼10 GeV up to at least 100 GeV [4]. At the same time, the ratiop/p fluxes is consistent with expectations based on astrophysical secondaries, up to the maximal probed energy of about 200 GeV [34,35].…”

Section: Details On the Dm Interpretations Of The E ± Anomaliessupporting

confidence: 72%

“…Since, motivated by peculiar spectral features, a plethora of models have appeared trying to fit the positron fraction and total electron data from PAMELA, Fermi and HESS [4,5,6,7] in terms of Dark Matter (as we review in Sec. 2.3), in Sec.…”

Section: Introductionmentioning

confidence: 99%

“…This is clearly an overconservative approach: in Sec. 4 we comment on the expected reach in exploring the DM parameter space after a better understanding of the astrophysical background is achieved.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Cirelli¹,

Panci²,

Serpico³

2010

Nuclear Physics B

201

246

View full text Add to dashboard Cite

We consider the diffuse gamma ray data from Fermi first year observations and compare them to the gamma ray fluxes predicted by Dark Matter annihilation or decay (both from prompt emission and from Inverse Compton Scattering), for different observation regions of the sky and a range of Dark Matter masses, annihilation/decay channels and Dark Matter galactic profiles. We find that the data exclude large regions of the Dark Matter parameter space not constrained otherwise and discuss possible directions for future improvements. Also, we further constrain Dark Matter interpretations of the e ± PAMELA/Fermi spectral anomalies, both for the annihilating and the decaying Dark Matter case: under very conservative assumptions, only models producing dominantly µ ± and assuming a cored Dark Matter galactic profile can fit the lepton data with masses around ∼ 2 TeV.

show abstract

Section: Details On the Dm Interpretations Of The E ± Anomaliessupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Cirelli¹,

Panci²,

Serpico³

2010

Nuclear Physics B

201

246

View full text Add to dashboard Cite

show abstract

“…Decay Over the last couple of years, a lot of attention has been given to the decaying DM as a possible explanation of the flux excesses of high-energy positrons and electrons measured by PAMELA [50], Fermi -LAT [51], H.E.S.S [52] and AMS-02 [53]. The needed DM particle lifetime in such a case, τ χ > 10 26 s, is much longer than the age of the Universe, so that the slow decay does not significantly reduce the overall DM abundance and, therefore, there is no contradiction with the astrophysical and cosmological observations.…”

Section: Secondary Photons From Final State Standard Model Particlesmentioning

confidence: 99%

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

Aleksić

2016

Springer Theses

View full text Add to dashboard Cite

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.

show abstract

“…Electrons produced in local SNRs are expected to fill out the electron spectrum above 100 GeV. In this picture the fraction of positrons in the cosmic ray lepton spectrum should decrease with increasing energy, in contradiction to results from ATIC [6], PAMELA [18], Fermi LAT [19] and AMS [4], which show that the positron fraction in fact increases with energy. While this effect could be produced by WIMP dark matter annihilation, the anomalous positron fraction can also be explained by nearby astrophysical sources, most notably pulsars and PWNe.…”

Section: Pulsar Wind Nebulae and The Positron Excessmentioning

confidence: 80%

Pulsar Wind Nebulae and Cosmic Rays: A Bedtime Story

Weinstein¹

2014

Nuclear Physics B - Proceedings Supplements

View full text Add to dashboard Cite

The role pulsar wind nebulae play in producing our locally observed cosmic ray spectrum remains murky, yet intriguing. Pulsar wind nebulae are born and evolve in conjunction with SNRs, which are favored sites of Galactic cosmic ray acceleration. As a result they frequently complicate interpretation of the gamma-ray emission seen from SNRs. However, pulsar wind nebulae may also contribute directly to the local cosmic ray spectrum, particularly the leptonic component. This paper reviews the current thinking on pulsar wind nebulae and their connection to cosmic ray production from an observational perspective. It also considers how both future technologies and new ways of analyzing existing data can help us to better address the relevant theoretical questions. A number of key points will be illustrated with recent results from the VHE (E > 100 GeV) gamma-ray observatory VERITAS. Keywords: IntroductionThe discovery of cosmic rays in the early twentieth century [1, 2] inaugurated a decades-long, serialized mystery story that has yet to be completed. At the heart of the mystery lies a set of of simple questions. What particles appear in the cosmic ray spectrum that we see from Earth? Where do these particles originate? How are they accelerated? In recent decades direct cosmic ray observations have brought us a wealth of information on the cosmic ray spectrum and its composition, clues to the types of environments in which cosmic rays are born. The interaction of these particles with interstellar magnetic fields, however, prevents them from being traced back to their point of origin.In order to pursue the other half of this mystery-the nature of cosmic ray accelerators-we must use the secondary photon radiation produced in these cosmic ray nurseries. These high-energy (300 MeV -100 GeV) and very high-energy (VHE; E > 100 GeV) gamma rays are not deflected by interstellar magnetic fields and can be used to map cosmic ray populations in and near their parent accelerators. The different processes by which relativistic cosmic ray electrons, protons, and heavier nuclei produce high-energy gamma rays leave characteristic imprints on the gamma-ray energy spectrum of particular astrophysical accelerators. These features may be used to constrain the composition and energy spectrum of accelerated particle populations.The local cosmic ray spectrum is known to be a mix of protons and heavier nuclei, with a smaller admixture of leptons. A mix of astrophysical accelerators within and outside our Galaxy is believed to contribute, including shocks arising in supernova remnants (SNRs), shocks formed by interacting high-velocity winds from massive stars [3], pulsars, and active galactic nuclei (AGN). We focus here on a single subplot of a much larger story-the role played by pulsar wind nebulae (PWNe) in our quest to understand the Galactic cosmic ray spectrum. Dramatis PersonaeNo single gamma-ray observatory provides a complete picture of the gamma-ray sky at all energies and spatial scales. The Fermi Gamma-ray Space Telescope (...

show abstract

An anomalous positron abundance in cosmic rays with energies 1.5–100 GeV

Cited by 2,027 publications

References 26 publications

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

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

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

Pulsar Wind Nebulae and Cosmic Rays: A Bedtime Story

Contact Info

Product

Resources

About