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Ellis, John; Ferstl, Andrew; Olive, Keith A.

doi:10.1023/a:1015834615268

Cited by 22 publications

(37 citation statements)

References 8 publications

(11 reference statements)

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“…This setup has been considered extensively in the contest of dark matter detection (a list of recent references includes, e.g., [39,40,41,42,43,44]) and therefore the comparison of our results with previous work and other complementary techniques should be transparent in this case.…”

Section: A Specific Wimp: the Lightest Neutralino In The Msugra Framementioning

confidence: 99%

The Galactic center as a dark matter gamma-ray source

Cesarini¹

2004

Astroparticle Physics

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The EGRET telescope has identified a gamma-ray source at the Galactic center. We point out here that the spectral features of this source are compatible with the gamma-ray flux induced by pair annihilations of dark matter weakly interacting massive particles (WIMPs). We show that the discrimination between this interpretation and other viable explanations will be possible with GLAST, the next major gamma-ray telescope in space, on the basis of both the spectral and the angular signature of the WIMP-induced component. If, on the other hand, the data will point to an alternative explanation, we prove that there will still be the possibility for GLAST to single out a weaker dark matter source at the Galactic center. The potential of GLAST has been explored both in the context of a generic simplified toy-model for WIMP dark matter, and in a more specific setup, the case of dark matter neutralinos in the minimal supergravity framework. In the latter, we find that even in the case of moderate dark matter densities in the Galactic center region, there are portions of the parameter space which will be probed by GLAST.

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Section: A Specific Wimp: the Lightest Neutralino In The Msugra Framementioning

confidence: 99%

The Galactic center as a dark matter gamma-ray source

Cesarini¹

2004

Astroparticle Physics

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“…The scattering cross section has in general both spin-dependent and spin-independent pieces. The former may be written as [58] …”

Section: Strangeness Mattersmentioning

confidence: 99%

“…We depend on measurements of the πN σ term for our knowledge of the f Tq , and p|ss|p plays a key role [58]. Fig.…”

Section: Strangeness Mattersmentioning

confidence: 99%

Strangeness and hadron structure

Ellis

2001

Nuclear Physics A

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The nucleon wave function may contain a significant component ofss pairs, according to several measurements including the π-nucleon σ term, charm production and polarization effects in deep-inelastic scattering. In addition, there are excesses of φ production in LEAR and other experiments, above predictions based the naive Okubo-Zweig-Iizuka rule, that may be explained if the nucleon wave function contains a polarizedss component. This model also reproduces qualitatively data on Λ polarization in deep-inelastic neutrino scattering. The strange component of the proton is potentially important for other physics, such as the search for astrophysical dark matter. CERN-TH/2000-112hep-ph/0005322 Strange IdeasDoes the nucleon wave function contain a (large) strange component? The starting point for any discussion of the quark flavour content is the amazingly successful naïve quark model (NQM), in which |p >= |UUD >, with each constituent quark weighing m U,D ∼ 300 MeV [1]. A simple non-relativistic S-wave function with v/c ≪ 1 is surprisingly successful: even better is a simple harmonic oscillator potential with a D-wave admixture of 6% (in amplitude) [2]. For comparison, we recall that the deuteron and 3 He wave functions contain similar D-wave admixtures. Neglecting any such D-wave component, the (overly?) naïve quark model would predict that the proton spin is the algebraic sum of the constituent quark spins: s P = s U + s U + s D . Axial current matrix elements indicated that the quark spins might contribute at most 60% of the proton spin, even before the EMC and its successor experiments [3], but we return to this later. Whatever the partial-wave decomposition, if the proton only contains |UUD Fock states, and one neglects pair creation, a consequence is the Okubo-Zweig-Iizuka (OZI) rule [4] forbidding the coupling of the proton |ss mesons. The validity of the OZI rule is another major theme of this talk.Although the NQM is very successful, it has never been derived from QCD, and is expected to be wrong and/or incomplete [1]. The validity of chiral symmetry informs us that the light quarks are indeed very light: m u,d < 10 MeV, m s ∼ 100 MeV [5]. These estimates refer to the current quarks visible in short-distance or light-cone physics. Such current quarks should be relativistic: v/c ∼ 1, and there is no obvious reason why pair production ofūu,dd orss should be suppressed. Indeed, non-perturbative interactions

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“…where using the results in [52], one finds approximately a p ≈ 0.705 V 11 , a n ≈ −0.555 V 11 , leading to σ The typical SD cross-section in the allowed region is much larger than the SI cross-section (σ SI χ 0 1 , p 10 −44 cm 2 ) because the latter is dominated by Higgs exchange. Relative to the SD-cross section, the SI contribution is suppressed by two powers of the small effective coupling of the Higgs to the nucleon, g hNN ∼ 10 −3 .…”

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confidence: 92%

“…The effective operator (in four-component notation) and SD scattering cross-section against nucleons arising from t-channel exchange of Z bosons is [52]:…”

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confidence: 99%

Electroweak baryogenesis and dark matter with an approximate R-symmetry

Kumar

Pontón

2011

J. High Energ. Phys.

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It is well known that R-symmetric models dramatically alleviate the SUSY flavor and CP problems. We study particular modifications of existing R-symmetric models which share the solution to the above problems, and have interesting consequences for electroweak baryogenesis and the Dark Matter (DM) content of the universe. In particular, we find that it is naturally possible to have a strongly first-order electroweak phase transition while simultaneously relaxing the tension with EDM experiments. The R-symmetry (and its small breaking) implies that the gauginos (and the neutralino LSP) are pseudo-Dirac fermions, which is relevant for both baryogenesis and DM. The singlet superpartner of the U (1) Y pseudo-Dirac gaugino plays a prominent role in making the electroweak phase transition strongly first-order. The pseudo-Dirac nature of the LSP allows it to behave similarly to a Dirac particle during freeze-out, but like a Majorana particle for annihilation today and in scattering against nuclei, thus being consistent with current constraints. Assuming a standard cosmology, it is possible to simultaneously have a strongly first-order phase transition conducive to baryogenesis and have the LSP provide the full DM relic abundance, in part of the allowed parameter space. However, other possibilities for DM also exist, which are discussed. It is expected that upcoming direct DM searches as well as neutrino signals from DM annihilation in the Sun will be sensitive to this class of models. Interesting collider and Gravity-wave signals are also briefly discussed.

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Cited by 22 publications

References 8 publications

The Galactic center as a dark matter gamma-ray source

The Galactic center as a dark matter gamma-ray source

Strangeness and hadron structure

Electroweak baryogenesis and dark matter with an approximate R-symmetry

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