1,721,044 research outputs found
SUSY dark matter and quintessence
No full textWe investigate the enhancement of neutralino relic density in the context of a realistic cosmological scenario with quintessence. The accurate relic density computation we perform allows us to be sensitive to cases with both shifts in the abundance at the per cent level, and enhancements as large as 10(6). We thoroughly analyse the dependence on the supersymmetric spectrum and on the mass and composition of the lightest neutralino. We point out that supersymmetric models yielding a wino- or higgsino-like lightest neutralino become cosmologically appealing in the presence of quintessence
The role of antimatter searches in the hunt for supersymmetric dark matter
No full textWe analyse the antimatter yield of supersymmetric (SUSY) models with large neutralino annihilation cross sections. We introduce three benchmark scenarios, featuring bino, wino and higgsino-like lightest neutralinos, respectively, and we study in detail the resulting antimatter spectral features. We carry out a systematic and transparent comparison between current and future prospects for direct detection, neutrino telescopes and antimatter searches. We demonstrate that often, in the models we consider, antimatter searches are the only detection channels that already constrain the SUSY parameter space. In particular large antiprotons fluxes are expected for wino-like lightest neutralinos, while significant antideuteron fluxes result from resonantly annihilating binos. We introduce a simple and general recipe which allows us to assess the visibility of a given SUSY model at future antimatter search facilities. We provide evidence that upcoming space-based experiments, like PAMELA or AMS, are going to be, in many cases, the unique open road towards dark matter discovery
Neutralino dark matter detection in split supersymmetry scenarios
No full textWe study the phenomenology of neutralino dark matter within generic supersymmetric scenarios where the gaugino and higgsino masses are much lighter than the scalar soft breaking masses (split supersymmetry). We consider a low-energy model-independent approach and show that the guidelines in the definition of this general framework come from cosmology, which forces the lightest neutralino to have a mass smaller than 2.2 TeV. The testability of the framework is addressed by discussing all viable dark matter detection techniques. Current data on cosmic rays antimatter, gamma-rays and on the abundance of primordial (6)Li already set significant constraints on the parameter space. Complementarity among future direct detection experiments, indirect searches for antimatter and with neutrino telescopes, and tests of the theory at future accelerators, such as the LHC and a NLC, is highlighted. In particular, we study in detail the regimes of wino-higgsino mixing and bino-wino transition, which have been most often neglected in the past. We emphasize that our analysis may apply to more general supersymmetric models where scalar exchanges do not provide the dominant contribution to annihilation rates. (c) 2005 Elsevier B.V. All rights reserved
Twisted Eguchi-Kawai Reduced Chiral Models
No full textWe study the twisted Eguchi-Kawai (TEK) reduction procedure for large-N
unitary matrix lattice models. In particular, we consider the case of
two-dimensional principal chiral models, and use numerical Monte Carlo (MC)
simulations to check the conjectured equivalence of TEK reduced model and
standard lattice model in the large-N limit. The MC results are compared with
the large-N limit of lattice principal chiral models to verify the supposed
equivalence. The consistency of the TEK reduction procedure is verified in the
strong-coupling region, i.e. for where is the
location of the large-N phase transition. On the other hand, in the
weak-coupling regime , relevant for the continuum limit, our MC
results do not support the equivalence of the large-N limits of the lattice
chiral model and the corresponding TEK reduction. The implications for the
correspondence between TEK model and noncommutative field theory are also
discussed
Multi-frequency analysis of neutralino dark matter annihilations in the Coma cluster
Full text linkWe study the astrophysical implications of neutralino dark matter annihilations in galaxy clusters, with a specific application to the Coma cluster. We first address the determination of the dark halo models for Coma, starting from structure formation models and observational data, and we discuss in detail the role of sub-halos. We then perform a thorough analysis of the transport and diffusion properties of neutralino annihilation products, and investigate the resulting multi-frequency signals, from radio to gamma-ray frequencies. We also study other relevant astrophysical effects of neutralino annihilations, like the DM-induced Sunyaev-Zel'dovich effect and the intracluster gas heating. As for the particle physics setup, we adopt a two-fold approach, resorting both to model-independent bottom-up scenarios and to benchmark, GUT-motivated frameworks. We show that the Coma radio-halo data ( the spectrum and the surface brightness) can be nicely fitted by the neutralino-induced signal for peculiar particle physics models and for magnetic field values, which we outline in detail. Fitting the radio data and moving to higher frequencies, we find that the multi-frequency spectral energy distributions are typically dim at EUV and X-ray frequencies ( with respect to the data), but show a non-negligible gamma-ray emission, depending on the amplitude of the Coma magnetic field. A simultaneous fit to the radio, EUV and HXR data is not possible without violating the gamma-ray EGRET upper limit. The best-fit particle physics models yields substantial heating of the intracluster gas, but not sufficient energy injection as to explain the quenching of cooling flows in the innermost region of clusters. Due to the specific multi-frequency features of the DM-induced spectral energy distribution in Coma, we find that supersymmetric models can be significantly and optimally constrained either in the gamma-rays or at radio and microwave frequencies
Charting WIMP territories at the neutrino floor
No full textWe establish comprehensive theoretical benchmarks for weakly interacting massive particles (WIMPs) accessible to ultimate direct detection experiments, focusing on the challenging parameter space between current experimental limits and the irreducible neutrino background. We systematically examine both thermal freeze-out and freeze-in production mechanisms across a range of simplified dark matter models, including s-channel scalar and vector portals, t-channel mediator scenarios, and electroweakly interacting multiplets. For thermal relics, we identify parameter regions where suppressed direct detection cross sections naturally arise through momentum-dependent interactions and blind-spot configurations, while maintaining the correct relic abundance. We extensively investigate freeze-in scenarios, demonstrating how feebly interacting massive particles in portal models can populate experimentally accessible parameter space despite their ultraweak couplings. Additionally, we explore how nonstandard cosmological histories —including early matter domination and fast-expanding Universe scenarios—can dramatically alter the relationship between relic density and detection prospects, opening new avenues for discovery. Our analysis provides a roadmap for next-generation experiments approaching the neutrino floor, highlighting complementary detection strategies and identifying the most promising theoretical targets for ultimate sensitivity dark matter searches. These benchmarks establish the theoretical foundation for the final push toward comprehensive coverage of well-motivated WIMP parameter space
Neutralino Dark Matter Detection in Split Supersymmetry
No full textWe study the phenomenology of neutralino dark matter within generic supersymmetric
scenarios where the Gaugino and Higgsino masses are much lighter than
the scalar soft breaking masses (Split Supersymmetry). We consider a low-energy
model-independent approach and show that the guidelines in the definition of this
general framework come from cosmology, which forces the lightest neutralino to
have a mass smaller than 2.2 TeV. The testability of the framework is addressed
by discussing all viable dark matter detection techniques. Current data on cosmic
rays antimatter, gamma-rays and on the abundance of primordial 6Li already
set significant constraints on the parameter space. Complementarity among future
direct detection experiments, indirect searches for antimatter and with neutrino
telescopes, and tests of the theory at future accelerators, such as the LHC and a
NLC, is highlighted. In particular, we study in detail the regimes of Wino-Higgsino
mixing and Bino-Wino transition, which have been most often neglected in the past.
We emphasize that our analysis may apply to more general supersymmetric models
where scalar exchanges do not provide the dominant contribution to annihilation
rates
Cosmic ray-dark matter scattering: a new signature of (asymmetric) dark matter in the gamma ray sky
No full textWe consider the process of scattering of Galactic cosmic-ray electrons and protons off of dark matter with the radiation of a final-state photon. This process provides a novel way to search for Galactic dark matter with gamma rays. We argue that for a generic weakly interacting massive particle, barring effects such as co-annihilation or a velocity-dependent cross section, the gamma-ray emission from cosmic-ray scattering off of dark matter is typically smaller than that from dark matter pair-annihilation. However, if dark matter particles cannot pair-annihilate, as is the case for example in asymmetric dark matter scenarios, cosmic-ray scattering with final state photon emission provides a unique window to detect a signal from dark matter with gamma rays. We estimate the expected flux level and its spectral features for a generic supersymmetric setup, and we also discuss dipolar and luminous dark matter. We show that in some cases the gamma-ray emission might be large enough to be detectable with the Fermi Large Area Telescope. © 2011 IOP Publishing Ltd and SISSA
Model independent approach to focus point supersymmetry: from dark matter to collider searches
Full text linkThe focus point region of supersymmetric models is compelling in that it simultaneously features low fine-tuning, provides a decoupling solution to the SUSY flavor and CP problems, suppresses proton decay rates and can accommodate the WMAP measured cold dark matter (DM) relic density through a mixed bino-higgsino dark matter particle. We present the focus point region in terms of a weak scale parameterization, which allows for a relatively model independent compilation of phenomenological constraints and prospects. We present direct and indirect neutralino dark matter detection rates for two different halo density profiles, and show that prospects for direct DM detection and indirect detection via neutrino telescopes such as IceCube and anti-deuteron searches by GAPS are especially promising. We also present LHC reach prospects via gluino and squark cascade decay searches, and also via clean trilepton signatures arising from chargino-neutralino production. Both methods provide a reach out to m(g) similar to 1.7TeV. At a TeV-scale linear e(+)e(-) collider (LC), the maximal reach is attained in the Z(1)Z(2) or Z(1)Z(3) channels. In the DM allowed region of parameter space, a root s = 0.5TeV LC has a reach which is comparable to that of the LHC. However, the reach of a 1TeV LC extends out to m(g) similar to 3.5TeV
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