10 research outputs found

    Dark Matter in SUSY Models

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    Direct detection experiments for neutralino dark matter in the Milky Way are examined within the framework of SUGRA models with R-parity invariance and grand unification at the GUT scale, M_G. Models of this type apply to a large number of phenomena, and all existing bounds on the SUSY parameter space due to current experimental constraints are included. For models with universal soft breaking at M_G (mSUGRA), the Higgs mass and b\to s\gamma constraints imply that the gaugino mass, m_{1/2}, obeys m_{1/2} >(300-400)GeV putting most of the parameter space in the co-annihilation domain where there is a relatively narrow band in the m_0 - m_{1/2} plane. For μ>0\mu > 0 we find that the neutralino -proton cross section >~ 10^{-10} pb for m_{1/2} < 1 TeV, making almost all of this parameter space accessible to future planned detectors. For \mu < 0, however, there will be large regions of parameter space with cross sections < 10^{-12} pb, and hence unaccessible experimentally. If, however, the muon magnetic moment anomaly is confirmed, then \mu >0 and m_{1/2}<~ 800 GeV. Models with non-universal soft breaking in the third generation and Higgs sector can allow for new effects arising from additional early universe annihilation through the Z-channel pole. Here cross sections that will be accessible in the near future to the next generation of detectors can arise, and can even rise to the large values implied by the DAMA data. Thus dark matter detectors have the possibility of studying the the post-GUT physics that control the patterns of soft breaking.Comment: 13 pages, latex, 10 figures, invited talk at NANP-01, Dubna, Russia, June 19--23, 200

    The Stau Neutralino Co-annihilation Region at an International Linear Collider

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    We probe the stau-neutralino co-annihilation domain of the parameter space allowed by the current experimental bounds on the light Higgs mass, the b-> s \gamma decay, and the amount of neutralino cold dark matter within the framework of minimal SUGRA models at a 500 GeV e+e- linear collider. The most favorable signals of SUSY are stau pair production and neutralino pair production where the small mass difference between the lighter stau and the lightest neutralino in the co-annihilation region is ~5-15 GeV and hence generates low-energy tau leptons in the final state. This small mass difference would be a striking signal of many SUGRA models. We find that a calorimeter covering down to 1^o from the beams is crucial to reduce the two-photon background and the mass difference could be measured at a level of 10% with 500 fb^-1 of data where an invariant mass of two-tau jets and missing energy is used as a discriminator.Comment: 17 pages, 7 figure

    Neutralino Proton Cross Sections In Supergravity Models

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    The neutralino-proton cross section is examined for supergravity models with R-parity invariance with universal and non-universal soft breaking. The region of parameter space that dark matter detectors are currently (or will be shortly) sensitive i.e. (0.110)×106(0.1-10)\times 10^{-6} pb, is examined. For universal soft breaking (mSUGRA), detectors with sensitivity σχ~10p1×106\sigma_{\tilde{\chi}_{1}^{0}-p} \geq 1 \times 10^{-6} pb will be able to sample parts of the parameter space for tanβ>25\tan \beta \stackrel{>}{\sim} 25. Current relic density bounds restrict mχ~10120m_{\tilde{\chi}_{1}^{0}} \leq 120 GeV for the maximum cross sections, which is below where astronomical uncertainties about the Milky Way are relevant. Nonuniversal soft breaking models can allow much larger cross sections and can sample the parameter space for tanβ>4\tan \beta \stackrel{>}{\sim} 4. In such models, m0m_0 can be quite large reducing the tension between proton decay bounds and dark matter analysis. We note the existance of two new domains where coannihilation effects can enter, i.e. for mSUGRA at large tanβ\tan \beta, and for nonuniversal models with small tanβ\tan \beta.Comment: 22 pages, latex, 18 figure

    WMAPing out Supersymmetric Dark Matter and Phenomenology

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    The recent WMAP data provide a rather restricted range of the Cold Dark Matter (CDM) density ΩCDMh2 \Omega_{CDM} h^2 of unprecedented accuracy. We combine these new data along with data from BNL E821 experiment measuring (gμ2) {(g_{\mu}-2)}, the {b\goes s \gamma} branching ratio and the light Higgs boson mass bound from LEP, to update our analysis of the allowed boundaries in the parameter space of the Constrained Minimal Supersymmetric Standard Model (CMSSM). The prospects of measuring Supersymmetry at LHC look like a very safe bet, and the potential of discovering SUSY particles at a s=1.1TeV \sqrt{s} = 1.1 \mathrm{TeV} linear collider is enhanced considerably. The implications for Dark Matter direct searches are also discussed.Comment: 12 pages LaTeX, 5 eps figures included, references adde

    How can distributed ledger technology systems accelerate the adoption of eHealth solutions by patients

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    This report’s goal is to understand how distributed ledger technology systems, especially blockchain, are beneficial in terms of eHealth adoption and patients control of their health data. According to an executive in a multinational company of the health industry, “private data limits the growth of eHealth but also represent a better future. We must be inventive, or we will never get to revolutionize this industry”. It is a fact that personal data can be processed through blockchain systems as well as in a diverse range of processing operations (transfer assets, ensure traceability, or even to launch a smart contract). Many enterprises and governmental institutions are already using blockchain techniques and adoption of eHealth has been broadly covered. However, patient’s perspective on the use of blockchain in digital health solutions has not been empirically researched and thus does not have solid real-life implementations and understandings. The analysis is based on empirical evidence from a group of 747 users of a live mobile application, Bowhead Health, which have utilised blockchain technology for developing solutions respecting user privacy and enabling considerable advances in the health industry; and from a broader online survey. Interviews of patients and experts in blockchain technology and health sector were also conducted. By assembling the finding of the literature and the qualitative and quantitative research, it has been shown that: (1) even if a great majority of people do not understand DLT systems, they are still able to trust it, just like many other elements of our society (banks, lockers, HTTPS secured connection); (2) Blockchain associated with smart contracts appear as one of the most convincing solutions to provide informed consent, transparency and control, hence generating patients trust and establishing health data ownership at patient level. Moreover, patients have a tendency to overlook privacy concerns if their health data could help clinical research. Ultimately, it is essential to simplify users’ understanding and ability to assess DLT by developing blockchain security indicators, facilitating the informed consent with user data flow control interfaces, as well as developing more partnerships with healthcare incumbents. Consequently, this paper adds to literature by providing insights for the development of a healthy digital healthcare system that respects patients’ needs and rights, especially privacy
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