5,210 research outputs found

    Interpreting Dark Matter Direct Detection Independently of the Local Velocity and Density Distribution

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    We demonstrate precisely what particle physics information can be extracted from a single direct detection observation of dark matter while making absolutely no assumptions about the local velocity distribution and local density of dark matter. Our central conclusions follow from a very simple observation: the velocity distribution of dark matter is positive definite, f(v) >= 0. We demonstrate the utility of this result in several ways. First, we show a falling deconvoluted recoil spectrum (deconvoluted of the nuclear form factor), such as from ordinary elastic scattering, can be "mocked up" by any mass of dark matter above a kinematic minimum. As an example, we show that dark matter much heavier than previously considered can explain the CoGeNT excess. Specifically, m_chi < m_Ge} can be in just as good agreement as light dark matter, while m_\chi > m_Ge depends on understanding the sensitivity of Xenon to dark matter at very low recoil energies, E_R ~ 6 keVnr. Second, we show that any rise in the deconvoluted recoil spectrum represents distinct particle physics information that cannot be faked by an arbitrary f(v). As examples of resulting non-trivial particle physics, we show that inelastic dark matter and dark matter with a form factor can both yield such a rise

    Direct Mass Limits for Chiral Fourth-Generation Quarks in All Mixing Scenarios

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    Present limits on chiral fourth-generation quark masses mbm_{b'} and mtm_{t'} are broadly generalized and strengthened by combining both tt' and bb' decays and considering the full range of tt' and bb' flavor-mixing scenarios (with the lighter generations). Various characteristic mass-splitting choices are considered. With mt>mbm_{t'} > m_{b'} we find that CDF limits on the bb' mass vary by no more than 10-20% with any choice of flavor-mixing, while for the tt' mass, we typically find stronger bounds, in some cases up to mt>430m_{t'} > 430 GeV. For mb>mtm_{b'} > m_{t'} we find mb>380430m_{b'} > 380 - 430 GeV, depending on the flavor-mixing and the size of the mtmbm_{t'} - m_{b'} mass splitting

    Erratum: Next-to-leading order supersymmetric QCD predictions for associated production of gauginos and gluinos [Phys. Rev. D 62, 095014 (2000)]

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    Errors in the published version of the paper are corrected, and new figures are provided.Comment: 3 pages, latex, 4 figure

    The WIMP Forest: Indirect Detection of a Chiral Square

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    The spectrum of photons arising from WIMP annihilation carries a detailed imprint of the structure of the dark sector. In particular, loop-level annihilations into a photon and another boson can in principle lead to a series of lines (a WIMP forest) at energies up to the WIMP mass. A specific model which illustrates this feature nicely is a theory of two universal extra dimensions compactified on a chiral square. Aside from the continuum emission, which is a generic prediction of most dark matter candidates, we find a "forest" of prominent annihilation lines that, after convolution with the angular resolution of current experiments, leads to a distinctive (2-bump plus continuum) spectrum, which may be visible in the near future with the Fermi Gamma-Ray Space Telescope (formerly known as GLAST).Comment: 11 pages, 4 figure

    Perceptions of service quality by clients and contact-personnel in the South African retail banking sector

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    A superior level of service quality is an important objective for South African retail banks. This paper investigates the levels of perceived service quality among 550 clients and 559 branch contactpersonnel in retail banks in central South Africa. The perceptions are compared, and the findings reveal that clients regard the levels of service they receive to be better than what the contact-personnel perceive them to be experiencing. The physical branch environment was also shown to be an important dimension of perceived service quality among retail clients. A cluster analysis identified three market segments to use when adopting marketing strategies, and the demographic factors of age, race and geographical location were found to be important considerations when developing these marketing strategies. An explicit micro-market marketing approach that is flexible and tailor-made to the characteristics of the location of the branch is a recommendation of the paper.Key words: service quality, central South Africa, retail bank

    Highly syntenic and yet divergent: a tale of two Theilerias

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    The published genomic sequences of the two major host-transforming Theileria species of cattle represent a rich resource of information that has allowed novel bioinformatic and experimental studies into these important apicomplexan parasites. Since their publication in 2005, the genomes of T. annulata and T. parva have been utilised for a diverse range of applications, ranging from candidate antigen discovery to the identification of genetic markers for population analysis. This has led to advancements in the quest for a sub-unit vaccine, while providing a greater understanding of variation among parasite populations in the field. The unique ability of these Theileria species to induce host cell transformation is the subject of considerable scientific interest and the availability of full genomic sequences has provided new insights into this area of research. This article reviews the data underlying published comparative analyses, focussing on the general features of gene expression, the major Tpr/Tar multi-copy gene family and a re-examination of the predicted macroschizont secretome. Codon usage between the Theileria species is reviewed in detail, as this underpins ongoing comparative studies investigating selection at the intra- and inter-species level. The TashAT/TpshAT family of genes, conserved between T. annulata and T. parva, encodes products targeted to the host nucleus and has been implicated in contributing to the transformed bovine phenotype. Species-specific expansion and diversification at this critical locus is discussed with reference to the availability, in the near future, of genomic datasets which are based on non-transforming Theileria species

    A Case of Cholangitis Glandularis Proliferans and Cholangiocarcinoma of the Common Bile Duct

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    A case of Cholangitis Glandularis Proliferans (CAGP) in association with a cholangiocarcinoma of the common bile duct as described. This is the eighth case of CAGP described and the second association with cholangiocarcinoma

    Hepatic Dystychoma: A Five Year Experience

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    In 5 years, 64 solid hepatic lesions have been referred for diagnosis and management which have been found unexpectedly on organ imaging in well patients. We have called this lesion a “dystychoma”

    Flavor changing scalar couplings and tγ(Z)t\gamma(Z) production at hadron colliders

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    We calculate the contributions of the flavor changing scalar (FCSFCS) couplings arised from topcolor-assisted technicolor (TC2TC2) models at tree-level to the tγt\gamma and tZtZ production at the Tevatron and LHCLHC experiments. We find that the production cross sections are very small at the Tevatron with s=1.96TeV\sqrt{s}=1.96TeV, which is smaller than 5 fb in most of the parameter space of TC2TC2 models. However, the virtual effects of the FCSFCS couplings on the tγ(Z)t\gamma(Z) production can be easily detected at the LHCLHC with s=14TeV\sqrt{s}=14TeV via the final state γlνˉb\gamma l\bar{\nu}b (l+llνˉbl^{+}l^{-}l\bar{\nu}b).Comment: 10 pages,5 figure
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