481 research outputs found

    The Higgs mass and natural supersymmetric spectrum from the landscape

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    In supersymmetric models where the superpotential mu term is generated with mu<< m_{soft} (e.g. from radiative Peccei-Quinn symmetry breaking or compactified string models with sequestration and stabilized moduli), and where the string landscape 1. favors soft supersymmetry (SUSY) breaking terms as large as possible and 2. where the anthropic condition that electroweak symmetry is properly broken with a weak scale m_{W,Z,h}~100 GeV ({\it i.e.} not too weak of weak interactions), then these combined landscape/anthropic requirements act as an attractor pulling the soft SUSY breaking terms towards values required by models with radiatively-driven naturalness: near the line of criticality where electroweak symmetry is barely broken and the Higgs mass is ~125 GeV. The pull on the soft terms serves to ameliorate the SUSY flavor and CP problems. The resulting sparticle mass spectrum may barely be accessible at high-luminosity LHC while the required light higgsinos should be visible at a linear e^+e^- collider with \sqrt{s}>2m(higgsino).Comment: 5 pages plus 3 figures; version 2 coincides with published version, some references adde

    Additional Records of Acanthocephalan Parasites from Arkansas Fishes, with New Records from Missouri Fishes

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    Over the last decade, our research consortium has provided information on acanthocephalan parasites of Arkansas vertebrates, including records from some of the state’s fishes. Here, we continue to provide data on new geographic and new host records of acanthocephalans from Arkansas fishes. In addition, for the first time, we report records of acanthocephalans for some Missouri fishes. We document 2 new state records as well as 10 new host records for some fish acanthocephalans

    Superparticle phenomenology from the natural mini-landscape

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    The methodology of the heterotic mini-landscape attempts to zero in on phenomenologically viable corners of the string landscape where the effective low energy theory is the Minimal Supersymmetric Standard Model with localized grand unification. The gaugino mass pattern is that of mirage-mediation. The magnitudes of various SM Yukawa couplings point to a picture where scalar soft SUSY breaking terms are related to the geography of fields in the compactified dimensions. Higgs fields and third generation scalars extend to the bulk and occur in split multiplets with TeV scale soft masses. First and second generation scalars, localized at orbifold fixed points or tori with enhanced symmetry, occur in complete GUT multiplets and have much larger masses. This picture can be matched onto the parameter space of generalized mirage mediation. Naturalness considerations, the requirement of the observed electroweak symmetry breaking pattern, and LHC bounds on m(gluino) together limit the gravitino mass to the m_{3/2}~ 5-60 TeV range. The mirage unification scale is bounded from below with the limit depending on the ratio of squark to gravitino masses. We show that while natural SUSY in this realization may escape detection even at the high luminosity LHC, the high energy LHC with \sqrt{s}=33 TeV could unequivocally confirm or exclude this scenario. It should be possible to detect the expected light higgsinos at the ILC if these are kinematically accessible, and possibly also discriminate the expected compression of gaugino masses in the natural mini-landscape picture from the mass pattern expected in models with gaugino mass unification. The thermal WIMP signal should be accessible via direct detection searches at the multi-ton noble liquid detectors such as Xenon-nT or LZ.Comment: 33 pages with 32 .png figure

    Supersymmetry with radiatively-driven naturalness: implications for WIMP and axion searches

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    By insisting on naturalness in both the electroweak and QCD sectors of the MSSM, the portrait for dark matter production is seriously modified from the usual WIMP miracle picture. In SUSY models with radiatively-driven naturalness (radiative natural SUSY or RNS) which include a DFSZ-like solution to the strong CP and SUSY mu problems, dark matter is expected to be an admixture of both axions and higgsino-like WIMPs. The WIMP/axion abundance calculation requires simultaneous solution of a set of coupled Boltzmann equations which describe quasi-stable axinos and saxions. In most of parameter space, axions make up the dominant contribution of dark matter although regions of WIMP dominance also occur. We show the allowed range of PQ scale f_a and compare to the values expected to be probed by the ADMX axion detector in the near future. We also show WIMP detection rates which are suppressed from usual expectations because now WIMPs comprise only a fraction of the total dark matter. Nonetheless, ton-scale noble liquid detectors should be able to probe the entirety of RNS parameter space. Indirect WIMP detection rates are less propitious since they are reduced by the square of the depleted WIMP abundance.Comment: 25 pages with 14 .png figures; submitted to special issue "Supersymmetry and Dark Matter" in Symmetry, edited by D. Clin
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