481 research outputs found
The Higgs mass and natural supersymmetric spectrum from the landscape
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
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
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
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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