108 research outputs found
Lessons and Prospects from the pMSSM after LHC Run I: Neutralino LSP
We study SUSY signatures at the 7, 8 and 14 TeV LHC employing the
19-parameter, R-Parity conserving p(henomenological)MSSM, in the scenario with
a neutralino LSP. Our results were obtained via a fast Monte Carlo simulation
of the ATLAS SUSY analysis suite. The flexibility of this framework allows us
to study a wide variety of SUSY phenomena simultaneously and to probe for weak
spots in existing SUSY search analyses. We determine the ranges of the
sparticle masses that are either disfavored or allowed after the searches with
the 7 and 8 TeV data sets are combined. We find that natural SUSY models with
light squarks and gluinos remain viable. We extrapolate to 14 TeV with both 300
fb and 3 ab of integrated luminosity and determine the expected
sensitivity of the jets + MET and stop searches to the pMSSM parameter space.
We find that the high-luminosity LHC will be powerful in probing SUSY with
neutralino LSPs and can provide a more definitive statement on the existence of
natural Supersymmetry.Comment: 41 pages, 27 figures. arXiv admin note: substantial text overlap with
arXiv:1307.844
Dark Matter in the Coming Decade: Complementary Paths to Discovery and Beyond
In this report we summarize the many dark matter searches currently being
pursued through four complementary approaches: direct detection, indirect
detection, collider experiments, and astrophysical probes. The essential
features of broad classes of experiments are described, each with their own
strengths and weaknesses. The complementarity of the different dark matter
searches is discussed qualitatively and illustrated quantitatively in two
simple theoretical frameworks. Our primary conclusion is that the diversity of
possible dark matter candidates requires a balanced program drawing from all
four approaches.Comment: Report prepared for the Community Summer Study (Snowmass) 2013, on
behalf of Cosmic Frontier Working Groups 1-4 (CF1: WIMP Dark Matter Direct
Detection, CF2: WIMP Dark Matter Indirect Detection, CF3: Non-WIMP Dark
Matter, and CF4: Dark Matter Complementarity); published versio
New Particles Working Group Report of the Snowmass 2013 Community Summer Study
This report summarizes the work of the Energy Frontier New Physics working
group of the 2013 Community Summer Study (Snowmass)
MFV Reductions of MSSM Parameter Space
The 100+ free parameters of the minimal supersymmetric standard model (MSSM)
make it computationally difficult to compare systematically with data,
motivating the study of specific parameter reductions such as the cMSSM and
pMSSM. Here we instead study the reductions of parameter space implied by using
minimal flavour violation (MFV) to organise the R-parity conserving MSSM, with
a view towards systematically building in constraints on flavour-violating
physics. Within this framework the space of parameters is reduced by expanding
soft supersymmetry-breaking terms in powers of the Cabibbo angle, leading to a
24-, 30- or 42-parameter framework (which we call MSSM-24, MSSM-30, and MSSM-42
respectively), depending on the order kept in the expansion. We provide a
Bayesian global fit to data of the MSSM-30 parameter set to show that this is
manageable with current tools. We compare the MFV reductions to the
19-parameter pMSSM choice and show that the pMSSM is not contained as a subset.
The MSSM-30 analysis favours a relatively lighter TeV-scale pseudoscalar Higgs
boson and with multi-TeV sparticles.Comment: 2nd version, minor comments and references added, accepted for
publication in JHE
The New Look pMSSM with Neutralino and Gravitino LSPs
The pMSSM provides a broad perspective on SUSY phenomenology. In this paper
we generate two new, very large, sets of pMSSM models with sparticle masses
extending up to 4 TeV, where the lightest supersymmetric particle (LSP) is
either a neutralino or gravitino. The existence of a gravitino LSP necessitates
a detailed study of its cosmological effects and we find that Big Bang
Nucleosynthesis places strong constraints on this scenario. Both sets are
subjected to a global set of theoretical, observational and experimental
constraints resulting in a sample of \sim 225k viable models for each LSP type.
The characteristics of these two model sets are briefly compared. We confront
the neutralino LSP model set with searches for SUSY at the 7 TeV LHC using both
the missing (MET) and non-missing ET ATLAS analyses. In the MET case, we employ
Monte Carlo estimates of the ratios of the SM backgrounds at 7 and 8 TeV to
rescale the 7 TeV data-driven ATLAS backgrounds to 8 TeV. This allows us to
determine the pMSSM parameter space coverage for this collision energy. We find
that an integrated luminosity of \sim 5-20 fb^{-1} at 8 TeV would yield a
substantial increase in this coverage compared to that at 7 TeV and can probe
roughly half of the model set. If the pMSSM is not discovered during the 8 TeV
run, then our model set will be essentially void of gluinos and lightest first
and second generation squarks that are \lesssim 700-800 GeV, which is much less
than the analogous mSUGRA bound. Finally, we demonstrate that non-MET SUSY
searches continue to play an important role in exploring the pMSSM parameter
space. These two pMSSM model sets can be used as the basis for investigations
for years to come.Comment: 54 pages, 22 figures; typos fixed, references adde
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