4 research outputs found
Atomic Dark Matter
We propose that dark matter is dominantly comprised of atomic bound states.
We build a simple model and map the parameter space that results in the early
universe formation of hydrogen-like dark atoms. We find that atomic dark matter
has interesting implications for cosmology as well as direct detection:
Protohalo formation can be suppressed below for weak scale dark matter due to Ion-Radiation interactions in the
dark sector. Moreover, weak-scale dark atoms can accommodate hyperfine
splittings of order 100 \kev, consistent with the inelastic dark matter
interpretation of the DAMA data while naturally evading direct detection
bounds.Comment: 17 pages, 3 figure
Visible Supersymmetry Breaking and an Invisible Higgs
If there are multiple hidden sectors which independently break supersymmetry,
then the spectrum will contain multiple goldstini. In this paper, we explore
the possibility that the visible sector might also break supersymmetry, giving
rise to an additional pseudo-goldstino. By the standard lore, visible sector
supersymmetry breaking is phenomenologically excluded by the supertrace sum
rule, but this sum rule is relaxed with multiple supersymmetry breaking.
However, we find that visible sector supersymmetry breaking is still
phenomenologically disfavored, not because of a sum rule, but because the
visible sector pseudo-goldstino is generically overproduced in the early
universe. A way to avoid this cosmological bound is to ensure that an R
symmetry is preserved in the visible sector up to supergravity effects. A key
expectation of this R-symmetric case is that the Higgs boson will dominantly
decay invisibly at the LHC.Comment: v1 - 27 pages, 13 figures, 1 table; v2 - references added; v3 -
expanded discussion of higgs sector, JHEP versio
Simplified Models for LHC New Physics Searches
This document proposes a collection of simplified models relevant to the
design of new-physics searches at the LHC and the characterization of their
results. Both ATLAS and CMS have already presented some results in terms of
simplified models, and we encourage them to continue and expand this effort,
which supplements both signature-based results and benchmark model
interpretations. A simplified model is defined by an effective Lagrangian
describing the interactions of a small number of new particles. Simplified
models can equally well be described by a small number of masses and
cross-sections. These parameters are directly related to collider physics
observables, making simplified models a particularly effective framework for
evaluating searches and a useful starting point for characterizing positive
signals of new physics. This document serves as an official summary of the
results from the "Topologies for Early LHC Searches" workshop, held at SLAC in
September of 2010, the purpose of which was to develop a set of representative
models that can be used to cover all relevant phase space in experimental
searches. Particular emphasis is placed on searches relevant for the first
~50-500 pb-1 of data and those motivated by supersymmetric models. This note
largely summarizes material posted at http://lhcnewphysics.org/, which includes
simplified model definitions, Monte Carlo material, and supporting contacts
within the theory community. We also comment on future developments that may be
useful as more data is gathered and analyzed by the experiments.Comment: 40 pages, 2 figures. This document is the official summary of results
from "Topologies for Early LHC Searches" workshop (SLAC, September 2010).
Supplementary material can be found at http://lhcnewphysics.or