Models with Dirac gauginos provide appealing scenarios for physics beyond the standard model. They have smaller radiative corrections to the Higgs mass, a suppression of certain SUSY production processes, and ameliorated flavor constraints. Unfortuna
tely, they also generally have tachyons, the solutions to which typically spoil these positive features. The recently proposed Goldstone Gaugino mechanism provides a simple solution that eliminates these tachyonic states. We provide details on this mechanism and explore models for its origin. In particular, we find SUSY QCD models that realize this idea simply, and discuss scenarios for unification.
Models of supersymmetry with Dirac gauginos provide an attractive scenario for physics beyond the standard model. The supersoft radiative corrections and suppressed SUSY production at colliders provide for more natural theories and an understanding o
f why no new states have been seen. Unfortunately, these models are handicapped by a tachyon which is naturally present in existing models of Dirac gauginos. We argue that this tachyon is absent, with the phenomenological successes of the model preserved, if the right handed gaugino is a (pseudo-)Goldstone field of a spontaneously broken anomalous flavor symmetry.
The energy dependence of the electroweak gauge couplings has not been measured above the weak scale. We propose that percent-level measurements of the energy dependence of $alpha_{1,2}$ can be performed now at the LHC and at future higher energy hadr
on colliders. These measurements can be used to set limits on new particles with electroweak quantum numbers without relying on any assumptions about their decay properties. The shape of the high invariant mass spectrum of Drell-Yan, $p p rightarrow Z^*/gamma^* rightarrow ell^+ ell^-$, constrains $alpha_{1,2}(Q)$, and the shape of the high transverse mass distribution of $p p rightarrow W^* rightarrow ell u$ constrains $alpha_{2}(Q)$. We use existing data to perform the first fits to $alpha_{1,2}$ above the weak scale. Percent-level measurements are possible because of high precision in theoretical predictions and existing experimental measurements. We show that the LHC already has the reach to improve upon electroweak precision tests for new particles that dominantly couple through their electroweak charges. The 14 TeV LHC is sensitive to the predicted Standard Model (SM) running of $alpha_2$, and can show that $alpha_2$ decreases with energy at $2-3 sigma$ significance. A future 100 TeV proton-proton collider will have significant reach to measure running weak couplings, with sensitivity to the SM running of $alpha_2$ at $4-5 sigma$ and sensitivity to winos with masses up to $sim$ 1.3 TeV at $2sigma$.
Within the context of supersymmetric theories, explaining a 125 GeV Higgs motivates a consideration of a broader range of models. We consider a simple addition to the MSSM of a Sister Higgs ($Sigma_d$), a Higgs field that participates in electroweak
symmetry breaking but does not give any direct masses to Standard Model matter fields. While a relatively minor addition, the phenomenological implications can be important. Such a field can be naturally charged under an additional symmetry group $G_s$. If gauged, the Higgs mass is naturally much larger than in the MSSM through an NMSSM-type interaction, but with $Sigma_d$ playing the role of $H_d$. The addition of the sister Higgs allows new R-parity violating operators $Sigma_d H_d E$, which are less constrained than conventional leptonic R-parity violation. Considerations of unification motivates the presence of colored $G_s$-charged fields. Production of these G-quarks can lead to new b-rich final states and modifications to decays of gluinos, as well as new opportunities for R-parity violation. Unlike a conventional fourth generation, G-quarks dominantly decay into a light jet and a scalar (potentially the Higgs), which then generally decays to b-jets. The presence of additional sister charges allows the possibilities that lightest sister-charged particle (LSiP) could be stable. We consider the possibility of an LSiP dark matter candidate and find it is generally very constrained.
In models where an additional SU(2)-doublet that does not have couplings to fermions participates in electroweak symmetry breaking, the properties of the Higgs boson are changed. At tree level, in the neighborhood of the SM-like range of parameter sp
ace, it is natural to have the coupling to vectors, cV, approximately constant, while the coupling to fermions, cf, is suppressed. This leads to enhanced VBF signals of gamma gamma while keeping other signals of Higgses approximately constant (such as WW* and ZZ*), and suppressing higgs to tau tau. Sizable tree-level effects are often accompanied by light charged Higgs states, which lead to important constraints from b to s gamma and top to b H+, but also often to similarly sizable contributions to the inclusive h to gamma gamma signal from radiative effects. In the simplest model, this is described by a Type I 2HDM, and in supersymmetry is naturally realized with sister Higgs fields. In such a scenario, additional light charged states can contribute further with fewer constraints from heavy flavor decays. With supersymmetry, Grand Unification motivates the inclusion of colored partner fields. These G-quarks may provide additional evidence for such a model.
We discuss the relevance of directional detection experiments in the post-discovery era and propose a method to extract the local dark matter phase space distribution from directional data. The first feature of this method is a parameterization of th
e dark matter distribution function in terms of integrals of motion, which can be analytically extended to infer properties of the global distribution if certain equilibrium conditions hold. The second feature of our method is a decomposition of the distribution function in moments of a model independent basis, with minimal reliance on the ansatz for its functional form. We illustrate our method using the Via Lactea II N-body simulation as well as an analytical model for the dark matter halo. We conclude that O(1000) events are necessary to measure deviations from the Standard Halo Model and constrain or measure the presence of anisotropies.
Recent evidence from the LHC for the Higgs boson with mass between 142 GeV < m_h < 147GeV points to PeV-scale Split Supersymmetry. This article explores the consequences of a Higgs mass in this range and possible discovery modes for Split Susy. Moder
ate lifetime gluinos, with decay lengths in the 25 microns to 10 years range, are its imminent smoking gun signature. The 7 TeV LHC will be sensitive to the moderately lived gluinos and trilepton signatures from direct electroweakino production. Moreover, the dark matter abundance may be obtained from annihilation through an s-channel Higgs resonance, with the LSP almost purely bino and mass m_chi = 70 GeV. The Higgs resonance region of Split Susy has visible signatures in dark matter direct and indirect detection and electric dipole moment experiments. If the anomalies go away, the majority of Split Susy parameter space will be excluded.
This work explores the potential reach of the 7 TeV LHC to new colored states in the context of simplified models and addresses the issue of which search regions are necessary to cover an extensive set of event topologies and kinematic regimes. This
article demonstrates that if searches are designed to focus on specific regions of phase space, then new physics may be missed if it lies in unexpected corners. Simple multiregion search strategies can be designed to cover all of kinematic possibilities. A set of benchmark models are created that cover the qualitatively different signatures and a benchmark multiregion search strategy is presented that covers these models.
The XENON100 and CRESST experiments will directly test the inelastic dark matter explanation for DAMAs 8.9? sigma anomaly. This article discusses how predictions for direct detection experiments depend on uncertainties in quenching factor measurement
s, the dark matter interaction with the Standard Model and the halo velocity distribution. When these uncertainties are accounted for, an order of magnitude variation is found in the number of expected events at CRESST and XENON100.
Composite dark matter is a natural setting for implementing inelastic dark matter - the O(100 keV) mass splitting arises from spin-spin interactions of constituent fermions. In models where the constituents are charged under an axial U(1) gauge symme
try that also couples to the Standard Model quarks, dark matter scatters inelastically off Standard Model nuclei and can explain the DAMA/LIBRA annual modulation signal. This article describes the early Universe cosmology of a minimal implementation of a composite inelastic dark matter model where the dark matter is a meson composed of a light and a heavy quark. The synthesis of the constituent quarks into dark mesons and baryons results in several qualitatively different configurations of the resulting dark matter hadrons depending on the relative mass scales in the system.
