Publications (28)5.83 Total impact
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Article: Surveying Extended GMSB Models with mh=125 GeV
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ABSTRACT: In order to achieve maximal stop mixing and m_h=125 GeV, we consider extensions of minimal GMSB that include marginal MSSM-messenger superpotential interactions. Using a new approach to analytic continuation in superspace, we derive general formulas for the soft masses in the presence of such interactions, correctly taking into account the role of MSSM-messenger mixing in a general framework for the first time. We classify and catalog all possible such interactions consistent with perturbative SU(5) unification, and we survey the impact of turning on one interaction at a time, from the point of view of fine tuning, spectrum and phenomenology. We find that the best models are fine-tuned to the sub-percent level and are accessible at the 14 TeV LHC. We highlight potential search strategies that can probe the characteristic spectra of these models.03/2013; -
Article: General Messenger Higgs Mediation
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ABSTRACT: We present a general formalism for analyzing supersymmetric models where the Higgs sector directly couples to the messengers of supersymmetry breaking. Such Higgs-messenger interactions are strongly motivated by the discovery of a Higgs boson near 125 GeV, but they also raise the specter of the mu/B_mu and A/m_H^2 problems. Using our formalism, we identify new avenues to solving these problems through strong dynamics in the messenger sector or hidden sector. Although our formalism is entirely general, we show how it reproduces familiar results in two simplifying limits: one where the hidden sector consists of a single spurion, and the other where it is approximately superconformal. In the latter limit, our formalism generalizes and clarifies the scenario of hidden sector sequestering, which we show can solve both the mu/B_mu and A/m_H^2 problems uniformly.02/2013; -
Article: A Complete Model of Low-Scale Gauge Mediation
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ABSTRACT: Recent signs of a Standard Model-like Higgs at 125 GeV point towards large A-terms in the MSSM. This presents special challenges for gauge mediation, which by itself predicts vanishing A-terms at the messenger scale. In this paper, we review the general problems that arise when extending gauge mediation to achieve large A-terms, and the mechanisms that exist to overcome them. Using these mechanisms, we construct weakly-coupled models of low-scale gauge mediation with extended Higgs-messenger couplings that generate large A-terms at the messenger scale and viable mu/B_mu-terms. Our models are simple, economical, and complete realizations of supersymmetry at the weak scale.06/2012; -
Article: Implications of a 125 GeV Higgs boson for the MSSM and low-scale supersymmetry breaking
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ABSTRACT: Recently, the ATLAS and CMS collaborations have announced exciting hints for a standard model-like Higgs boson at a mass of ≈125 GeV. In this paper, we explore the potential consequences for the MSSM and low-scale SUSY-breaking. As is well-known, a 125 GeV Higgs implies either extremely heavy stops (≳10 TeV), or near-maximal stop mixing. We review and quantify these statements, and investigate the implications for models of low-scale SUSY-breaking such as gauge mediation where the A-terms are small at the messenger scale. For such models, we find that either a gaugino must be superheavy or the NLSP is long-lived. Furthermore, stops will be tachyonic at high scales. These are very strong restrictions on the mediation of supersymmetry breaking in the MSSM, and suggest that if the Higgs truly is at 125 GeV, viable models of gauge-mediated supersymmetry breaking are reduced to small corners of parameter space or must incorporate new Higgs-sector physics.Phys. Rev. D. 05/2012; 85(9). -
Article: Spontaneous R-symmetry Breaking with Multiple Pseudomoduli
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ABSTRACT: We examine generalized O'Raifeartaigh models that feature multiple tree-level flat directions and only contain fields with R-charges 0 or 2. We show that spontaneous R-breaking at up to one-loop order is impossible in such theories. Specifically, we prove that the R-symmetric origin of field space is always a local minimum of the one-loop Coleman-Weinberg potential, generalizing an earlier result for the case of a single flat direction. This result has consequences for phenomenology and helps elucidate the behavior of various models of dynamical SUSY breaking.02/2012; -
Article: Implications of a 125 GeV Higgs for the MSSM and Low-Scale SUSY Breaking
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ABSTRACT: Recently, the ATLAS and CMS collaborations have announced exciting hints for a Standard Model-like Higgs boson at a mass of approximately 125 GeV. In this paper, we explore the potential consequences for the MSSM and low scale SUSY-breaking. As is well-known, a 125 GeV Higgs implies either extremely heavy stops (>~ 10 TeV), or near-maximal stop mixing. We review and quantify these statements, and investigate the implications for models of low-scale SUSY breaking such as gauge mediation where the A-terms are small at the messenger scale. For such models, we find that either a gaugino must be superheavy or the NLSP is long-lived. Furthermore, stops will be tachyonic at high scales. These are very strong restrictions on the mediation of supersymmetry breaking in the MSSM, and suggest that if the Higgs truly is at 125 GeV, viable models of gauge-mediated supersymmetry breaking are reduced to small corners of parameter space or must incorporate new Higgs-sector physics.12/2011; -
Article: The Status of GMSB After 1/fb at the LHC
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ABSTRACT: We thoroughly investigate the current status of supersymmetry in light of the latest searches at the LHC, using General Gauge Mediation (GGM) as a well-motivated signature generator that leads to many different simplified models. We consider all possible promptly-decaying NLSPs in GGM, and by carefully reinterpreting the existing LHC searches, we derive limits on both colored and electroweak SUSY production. Overall, the coverage of GGM parameter space is quite good, but much discovery potential still remains even at 7 TeV. We identify several regions of parameter space where the current searches are the weakest, typically in models with electroweak production, third generation sfermions or squeezed spectra, and we suggest how ATLAS and CMS might modify their search strategies given the understanding of GMSB at 1/fb. In particular, we propose the use of leptonic $M_{T2}$ to suppress $t{\bar t}$ backgrounds. Because we express our results in terms of simplified models, they have broader applicability beyond the GGM framework, and give a global view of the current LHC reach. Our results on 3rd generation squark NLSPs in particular can be viewed as setting direct limits on naturalness.10/2011; -
Article: Light Stop NLSPs at the Tevatron and LHC
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ABSTRACT: How light can the stop be given current experimental constraints? Can it still be lighter than the top? In this paper, we study this and related questions in the context of gauge-mediated supersymmetry breaking, where a stop NLSP decays into a W, b and gravitino. Focusing on the case of prompt decays, we simulate several existing Tevatron and LHC analyses that would be sensitive to this scenario, and find that they allow the stop to be as light as 150 GeV, mostly due to the large top production background. With more data, the existing LHC analyses will be able to push the limit up to at least 180 GeV. We hope this work will motivate more dedicated experimental searches for this simple scenario, in which, for most purposes, the only free parameters are the stop mass and lifetime.05/2011; -
Article: Simplified Models for LHC New Physics Searches
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ABSTRACT: 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.05/2011; -
Article: Anomalous Dimensions of Non-Chiral Operators from AdS/CFT
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ABSTRACT: Non-chiral operators with positive anomalous dimensions can have interesting applications to supersymmetric model building. Motivated by this, we develop a new method for obtaining the anomalous dimensions of non-chiral double-trace operators in N=1 superconformal field theories (SCFTs) with weakly-coupled AdS duals. Via the Hamiltonian formulation of AdS/CFT, we show how to directly compute the anomalous dimension as a bound state energy in the gravity dual. This simplifies previous approaches based on the four-point function and the OPE. We apply our method to a class of effective AdS5 supergravity models, and we find that the binding energy can have either sign. If such models can be UV completed, they will provide the first calculable examples of SCFTs with positive anomalous dimensions.04/2011; -
Article: General Neutralino NLSPs at the Early LHC
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ABSTRACT: Gauge mediated supersymmetry breaking (GMSB) is a theoretically well-motivated framework with rich and varied collider phenomenology. In this paper, we study the Tevatron limits and LHC discovery potential for a wide class of GMSB scenarios in which the next-to-lightest superpartner (NLSP) is a promptly-decaying neutralino. These scenarios give rise to signatures involving hard photons, $W$'s, $Z$'s, jets and/or higgses, plus missing energy. In order to characterize these signatures, we define a small number of minimal spectra, in the context of General Gauge Mediation, which are parameterized by the mass of the NLSP and the gluino. Using these minimal spectra, we determine the most promising discovery channels for general neutralino NLSPs. We find that the 2010 dataset can already cover new ground with strong production for all NLSP types. With the upcoming 2011-2012 dataset, we find that the LHC will also have sensitivity to direct electroweak production of neutralino NLSPs.03/2011; -
Article: Slepton co-NLSPs at the Tevatron
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ABSTRACT: We study the Tevatron signatures of promptly-decaying slepton co-NLSPs in the context of General Gauge Mediation (GGM). The signatures consist of trileptons plus MET and same-sign dileptons plus MET. Focusing first on electroweak production, where the Tevatron has an advantage over the early LHC, we establish four simple benchmark scenarios within the parameter space of GGM which qualitatively capture all the relevant phenomenology. We derive limits on these benchmarks from existing searches, estimate the discovery potential with 10 fb^-1, and discuss ways in which these searches can be optimized for slepton co-NLSPs. We also analyze the Tevatron constraints on a scenario with light gluinos that could be discovered at the early LHC. Overall, we find that the Tevatron still has excellent reach for the discovery of SUSY in multilepton final states. Finally, we comment on the possible interpretation of a mild "excess" in the CDF same-sign dilepton search in terms of slepton co-NLSPs. Comment: 31 pages + appendices09/2010; -
Article: Long-Lived Neutralino NLSPs
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ABSTRACT: We investigate the collider signatures of heavy, long-lived, neutral particles that decay to charged particles plus missing energy. Specifically, we focus on the case of a neutralino NLSP decaying to Z and gravitino within the context of General Gauge Mediation. We show that a combination of searches using the inner detector and the muon spectrometer yields a wide range of potential early LHC discoveries for NLSP lifetimes ranging from 10^(-1)-10^5 mm. We further show that events from Z(l+l-) can be used for detailed kinematic reconstruction, leading to accurate determinations of the neutralino mass and lifetime. In particular, we examine the prospects for detailed event study at ATLAS using the ECAL (making use of its timing and pointing capabilities) together with the TRT, or using the muon spectrometer alone. Finally, we also demonstrate that there is a region in parameter space where the Tevatron could potentially discover new physics in the delayed Z(l+l-)+MET channel. While our discussion centers on gauge mediation, many of the results apply to any scenario with a long-lived neutral particle decaying to charged particles. Comment: 31 pages, 12 figures06/2010; -
Article: General Messenger Gauge Mediation
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ABSTRACT: We discuss theories of gauge mediation in which the hidden sector consists of two subsectors which are weakly coupled to each other. One sector is made up of messengers and the other breaks supersymmetry. Each sector by itself may be strongly coupled. We provide a unifying framework for such theories and discuss their predictions in different settings. We show how this framework incorporates all known models of messengers. In the case of weakly-coupled messengers interacting with spurions through the superpotential, we prove that the sfermion mass-squared is positive, and furthermore, that there is a lower bound on the ratio of the sfermion mass to the gaugino mass.03/2010; -
Article: Prompt Decays of General Neutralino NLSPs at the Tevatron
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ABSTRACT: Recent theoretical developments have shown that gauge mediation has a much larger parameter space of possible spectra and mixings than previously considered. Motivated by this, we explore the collider phenomenology of gauge mediation models where a general neutralino is the lightest MSSM superpartner (the NLSP), focusing on the potential reach from existing and future Tevatron searches. Promptly decaying general neutralino NLSPs can give rise to final states involving missing energy plus photons, Zs, Ws and/or Higgses. We survey the final states and determine those where the Tevatron should have the most sensitivity. We then estimate the reach of existing Tevatron searches in these final states and discuss new searches (or optimizations of existing ones) that should improve the reach. Finally we comment on the potential for discovery at the LHC. Comment: 41 pages, minor changes, added refs and discussion of previous literature11/2009; -
Article: Notes on SUSY and R-Symmetry Breaking in Wess-Zumino Models
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ABSTRACT: We study aspects of Wess-Zumino models related to SUSY and R-symmetry breaking at tree-level. We present a recipe for constructing a wide class of tree-level SUSY and R-breaking models. We also deduce a general property shared by all tree-level SUSY breaking models that has broad application to model building. In particular, it explains why many models of direct gauge mediation have anomalously light gauginos (even if the R-symmetry is broken spontaneously by an order one amount). This suggests new approaches to dynamical SUSY breaking which can generate large enough gaugino masses. Comment: 23 pages. v2: references added, minor changes. v3: comment on non-renormalizable case added02/2009; -
Article: Exploring General Gauge Mediation
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ABSTRACT: We explore various aspects of General Gauge Mediation(GGM). We present a reformulation of the correlation functions used in GGM, and further elucidate their IR and UV properties. Additionally we clarify the issue of UV sensitivity in the calculation of the soft masses in the MSSM, highlighting the role of the supertrace over the messenger spectrum. Finally, we present weakly coupled messenger models which fully cover the parameter space of GGM. These examples demonstrate that the full parameter space of GGM is physical and realizable. Thus it should be considered a valid basis for future phenomenological explorations of gauge mediation. Comment: 27 pages, minor changes, typos fixed in appendix B12/2008; -
Article: Surveying Pseudomoduli: the Good, the Bad and the Incalculable
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ABSTRACT: We classify possible types of pseudomoduli which arise when supersymmetry is dynamically broken in infrared-free low-energy theories. We show that, even if the pseudomoduli potential is generated only at higher loops, there is a regime where the potential can be simply determined from a combination of one-loop running data. In this regime, we compute whether the potential for the various types of pseudomoduli is safe, has a dangerous runaway to the UV cutoff of the low-energy theory, or is incalculable. Our results are applicable to building new models of supersymmetry breaking. We apply the results to survey large classes of models.10/2008; -
Article: Dynamical SUSY and R-symmetry breaking in SQCD with massive and massless flavors
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ABSTRACT: We show that supersymmetry and R-symmetry can be dynamically broken in a long-lived metastable vacuum of SQCD with massive and massless flavors. The vacuum results from a competition of a (leading) two-loop effect and small "Planck" suppressed higher-dimension operators. This mechanism provides a particularly simple realization of dynamical SUSY and R-symmetry breaking, and as such it is a good starting point for building phenomenologically viable models of gauge mediation. We take a preliminary step in this direction by constructing a complete model of minimal gauge mediation. Here we find that the parameters of the model are surprisingly constrained by the hidden sector. Similar mechanisms for creating long-lived states operate in a large class of models. Comment: 25 pages. v2: added references, minor correction08/2008; -
Article: General Gauge Mediation
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ABSTRACT: We give a general definition of gauge mediated supersymmetry breaking which encompasses all the known gauge mediation models. In particular, it includes both models with messengers as well as direct mediation models. A formalism for computing the soft terms in the generic model is presented. Such a formalism is necessary in strongly-coupled direct mediation models where perturbation theory cannot be used. It allows us to identify features of the entire class of gauge mediation models and to distinguish them from specific signatures of various subclasses. Comment: 19 pages, 1 figure, minor changes01/2008;
Top co-authors
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Institutions
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2012
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Rutgers, The State University of New Jersey
New Brunswick, NJ, USA
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2004
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Princeton University
- Department of Physics
Princeton, NJ, USA
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