Recently a new class of theories of electroweak symmetry breaking have been constructed. These models, based on deconstruction and the physics of theory space, provide the first alternative to weak-scale supersymmetry with naturally light Higgs fields and perturbative new physics at the TeV scale. The Higgs is light because it is a pseudo-Goldstone boson, and the quadratically divergent contributions to the Higgs mass are cancelled by new TeV scale "partners" of the same statistics. In this paper we present the minimal theory space model of electroweak symmetry breaking, with two sites and four link fields, and the minimal set of fermions. There are very few parameters and degrees of freedom beyond the Standard Model. Below a TeV, we have the Standard Model with two light Higgs doublets, and an additional complex scalar weak triplet and singlet. At the TeV scale, the new particles that cancel the 1-loop quadratic divergences in the Higgs mass are revealed. The entire Higgs potential needed for electroweak symmetry breaking-the quartic couplings as well as the familiar negative mass squared-can be generated by the top Yukawa coupling, providing a novel link between the physics of flavor and electroweak symmetry breaking.

The presence of many axion fields in four-dimensional string vacua can lead to a simple, radiatively stable realization of chaotic inflation.

We present a new paradigm for achieving thermal relic dark matter. The mechanism arises when a nearly secluded dark sector is thermalized with the standard model after reheating. The freeze-out process is a number-changing 3→2 annihilation of strongly interacting massive particles (SIMPs) in the dark sector, and points to sub-GeV dark matter. The couplings to the visible sector, necessary for maintaining thermal equilibrium with the standard model, imply measurable signals that will allow coverage of a significant part of the parameter space with future indirect- and direct-detection experiments and via direct production of dark matter at colliders. Moreover, 3→2 annihilations typically predict sizable 2→2 self-interactions which naturally address the "core versus cusp" and "too-big-to-fail" small-scale structure formation problems.

We present an explicit formulation of supersymmetric Yang-Mills theories from D = 5 to 10 dimensions in the familiar N = 1, D = 4 superspace. This provides the rules for globally supersymmetric model building with extra dimensions and in particular allows us to simply write down N = 1 SUSY preserving interactions between bulk fields and fields localized on branes. We present a few applications of the formalism by way of illustration, including supersymmetric "shining" of bulk fields, orbifolds and localization of chiral fermions, anomaly inflow and super-Chern-Simons theories.observation is that, whatever the higher-dimensional theories are, they certainly contain the ordinary 4D SUSY, and therefore they must have an ordinary 4D superspace description. The superfield content of the 4D theory is easy to guess, simply by knowing the total number of SUSY generators in the full theory. For instance in 5D, the smallest spinor is a Dirac spinor with 8 real components, which means there are a minimum of 8 supercharges, or N = 2 in 4D. From the 4D viewpoint, we have either hypermultiplets or vector multiplets. Consider hypermultiplets for simplicity. In N = 1 language, they break into two chiral multiplets H, H c . Furthermore, we have one of these superfields for each point x 5 in the 5'th dimension. So, our field content consist of superfields H(x 5 ), H c (x 5 ). From the 4D point of view x 5 can simply be thought of as a label. Now, our task is to write down a superspace action for these fields that, once all auxilliary fields have been integrated out, reduces to the correct component action for the 5D theory. This is very easy to do, as the possible terms are heavily constrained by various symmetries. For this particular example this was done in [11], and will be reviewed in the next section. We will carry this procedure out for all globally supersymmetric theories from D = 5 to 10 dimensions in this paper. But in any case, once we have the action for the bulk theory written in 4D superspace, it is trivial to couple bulk fields to fields localized on 3-branes, in a way preserving N = 1 SUSY. We simply add additional 4D superspace interactions localized at particular locations in the transverse dimensions.We will begin by describing SUSY gauge theories in 5, 6 dimensions, where the field content is the same as N = 2 in 4D. We then move on to the cases D = 7 to 10, where the field content is that of N = 4 in 4D. For the gauge multiplets, we first discuss the Abelian theory before giving the non-Abelian generalizations. We then discuss a number of applications in the remainder of the paper.After this work was posted to hep-th, we were informed by A. Sagnotti and W. Siegel that a superfield formulation of D = 10 SYM was given in [12]. The formulation there is essentially identical to the one we present for this case. The action given in [12] has an extra Wess-Zumino-Witten type term required to make it fully gauge invariant-this term was missed in the first version of our paper. However, the new term vanishes in Wess-Zu...

It has recently been proposed that dark matter could be a thermal relic of 3 → 2 scatterings in a strongly coupled hidden sector. We present explicit classes of strongly coupled gauge theories that admit this behavior. These are QCD-like theories of dynamical chiral symmetry breaking, where the pions play the role of dark matter. The number-changing 3 → 2 process, which sets the dark matter relic abundance, arises from the Wess-Zumino-Witten term. The theories give an explicit relationship between the 3 → 2 annihilation rate and the 2 → 2 self-scattering rate, which alters predictions for structure formation. This is a simple calculable realization of the stronglyinteracting-massive-particle (SIMP) mechanism.

This document proposes a collection of simplified models relevant to the design of new-physics searches at the Large Hadron Collider (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

We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.

In this paper, we review recent theoretical progress and the latest experimental results in jet substructure from the Tevatron and the LHC. We review the status of and outlook for calculation and simulation tools for studying jet substructure. Following up on the report of the Boost 2010 workshop, we present a new set of benchmark comparisons of substructure techniques, focusing on the set of variables and grooming methods that are collectively known as 'top taggers'. To facilitate further exploration, we have attempted to collect, harmonize and publish software implementations of these techniques.