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 construct a general class of pseudo-Goldstone composite Higgs models, within the minimal SO(5)/SO(4) coset structure, that are not necessarily of moose-type. We characterize the main properties these models should have in order to give rise to a Higgs mass around 125 GeV. We assume the existence of relatively light and weakly coupled spin 1 and 1/2 resonances. In absence of a symmetry principle, we introduce the Minimal Higgs Potential (MHP) hypothesis: the Higgs potential is assumed to be one-loop dominated by the SM fields and the above resonances, with a contribution that is made calculable by imposing suitable generalizations of the first and second Weinberg sum rules. We show that a 125 GeV Higgs requires light, often sub-TeV, fermion resonances. Their presence can also be important for the models to successfully pass the electroweak precision tests. Interestingly enough, the latter can also be passed by models with a heavy Higgs around 320 GeV. The composite Higgs models of the moose-type considered in the literature can be seen as particular limits of our class of models.1 From now on a pNGB Higgs will always be assumed. 2 This is not the case for little Higgs models where a hierarchy between v and f can naturally be realized, but the explicit working implementations of this idea are a bit cumbersome. We will not consider little Higgs models in this paper.3 The idea of partially composite SM fermions dates back to [9], but only extra dimensions have allowed us to appreciate its full power [10].3 directly related by deconstruction to five-dimensional models, where the Higgs mass can at least be assumed to be calculable, and characterize the main properties these models should have in order to give rise to a Higgs mass at around 125 GeV. More specifically, we focus on the minimal SO(5)/SO(4) coset structure and consider models with an arbitrary number of spin 1 ("vector" and "axial") and spin 1/2 resonances. These resonances are assumed to be the only ones below the cut-off of the model at Λ = 4πf . Partial compositeness is assumed. The divergencies of the Higgs potential are cancelled by imposing that certain form factors, both in the gauge and in the fermion sectors, vanish sufficiently fast for large euclidean values of the momentum. These conditions are straightforward generalizations of the first and second Weinberg sum rules [15] and guarantee that the calculable part of the one-loop Higgs potential is finite. Being the Higgs potential a UV-sensitive quantity, and in absence of a symmetry mechanism protecting it, we will simply assume that the one-loop form factors above represent the main contributions to the potential, with higher-loop and higher-order operators giving only a sub-leading correction. We will denote the above assumption as the Minimal Higgs Potential (MHP) hypothesis. This is by far the strongest assumption underlying our construction. A similar approach is known to describe quite well the pion mass difference in QCD (see [16] for a very nice review), in which case the knowledge of ...

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We observe a generic connection between LHC Higgs data and electroweak baryogenesis: the particle that contributes to the CP-odd hgg or hγγ vertex would provide the CP-violating source during a first-order phase transition. It is illustrated in the two Higgs doublet model that a common complex phase controls the lightest Higgs properties at the LHC, electric dipole moments, and the CP-violating source for electroweak baryogenesis. We perform a general parametrization of Higgs effective couplings and a global fit to the LHC Higgs data. Current LHC measurements prefer a nonzero phase for tanβ≲1 and electric dipole moment constraints still allow an order-one phase for tanβ∼1, which gives sufficient room to generate the correct cosmic baryon asymmetry. We also give some prospects in the direct measurements of CP violation in the Higgs sector at the LHC.