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Register a new userAutomated simulations beyond the Standard Model: supersymmetry
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The MadGraph5 aMC@NLO framework aims to automate all types of leading- and next-to-leading-order-accurate simulations for any user-defined model that stems from a renormalisable Lagrangian. In this paper, we present all of the key ingredients of such models in the context of supersymmetric theories. In order to do so, we extend the FeynRules package by giving it the possibility of dealing with different renormalisation options that are relevant to supersymmetric models. We also show how to deal with the problem posed by the presence of narrow resonances, thus generalising the so-called on-shell subtraction approaches. We extensively compare our total rate results with those of both Prospino2 and Resummino, and present illustrative applications relevant to the 13 TeV LHC, both at the total-rate and differential levels. The computer programs that we have used to obtain the predictions presented here are all publicly available.
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This collection of studies on new physics at the LHC constitutes the report of the supersymmetry working group at the Workshop `Physics at TeV Colliders, Les Houches, France, 2007. They cover the wide spectrum of phenomenology in the LHC era, from alternative models and signatures to the extraction of relevant observables, the study of the MSSM parameter space and finally to the interplay of LHC observations with additional data expected on a similar time scale. The special feature of this collection is that while not each of the studies is explicitely performed together by theoretical and experimental LHC physicists, all of them were inspired by and discussed in this particular environment.
We cover some current topics in Beyond the Standard Model phenomenology, with an emphasis on collider (particularly Large Hadron Collider) phenomenology. We begin with a review of the Standard Model and some unresolved mysteries that it leaves. Then, we shall heuristically introduce supersymmetry, grand unified theories and extra dimensions as paradigms for expanding the Standard Model. The collider phenomenology of such models is too rich and complex to review, but we give some key examples of how the new states associated with the models might be inferred in Large Hadron Collider events. Before concluding, we finish with a brief description of a quantum field theory approximation that can be used in some cases to reduce model dependence: effective field theory. We show how this can be employed to explain recent measurements of decays of $B$ mesons, which disagree with Standard Model predictions.
We briefly review the global Standard Model fit to electroweak precision data, and discuss the status of electroweak constraints on new interactions. We follow a general effective Lagrangian approach to obtain model-independent limits on the dimension-six operators, as well as on several common new physics extensions.
Estimates of the CP violating observable $varepsilon/varepsilon$ have gained some attention in the past few years. Depending on the long-distance treatment used, they exhibit up to $2.9sigma$ deviation from the experimentally measured value. Such a deviation motivates the investigation of New Physics (NP) effects in the process $Ktopipi$. In my talk I will review the Standard Model (SM) prediction for $varepsilon/varepsilon$, with a special focus on the Dual QCD approach. On the NP side, I will discuss a recent computation of the hadronic matrix elements of NP operators. Furthermore a master formula for BSM effects in $varepsilon/varepsilon$ is presented. Finally, a treatment of $varepsilon/varepsilon$ using the SM effective theory (SMEFT) will be discussed together with possible correlations to other observables.
We present for the first time a model-independent anatomy of the ratio $varepsilon/varepsilon$ in the context of the $Delta S = 1$ effective theory with operators invariant under QCD and QED and in the context of the Standard Model Effective Field Theory (SMEFT) with the operators invariant under the full SM gauge group. Our goal is to identify the new physics scenarios that are probed by this ratio and which could help to explain a possible deviation from the SM that is hinted by the data. To this end we derive a master formula for $varepsilon/varepsilon$, which can be applied to any theory beyond the Standard Model (BSM) in which the Wilson coefficients of all contributing operators have been calculated at the electroweak scale. The relevant hadronic matrix elements of BSM operators are from the Dual QCD approach and the SM ones from lattice QCD. Within SMEFT, the constraints from $K^0$ and $D^0$ mixing as well as electric dipole moments limit significantly potential new physics contributions to $varepsilon/varepsilon$. Correlations of $varepsilon/varepsilon$ with $Ktopi ubar u$ decays are briefly discussed. Building on our EFT analysis and the model-independent constraints, we discuss implications of a possible deviation from the SM in $varepsilon/varepsilon$ for model building, highlighting the role of the new scalar and tensor matrix elements in models with scalar mediators.
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