The Higgs Mass and the Stueckelberg Mechanism in Supersymmetry

We investigate a class of theories where the mass of the lightest Higgs boson of the Minimal Supersymmetric Standard Model (MSSM) can be larger than the Z gauge boson mass at tree level. In this context the MSSM fields feel a new force, whose corresponding gauge boson attains its mass through the Stueckelberg mechanism. We show how one can achieve a Higgs mass around 126 GeV without assuming a heavy stop spectrum or a large stop trilinear term. The application of this class of models to the conservation of R-parity is also discussed.Comment: to appear in Physical Review

The Fate of R-Parity

The possible origin of the R-parity violating interactions in the minimal supersymmetric standard model and its connection to the radiative symmetry breaking mechanism (RSBM) is investigated. In the context of the simplest model where the implementation of the RSBM is possible, we find that in the majority of the parameter space R-parity is spontaneously broken at the low-scale. These results hint at the possibility that R-parity violating processes will be observed at the Large Hadron Collider, if Supersymmetry is realized in nature

On the Higgs Mass and Perturbativity

The predictions for the Higgs mass in extensions of the Minimal Supersymmetric Standard Model are discussed. We propose a simple theory where the Higgs mass is modified at tree-level and one can achieve a mass around 125 GeV without assuming heavy stops or large left-right mixing in the stop sector. All the parameters in the theory can be perturbative up to the grand unified scale, and one predicts the existence of new colored fields at the TeV scale. We refer to this model as Adjoint MSSM. We discuss the main phenomenological aspects of this scenario and the possible signatures at the Large Hadron Collider.Comment: title and format changed, new plot, to appear in Physics Letters

The Minimal SUSY B−LB-L Model: From the Unification Scale to the LHC

This paper introduces a random statistical scan over the high-energy initial parameter space of the minimal SUSY $B-L$ model--denoted as the $B-L$ MSSM. Each initial set of points is renormalization group evolved to the electroweak scale--being subjected, sequentially, to the requirement of radiative $B-L$ and electroweak symmetry breaking, the present experimental lower bounds on the $B-L$ vector boson and sparticle masses, as well as the lightest neutral Higgs mass of $\sim$125 GeV. The subspace of initial parameters that satisfies all such constraints is presented, shown to be robust and to contain a wide range of different configurations of soft supersymmetry breaking masses. The low-energy predictions of each such "valid" point - such as the sparticle mass spectrum and, in particular, the LSP - are computed and then statistically analyzed over the full subspace of valid points. Finally, the amount of fine-tuning required is quantified and compared to the MSSM computed using an identical random scan. The $B-L$ MSSM is shown to generically require less fine-tuning.Comment: 65 pages, 18 figure

Gauge Origin of M-Parity and the mu-Term in Supersymmetry

In this article we present a simple theoretical framework where the origin of the mu-term and the matter-parity violating interactions of the minimal supersymmetric standard model can be understood from the spontaneous breaking of new Abelian gauge symmetries. In this context the masses of the Z' gauge bosons, the M-parity violating scale and the mu-term are determined by the supersymmetry breaking scale. The full spectrum of the theory is discussed in detail. We investigate the predictions for the Higgs masses in detail showing that it is possible to satisfy the LEP2 bounds even with sub-TeV squark masses. The model predicts the existence of light colored fields, lepton and baryon number violation, and new neutral gauge bosons at the Large Hadron Collider.Comment: 14 pp. Minor corrections, to appear in Physical Review

Uncertainty-Aware Principal Component Analysis

We present a technique to perform dimensionality reduction on data that is subject to uncertainty. Our method is a generalization of traditional principal component analysis (PCA) to multivariate probability distributions. In comparison to non-linear methods, linear dimensionality reduction techniques have the advantage that the characteristics of such probability distributions remain intact after projection. We derive a representation of the PCA sample covariance matrix that respects potential uncertainty in each of the inputs, building the mathematical foundation of our new method: uncertainty-aware PCA. In addition to the accuracy and performance gained by our approach over sampling-based strategies, our formulation allows us to perform sensitivity analysis with regard to the uncertainty in the data. For this, we propose factor traces as a novel visualization that enables to better understand the influence of uncertainty on the chosen principal components. We provide multiple examples of our technique using real-world datasets. As a special case, we show how to propagate multivariate normal distributions through PCA in closed form. Furthermore, we discuss extensions and limitations of our approach

Minimal gauged U(1)_{B-L} model with spontaneous R-parity violation

We study the minimal gauged U(1)_{B-L} supersymmetric model and show that it provides an attractive theory for spontaneous R-parity violation. Both U(1)_{B-L} and R-parity are broken by the vacuum expectation value of the right-handed sneutrino (proportional to the soft SUSY masses), thereby linking the B-L and soft SUSY scales. In this context we find a consistent mechanism for generating neutrino masses and a realistic mass spectrum, all without extending the Higgs sector of the minimal supersymmetry standard model. We discuss the most relevant collider signals and the connection between the Z' gauge boson and R-parity violation.Comment: 4 pages, new title, to appear in Physical Review Letter

Higgs boson decays, baryon number violation, and supersymmetry at the LHC

Baryon number violating interactions could modify the signatures of supersymmetric models at the Large Hadron Collider. In this article we investigate the predictions for the Higgs mass and the Higgs decays in a simple extension of the minimal supersymmetric standard model where the local baryon and lepton numbers are spontaneously broken at the TeV scale. This theory predicts baryon number violation at the low scale which can change the current LHC bounds on the supersymmetric spectrum. Using the ATLAS and CMS bounds on the Higgs mass we show the constraints on the sfermion masses, and show the subsequent predictions for the radiative Higgs decays. We found that the Higgs decay into two photons is suppressed due to the existence of new light leptons. In this theory the stops can be very light in agreement with all experimental bounds and we make a brief discussion of the possible signals at the LHC

Zuhören lernen: Hinweise für den Unterricht in der Grundschule

Zuhören lernen: Hinweise für den Unterricht in der Grundschul