Electroweak interaction

About: Electroweak interaction is a research topic. Over the lifetime, 16333 publications have been published within this topic receiving 468927 citations. The topic is also known as: electroweak force.

Minimal Composite Dynamics versus Axion Origin of the Diphoton excess

Abstract: ATLAS and CMS observe deviations from the expected background in the diphoton invariant mass searches of new resonances around 750 GeV. We show that a simple realization in terms of a new pseudoscalar state can accommodate the observations. The model leads to further footprints that can be soon observed. The new state can be interpreted both as an axion or as a {highly natural} composite state arising from minimal models of dynamical electroweak symmetry breaking. We further show how to disentangle the two scenarios. Beyond the possible explanation of the diphoton excess the results show that it is possible to directly test and constrain composite dynamics via processes stemming from its distinctive topological sector.

Constrained exceptional supersymmetric standard model

Abstract: We propose and study a constrained version of the exceptional supersymmetric standard model (E6SSM), which we call the cE6SSM, based on a universal high energy scalar mass m0, trilinear scalar coupling A0 and gaugino mass M1/2. We derive the renormalization group (RG) Equations for the cE6SSM, including the extra U(1)N gauge factor and the low-energy matter content involving three 27 representations of E6. We perform a numerical RG analysis for the cE6SSM, imposing the usual low-energy experimental constraints and successful electroweak symmetry breaking. Our analysis reveals that the sparticle spectrum of the cE6SSM involves a light gluino, two light neutralinos, and a light chargino. Furthermore, although the squarks, sleptons, and Z? boson are typically heavy, the exotic quarks and squarks can also be relatively light. We finally specify a set of benchmark points, which correspond to particle spectra, production modes, and decay patterns peculiar to the cE6SSM, altogether leading to spectacular new physics signals at the Large Hadron Collider.

New gauge bosons from string models

Abstract: We address the mass ranges of new neutral gauge bosons and constraints on the accompanying exotic particles as predicted by a class of superstring models. Under certain assumptions about the supersymmetry breaking parameters we show that breaking of an additional U(1)′ symmetry is radiative when the appropriate Yukawa couplings of exotic particles are of order one, analogous to the radiative breaking of the electroweak symmetry in the supersymmetric standard model due to the large top-quark Yukawa coupling. Such large Yukawa couplings occur for a large class of string models. The Z′ and exotic masses are either of , or of a scale intermediate between the string and electroweak scales. In the former case, may be achieved without excessive fine-tuning, and is within future experimental reach.

Probable or Improbable Universe? Correlating Electroweak Vacuum Instability with the Scale of Inflation

Abstract: Measurements of the Higgs boson and top quark masses indicate that the Standard Model Higgs potential becomes unstable around $\Lambda_I \sim 10^{11}$ GeV. This instability is cosmologically relevant since quantum fluctuations during inflation can easily destabilize the electroweak vacuum if the Hubble parameter during inflation is larger than $\Lambda_I$ (as preferred by the recent BICEP2 measurement). We perform a careful study of the evolution of the Higgs field during inflation, obtaining different results from those currently in the literature. We consider both tunneling via a Coleman-de Luccia or Hawking-Moss instanton, valid when the scale of inflation is below the instability scale, as well as a statistical treatment via the Fokker-Planck equation appropriate in the opposite regime. We show that a better understanding of the post-inflation evolution of the unstable AdS vacuum regions is crucial for determining the eventual fate of the universe. If these AdS regions devour all of space, a universe like ours is indeed extremely unlikely without new physics to stabilize the Higgs potential; however, if these regions crunch, our universe survives, but inflation must last a few e-folds longer to compensate for the lost AdS regions. Lastly, we examine the effects of generic Planck-suppressed corrections to the Higgs potential, which can be sufficient to stabilize the electroweak vacuum during inflation.

Model independent electroweak penguins in B decays to two pseudoscalars

Abstract: We study the effects of electroweak penguin (EWP) amplitudes in B meson decays into two charmless pseudoscalars in the approximation of retaining only the dominant EWP operators Q9 and Q10. Using flavor SU(3) symmetry, we derive a set of model-independent relations between EWP contributions and tree-level decay amplitudes one of which was noted recently by Neubert and Rosner. Two new applications of these relations are demonstrated in which uncertainties due to EWP corrections are eliminated in order to determine a