A Novel Method of Synthesizing Graphene for Electronic Device Applications

This article reports a novel and efficient method to synthesize graphene using a thermal decomposition process. In this method, silicon carbide (SiC) thin films grown on Si(100) wafers with an AlN buffer layer were used as substrates. CO₂ laser beam heating, without vacuum or controlled atmosphere, was applied for SiC thermal decomposition. The physical, chemical, morphological, and electrical properties of the laser-produced graphene were investigated for different laser energy densities. The results demonstrate that graphene was produced in the form of small islands with quality, density, and properties depending on the applied laser energy density. Furthermore, the produced graphene exhibited a sheet resistance characteristic similar to graphene grown on mono-crystalline SiC wafers, which indicates its potential for electronic device applications.

The post-Higgs MSSM scenario: habemus MSSM?

We analyze the Minimal Supersymmetric extension of the Standard Model that we have after the discovery of the Higgs boson at the LHC, the hMSSM (habemus MSSM?), i.e. a model in which the lighter h boson has a mass of approximately 125 GeV which, together with the non-observation of superparticles at the LHC, indicates that the SUSY-breaking scale MS is rather high, MS ≳1 TeV. We first demonstrate that the value Mh ≈125 GeV fixes the dominant radiative corrections that enter the MSSM Higgs boson masses, leading to a Higgs sector that can be described, to a good approximation, by only two free parameters. In a second step, we consider the direct supersymmetric radiative corrections and show that, to a good approximation, the phenomenology of the lighter Higgs state can be described by its mass and three couplings: those to massive gauge bosons and to top and bottom quarks. We perform a fit of these couplings using the latest LHC data on the production and decay rates of the light h boson and combine it with the limits from the negative search of the heavier H,A and H± states, taking into account the current uncertainties.

Constrained next-to-minimal supersymmetric standard model

We consider the fully constrained version of the next-to-minimal supersymmetric extension of the standard model (cNMSSM) in which a singlet Higgs superfield is added to the two doublets that are present in the minimal extension (MSSM). Assuming universal boundary conditions at a high scale for the soft supersymmetry-breaking mass parameters as well as for the trilinear interactions, we find that the model is more constrained than the celebrated minimal supergravity model. The phenomenologically viable region in the parameter space of the cNMSSM corresponds to a small value for the universal scalar mass m_{0}: in this case, one single input parameter is sufficient to describe the model's phenomenology once constraints from collider data and cosmology are imposed.

Determining the CP properties of the Higgs boson

The search and the probe of the fundamental properties of Higgs boson(s) and, in particular, the determination of their charge conjugation and parity (CP) quantum numbers, are the main tasks of future high-energy colliders. We demonstrate that the CP properties of a standard model-like Higgs particle can be unambiguously assessed by measuring just the total cross section and the top polarization in associated Higgs boson production with top quark pairs in e(+)e(-) collisions.