CLIC Background Studies and optimization of the innermost tracker elements

The harsh machine background at the Compact Linear Collider (CLIC) forms a strong constraint on the design of the innermost part of the tracker. For the CLIC Conceptual Design Report, the detector concepts developed for the International Linear Collider (ILC) were adapted to the CLIC environment. We present the new layout for the Vertex Detector and the Forward Tracking Disks of the CLIC detector concepts, as well as the background levels in these detectors. We also study the dependence of the background rates on technology parameters like thickness of the active layer and detection threshold.Comment: 7 pages, 5 figures, LCWS 201

Method to make a single-step etch mask for 3D monolithic nanostructures

Current nanostructure fabrication by etching is usually limited to planar structures as they are defined by a planar mask. The realisation of three-dimensional (3D) nanostructures by etching requires technologies beyond planar masks. We present a method to fabricate a 3D mask that allows to etch three-dimensional monolithic nanostructures by using only CMOS-compatible processes. The mask is written in a hard-mask layer that is deposited on two adjacent inclined surfaces of a Si wafer. By projecting in single step two different 2D patterns within one 3D mask on the two inclined surfaces, the mutual alignment between the patterns is ensured. Thereby after the mask pattern is defined, the etching of deep pores in two oblique directions yields a three-dimensional structure in Si. As a proof of concept we demonstrate 3D mask fabrication for three-dimensional diamond-like photonic band gap crystals in silicon. The fabricated crystals reveal a broad stop gap in optical reflectivity measurements. We propose how 3D nanostructures with five different Bravais lattices can be realised, namely cubic, tetragonal, orthorhombic, monoclinic, and hexagonal, and demonstrate a mask for a 3D hexagonal crystal. We also demonstrate the mask for a diamond-structure crystal with a 3D array of cavities. In general, the 2D patterns for the different surfaces can be completely independent and still be in perfect mutual alignment. Indeed, we observe an alignment accuracy of better than 3.0 nm between the 2D mask patterns on the inclined surfaces, which permits one to etch well-defined monolithic 3D nanostructures.Comment: 18 pages, 10 figure

Extracting the top-quark running mass using ttˉt\bar{t}+1-jet events produced at the Large Hadron Collider

We present the calculation of the next-to-leading order QCD corrections for top-quark pair production in association with an additional jet at hadron colliders, using the modified minimal subtraction scheme to renormalize the top-quark mass. The results are compared to measurements at the Large Hadron Collider run I. In particular, we determine the top-quark running mass from a fit of the theoretical results presented here to the LHC data

Modulating active sites in MOFs for improved Lewis acid or base catalysis

International audienc

Top quark precision physics at the International Linear Collider

Top quark production in the process $e^+e^- \rightarrow t\bar{t}$ at a future linear electron positron collider with polarized beams is a powerful tool to determine the scale of new physics. Studies at the \ttbar threshold will allow for precise determination of the top quark mass in a well defined theoretical framework. At higher energies vector, axial vector and tensorial CP conserving couplings can be separately determined for the photon and the $Z^0$ component in the electro-weak production process. The sensitivity to new physics would be dramatically improved w.r.t. to what expected from LHC for electroweak couplings.Comment: White paper for Snowmass CSS 201

Scattering Lens Resolves sub-100 nm Structures with Visible Light

The smallest structures that conventional lenses are able to optically resolve are of the order of 200 nm. We introduce a new type of lens that exploits multiple scattering of light to generate a scanning nano-sized optical focus. With an experimental realization of this lens in gallium phosphide we have succeeded to image gold nanoparticles at 97 nm optical resolution. Our work is the first lens that provides a resolution in the nanometer regime at visible wavelengths.Comment: 4 pages, 3 figure