The electron-positron stage of the Future Circular Collider, FCC-ee, is a frontier factory for Higgs, top, electroweak, and flavour physics. It is designed to operate in a 100 km circular tunnel ...built at CERN, and will serve as the first step towards ≥100 TeV proton-proton collisions. In addition to an essential and unique Higgs program, it offers powerful opportunities to discover direct or indirect evidence of physics beyond the Standard Model. Direct searches for long-lived particles at FCC-ee could be particularly fertile in the high-luminosity
Z
run, where 5 × 10
12
Z
bosons are anticipated to be produced for the configuration with two interaction points. The high statistics of Higgs bosons,
W
bosons and top quarks in very clean experimental conditions could offer additional opportunities at other collision energies. Three physics cases producing long-lived signatures at FCC-ee are highlighted and studied in this paper: heavy neutral leptons (HNLs), axion-like particles (ALPs), and exotic decays of the Higgs boson. These searches motivate out-of-the-box optimization of experimental conditions and analysis techniques, which could lead to improvements in other physics searches.
An overview of different dual damascene approaches is given. Three approaches – trench first, trench first with metal hardmask, and via first – are described in detail. Trench first is the easiest ...approach but due to its limitation only suitable for wide ground rules with moderate aspect ratios. Via first is capable to run fine pitches and/or higher aspect ratios but has many problems to reach a proper transition between trench and via. With respect to this transition the trench first with metal hardmask concept seems to be advantageous, but it has its own challenges and problems. This article describes our solutions to these problems.
the design of the low-temperature scanning probe microscope, which works in field emission regime with spin polarization analysis, is proposed. A performance at temperature of 77 K has been achieved. ...The first result of STM imaging with atomic resolution is demonstrated.
In this study, we use Scanning Field Emission Microscopy (SFEM) combined with a miniature electron energy analyzer known as a Bessel box to measure electron energy spectra emitted from a sample. ...Previous studies using SFEM have revealed that the work function (ϕ) of the material under study has a significant role to play in the formation of the signal intensity. Hence, in order to understand the role of ϕ in greater detail, a sample of W(110) (ϕ = 5.25 eV) and a sample of Cs deposited on W(110) (ϕ ≈ 1.7 eV) were investigated. STM images show that the Cs covered surface has a speckled appearance indicating small Cs islands. The electron energy loss spectra obtained (which are the first using the Bessel box in SFEM) show differing structure in the elastic peak region. Monte Carlo (MC) simulations including quantum mechanical "bouncing" have been carried out. The results are consistent with MC simulations of the electrons escaping from the tip-sample junction.
Scanning Field Emission Microscopy with Polarization Analysis was recently introduced to detect the spin polarization of electrons excited in the field emission regime of Scanning Tunnelling ...Microscopy. In this work, a miniature electron energy analyzer, called Bessel Box, is implemented into the Scanning Field Emission Microscope with Polarization Analysis setup. It is used to filter electrons according to their energy before they reach the spin detector. The Bessel Box allows, e.g., the spin polarization of elastically scattered electrons to be compared with the spin polarization obtained with the full energy spectrum. We use this technology to measure the local in-plane polarization signal as a function of the magnetic field B at room temperature for 10 monolayers Fe deposited on top of a W(011)-single crystal surface through a half mask (half of the surface is covered with Fe, the other half is uncovered). The spin polarization at the Fe-W crossing drops sharply from 9% above Fe to 0% above W(011) only if the elastically scattered electrons are selected for spin analysis. The mechanism of signal generation in Scanning Field Emission Microscope with Polarization Analysis including the formation of cascade of inelastically scattered electrons is discussed as an explanation for the different spin polarization profiles observed with and without Bessel Box (energy filtered).
