Reports

Cherenkov radiators based on silica aerogel are used to measure the electron bunch length at the photo injector test facility at DESY Zeuthen (PITZ). The energy range of those electrons is 4–5 MeV. [...]

The operation of a Free Electron Laser at the TESLA Test Facility requires the electron trajectory to be aligned with precision of few micrometer in overlap with the photon beam. To achieve this goal precise position monitoring of the electron beam in the narrow undulator gap is mandatory. [...]

In this paper, we study a possible microbunching instability in the TESLA Test Facility linac. A longitudinal space charge is found to be the main effect driving the instability. [...]

Aim of the control system development for TESLA cavity is a more efficient stabilization of the pulsed, accelerating EM field inside resonator. Cavity parameters identification is an essential task for the comprehensive control algorithm. [...]

An extrapolation to assess the expected sensitivity of pp→H→ττcross-section measurements at the HL-LHC is performed using the results obtained with 139 fb−1 of pp collisions at s√=13 TeV. A HL-LHC scenario corresponding to a dataset of 3000 fb−1 of pp collisions at s√=14 TeV is considered. [...]

A prospect study for the search for non-resonant Higgs boson pair production in the bb¯γγdecay channel is presented, assuming 3000 fb−1 of pp collisions at s√=14 TeV with the ATLAS detector at the High Luminosity LHC (HL-LHC). The projected results are based on extrapolations of the Run 2 analysis conducted with 139 fb−1 at s√=13 TeV. [...]

The High-Luminosity LHC (HL-LHC) with its large number of collisions per proton-proton bunch crossing every 25 ns will present a challenging environment for particle detectors. The ATLAS Upgrade Program foresees the complete replacement of the current tracking system with a full-silicon Inner Tracker (ITk) made of a pixel and a strip subdetectors. [...]

A search for events with one top quark and missing transverse momentum in the final state is presented. The fully hadronic decay of the top quark is explored by selecting events with a reconstructed boosted top quark topology produced in association with large missing transverse momentum. [...]

A search for potential $cc\bar{c}\bar{c}$ tetraquarks decaying into a pair of charmonium states in the four muon final state is performed using proton-proton collision data at $\sqrt{s}=13$ TeV, corresponding to an integrated luminosity of 139 fb$^{-1}$ recorded by the ATLAS experiment at the Large Hadron Collider (LHC). Two different decay channels, $T_{cc\bar{c}\bar{c}}\to J/\psi~J/\psi\to 4\mu$ and $T_{cc\bar{c}\bar{c}}\to J/\psi~\psi(2S)\to 4\mu$, are studied. [...]

A search for leptoquark pair production decaying to $t \ell^- \bar{t} \ell^+$ in final states with multiple leptons is presented. The search is based on a dataset of $pp$ collisions at $\sqrt{s}=13$ TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$. [...]