# Reports

 2020-05-2509:25 [PUBDB-2020-02186] Report/Journal Article et al Comparison of topological charge definitions in Lattice QCD [DESY-17-115; arXiv:1708.00696] In this paper, we show a comparison of different definitions of the topological charge on the lattice. We concentrate on one small-volume ensemble with 2 flavours of dynamical, maximally twisted mass fermions and use three more ensembles to analyze the approach to the continuum limit. [...] OpenAccess: PDF PDF (PDFA); 2020-05-2015:36 [PUBDB-2020-02176] Book/Report/Dissertation / PhD Thesis Gallo-Voss, E. Search for supersymmetric particles in gluino-gluino pair production events at CMS [DESY-THESIS-2020-008] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY THESIS 133 pp. (2020) [10.3204/PUBDB-2020-02176] = Dissertation, Universität Hamburg, 2019   A search for gluino pair production with events using 35.9 fb−1of data from ppcollisions at a center-of-mass energy of 13 TeV in 2016 is presented. Two differentcascade decay modes of gluinos are considered, and separate analyses for each of themodels are performed [...] OpenAccess: PhDthesisAkshanshSUSY - PDF PDF (PDFA); PhDthesisAkshanshSUSY-new - PDF PDF (PDFA); desy-thesis-20-008.title - PDF PDF (PDFA); 2020-05-1914:05 [PUBDB-2020-02166] Preprint/Report et al Superradiant Cherenkov-Wakefield Radiation as THz Source for FEL Facilities [DESY-20-081; arXiv:2005.05640]   An electron beam passing through a tube which is lined on the inside with a dielectric layer will radiate energy in the THz range due to the interaction with the boundary. The resonant enhancement of certain frequencies is conditioned by structure parameters as tube radius and permittivity of the dielectric layer. [...] OpenAccess: PDF PDF (PDFA); 2020-05-1812:43 [PUBDB-2020-02149] Report/Journal Article et al LOFAR 144-MHz follow-up observations of GW170817 [arXiv:2004.01726] Monthly notices of the Royal Astronomical Society 494(4), 5110 - 5117 (2020) [10.1093/mnras/staa950]   We present low-radio-frequency follow-up observations of AT 2017gfo, the electromagnetic counterpart of GW170817, which was the first binary neutron star merger to be detected by Advanced LIGO-Virgo. These data, with a central frequency of 144 MHz, were obtained with LOFAR, the Low-Frequency Array. [...] OpenAccess: PDF PDF (PDFA); 2020-05-1811:47 [PUBDB-2020-02146] Report/Journal Article Ohm, S. Background Rejection in Atmospheric Cherenkov Telescopes using Recurrent Convolutional Neural Networks [arXiv:1910.09435] In this work, we present a new, high performance algorithm for background rejection in imaging atmospheric Cherenkov telescopes. We build on the already popular machine-learning techniques used in gamma-ray astronomy by the application of the latest techniques in machine learning, namely recurrent and convolutional neural networks, to the background rejection problem. [...] OpenAccess: PDF PDF (PDFA); 2020-05-1516:48 [PUBDB-2020-02143] Book/Report/Dissertation / PhD Thesis Gallo-Voss, E. Search for Light Bosons in Exotic Decays of the 125 GeV Higgs Boson [DESY-THESIS-2020-007] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 173 pp. (2020) [10.3204/PUBDB-2020-02143] = Dissertation, Universität Hamburg, 2020   A search for pairs of light bosons produced from decays of the 125 GeV Higgs boson is presented. The search covers the light boson mass region where the particle could have an enhanced decay rate to a pair of τ leptons, according to different models and scenarios.The leptonic decay channels corresponding to the 4τ and 2μ2τ final states are used. [...] OpenAccess: Thesis_PhD_DanyerPerezAdan - PDF PDF (PDFA); desy-thesis-20-007.title - PDF PDF (PDFA); 2020-05-1514:26 [PUBDB-2020-02140] Report/Journal Article et al Nucleon strange electromagnetic form factors [arXiv:1909.10744] Physical review / D D 101(3), 031501 (2020) [10.1103/PhysRevD.101.031501]   The role of the strange quarks on the low-energy interactions of the proton can be probed through the strange electromagnetic form factors. Knowledge of these form factors provides essential input for parity-violating processes and contributes to the understanding of the sea quark dynamics. [...] OpenAccess: PDF PDF (PDFA); 2020-05-1513:58 [PUBDB-2020-02139] Report/Journal Article Kühn, S. Topological vacuum structure of the Schwinger model with matrix product states [arXiv:1908.00551] Physical review / D D 101(5), 054507 (2020) [10.1103/PhysRevD.101.054507]   We numerically study the single-flavour Schwinger model in the Hamiltonian formulation with a topological $\theta$-term corresponding to a constant electric background field. By using numerical methods based on tensor networks, especially the one-dimensional matrix product states, we explore the non-trivial $\theta$-dependence of several lattice and continuum quantities. [...] OpenAccess: PDF PDF (PDFA); 2020-05-1414:43 [PUBDB-2020-01848] Report/Journal Article et al Lattice calculation of the hadronic leading order contribution to the muon $g-2$ [MITP/19-084] The persistent discrepancy of about 3.5 standard deviations between the experimental measurement and the Standard Model prediction for the muon anomalous magnetic moment, $a_\mu$, is one of the most promising hints for the possible existence of new physics. Here we report on our lattice QCD calculation of the hadronic vacuum polarisation contribution $a_\mu^{\rm hvp}$, based on gauge ensembles with $N_f=2+1$ flavours of O($a$) improved Wilson quarks. [...] OpenAccess: PDF PDF (PDFA); 2020-05-1411:02 [PUBDB-2020-01845] Report/Contribution to a conference proceedings et al Higgs Boson Pair Production at Colliders: Status and Perspectives [FERMILAB-CONF-19-468-E-T; LHCXSWG-2019-005; arXiv:1910.00012] Double Higgs Production at Colliders, BataviaBatavia, United States, 4 Sep 2018 - 9 Sep 2019 279 pp. (2020) [10.3204/PUBDB-2020-01845]   This document summarises the current theoretical and experimental status of the di-Higgs boson production searches, and of the direct and indirect constraints on the Higgs boson self-coupling, with the wish to serve as a useful guide for the next years. The document discusses the theoretical status, including state-of-the-art predictions for di-Higgs cross sections, developments on the effective field theory approach, and studies on specific new physics scenarios that can show up in the di-Higgs final state. [...] OpenAccess: PDF;