# Ph.D. Theses

 2019-05-2818:36 [PUBDB-2019-02386] Dissertation / PhD Thesis Passerini, S. Lithium- and oxygen-driven structural evolution in Co-free Li-Mn-rich oxides as cathodes for lithium ion batteries Karlsruhe 121 pp. (2019) [10.5445/IR/1000094410] = Dissertation, Karlsruhe Institute of Technology (KIT), 2019   Nowadays, the lithium-rich layered 3d-transition-metal (TM) oxides (LLOs) are regarded as one of the most attractive cathode materials for next-generation lithium-ion batteries (LIBs), because they can exhibit a discharge capacity (approaching 300 mAh g$^{-1}$ at 0.1 C) much higher than that of the currently used materials(~ 180 mAh g$^{-1}$at 0.1 C). However, the formation mechanism of LLOs has not been fully understood on a fundamental level yet.One of the most interesting and still open questionsis aboutlithium and oxygen atoms are incorporatedinto the precursor’s crystal structure during the synthesisoffinal LLO products.Asystematic exploration of this subject was conducted in this PhD work. [...] OpenAccess: PDF PDF (PDFA); 2019-05-2809:45 [PUBDB-2019-02383] Dissertation / PhD Thesis Pearson, A. Microfluidic Sample Environments for Time-resolved Macromolecular Structure Formation Studies Hamburg 186 pp. (2019) [10.3204/PUBDB-2019-02383] = Dissertation, University of Hamburg, 2019   This thesis deals with the polymerization-induced self-assembly (PISA) of amphiphilic blockcopolymer nano-objects, which were synthesized using a controlled radical polymerization(CRP) method, in particular, the reversible addition-fragmentation chain-transfer (RAFT)aqueous polymerization in the presence of a poly(N,N-dimethylacrylamide) stabilizer agent(macro RAFT agent). Besides the use of N-isopropylacrylamide (NIPAm) as core-formingblock for thermo-responsive nanoparticle, the aqueous dispersion polymerization of 2-methoxyethyl acrylate (MEA) was pursued as a model to study hydrophilic-hydrophobic phasetransitions: as a monomer, MEA is water-soluble. [...] OpenAccess: PDF; 2019-05-0713:39 [PUBDB-2019-02167] Book/Report/Dissertation / PhD Thesis Raspereza, A. Tau Lepton: As a Tool for Hunting Standard Model and Beyond Standard Model Higgs [DESY-THESIS-2019-009] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 189 pp. (2019) [10.3204/PUBDB-2019-02167] = Dissertation, Universität Hamburg, 2019   This thesis presents a study of the Standard Model (SM) Higgs boson in the decay channelof ! eμ, as well as a search for neutral Minimal Supersymmetric Standard Model (MSSM)Higgs boson in the same decay channel, using data corresponding to an integrated luminosityof 35.9 fb−1 in proton-proton collisions with a center-of-mass energy of 13 TeV, collected bythe CMS detector at the Large Hadron Collider. The results of eμ channel in both analysesare combined with other channels of Higgs to decay: eh, μh and hh.An observation of the SM Higgs boson to is established with a significance of 4.9 standarddeviations, to be compared to an expected significance of 4.7 standard deviations [...] OpenAccess: Thesis_PhD_PublishedVersion - PDF; desy-thesis-19-009.title - PDF PDF (PDFA); 2019-05-0614:03 [PUBDB-2019-02142] Book/Report/Dissertation / PhD Thesis Brüggen, M. Astrophysical Implications of Self-interacting Dark Matter [DESY-THESIS-2019-008] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 127 pp. (2019) [10.3204/PUBDB-2019-02142] = Dissertation, Universität Hamburg, 2019   In this thesis we study the astrophysical implication of self-interacting dark matter. Observations on different scales suggest the existence of an additional form of matter which interacts gravitationally. [...] OpenAccess: desy-thesis-19-008.title - PDF PDF (PDFA); Thesis_PhD_Janis_Kummer - PDF PDF (PDFA); 2019-04-0208:07 [PUBDB-2019-01791] Book/Report/Dissertation / PhD Thesis Foster, B. Numerical beam stability studies in external injection plasma-wakefield acceleration regimes [DESY-THESIS-2019-005] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 177 pp. (2019) [10.3204/PUBDB-2019-01791] = Dissertation, Universität Hamburg, 2019   This work considers the phase-space evolution of an externally injectedelectron beam under various plasma-based acceleration scenariosusing numerical methods.Plasma wakefield acceleration, an exceptional technology with thepotential to drive the next generation of particle accelerators, uses aparticle driver to excite a wakefield carrying gradients in the rangeof10 GV m−1to100 GV m−1, orders of magnitude higher than theconventional cavities currently available. However, the plasma envi-ronment has stringent requirements with respect to acceptable beamparameters which need to be carefully analyzed to enable stable beamtransport and acceleration. [...] OpenAccess: Thesis_Alexander Aschikhin_Numerical beam stability studies in external injection plasma-wakefield acceleration regimes - PDF PDF (PDFA); desy-thesis-19-005.title - PDF PDF (PDFA); 2019-03-2909:13 [PUBDB-2019-01768] Book/Report/Dissertation / PhD Thesis Servant, G. Flavour cosmology: Electroweak baryogenesis from varying Yukawas [DESY-THESIS-2019-004] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 168 pp. (2019) [10.3204/PUBDB-2019-01768] = Dissertation, Universität Hamburg, 2018   Despite its outstanding phenomenological successes, the Standard Model of particle physicshas a number of severe shortcomings. In this thesis, I address some of the most strikingof these. [...] OpenAccess: desy-thesis-19-004.title - PDF PDF (PDFA); thesis_Bruggisser-1 - PDF PDF (PDFA); 2019-03-1910:07 [PUBDB-2019-01602] Dissertation / PhD Thesis Jones, R. M. Higher-Order-Mode-based Beam Phase and Beam Position Measurements in Superconducting Accelerating Cavities at the European XFEL 183 pp. (2019) [10.3204/PUBDB-2019-01602] = Dissertation, University of Manchester, 2017   Instrumentation of higher order modes (HOMs) excited in accelerating cavities for beam phase and position inference provides a noninvasive and economical beam diagnostic. The principles and techniques for this purpose are investigated for TESLA (TeV Energy Superconducting Linear Accelerator) cavities at the injector part of the newly built European XFEL and at FLASH, two free electron laser facilities based on the TESLA technology.I have designed and instrumented unconventional beam phase monitors based on monopole modes in TESLA cavities and demonstrated a routine resolution of 0.1° with a broadband setup [...] OpenAccess: PDF PDF (PDFA); 2019-03-1612:26 [PUBDB-2019-01563] Dissertation / PhD Thesis Braz Fernandes, F. M. Structural Evolution of Ni-Ti Alloy Wires Produced by Hot and Cold Rotary Forging Monte de Caparica, Portugal : Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa 174 pp. (2018) [10.3204/PUBDB-2019-01563] = Dissertation, Universidade Nova de Lisboa, 2018   Ni-Ti shape memory alloys (SMA), have interesting functional properties such as shape memory effect and superelasticity that enable their use in different segments. These functional characteristics are obtained through the thermomechanical processing (hot and cold). [...] OpenAccess: PDF PDF (PDFA); 2019-03-1510:39 [PUBDB-2019-01556] Book/Report/Dissertation / PhD Thesis Gruener, F. Study of self-modulation of an electron beam in plasma [DESY-THESIS-2019-003] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 142 pp. (2019) [10.3204/PUBDB-2019-01556] = Dissertation, University of Hamburg, 2018   The acceleration of electron beams in plasma wakefields driven by charged particlebeams is among the most promising candidates for future TeV-scale compact electronaccelerators. Currently available high energy proton beams that could serve as driverbeams in a plasma wakefeld accelerator (PWFA) are much longer than what is requiredfor efficient excitation of high-amplitude wakefields and thus for generating the desiredhigh acceleration gradients. [...] OpenAccess: desy-thesis-19-003.title - PDF PDF (PDFA); thesis-Lishilin - PDF PDF (PDFA); 2019-02-2014:25 [PUBDB-2019-01182] Book/Report/Dissertation / PhD Thesis Gallo-Voss, E. Search for high mass higgs bosons in the final state with $b$-quarks with the CMS 2016 data [DESY-THESIS-2019-002] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 216 pp. (2019) [10.3204/PUBDB-2019-01182] = Dissertation, Universität Hamburg, 2019   A search for high mass Higgs bosons produced in association with at least one $b$-quark and decaying into a pair of $b$-quarks using the LHC Run 2 data collected by the CMS detector is presented. The corresponding data sample was accumulated during the proton-proton collisions in 2016 at a centre-of-mass energy of $\sqrt{s} = 13$ TeV, corresponding to an integrated luminosity of 35.7 fb$^{-1}$.An extended Higgs sector containing high mass Higgs states is predicted by many theories beyond the Standard Model, such as a general two Higgs doublet model (2HDM) and its realization in the Minimal Supersymmetric extension of the Standard Model (MSSM).In many scenarios within these models Higgs couplings to $b$-quarks are significantly enhanced and therefore the final state exploited in this work is of particular interest.From the experimental point of view this final state leads to at least three highly energetic $b$-jets in the event, of which the two with the highest transverse momentum, are assumed to originate from the Higgs boson decay and another one comes from the associated production mechanism. [...] OpenAccess: desy-thesis-19-002.title - PDF PDF (PDFA); Thesis_Rostyslav_Shevchenko - PDF PDF (PDFA);