@article{OPUS4-17246,
  title     = {Search for new high-mass phenomena in the dilepton final state using 36 fb\(^{-1}\) of proton-proton collision data at \(\sqrt{s}=13\) TeV with the ATLAS detector},
  series = {Journal of High Energy Physics},
  volume    = {2017},
  journal   = {Journal of High Energy Physics},
  number    = {182},
  organization    = {The ATLAS Collaboration},
  doi       = {10.1007/JHEP10(2017)182},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172462},
  year      = {2017},
  abstract  = {A search is conducted for new resonant and non-resonant high-mass phenomena in dielectron and dimuon final states. The search uses 36.1 fb\(^{-1}\) of proton-proton collision data, collected at \(\sqrt{s}=13\) TeV by the ATLAS experiment at the LHC in 2015 and 2016. No significant deviation from the Standard Model prediction is observed. Upper limits at 95\% credibility level are set on the cross-section times branching ratio for resonances decaying into dileptons, which are converted to lower limits on the resonance mass, up to 4.1 TeV for the E\(_6\)-motivated \(Z^′_χ\). Lower limits on the \({qqℓℓ}\) contact interaction scale are set between 2.4 TeV and 40 TeV, depending on the model.},
  language  = {en}
}
@article{OPUS4-17312,
  title     = {Measurement of the inclusive jet cross-sections in proton-proton collisions at \(\sqrt{s}=8\) TeV with the ATLAS detector},
  series = {Journal of High Energy Physics},
  volume    = {2017},
  journal   = {Journal of High Energy Physics},
  number    = {09},
  organization    = {The ATLAS Collaboration},
  doi       = {10.1007/JHEP09(2017)020},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-173123},
  year      = {2017},
  abstract  = {Inclusive jet production cross-sections are measured in proton-proton collisions at a centre-of-mass energy of \(\sqrt{s} = 8\) TeV recorded by the ATLAS experiment at the Large Hadron Collider at CERN. The total integrated luminosity of the analysed data set amounts to 20.2 fb\(^{-1}\). Double-differential cross-sections are measured for jets defined by the anti-\(k_t\) jet clustering algorithm with radius parameters of \(R\) = 0.4 and \(R\) = 0.6 and are presented as a function of the jet transverse momentum, in the range between 70 GeV and 2.5 TeV and in six bins of the absolute jet rapidity, between 0 and 3.0. The measured cross-sections are compared to predictions of quantum chromodynamics, calculated at next-to-leading order in perturbation theory, and corrected for non-perturbative and electroweak effects. The level of agreement with predictions, using a selection of different parton distribution functions for the proton, is quantified. Tensions between the data and the theory predictions are observed.},
  language  = {en}
}
@article{OPUS4-17321,
  title     = {Search for direct top squark pair production in events with a Higgs or \(Z\) boson, and missing transverse momentum in \(\sqrt{s}\) = 13 TeV \(pp\) collisions with the ATLAS detector},
  series = {Journal of High Energy Physics},
  volume    = {2017},
  journal   = {Journal of High Energy Physics},
  number    = {08},
  organization    = {The ATLAS Collaboration},
  doi       = {https://doi.org/10.1007/JHEP08(2017)006},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-173210},
  year      = {2017},
  abstract  = {A search for direct top squark pair production resulting in events with either a same-flavour opposite-sign dilepton pair with invariant mass compatible with a \(Z\) boson or a pair of jets compatible with a Standard Model (SM) Higgs boson (\(h\)) is presented. Requirements on the missing transverse momentum, together with additional selections on leptons, jets, jets identified as originating from \(b\)-quarks are imposed to target the other decay products of the top squark pair. The analysis is performed using proton-proton collision data at \(\sqrt{s}\) = 13 TeV collected with the ATLAS detector at the LHC in 2015-2016, corresponding to an integrated luminosity of 36.1 fb\(^{-1}\). No excess is observed in the data with respect to the SM predictions. The results are interpreted in two sets of models. In the first set, direct production of pairs of lighter top squarks (\(\tilde{t}_1\)) with long decay chains involving \(Z\) or Higgs bosons is considered. The second set includes direct pair production of the heavier top squark pairs (\(\tilde{t}_2\)) decaying via \(\tilde{t}_2\) → \(Z\tilde{t}_1\) or \(\tilde{t}_2\) → \(h\tilde{t}_1\). The results exclude at 95\% confidence level \(\tilde{t}_2\) and \(\tilde{t}_1\) masses up to about 800 GeV, extending the exclusion region of supersymmetric parameter space covered by previous LHC searches.},
  language  = {en}
}
@article{UllherrDiezZabler2022,
  author    = {Ullherr, Maximilian and Diez, Matthias and Zabler, Simon},
  title     = {Robust image reconstruction strategy for multiscalar holotomography},
  series = {Journal of Imaging},
  volume    = {8},
  journal   = {Journal of Imaging},
  number    = {2},
  issn      = {2313-433X},
  doi       = {10.3390/jimaging8020037},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-262112},
  year      = {2022},
  abstract  = {Holotomography is an extension of computed tomography where samples with low X-ray absorption can be investigated with higher contrast. In order to achieve this, the imaging system must yield an optical resolution of a few micrometers or less, which reduces the measurement area (field of view = FOV) to a few mm at most. If the sample size, however, exceeds the field of view (called local tomography or region of interest = ROI CT), filter problems arise during the CT reconstruction and phase retrieval in holotomography. In this paper, we will first investigate the practical impact of these filter problems and discuss approximate solutions. Secondly, we will investigate the effectiveness of a technique we call "multiscalar holotomography", where, in addition to the ROI CT, a lower resolution non-ROI CT measurement is recorded. This is used to avoid the filter problems while simultaneously reconstructing a larger part of the sample, albeit with a lower resolution in the additional area.},
  language  = {en}
}
@article{OPUS4-17272,
  title     = {Measurement of inclusive and differential cross sections in the \(H\) → \({ZZ}^*\) → \(4{ℓ}\) decay channel in \({pp}\) collisions at \(\sqrt{s} = 13\) TeV with the ATLAS detector},
  series = {Journal of High Energy Physics},
  volume    = {2017},
  journal   = {Journal of High Energy Physics},
  number    = {10},
  organization    = {The ATLAS Collaboration},
  doi       = {https://doi.org/10.1007/JHEP10(2017)132},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172724},
  year      = {2017},
  abstract  = {Inclusive and differential fiducial cross sections of Higgs boson production in proton-proton collisions are measured in the \(H\) → \({ZZ^*}\) → \(4{ℓ}\) decay channel. The proton-proton collision data were produced at the Large Hadron Collider at a centre-of-mass energy of 13 TeV and recorded by the ATLAS detector in 2015 and 2016, corresponding to an integrated luminosity of 36.1 fb\(^{-1}\). The inclusive fiducial cross section in the \(H\) → \({ZZ^*}\) → \(4{ℓ}\) decay channel is measured to be 3.62 ± 0.50(stat)\(^{+0.25}_{- 0.20}\) (sys) fb, in agreement with the Standard Model prediction of 2.91 ± 0.13 fb. The cross section is also extrapolated to the total phase space including all Standard Model Higgs boson decays. Several differential fiducial cross sections are measured for observables sensitive to the Higgs boson production and decay, including kinematic distributions of jets produced in association with the Higgs boson. Good agreement is found between data and Standard Model predictions. The results are used to put constraints on anomalous Higgs boson interactions with Standard Model particles, using the pseudo-observable extension to the kappa-framework.},
  language  = {en}
}
@article{OPUS4-17256,
  title     = {Search for top quark decays \(t → qH\), with \(H → γγ\), in \(\sqrt{s} = 13\) TeV \(pp\) collisions using the ATLAS detector},
  series = {Journal of High Energy Physics},
  volume    = {2017},
  journal   = {Journal of High Energy Physics},
  number    = {10},
  organization    = {The ATLAS Collaboration},
  doi       = {https://doi.org/10.1007/JHEP10(2017)129},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172568},
  year      = {2017},
  abstract  = {This article presents a search for flavour-changing neutral currents in the decay of a top quark into an up-type (\({q = c, u}\)) quark and a Higgs boson, where the Higgs boson decays into two photons. The proton-proton collision data set analysed amounts to 36.1 fb\(^{-1}\) at \(\sqrt{s} = 13\) TeV collected by the ATLAS experiment at the LHC. Top quark pair events are searched for, where one top quark decays into \(qH\) and the other decays into \(bW\). Both the hadronic and leptonic decay modes of the \(W\) boson are used. No significant excess is observed and an upper limit is set on the \({t → cH}\) branching ratio of 2.2 × 10\(^{-3}\) at the 95\% confidence level, while the expected limit in the absence of signal is 1.6 × 10\(^{-3}\). The corresponding limit on the \(tcH\) coupling is 0.090 at the 95\% confidence level. The observed upper limit on the \({t → uH}\) branching ratio is 2.4 × 10\(^{-3}\).},
  language  = {en}
}
@article{OPUS4-17216,
  title     = {Search for a scalar partner of the top quark in the jets plus missing transverse momentum final state at \(\sqrt{s}\) = 13 TeV with the ATLAS detector},
  series = {Journal of High Energy Physics},
  volume    = {12},
  journal   = {Journal of High Energy Physics},
  organization    = {The ATLAS Collaboration},
  doi       = {10.1007/JHEP12(2017)085},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172161},
  year      = {2017},
  abstract  = {A search for pair production of a scalar partner of the top quark in events with four or more jets plus missing transverse momentum is presented. An analysis of 36.1 fb\(^{-1}\) of \(\sqrt{s}\) = 13 TeV proton-proton collisions collected using the ATLAS detector at the LHC yields no significant excess over the expected Standard Model background. To interpret the results a simplified supersymmetric model is used where the top squark is assumed to decay via \(\tilde{t}_1\) → \(t^{(∗)}\)\(\tilde{χ}^0_1\) and \(\tilde{t}_1\) → \(b\tilde{χ}^±_1\) → \({bW}^{(∗)}\tilde{χ}^0_1\), where \(\tilde{χ}^0_1\) (\(\tilde{χ}^±_1\)) denotes the lightest neutralino (chargino). Exclusion limits are placed in terms of the top-squark and neutralino masses. Assuming a branching ratio of 100\% to \(t\tilde{χ}^0_1\), top-squark masses in the range 450-1000 GeV are excluded for \(\tilde{χ}^0_1\) masses below 160 GeV. In the case where \(m_{\tilde{t}_1}\) ∼ \(m_t\) + \(m_{\tilde{χ}^0_1}\), top-squark masses in the range 235-590 GeV are excluded.},
  language  = {en}
}
@article{OPUS4-22066,
  title     = {Measurement of dijet azimuthal decorrelations in \({pp}\) collisions at root s=8 TeV with the ATLAS detector and determination of the strong coupling},
  series = {Physical Review D},
  volume    = {98},
  journal   = {Physical Review D},
  number    = {9},
  organization    = {The ATLAS Collaboration},
  doi       = {10.1103/PhysRevD.98.092004},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-220665},
  pages     = {1-31},
  year      = {2018},
  abstract  = {measurement of the rapidity and transverse momentum dependence of dijet azimuthal decorrelations is presented, using the quantity R-Delta phi. The quantity R-Delta phi specifies the fraction of the inclusive dijet events in which the azimuthal opening angle of the two jets with the highest transverse momenta is less than a given value of the parameter Delta phi(max). The quantity R-Delta phi is measured in proton-proton collisions at root s = 8 TeV as a function of the dijet rapidity interval, the event total scalar transverse momentum, and Delta phi(max). The measurement uses an event sample corresponding to an integrated luminosity of 20.2 fb(-1) collected with the ATLAS detector at the CERN Large Hadron Collider. Predictions of a perturbative QCD calculation at next-to-leading order in the strong coupling with corrections for nonperturbative effects are compared to the data. The theoretical predictions describe the data in the whole kinematic region. The data are used to determine the strong coupling alpha(S) and to study its running for momentum transfers from 260 GeV to above 1.6 TeV. Analysis that combines data at all momentum transfers results in alpha(S) (m(Z)) = 0.1127(- 0.0027) (+0.0063).},
  language  = {en}
}
@phdthesis{Dietrich2024,
  author    = {Dietrich, Philipp},
  title     = {Traveling Wave Magnetic Particle Imaging: Visuelle Stenosequantifizierung und Perkutane Transluminale Angioplastie im Gef{\"a}ßmodell},
  doi       = {10.25972/OPUS-35251},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-352517},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2024},
  abstract  = {Magnetic Particle Imaging (MPI) ist ein innovatives tomographisches Bildgebungs­verfahren, mit dem Tracerpartikel {\"a}ußerst sensitiv und schnell mehrdimensional abgebildet werden k{\"o}nnen. Die Methode basiert auf der nichtlinearen Magnetisierungs­antwort superparamagnetischer Eisenoxidnanopartikel (SPION) in einem Messpunkt, welcher ein Messvolumen rastert. In vorliegender Arbeit wurde das sog. Traveling Wave MPI (TWMPI) Verfahren eingesetzt, wodurch im Vergleich zu konventionellen MPI-Scannern ein gr{\"o}ßeres Field of View (FOV) und eine geringere Latenz bis zur Bildanzeige erreicht werden konnte. TWMPI weist einige f{\"u}r medizinische Zwecke vielversprechende Eigenschaften auf: Es liefert zwei- und dreidimensionale Bildrekonstruktionen in Echtzeit mit hoher zeitlicher und r{\"a}umlicher Aufl{\"o}sung. Dabei ist die Bildgebung von Grund auf hintergrundfrei und erfordert keinerlei ionisierende Strahlung. Zudem ist die Technik {\"a}ußerst sensitiv und kann SPION-Tracer noch in mikromolaren Konzentrationen detektieren. Ziel dieser Arbeit war es daher zu untersuchen, inwiefern es mittels TWMPI m{\"o}glich ist, k{\"u}nstliche Stenosen im Gef{\"a}ßmodell visuell in Echtzeit darzustellen und quantitativ zu beurteilen sowie {\"u}berdies eine perkutane transluminale Angioplastie (PTA) im Gef{\"a}ßmodell unter TWMPI-Echtzeit-Bildgebung durchzuf{\"u}hren. Alle Experimente wurden in einem speziell angefertigten TWMPI-Scanner durchgef{\"u}hrt (JMU W{\"u}rzburg, Experimentelle Physik V (Biophysik), FOV: 65 x 29 x 29 mm³, Aufl{\"o}sung: ca. 1.5 - 2 mm). Die Lumen-Darstellungen erfolgten mittels des SPION-Tracers Ferucarbotran in einer Verd{\"u}nnung von 1 : 50 (entspr. 10 mmol [Fe]/l). Das PTA-Instrumentarium wurde mit eigens hergestelltem ferucarbotran­haltigem Lack (100 mmol [Fe]/l) markiert. F{\"u}r die verschiedenen Teilexperimente wurden den jeweiligen speziellen Anforderungen entsprechend mehrere Gef{\"a}ßmodelle handgefertigt. F{\"u}r die visuelle Stenosequantifizierung wurden f{\"u}nf starre Stenosephantome unterschiedlicher Stenosierung (0\%, 25\%, 50\%, 75\%, 100\%) aus Polyoxymethylen her­gestellt (l: 40 mm, ID: 8 mm). Die Gef{\"a}ßmodelle wurden mehrfach zentral im FOV platz­iert und das stenosierte Lumen mittels sog. Slice-Scanning Modus (SSM, Einzel­aufnahme inkl. 10 Mittelungen: 200 ms, Bildfrequenz: 5 Bilder pro Sekunde, Latenz: ca. 100 ms) als zweidimensionale Quasi-Projektionen abgebildet. Diese Aufnahmen (n = 80, 16 je Phantom) wurden mit einer ein­heitlichen Grauskalierung versehen und anschließend entsprechend den NASCET-Kriterien visuell ausgewertet. Alle achtzig Aufnahmen waren unabh{\"a}ngig vom Stenosegrad aufgrund einheitlicher Fensterung sowie konstanter Scannerparameter untereinander gut vergleichbar. Niedrig­gradige Stenosen konnten insgesamt genauer abgebildet werden als h{\"o}hergradige, was sich neben der subjektiven Bildqualit{\"a}t auch in geringeren Standardabweichungen zeigte (0\%: 3.70 \% ± 2.71, 25\%: 18.64 \% ± 1.84, 50\%: 52.82 \% ± 3.66, 75\%: 77.84 \% ± 14.77, 100\%: 100 \% ± 0). Mit zunehmendem Stenosegrad kam es vermehrt zu geometrischen Ver­zerrungen im Zentrum, sodass bei den 75\%-Stenosen eine breitere Streuung der Messwerte mit einer h{\"o}heren Standardabweichung von 14.77\% einherging. Leichte, randst{\"a}ndige Artefakte konnten bei allen Datens{\"a}tzen beobachtet werden. F{\"u}r die PTA wurden drei interaktive Gef{\"a}ßmodelle aus Polyvinylchlorid (l: 100 mm, ID: 8 mm) mit zu- und abf{\"u}hrendem Schlauchsystem entwickelt, welche mittels Kabelband von außen hochgradig eingeengt werden konnten. Analog zu einer konventionellen PTA mittels r{\"o}ntgenbasierter digitaler Subtraktionsangiographie (DSA), wurden alle erforder­lichen Arbeitsschritte (Gef{\"a}ßdarstellung, Drahtpassage, Ballonplatzierung, Angioplastie, Erfolgskontrolle) unter (TW)MPI-Echtzeit-Bildgebung (Framerate: 2 - 4 FPS, Latenz: ca. 100 ms) abgebildet bzw. durchgef{\"u}hrt. Im Rahmen der PTA war eine Echtzeit-Visualisierung der Stenose im Gef{\"a}ßmodell durch Tracer-Bolusgabe sowie die F{\"u}hrung des markierten Instrumentariums zum Zielort m{\"o}glich. Die Markierung der Instrumente hielt der Beanspruchung w{\"a}hrend der Prozedur stand und erm{\"o}glichte eine genaue Platzierung des Ballonkatheters. Die Stenose konnte mittels Angioplastie-Ballons unter Echtzeit-Darstellung gesprengt werden und der Interventionserfolg im Anschluss durch erneute Visualisierung des Lumens validiert werden. Insgesamt zeigt sich MPI somit als ad{\"a}quate Bildgebungstechnik f{\"u}r die beiden in der Fragestellung bzw. Zielsetzung definierten experimentellen Anwendungen. Stenosen im Gef{\"a}ßmodell konnten erfolgreich in Echtzeit visualisiert und bildmorphologisch nach NASCET-Kriterien quantifiziert werden. Ebenso war eine PTA im Gef{\"a}ßmodell unter TWMPI-Echtzeit-Bildgebung machbar. Diese Ergebnisse unter­streichen das grundlegende Potenzial von MPI f{\"u}r medizinische Zwecke. Um zu den bereits etablierten Bildgebungsmethoden aufzuschließen, ist jedoch weitere Forschung im Bereich der Scanner-Hard- und -Software sowie bez{\"u}glich SPION-Tracern n{\"o}tig.},
  subject      = {Medizinische Radiologie},
  language  = {de}
}
@article{GlinzŠleichrtKytyřetal.2021,
  author    = {Glinz, Jonathan and Šleichrt, Jan and Kyt{\´y}ř, Daniel and Ayalur-Karunakaran, Santhosh and Zabler, Simon and Kastner, Johann and Senck, Sascha},
  title     = {Phase-contrast and dark-field imaging for the inspection of resin-rich areas and fiber orientation in non-crimp vacuum infusion carbon-fiber-reinforced polymers},
  series = {Journal of Materials Science},
  volume    = {56},
  journal   = {Journal of Materials Science},
  number    = {16},
  doi       = {10.1007/s10853-021-05907-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-351581},
  pages     = {9712-9727},
  year      = {2021},
  abstract  = {In this work, we present a multimodal approach to three-dimensionally quantify and visualize fiber orientation and resin-rich areas in carbon-fiber-reinforced polymers manufactured by vacuum infusion. Three complementary image modalities were acquired by Talbot-Lau grating interferometer (TLGI) X-ray microcomputed tomography (XCT). Compared to absorption contrast (AC), TLGI-XCT provides enhanced contrast between polymer matrix and carbon fibers at lower spatial resolutions in the form of differential phase contrast (DPC) and dark-field contrast (DFC). Consequently, relatively thin layers of resin, effectively indiscernible from image noise in AC data, are distinguishable. In addition to the assessment of fiber orientation, the combination of DPC and DFC facilitates the quantification of resin-rich areas, e.g., in gaps between fiber layers or at binder yarn collimation sites. We found that resin-rich areas between fiber layers are predominantly developed in regions characterized by a pronounced curvature. In contrast, in-layer resin-rich areas are mainly caused by the collimation of fibers by binder yarn. Furthermore, void volume around two adjacent 90°-oriented fiber layers is increased by roughly 20\% compared to a random distribution over the whole specimen.},
  language  = {en}
}