Radiative corrections to Compton processes on the proton and to the Drell-Yan process

For a solid interpretation of experimental data and comparison with predictions from the Standard Model of Particle Physics, one needs a precise theoretical understanding of the underlying scattering processes and incorporate higher-order corrections into theoretical predictions. However, the calculation of these corrections is in general very cumbersome and time-consuming and new techniques need to be developed that facilitate the computation. In this thesis, we study radiative corrections to two different processes at very different energy scales. Despite the fact that the underlying theories are quite different, the techniques and tools to calculate higher-order effects in both situations are the same. In the first project, we calculate the leading-order corrections in quantum electrodynamics to the Compton process on the proton in different experimental setups. The Compton process is one of the most important processes to study the internal structure of nucleons using scattering data at different energies and from different experiments to access the Compton amplitude phenomenologically. To extract structure functions from the data, it is important to know the size of radiative corrections on the level of the theoretically predicted cross section when comparing with experimental data. We study these corrections in various experimental situations and for different models, describing the Compton amplitude in two different energy regimes. In the second project, we study the mixed electroweak-strong radiative corrections to the Drell-Yan process. Although this type of correction received a significant amount of attention in the particle physics community during the last decades, the calculation of the full set of contributions without any approximation remained a challenge for a long time. The main technical issue was the calculation of the master integrals with two masses using differential equations. They fall into a class of integrals whose differential equations contain non-rationalizable algebraic functions such that the standard algorithm to integrate the differential equation does not work. We develop new techniques to tackle this class of differential equations and successfully calculate all master integrals for the mixed electroweak-strong two-loop corrections to the Drell-Yan process. Using these integrals, we furthermore calculate the virtual two-loop mixed electroweak-strong helicity amplitudes for the first time.201 Seiten, Illustratione

Social Justice in the EU – Index Report 2017 Social Inclusion Monitor Europe. Bertelsmann Stiftung Social Inclusion Monitor Europe 2017

1. Europe is recovering not only economically, but also in the domain of social justice After years of downward movement, an upward trend in the domain of social justice is evident in the broad majority of EU member states. Although far from all member states have regained their pre-crisis levels, the most recent EU Social Justice Index data give cause for hope that the worst is over not just in economic terms, but also from a social perspective. At the top of this year’s Social Justice Index are the northern European states of Denmark, Sweden and Finland. Rounding out the top group are the Czech Republic, Slovenia, the Netherlands, Austria and Germany, while Greece, despite again posting slight gains this year, remains clearly in last place

Hot bubbles of planetary nebulae with hydrogen-deficient winds - II. Analytical approximations with application to BD+30∘^\circ3639

The first high-resolution X-ray spectroscopy of the planetary nebula BD+30$^\circ$3639 allowed to study X-ray emitting "hot bubbles" (HBs) of planetary nebulae in unprecedented detail. We investigate (i) how diagnostic line ratios are affected by the HB thermal structure and chemical profile, (ii) if the HB chemical composition of BD+30$^\circ$3639 is consistent with the H-poor (H for hydrogen) composition of the stellar photosphere, and (iii) if H-rich nebular matter has been added to this HB by evaporation. We apply an analytical, 1D model for wind-blown HBs with temperature and density profiles based on self-similar solutions including thermal conduction. We construct heat-conduction HBs with chemical stratification. The X-ray emission is computed using the CHIANTI code. Our HB models are used to re-analyse the high-resolution X-ray spectrum of BD+30$^\circ$3639. Our models reproduce the observed line ratios much better than plasmas with single electron temperatures. All the temperature- and abundance-sensitive line ratios are consistent with BD+30$^\circ$3639 X-ray observations for (i) an intervening column density of neutral H, $N_{\rm H} = 0.20_{-0.10}^{+0.05}\times\!10^{22}\rm\ cm^{-2}$, (ii) a characteristic HB X-ray temperature of ${T_{\rm X} = 1.8\pm 0.1~ }$MK together with (iii) a very high neon mass fraction of about 0.05, virtually as high as that of oxygen. For lower values of $N_{\rm H}$, we cannot exclude that the HB of BD+30$^\circ$3639 contains a small amount of evaporated (or mixed) H-rich nebular matter. Given the possible range of $N_{\rm H}$, the fraction of evaporated H-rich matter cannot exceed 3% of the HB mass. The diffuse X-ray emission from BD+30$^\circ$3639 can well be explained by models of wind-blown HBs with thermal conduction and a chemical composition equal to that of the H-poor and carbon-, oxygen-, and neon-rich stellar surface.Comment: 24 pages, 19 figures (col and b/w), 4 tables, accepted for publication in A&A, Fig. 18 adapted to accepted versio

Social Justice in the EU and OECD. Bertelsmann Stiftung Index Report 2019

With the onset of the economic and financial crisis, social justice has deteriorated – on average – in the OECD and EU countries surveyed by the SJI.1 While the Social Justice Index shows a slight but ongoing upward trend since economic recovery began in 2014, the overall score remains below the pre-crisis level. In addition, there are still striking discrepancies with regard to available opportunities to participate in society in the 41 countries surveyed

Dust and gas emission from cometary nuclei: the case of comet 67P/Churyumov-Gerasimenko

Comets display with decreasing solar distance an increased emission of gas and dust particles, leading to the formation of the coma and tail. Spacecraft missions provide insight in the temporal and spatial variations of the dust and gas sources located on the cometary nucleus. For the case of comet 67P/Churyumov-Gerasimenko (67P/C-G), the long-term observations from the Rosetta mission point to a homogeneous dust emission across the entire illuminated surface. Despite the homogeneous initial distribution, a collimation in jet-like structures becomes visible. We propose that this observation is linked directly to the complex shape of the nucleus and projects concave topographical features into the dust coma. To test this hypothesis, we put forward a gas-dust description of 67P/C-G, where gravitational and gas forces are accurately determined from the surface mesh and the rotation of the nucleus is fully incorporated. The emerging jet-like structures persist for a wide range of gas-dust interactions and show a dust velocity dependent bending.Comment: 17 pages, with 7 figures. To appear in Advances in Physics X (2018

Mapping quantum circuits to shallow-depth measurement patterns based on graph states

The paradigm of measurement-based quantum computing (MBQC) starts from a highly entangled resource state on which unitary operations are executed through adaptive measurements and corrections ensuring determinism. This is set in contrast to the more common quantum circuit model, in which unitary operations are directly implemented through quantum gates prior to final measurements. In this work, we incorporate concepts from MBQC into the circuit model to create a hybrid simulation technique, permitting us to split any quantum circuit into a classically efficiently simulatable Clifford-part and a second part consisting of a stabilizer state and local (adaptive) measurement instructions, a so-called standard form, which is executed on a quantum computer. We further process the stabilizer state with the graph state formalism, thus enabling a significant decrease in circuit depth for certain applications. We show that groups of fully commuting operators can be implemented using fully-parallel, i.e., non-adaptive, measurements within our protocol. In addition, we discuss how such circuits can be implemented in constant quantum depths by employing quantum teleportation. Finally, we demonstrate the utility of our technique on two examples of high practical relevance: the Quantum Approximate Optimization Algorithm (QAOA) and the Variational Quantum Eigensolver (VQE)

Dosiseskalationsstudie zur intraarteriellen Applikation von Gemcitabine bei Patienten mit inoperablen primären und sekundären Lebermalignomen

Die vorliegende Studie befasst sich mit der palliativen Chemotherapie von inoperablen hepatischen Metastasen des Pankreaskarzinoms sowie inoperablen Intrahepatischen Cholangiozellulären Karzinomen. Sie beschäftigt sich mit dem intraarteriellen Therapieansatz. Untersucht und verglichen wurden hier zwei verschiedene Applikationsarten (intraarteriell appliziertes Gemcitabine als Chemoperfusion gegenüber intraarteriell appliziertem Gemcitabine in Kombination mit Stärkemikrosphären als Chemoembolisation) im Bezug auf Erfassung der maximal tolerablen Dosis sowie die Evaluation der Ansprechraten, der Überlebenszeit und des Klinischen Benefits. Im Rahmen der Studie konnte gezeigt werden, dass höhere Dosen als die empfohlenen 1000mg/m2KO Gemcitabine bei guter Verträglichkeit möglich sind, und die Kombination der intraarteriellen Chemotherapieapplikation mit Gemcitabine und zusätzlicher Gabe von Embolisationspartikeln eine signifikant effektive Therapieerweiterung bezüglich einer Lebensverlängerung, nicht aber bezüglich der Ansprechraten, darstellt. Aktuell gilt dieses Verfahren nicht als Standard, sondern wird meist nur bei Versagen einer systemischen Chemotherapie angewendet. Sinnvoll erscheint die Entscheidung zu einer intraarteriellen Therapie jedoch nur, wenn eine isolierte hepatische Metastasierung bzw. ein primärer Lebertumor ohne Fernmetastasen vorliegt mit dem Ziel einer regionalen Tumorkontrolle und im Idealfall einer Tumorverkleinerung.This clinical study deals with the palliative chemotherapy of inoperable hepatic metastases of the pancreatic carcinoma and inoperable intrahepatic cholangiocarcinomas using an intraarterial approach regimen. Two groups with different application regimens (intraarterial applied Gemcitabine as a chemoperfusion regime versus intraarterial applied Gemcitabine along with starch microspheres as a chemoembolisation regime) were studied and analyzed for evaluation of the maximum tolerable dose of Gemcitabine along with response rates, survival times and clinical benefit. This study indicates that higher doses than the recommended 1000mg/m2 of Gemcitabine are well tolerated and that the intraarterial chemotherapy using a combination with embolisation particles as a chemoembolisation regimen yields significantly better results in survival rates but not in tumor response rates. In current therapy regimes the intraarterial approach is only used in patients with systemic chemotherapy failures. The intraarterial approach is only reasonable in patients with isolated hepatic tumors without other distant metastases with the intention of a local tumor control or to ideally decrease the size of the tumor