Combining states without scale hierarchies with ordered parton showers

We present a parameter-free scheme to combine fixed-order multi-jet results with parton-shower evolution. The scheme produces jet cross sections with leading-order accuracy in the complete phase space of multiple emissions, resumming large logarithms when appropriate, while not arbitrarily enforcing ordering on momentum configurations beyond the reach of the parton-shower evolution equation. This requires the development of a matrix-element correction scheme for complex phase-spaces including ordering conditions as well as a systematic scale-setting procedure for unordered phase-space points. The resulting algorithm does not require a merging-scale parameter. We implement the new method in the Vincia framework and compare to LHC data.Comment: updated to version published in EPJ

Revisiting Radiation Patterns in e+e−e^+e^- Collisions

We propose four simple event-shape variables for semi-inclusive $e^+e^- \to 4$-jet events. The observables and cuts are designed to be especially sensitive to subleading aspects of the event structure, and allow to test the reliability of phenomenological QCD models in greater detail. Three of them, $\theta_{14}$, $\theta^*$, and $C_2^{(1/5)}$, focus on soft emissions off three-jet topologies with a small opening angle, for which coherence effects beyond the leading QCD dipole pattern are expected to be enhanced. A complementary variable, $M_L^2/M_H^2$, measures the ratio of the hemisphere masses in 4-jet events with a compressed scale hierarchy (Durham $y_{23}\sim y_{34}$), for which subleading $1\to 3$ splitting effects are expected to be enhanced. We consider several different parton-shower models, spanning both conventional and dipole/antenna ones, all tuned to the same $e^+e^-$ reference data, and show that a measurement of the proposed observables would allow for additional significant discriminating power between the models.Comment: 27 pages, 10 figure

Vincia for Hadron Colliders

We present the first public implementation of antenna-based QCD initial- and final-state showers. The shower kernels are $2\to 3$ antenna functions, which capture not only the collinear dynamics but also the leading soft (coherent) singularities of QCD matrix elements. We define the evolution measure to be inversely proportional to the leading poles, hence gluon emissions are evolved in a $p_\perp$ measure inversely proportional to the eikonal, while processes that only contain a single pole (e.g., $g\to q\bar{q}$) are evolved in virtuality. Non-ordered emissions are allowed, suppressed by an additional power of $1/Q^2$. Recoils and kinematics are governed by exact on-shell $2\to 3$ phase-space factorisations. This first implementation is limited to massless QCD partons and colourless resonances. Tree-level matrix-element corrections are included for QCD up to $\mathcal{O}(\alpha_s^4)$ (4 jets), and for Drell-Yan and Higgs production up to $\mathcal{O}(\alpha_s^3)$ ($V/H$ + 3 jets). The resulting algorithm has been made publicly available in Vincia 2.0

Enterprise risk management in financial groups: analysis of risk concentration and default risk

In financial groups, enterprise risk management is becoming increasingly important in controlling and managing the different independent legal entities in the group. The aim of this paper is to assess and relate risk concentration and joint default probabilities of the group's legal entities in order to achieve a more comprehensive picture of a financial group's risk situation. We further examine the impact of the type of dependence structure on results by comparing linear and nonlinear dependencies using different copula concepts under certain distributional assumptions. Our results show that even if financial groups with different dependence structures do have the same risk concentration factor, joint default probabilities of different sets of subsidiaries can vary tremendousl

Introducing Real Time Communication: Frames, Modes & Rules

The paper reports on the implementation of Lotus® Sametime® in a large financial services company. The paper uses the distinction of application and infrastructure view to elaborate on distinct modes of RTC use. Moreover, it provides a classification of managerial tasks and responsibilities and reflects on the balancing act of the managerial dictum and space for experimentation and organizational learning. The case highlights organizational design choices as well as managerial challenges. It provides rich insights into the processes of organizational embedding and rule setting, complemented by individual appropriation and self-organization on a group level. Processes of managerial and organizational alignment unfold against the backdrop of the dynamics of implementation

“Don’t pressure me!” Exploring the Anatomy of Voluntariness in the Organizational Adoption of Network Technologies

The design and management of the roll-out of new IT in an organization comprises several managerial decisions, one of which is whether IT adoption should be mandatory. Voluntariness to adopt has mainly been researched as a variable in explaining individual IT acceptance, however with contradicting results. By drawing on a case study of a financial service company, we aim to expand our understanding of the notion of voluntariness. We distinguish between management’s claim that adoption is voluntary (espoused voluntariness) and the perception of this claim at the employee (perceived voluntariness) and team level. Moreover we elaborate on the changing role of voluntariness in the different stages of the roll-out process of a particular network technology. This allows us to observe a dilemma presented in the case: While voluntariness initial seems to be prerequisite for implementation and technology roll-out, it may act as an inhibitor to full diffusion in later stages

Writing, Calculating and Peer Feedback in a Mathematically-oriented Course for Process Engineers: Raising Motivation and Initiating Processes of Thinking and Learning

Writing assignments can be seen as an important component of learning processes. Especially in the fields of engineering and sciences, writing assignments have the potential to consolidate subject-specific skills and to enhance motivation for solving technical problems. This paper introduces readers to a revised course structure that aims to strengthen motivation and mathematical understanding through written peer feedback based on mathematical exercises with written elements. The assignment was developed for the course Computational Fluid Dynamics in Process Engineering, a mathematically-oriented course for Master students of theoretical mechanical engineering and process engineering. Since the learning content was perceived as complex, students seemed to lack motivation in preparing for the course with the provided exercises. This paper suggests – based on the collected data, consisting of answers to mathematical problems, feedback texts, evaluation results, teachers’ observation, and examination results – that the introduced assignment enhances students’ understanding and has a positive impact on students’ motivation to solve the mathematical exercises

The Global Polarity of Alcoholic Solvents and Water – Importance of the Collectively Acting Factors Density, Refractive Index and Hydrogen Bonding Forces

The DHBD quantity represents the hydroxyl group density of alcoholic solvents or water. DHBD is purely physically defined by the product of molar concentration of the solvent (N) and the factor Σn=n×f which reflects the number n and position (f-factor) of the alcoholic OH groups per molecule. Whether the hydroxyl group is either primary, secondary or tertiary is taken into account by f. Σn is clearly linearly correlated with the physical density or the refractive index of the alcohol derivative. Relationships of solvent-dependent UV/Vis absorption energies as ET(30) values, 129Xe NMR shifts and kinetic data of 2-chloro-2-methylpropane solvolysis with DHBD are demonstrated. It can be shown that the ET(30) solvent parameter reflects the global polarity of the hydrogen bond network rather than specific H-bond acidity. Significant correlations of the log k1 rate constants of the solvolysis reaction of 2-chloro-2-methylpropane with DHBD show the physical reasoning of the approach