Dimensional Reduction applied to QCD at three loops

Dimensional Reduction is applied to \qcd{} in order to compute various renormalization constants in the \drbar{} scheme at higher orders in perturbation theory. In particular, the $\beta$ function and the anomalous dimension of the quark masses are derived to three-loop order. Special emphasis is put on the proper treatment of the so-called $\epsilon$-scalars and the additional couplings which have to be considered.Comment: 13 pages, minor changes, references adde

Phosphorus Efficient Phenotype of Rice

The ideal phenotype to cope with P deficiency is suggested to be a larger root system, both in terms of length and foraging area, coupled with a high capacity for P solubilization from compounds exuded from roots. Greater soil exploration results in a large number of roots in the top soil, longer roots in general with more cortical aerenchyma, more and longer root hairs, and a shift in mycorrhizal and bacterial colonization. However, these assumptions often result from experiments in highly controlled, sterile and soil-free conditions using model plants or single ecotypes where results are then extrapolated to all genotypes and plant species. In recent years this generalization has been questioned. Here, we summarize recent rice research analyzing the natural diversity of rice root systems under P deficiency. Interestingly, while some of the high yielding genotypes do show the expected, large root system phenotype, some have a surprisingly small root system—as little as a quarter of that of the large root system varieties—but achieve similar yield and P uptake under P deficiency. This effect has recently been termed root efficiency, which we discuss in this chapter in conjunction with root foraging traits

Four-loop beta function and mass anomalous dimension in Dimensional Reduction

Within the framework of QCD we compute renormalization constants for the strong coupling and the quark masses to four-loop order. We apply the DR-bar scheme and put special emphasis on the additional couplings which have to be taken into account. This concerns the epsilon-scalar--quark Yukawa coupling as well as the vertex containing four epsilon-scalars. For a supersymmetric Yang Mills theory, we find, in contrast to a previous claim, that the evanescent Yukawa coupling equals the strong coupling constant through three loops as required by supersymmetry.Comment: 15 pages, fixed typo in Eq. (18

Ambivalenz der Wissenschaft: Wissenschaftsforschung Jahrbuch 2017

Peer Reviewe

Hydra: Fast Isomorphic State Channels

State channels are an attractive layer-two solution for improving the throughput and latency of blockchains. They offer optimistic offchain settlement of payments and expedient offchain evolution of smart contracts between multiple parties without imposing any additional assumptions beyond those of the underlying blockchain. In the case of disputes, or if a party fails to respond, cryptographic evidence collected in the offchain channel is used to settle the last confirmed state onchain, such that in-progress contracts can be continued under mainchain consensus. A serious disadvantage present in current layer-two state channel protocols is that existing layer-one smart contract infrastructure and contract code cannot be reused offchain without change. In this paper, we introduce Hydra, an isomorphic multi-party state channel. Hydra simplifies offchain protocol and smart contract development by directly adopting the layer-one smart contract system, in this way allowing the same code to be used both on- and offchain. Taking advantage of the extended UTxO model, we develop a fast off-chain protocol for evolution of Hydra heads (our isomorphic state channels) that has smaller round complexity than all previous proposals and enables the state channel processing to advance on-demand, concurrently and asynchronously. We establish strong security properties for the protocol, and we present and evaluate extensive simulation results that demonstrate that Hydra approaches the physical limits of the network in terms of transaction confirmation time and throughput while keeping storage requirements at the lowest possible. Finally, our experimental methodology may be of independent interest in the general context of evaluating consensus protocols

Towards Higgs boson production in gluon fusion to NNLO in the MSSM

We consider the Higgs boson production in the gluon-fusion channel to next-to-next-to-leading order within the Minimal Supersymmetric Standard Model. In particular, we present analytical results for the matching coefficient of the effective theory and study its influence on the total production cross section in the limit where the masses of all MSSM particles coincide. For supersymmetric masses below 500 GeV it is possible to find parameters leading to a significant enhancement of the Standard Model cross section, the $K$-factors, however, change only marginally.Comment: 20 pages; v2: modification of discussion of numerical effect, version to appear in EPJC; v3: eq.(18) corrected, minor correction

Wissenschaftliche Zeitschrift und Digitale Bibliothek: Wissenschaftsforschung Jahrbuch 2002

Elektronische Produktion, Verbreitung und Rezeption von wissenschaftlichen Zeitschriften - deren integrative Wechselbeziehungen eingeschlossen - verändern unausweichlich die Forschungssituation unserer Zeit. Inzwischen sind elektronische Zeitschriften ein fester Bestandteil des wissenschaftlichen Publikationswesens geworden, auf den die meisten Forscher nicht mehr verzichten möchten. In diesem Wandel braucht es Orientierungen und Kompetenzen. Seit ihrem Aufkommen in der zweiten Hälfte des 17. Jahrhunderts haben wissenschaftliche Zeitschriften sich selbst als Forschungsbibliotheken der Wissenschaftsdisziplinen verstanden und dies mit der weiteren Differenzierung der Wissenschaft in einem Maße realisiert, dass ihre zunehmend elektronische Produktion die Entwicklung der Digitalen Bibliothek in der Wissenschaft nachhaltig forciert. Untersuchungen über diesen grundlegenden Vorgang neuerer Wissenschaftsentwicklung sind ein wichtiges Anliegen der Wissenschaftsforschung. Die Gesellschaft für Wissenschaftsforschung hat sich dieser Fragestellung angenommen und sie im Rahmen ihrer Jahrestagung 2002 unter dem Thema „Wissenschaftliche Zeitschrift und Digitale Bibliothek“ analysiert. Vorausgegangen waren Diskussionen über „Wissenschaft - Informationszeitalter - Digitale Bibliothek“ auf der Jahrestagung 1998 und über „Organisationsinformatik und Digitale Bibliothek in der Wissenschaft“ auf der Jahrestagung 2000, die in den jeweiligen Jahrbüchern Wissenschaftsforschung 1998 und 2000 publiziert wurden. Die Ergebnisse der Tagung vom März 2002, die im Institut für Bibliothekswissenschaft der Humboldt-Universität zu Berlin stattgefunden hat, werden hiermit - in Fortführung der Publikationsreihe - als Wissenschaftsforschung Jahrbuch 2002 dem interessierten Leser vorgestellt.Peer Reviewe

Three-loop anomalous dimensions for squarks in supersymmetric QCD

In this paper we evaluate the renormalization constants and anomalous dimensions for the squark wave function and mass within supersymmetric QCD. These results complement the ones obtained in Ref. \cite{Harlander:2009mn} and thus provide further confirmation on the applicability of dimensional reduction to supersymmetric QCD at three-loop order. The three-loop anomalous dimension constitute important input to precision predictions of the supersymmetric mass spectrum as obtained from the evolution from the GUT to the TeV energy scale.Comment: 17 pages, 1 figur