21 research outputs found
The anomalous chiral perturbation theory meson Lagrangian to order revisited
We present a revised and extended construction of the mesonic Lagrangian
density in chiral perturbation theory (ChPT) at order in the anomalous
(or epsilon) sector, . After improving several aspects
of the strategy we used originally, i.e., a more efficient application of
partial integration, the implementation of so-called Bianchi identities, and
additional trace relations, we find the new monomial sets to include 24
, 23 SU(3), and 5 SU(2) elements. Furthermore, we introduce 8
supplementary terms due to the extension of the chiral group to .Comment: 21 pages, Latex, using RevTe
The BIM2LCA approach: An industry foundation classes (IFC)-based interface to integrate life cycle assessment in integral planning
An increasing degree of digitalization in construction planning offers significant potential for building life cycle assessment (LCA) to reduce access barriers, as well as the assessment effort itself. To realize the widespread application of LCA tools and their potential to effectively minimize life cycle impacts, an open approach is required that allows for flexible application of comprehensive LCA studies and early integration in planning processes. The authors present an approach for LCA integration in all phases of digital planning which aims at a DGNB (Deutsche Gesellschaft für nachhaltiges Bauen) certification based on the open Building Information Modeling (BIM) standard Industry Foundation Classes (IFC). The approach takes into account varying levels of development and resulting data availability during integral planning phases, as well as resulting LCA application contexts. It goes beyond existing strategies and allows one to consider both BIM and LCA software through a workflow based on a single data format. The assessment framework is operationalized through standardized interface development and technical realization following the information delivery manual (IDM) process standardized for IFC interfaces. The Extensible Markup Language (XML) schema, as a specific implementation for certification, provides the target system for LCA data requirements and is generalized to a planning phase specific IDM base table. The technical realization based on respective model view definitions and distributed data suggests a pathway to the standardization of LCA-IFC integration based on an open approach. The overall approach exemplarily applies to the “LERNZENTRUM” at the Karlsruhe Institute of Technology (KIT) campus. We conclude that an open BIM approach for LCA integration in model-based planning is feasible, but requires several adjustments in IFC, LCA, and planning practice. Adding a lifecycle element to the IFC to connect BIM and LCA provides comprehensive feedback for informed decision making based on environmental impact
A new determination of the anomalous amplitude via data
We discuss the reaction with the purpose of
obtaining information on the anomalous amplitude . We compare a full calculation at in chiral
perturbation theory and various phenomenological predictions with the existing
data of Amendolia {\em et al}. By integrating our theory results using Monte
Carlo techniques we obtain nb at and nb after including the dominant electromagnetic correction. Both results
are in good agreement with the experimental cross section of nb. On the basis of the ChPT results one would extract from the the
experimental cross section as amplitudes GeV and
GeV, respectively, which have to be compared with the low-energy theorem
. We emphasize the need for
new data to allow for a comparison of experimental and theoretical
distributions and to obtain with smaller uncertainty.Comment: 23 pages, 14 figures, discussion of the ChPT calculation extende
Renormalization of relativistic baryon chiral perturbation theory and power counting
We discuss a renormalization scheme for relativistic baryon chiral
perturbation theory which provides a simple and consistent power counting for
renormalized diagrams. The method involves finite subtractions of dimensionally
regularized diagrams beyond the standard scheme of chiral
perturbation theory to remove contributions violating the power counting. This
is achieved by a suitable renormalization of the parameters of the most general
effective Lagrangian. In addition to simplicity our method has the benefit that
it can be easily applied to multiloop diagrams. As an application we discuss
the mass and the scalar form factor of the nucleon and compare the results with
the expressions of the infrared regularization of Becher and Leutwyler.Comment: 20 pages, RevTex, 1 figure, published version is shortene
Coherent \pi^0 threshold production from the deuteron at Q^2 = 0.1 GeV^2/c^2
First data on coherent threshold \pi^0 electroproduction from the deuteron
taken by the A1 Collaboration at the Mainz Microtron MAMI are presented. At a
four-momentum transfer of q^2=-0.1 GeV^2/c^2 the full solid angle was covered
up to a center-of-mass energy of 4 MeV above threshold. By means of a
Rosenbluth separation the longitudinal threshold s wave multipole and an upper
limit for the transverse threshold s wave multipole could be extracted and
compared to predictions of Heavy Baryon Chiral Perturbation Theory.Comment: 7 pages, 7 figures, latex2
Electromagnetic transitions in an effective chiral Lagrangian with the eta-prime and light vector mesons
We consider the chiral Lagrangian with a nonet of Goldstone bosons and a
nonet of light vector mesons. The mixing between the pseudoscalar mesons eta
and eta-prime is taken into account. A novel counting scheme is suggested that
is based on hadrogenesis, which conjectures a mass gap in the meson spectrum of
QCD in the limit of a large number of colors. Such a mass gap would justify to
consider the vector mesons and the eta-prime meson as light degrees of freedom.
The complete leading order Lagrangian is constructed and discussed. As a first
application it is tested against electromagnetic transitions of light vector
mesons to pseudoscalar mesons. Our parameters are determined by the
experimental data on photon decays of the omega, phi and eta-prime meson. In
terms of such parameters we predict the corresponding decays into virtual
photons with either dielectrons or dimuons in the final state.Comment: 17 pages, extended discussion on mixin
Unterstützung kommunalplanerischer Prozesse mit CityGLM-basierter Anbindung Modelica-getriebener Quartierssimulationen
Eine integrale Planung städtischer (Energie-)Systeme bedarf einer planungsbegleitenden Unterstützung durch IT-basierte Planungs- und Simulationswerkzeuge. Die durchgängige Anwendung dieser digitalen Planungshilfsmittel wird allerdings bislang insbesondere durch den sehr hohen Aufwand bei der Spezifizierung und Erfassung benötigter Datengrundlagen sowie eine mangelhafte Interoperabilität zwischen den Systemen gehemmt. Im Rahmen eines Forschungsverbundprojektes wird dieses Problemfeld mittels praxisbezogener Prozessanalysen genauer spezifiziert und die technische und fachliche Integration durch die prozessbezogene Spezifikation relevanter Informationsbedarfe sowie die Entwicklung einer darauf aufbauenden, bidirektionalen Schnittstelle auf Basis des etablierten virtuellen Stadtmodellstandards CityGML verbessert. Als exemplarisches Anwendungsszenario innerhalb kommunaler Planungsprozesse wurde die Ausweisung von Vorranggebieten der Fernwärmenutzung basierend auf einer räumlichen Analyse des Wärmebedarfs für verschiedene Entwicklungsszenarien mittels einer bidirektionalen standard-basierten Koppelung von CityGML und Modelica ausgearbeitet
Chiral perturbation theory - Success and challenge
Chiral perturbation theory is the effective field theory of the strong
interactions at low energies. We will give a short introduction to chiral
perturbation theory for mesons and will discuss, as an example, the
electromagnetic polarizabilities of the pion. These have recently been
extracted from an experiment on radiative photoproduction from the
proton () at the Mainz Microtron MAMI. Next we will
turn to the one-baryon sector of chiral perturbation theory and will address
the issue of a consistent power counting scheme. As examples of the
heavy-baryon framework we will comment on the extraction of the axial radius
from pion electroproduction and will discuss the generalized polarizabilities
of the proton. Finally, we will discuss two recently proposed manifestly
Lorentz-invariant renormalization schemes and illustrate their application in a
calculation of the nucleon electromagnetic form factors.Comment: 12 pages, 13 figures, invited talk given at the Symposium 20 Years of
Physics at the Mainz Microtron MAMI, 20 - 22 October 2005, Mainz, German
Chiral effective field theories of the strong interactions
Effective field theories of the strong interactions based on the approximate
chiral symmetry of QCD provide a model-independent approach to low-energy
hadron physics. We give a brief introduction to mesonic and baryonic chiral
perturbation theory and discuss a number of applications. We also consider the
effective field theory including vector and axial-vector mesons.Comment: 22 pages, 9 figures, proceedings of "Many-Body Structure of Strongly
Interacting Systems", Mainz, Germany, Feb. 23-25 201
ifcModelCheck
On behalf of the BBR (German Federal Office for Building and Regional Planning) the development of an Industry Foundation Classes (IFC) based inspection tool was accomplished as application on an underlying work-in-progress development framework. By providing a machine-based checking process the tool ModelCheck was rolled out to meet demands emerged during pilot projecting. Thus it is capable of processing automated compliance checks on quality criteria for the authorities, e.g. documentation guidelines of BBR regarding building and real estate documentation or building information modeling (BIM) quality criteria formed for the Humboldt-Forum project – a BIM pilot-project managed by BBR. ModelCheck supports checks on IFC models - formal against schemes and logical inspection with regards to alpha-numeric content by using xml-based configurable rules