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A nonlinear chiral SU(3) approach including the spin 3 2 decuplet is developed to describe dense matter. The coupling constants of the baryon resonances to the scalar mesons are determined from the decuplet vacuum masses and SU(3) symmetry relations. Di erent methods of mass generation show significant differences in the properties of the spin- 3 2 particles and in the nuclear equation of state
Compelling evidence for a new form of matter has been claimed to be formed in Pb+Pb collisions at SPS. We critically review two suggested signatures for this new state of matter: First the suppression of the J/psi , which should be strongly suppressed in the QGP by two different mechanisms, the color-screening [1] and the QCD-photoe ect [2]. Secondly the measured particle, in particular strange hadronic, ratios might signal the freeze-out from a quark-gluon phase.
Animal experiments report contradictory findings on the presence of a behavioural and neuronal anisotropy exhibited in vertical and horizontal capabilities of spatial orientation and navigation. We performed a pointing experiment in humans on the imagined 3-D direction of the location of various invisible goals that were distributed horizontally and vertically in a familiar multilevel hospital building. The 21 participants were employees who had worked for years in this building. The hypothesis was that comparison of the experimentally determined directions and the true directions would reveal systematic inaccuracy or dimensional anisotropy of the localizations. The study provides first evidence that the internal representation of a familiar multilevel building was distorted compared to the dimensions of the true building: vertically 215% taller and horizontally 51% shorter. This was not only demonstrated in the mathematical reconstruction of the mental model based on the analysis of the pointing experiments but also by the participants’ drawings of the front view and the ground plan of the building. Thus, in the mental model both planes were altered in different directions: compressed for the horizontal floor plane and stretched for the vertical column plane. This could be related to human anisotropic behavioural performance of horizontal and vertical navigation in such buildings.
What is the magnetic field distribution for the equation of state of magnetized neutron stars?
(2017)
In this Letter, we report a realistic calculation of the magnetic field profile for the equation of state inside strongly magnetized neutron stars. Unlike previous estimates, which are widely used in the literature, we find that magnetic fields increase relatively slowly with increasing baryon chemical potential (or baryon density) of magnetized matter. More precisely, the increase is polynomial instead of exponential, as previously assumed. Through the analysis of several different realistic models for the microscopic description of stellar matter (including hadronic, hybrid and quark models) combined with general relativistic solutions endowed with a poloidal magnetic field obtained by solving Einstein–Maxwell's field equations in a self-consistent way, we generate a phenomenological fit for the magnetic field distribution in the stellar polar direction to be used as input in microscopic calculations.
The effect of a non-zero strangeness chemical potential on the strong interaction phase diagram has been studied within the framework of the SU(3) quark-hadron chiral parity-doublet model. Both, the nuclear liquid-gas and the chiral/deconfinement phase transitions are modified. The first-order line in the chiral phase transition is observed to vanish completely, with the entire phase boundary becoming a crossover. These changes in the nature of the phase transitions are expected to modify various susceptibilities, the effects of which might be detectable in particle-number distributions resulting from moderate-temperature and high-density heavy-ion collision experiments.
Die Nutzung der natürlichen Ressourcen ist zur Sicherung gesellschaftlichen Aktivitäten unverzichtbar, gleichwohl stehen ihrer nachhaltigen Bewirtschaftung immer neue Veränderungsprozesse und damit einhergehende Herausforderungen gegenüber. In Anbetracht von wirtschaftlichen Konzentrationsprozessen, sozio-strukturellen und demographischen Entwicklungen, technischen Innovationen, globalem Wandel und neuen Erkenntnissen zu Risiken stoßen etablierte klassische Verfahren des Planungsdenkens zunehmend an ihre Grenzen. Vor diesem Hintergrund wurden neue und innovative Ansätze zur Ressourcensicherung entwickelt, die vereinzelt auch bereits in der Praxis realisiert wurden. Sie greifen die Herausforderung gegenwärtiger Veränderungsprozesse konzeptionell auf und überführen sie in angepasste Strukturen und Verfahren. Die vorliegende Arbeit beschreibt diesen Übergang zu einem neuen, angepassten Planungsdenken. In seinem Mittelpunkt steht der Begriff der „sozial-ökologischen Ressourcenregulation“. Am Beispiel der Bewirtschaftung der Wasserressourcen werden aktuelle Entwicklungen vorgestellt und exemplarisch anhand von zwei Fallbeispielen vertieft: dem Fuhrberger Feld und dem Hessische Ried unter den spezifischen Gesichtspunkten von Wassergüte und Wassermenge. Die Entwicklungen in beiden Regionen werden zunächst anhand der Anforderungen an eine sozial-ökologische Regulation bewertet. In einem weiteren Schritt werden verallgemeinerte Schlussfolgerungen für eine verbesserte Ressourcenbewirtschaftung und deren Regulation sowohl hinsichtlich der Wassergüte als auch der Wassermenge gezogen. Es zeigt sich hierbei die große Bedeutung der Entstehung adaptiver Strukturen durch Rückkopplungen und den Einbezug der relevanten gesellschaftlichen Akteure; so ist langfristig auch eine Koexistenz von tendenziell konfligierenden Ressourcennutzungen und deren nachhaltige Entwicklung möglich.
This assessment concept paper provides a methodological approach for the formative assessment and summative assessment of GIZ’s International Water Stewardship Programme (IWaSP) and its component partnerships. IWaSP promotes partnerships between the private sector (corporations and SMEs), the public sector and the society to tackle shared water risks and to manage water equitably to meet competing demands. This evaluative assessment concept describes the generic approach of the assessment, the cycle for the assessment of partnerships, the country coordination and the programme.
The overall goal of the assessment is to provide evidence for taxpayers in the donor countries and for citizens in the partnership countries. It also aims to examine the relevance of the programme’s approach, its underlying assumptions, and the heterogeneity of stakeholders and their specific interests. Since the assessment is also formative feedback to GIZ and IWaSP stakeholders, it aims to guide the future implementation of the partnerships and the programme.
The assessment is guided by several generic principles: assessing for learning (formative assessment); assessment of learning (summative assessment); iteration; structuring complex problems; unblocking results; and conformity with other assessment criteria set out by the OECD the Development Assistance Committee (DAC) and GIZ’s Capacity Works success factors (GTZ 2010).
These generic criteria are adapted to the three levels of the IWaSP structure. First, the assessment cycle for partnerships includes the validation of stakeholders (mapping), the analysis of secondary literature, face-to-face interviews and a process for feeding back the findings. Generic tools are provided to guide the assessment, such as a list of key documents and an interview guide. Partnerships will undergo a baseline, interim assessment and final assessment. As progress varies across individual IWaSP partnerships, the steps taken by each partnership to assess shared water risks, prioritise and agree interventions, are expected to differ slightly. In response to these differences the sequencing and content of the assessment may need to be adapted for the different partnerships.
Second, the country-level assessment considers issues such as the coordination of partnerships within a country, scoping strategies, and interaction between partnership and the programme. Information gathered during the partnership assessment feeds into the country-level assessment.
Third, the assessment cycle for the programme involves a document and monitoring plan analysis, reflection on the different perspectives of the programme staff, country staff and external stakeholders.
The final section is concerned with reporting. Several annexes are provided relating to the organisation and preparation of the assessment, including question guidelines and analysis procedures.
We study the phase diagram of a generalized chiral SU(3)-flavor model in mean-field approxi- mation. In particular, the influence of the baryon resonances, and their couplings to the scalar and vector fields, on the characteristics of the chiral phase transition as a function of temperature and baryon-chemical potential is investigated. Present and future finite-density lattice calculations might constrain the couplings of the fields to the baryons. The results are compared to recent lattice QCD calculations and it is shown that it is non-trivial to obtain, simultaneously, stable cold nuclear matter.
Abstract: The measured particle ratios in central heavy-ion collisions at RHIC-BNL are investigated within a chemical and thermal equilibrium chiral SU(3) Ã É approach. The commonly adopted non-interacting gas calculations yield temperatures close to or above the critical temperature for the chiral phase transition, but without taking into account any interactions. In contrast, the chiral SU(3) model predicts temperature and density dependent effective hadron masses and effective chemical potentials in the medium and a transition to a chirally restored phase at high temperatures or chemical potentials. Three different parametrizations of the model, which show different types of phase transition behaviour, are investigated. We show that if a chiral phase transition occured in those collisions, freezing of the relative hadron abundances in the symmetric phase is excluded by the data. Therefore, either very rapid chemical equilibration must occur in the broken phase, or the measured hadron ratios are the outcome of the dynamical symmetry breaking. Furthermore, the extracted chemical freeze-out parameters differ considerably from those obtained in simple non-interacting gas calculations. In particular, the three models yield up to 35 MeV lower temperatures than the free gas approximation. The inmedium masses turn out to differ up to 150 MeV from their vacuum values.
The measured particle ratios in central heavy-ion collisions at RHIC-BNL are investigated within a chemical and thermal equilibrium chiral SU(3) σ–ω approach. The commonly adopted noninteracting gas calculations yield temperatures close to or above the critical temperature for the chiral phase transition, but without taking into account any interactions. Contrary, the chiral SU(3) model predicts temperature and density dependent effective hadron masses and effective chemical potentials in the medium and a transition to a chirally restored phase at high temperatures or chemical potentials. Three different parametrizations of the model, which show different types of phase transition behaviour, are investigated. We show that if a chiral phase transition occured in those collisions, “freezing” of the relative hadron abundances in the symmetric phase is excluded by the data. Therefore, either very rapid chemical equilibration must occur in the broken phase, or the measured hadron ratios are the outcome of the dynamical symmetry breaking. Furthermore, the extracted chemical freeze-out parameters differ considerably from those obtained in simple noninteracting gas calculations. In particular, the three models yield up to 35 MeV lower temperatures than the free gas approximation. The in-medium masses turn out to differ up to 150 MeV from their vacuum values.