The electric dipole form factor of the nucleon

The electric dipole form factor of the nucleon stemming from the QCD $\bar{\theta}$ term is calculated in chiral perturbation theory in leading order. To this order, the form factor originates from the pion cloud. Its momentum-dependence is proportional to a non-derivative time-reversal-violating pion-nucleon coupling, and the scale for momentum variation--appearing, in particular, in the radius of the form factor--is the pion mass.Comment: 8 pages, 2 figure

Strong and Radiative Meson Decays in a Generalized Nambu--Jona-Lasinio Model

We investigate strong and radiative meson decays in a generalized Nambu--Jona-Lasinio model. The one loop order calculation provides a satisfactory agreement with the data for the mesonic spectrum and for radiative decays. Higher order effects for strong decays of $\rho$ and $K^*$ are estimated to be large. We also discuss the role of the flavour mixing determinantal interaction.Comment: 7 pages, LaTeX, 2 figs available upon request, CRN 92-4

Scalar mesons in a finite volume

Using effective field theory methods, we discuss the extraction of the mass and width of the scalar mesons f0(980) and a0(980) from the finite-volume spectrum in lattice QCD. In particular, it is argued that the nature of these states can be studied by invoking twisted boundary conditions, as well as investigating the quark mass dependence of the spectrum.Comment: 18 pages, 3 figure

New insights into the spin structure of the nucleon

We analyze the low-energy spin structure of the nucleon in a covariant effective field theory with explicit spin-3/2 degrees of freedom to third order in the small scale expansion. Using the available data on the strong and electromagnetic width of the Delta-resonance, we give parameter-free predictions for various spin-polarizabilities and moments of spin structure functions. We find an improved description of the nucleon spin structure at finite photon virtualities for some observables and point out the necessity of a fourth order calculation.Comment: 13 pages, 6 figure

Improved analysis of neutral pion electroproduction off deuterium in chiral perturbation theory

Near threshold neutral pion electroproduction on the deuteron is studied in the framework of heavy baryon chiral perturbation theory. We include the next-to-leading order corrections to the three-body contributions. We find an improved description of the total and differential cross section data measured at MAMI. We also obtain more precise values for the threshold S-wave multipoles. We discuss in detail the theoretical uncertainties of the calculation.Comment: 14 pp, 11 figs, uses svjour.cl

2+1 flavor simulations of QCD with improved staggered quarks

The MILC collaboration has been performing realistic simulations of full QCD with 2+1 flavors of improved staggered quarks. Our simulations allow for controlled continuum and chiral extrapolations. I present results for the light pseudoscalar sector: masses and decay constants, quark masses and Gasser-Leutwyler low-energy constants. In addition I will present some results for heavy-light mesons, decay constants and semileptonic form factors, obtained in collaboration with the HPQCD and Fermilab lattice collaborations. Such calculations will help in the extraction of CKM matrix elements from experimental measurements.Comment: To appear in the proceedings of QNP06, IVth International Conference on Quarks and Nuclear Physics, Madrid, June 200

Aspects of Nucleon Compton Scattering

We consider the spin-averaged nucleon forward Compton scattering amplitude in heavy baryon chiral perturbation theory including all terms to order ${\cal O} (q^4)$. The chiral prediction for the spin-averaged forward Compton scattering amplitude is in good agreement with the data for photon energies $\omega \le 110$ MeV. We also evaluate the nucleon electric and magnetic Compton polarizabilities to this order and discuss the uncertainties of the various counter terms entering the chiral expansion of these quantities.Comment: 17 pp, TeX, 7 figures available from the authors, preprint CRN-93/5

Ausgestaltung von Management by Objectives innerhalb von Leistungslohnsystemen: Unterschiede in der Motivation zwischen Mitarbeitenden und Managern

Management by Objectives (MbO) wird definiert als Synthese von Zielsetzung, Partizipation bei Zielvereinbarungen und Feedback über die Zielerreichung. Dieser Beitrag untersucht, wie sich die Ausgestaltung von MbO innerhalb von Leistungsvergütungssystemen auf die Motivation von Mitarbeitenden und Vorgesetzten auswirkt. Als Datenbasis dient eine Stichprobe von 342 Unternehmen in der Schweiz. Die Untersuchungsergebnisse zeigen, dass 96% der betrachteten Leistungslohngruppen Management by Objectives anwenden. Bei 83% ist die Leistungsvergütung direkt mit dem MbO-System verknüpft. Eine detaillierte Betrachtung zeigt, dass die Ausgestaltung der einzelnen Elemente von MbO – Zielsetzung, Partizipation und Feedback – je nach Hierarchiestufe verschiedene Bedeutungen haben. Während für die Mitarbeitenden ohne Führungsfunktion in erster Linie die Kommunikation über die Zielerreichung einen positiven Einfluss auf die Motivation hat, ist für das Management die Qualität der Zielsetzungen zentral

The Nucleon Anapole Form Factor in Chiral Perturbation Theory to Sub-leading Order

The anapole form factor of the nucleon is calculated in chiral perturbation theory to sub-leading order. This is the lowest order in which the isovector anapole form factor does not vanish. The anapole moment depends on counterterms that reflect short-range dynamics, but the momentum dependence or the form factor is determined by pion loops in terms of parameters that could in principle be fixed from other processes. If these parameters are assumed to have natural size, the sub-leading corrections do not exceed ~ 30% at momentum Q ~ 300 MeV.Comment: 11 pages, 6 figures, epsf.sty, submitted to Phys. Lett