Experiments with polarized 3He at MAMI

Experiments with polarized 3He at MAMI have already a long tradition. The A3 collaboration started in 1993 with the aim to measure the electric form factor of the neutron. At this time MAMI was the second accelerator where experiments with 3He were possible. Some years before this pilot experiment the development of the apparatus to polarize 3He in Mainz started. There are two techniques which allow to polarize sufficient large quantities of 3He. Both techniques will be compared and the benefit of 3He for nuclear physics will be discussed. An review of the experiments done so far with 3He at MAMI will be given and the progress in the target development, the detector setup and the electron beam performance will be pointed out.Comment: Contribution to the Symposium "20 Years of Physics at the Mainz Microtron MAMI", to be published in Eur. Phys. Journal

SU(3) Predictions for Weak Decays of Doubly Heavy Baryons -- including SU(3) breaking terms

We find expressions for the weak decay amplitudes of baryons containing two b quarks (or one b and one c quark -- many relationship are the same) in terms of unknown reduced matrix elements. This project was originally motivated by the request of the FNAL Run II b Physics Workshop organizers for a guide to experimentalists in their search for as yet unobserved hadrons. We include an analysis of linear SU(3) breaking terms in addition to relationships generated by unbroken SU(3) symmetry, and relate these to expressions in terms of the complete set of possible reduced matrix elements.Comment: 49 page

Financial Contracting

This paper discusses how economists' views of firms' financial structure decisions have evolved from treating firms' profitability as given; to acknowledging that managerial actions affect profitability; to recognizing that firm value depends on the allocation of decision or control rights. The paper argues that the decision or control rights approach is useful, even though it is at an early stage of development, and that the approach has some empirical content: it can throw light on the structure of venture capital contracts and the reasons for the diversity of claims.

Institutional Determinants of Labor Reallocation in Transition

Studying the transition means analyzing the interactions between institutions and structural change, a process we still know very little about. In this paper we show that the transition process has been very different in the countries of the Former Soviet Union (FSU) and those of Central and Eastern Europe (CEE) in terms of reallocation of labor from the old to the new sector, the extent of real wage decline and responsiveness of employment to output changes. We sift through the theoretical and empirical literature to find an explanation for these diverging adjustment trajectories and conclude that the difference can be explained in part by different policy models. The CEE countries adopted social policies that upheld wages at the bottom of the distribution and hence forced the unproductive old sector to restructure or collapse. The FSU countries allowed wages to free fall and hence did not force the hand of the old sector. Why these two models were adopted is the subject for political-economy research, however we speculate that it has to do with the relative appeal of joining the EU.http://deepblue.lib.umich.edu/bitstream/2027.42/39768/3/wp384.pd

Magnetofluid dynamics of magnetized cosmic plasma: firehose and gyrothermal instabilities

Both global dynamics and turbulence in magnetized weakly collisional cosmic plasmas are described by general magnetofluid equations that contain pressure anisotropies and heat fluxes that must be calculated from microscopic plasma kinetic theory. It is shown that even without a detailed calculation of the pressure anisotropy or the heat fluxes, one finds the macroscale dynamics to be generically unstable to microscale Alfvenically polarized fluctuations. Two instabilities are considered in detail: the parallel firehose instability (including the finite-Larmor-radius effects that determine the fastest growing mode) and the gyrothermal instability (GTI). The latter is a new result - it is shown that a parallel ion heat flux destabilizes Alfvenically polarized fluctuations even in the absence of the negative pressure anisotropy required for the firehose. The main conclusion is that both pressure anisotropies and heat fluxes trigger plasma microinstabilities and, therefore, their values will likely be set by the nonlinear evolution of these instabilities. Ideas for understanding this nonlinear evolution are discussed. It is argued that cosmic plasmas will generically be "three-scale systems," comprising global dynamics, mesoscale turbulence and microscale plasma fluctuations. The astrophysical example of cool cores of galaxy clusters is considered and it is noted that observations point to turbulence in clusters being in a marginal state with respect to plasma microinstabilities and so it is the plasma microphysics that is likely to set the heating and conduction properties of the intracluster medium. In particular, a lower bound on the scale of temperature fluctuations implied by the GTI is derived.Comment: 10 pages, MNRAS tex style, 1 figur