Spin effects in hard exclusive electroproduction of mesons

In this talk various spin effects in hard exclusive electroproduction of mesons are briefly reviewed. The data are discussed in the light of recent theoretical calculations within the frame work of the handbag approach.Comment: 11 pages, 12 figures, using Latex, talk presented at the conference in honor of Prof. A. Efremov's 75th birthday held at Trento, July, 200

Mixing and Decay Constants of Pseudoscalar Mesons: The Sequel

We present further tests and applications of the new eta-eta' mixing scheme recently proposed by us. The particle states are decomposed into orthonormal basis vectors in a light-cone Fock representation. Because of flavor symmetry breaking the mixing of the decay constants can be identical to the mixing of particle states at most for a specific choice of this basis. Theoretical and phenomenological considerations show that the quark flavor basis has this property and allows, therefore, for a reduction of the number of mixing parameters. A detailed comparison with other mixing schemes is also presented.Comment: 9 page

The St. Petersburg Paradox despite risk-seeking preferences: An experimental study

The St. Petersburg is one of the oldest violations of expected utility theory. Thus far, explanations of the paradox aim at small probabili- ties being perceived as zero and the boundedness of utility. This paper provides experimental results showing that neither risk attitudes nor perception of small probabilities explain the paradox. We nd that even in situations where subjects are risk-seeking, the St. Petersburg Paradox exists. This indicates that the paradox lies at the very core of human decision-making processes and cannot be explained by the parameters discussed in previous research so far.

Loss Aversion for time: An experimental investigation of time preferences

This paper investigates decisions about inter-temporal tradeoffs. The objective of the study is to explore the valuation of time itself without tradeoffs between time and consequences. In an experimental study subjects made decisions about waiting time, where the time was subject to risk. We find that subjects are risk-seeking for decisions about time, which leads to the conclusion that waiting time is experienced as a loss. Subjects in this experiment show similar choice patters as can be seen in studies about money when losses are involved.

Attraction to Chance in Germany and Australia. An experimental study of cultural differences

This paper explores cultural differences in risky choices between Australian and German students. The focus is not on risk itself, but on tension which is a positive attribute of risky choices. Furthermore, the effects of real versus hypothetical payoffs are analysed. The experiment of this paper shows that in a given set of tension creating choices, Australians do choose tension more often than Germans, while Germans prefer higher tension. Additionally it is shown that real payoffs do make a difference in the data, but the real payoff even increases the effect.

The Relevance of Irrelevant Alternatives: An experimental investigation of risky choices

Experimental economists have discovered various violations of expected utility theory and offered alternative models that can explain laboratory results. This study discovers a new violation in risky choices that cannot be explained by theories like Prospect Theory, Disappoint- ment or Regret Theory. In an experimental setting using a between- subject design, the influence of a dominated alternative on certainty equivalents is shown. One group of subjects was offered a series of choices between a lottery ticket with a 50-50 chance of winning and a sure payoff. A second group was offered the same choice plus a third alternative, that as it turned out was not chosen by any participant. As a result, the average chosen sure payoff in the second group was higher than in the first group. That means, by adding a dominated alternative to a choice set, the certainty equivalent of a lottery is in- creased.

Ising magnets with mobile defects

Motivated by recent experiments on cuprates with low-dimensional magnetic interactions, a new class of two-dimensional Ising models with short-range interactions and mobile defects is introduced and studied. The non-magnetic defects form lines, which, as temperature increases, first meander and then become unstable. Using Monte Carlo simulations and analytical low- and high-temperature considerations, the instability of the defect stripes is monitored for various microscopic and thermodynamic quantities in detail for a minimal model, assuming some of the couplings to be indefinitely strong. The robustness of the findings against weakening the interactions is discussed as well

A Correlation Between Changes in Solar Luminosity and Differential Radius Measurements

Solar luminosity variations occurring during solar cycle 21 can be attributed in large part to the presence of sunspots and faculae. Nevertheless, there remains a residual portion of the luminosity variation distinctly unaccounted for by these phenomena of solar activity. At the Santa Catalina Laboratory for Experimental Relativity by Astrometry (SCLERA), observations of the solar limb are capable of detecting changes in the solar limb darkening function by monitoring a quantity known as the differential radius. These observations are utilized in such a way that the effects of solar activity are minimized in order to reveal the more fundamental structure of the photosphere. The results of observations made during solar cycle 21 at various solar latitudes indicate that a measurable change did occur in the global photospheric limb darkening function. It is proposed that the residual luminosity change is associated in part with this change in limb darkening