New effects observed in central production by experiment WA102 at the CERN Omega Spectrometer

A partial wave analysis of the centrally produced KK and pipi systems shows that the fJ(1710) has J = 0. In addition, a study of central meson production as a function of the difference in transverse momentum (dPT) of the exchanged particles shows that undisputed qqbar mesons are suppressed at small dPT whereas the glueball candidates are enhanced and that the production cross section for different resonances depends strongly on the azimuthal angle between the two outgoing protons.Comment: 5 pages, Latex, 3 Figures to appear in the proceeding of PANIC 99, Uppsala, Sweden, June 199

Wiring optimization explanation in neuroscience: What is Special about it?

This paper examines the explanatory distinctness of wiring optimization models in neuroscience. Wiring optimization models aim to represent the organizational features of neural and brain systems as optimal (or near-optimal) solutions to wiring optimization problems. My claim is that that wiring optimization models provide design explanations. In particular, they support ideal interventions on the decision variables of the relevant design problem and assess the impact of such interventions on the viability of the target system

A study of the pi^0pi^0 system produced in charge exchange and central collisions

A study of the $\pi^0\pi^0$ system produced in charge exchange $\pi^-p$ collisions at 38 and 100 GeV/c and in central $pp$ interactions at 450 GeV/c has been carried out. The $S$ wave has rather a complicated structure in both processes indicating the existence of several scalar resonances. The $f_0(980)$ and $f_0(1500)$ appear as dips at 1 and 1.5 GeV in the $S$ wave for charge exchange reaction, and as shoulders at these masses in the $S$ wave for central production. The production of the $f_0(980)$, $f_0(1300)$ and $f_0(1500)$ in the reaction $pp \to p_f\pi^0\pi^0p_s$ as a function of the $dP_{T}$ kinematical filter shows the behaviour differed from what has been observed for the undisputed $q\bar{q}$ mesons. An extra $f_0(2000)$ state is seen in the $S$ wave for charge exchange reaction as a dip at 2 GeV. Resonances with higher spins, $f_2(1270)$, $f_4(2050)$ and $f_6(2510)$, have also been studied. All the three mesons are produced in the reaction $\pi^-p\to\pi^0\pi^0{n}$ mainly via an one-pion exchange for small $-t$, whereas a natural-parity exchange domimates for large $-t$. The behaviour of the centrally produced $f_2(1270)$ as a function of the $dP_{T}$ is consistent with what has been observed for other $q\bar{q}$ states.Comment: 6 pages, 6 figures, use file stwol.sty, presented at International High-Energy Physics Euroconference in Quantum Chromodynamics, 2-8 July 1998, Montpellier, France on behalf of the GAMS and WA102 Collaboration

Resonance production in central pp collisions at the CERN Omega Spectrometer

A study of resonance production in central pp collisions is presented as a function of several kinematical variables. In particular the difference in the transverse momentum (dPT) of the exchanged particles shows that undisputed qqbar mesons are suppressed at small dPT whereas glueball candidates are enhanced and in addition, the azimuthal angle phi gives information on the nature of the Pomeron.Comment: 14 pages, Latex, 5 Figure

What Drives the Disposition Effect? An Analysis of a Long-Standing Preference-Based Explanation

One of the most striking portfolio puzzles is the %u201Cdisposition effect%u201D: the tendency of individuals to sell stocks in their portfolios that have risen in value since purchase, rather than fallen in value. Perhaps the most prominent explanation for this puzzle is based on prospect theory. Despite its prominence, this explanation has received little formal scrutiny. We take up this task, and analyze the trading behavior of investors with prospect theory preferences. We find that, at least for the simplest implementation of prospect theory, the link between these preferences and the disposition effect is not as obvious as previously thought: in some cases, prospect theory does indeed predict a disposition effect, but in others, it predicts the opposite. We provide intuition for these results, and identify the conditions under which the disposition effect holds or fails. We also discuss the implications of our results for other disposition-type effects that have been documented in settings such as the housing market, futures trading, and executive stock options.

The Loss Aversion / Narrow Framing Approach to the Equity Premium Puzzle

We review a recent approach to understanding the equity premium puzzle. The key elements of this approach are loss aversion and narrow framing, two well-known features of decision-making under risk in experimental settings. In equilibrium, models that incorporate these ideas can generate a large equity premium and a low and stable risk-free rate, even when consumption growth is smooth and only weakly correlated with the stock market. Moreover, they can do so for parameter values that correspond to sensible attitudes to independent monetary gambles. We conclude by suggesting some possible directions for future research.