Detection of brown dwarfs by the micro-lensing of unresolved stars

The presence of brown dwarfs in the dark galactic halo could be detected through their gravitational lensing effect and experiments under way monitor about one million stars to observe a few lensing events per year. We show that if the photon flux from a galaxy is measured with a good precision, it is not necessary to resolve the stars and besides more events could be observed.Comment: 14 p., LaTeX, 4 figures available on request, PAR-LPTHE 92 39/LPC 92 1

Do the Kamiokande results need neutrino oscillations?

Neutrino oscillations are a delicate and important subject. One needs to be sure that every aspect of it is well understood. The recent results of the Kamiokande experiment [1], indicate the possibility of -- neutrino oscillations. The period of oscillation observed by Kamiokande is not compatible with what one may deduce from the solar neutrino experiments [2]. In this letter, we examine if another mechanism could fake neutrino oscillations and could be measurement dependen

Bayesian markets to elicit private information

Financial markets reveal what investors think about the future, and prediction markets are used to forecast election results. Could markets also encourage people to reveal private information, such as subjective judgments (e.g., “Are you satisfied with your life?”) or unverifiable facts? This paper shows how to design such markets, called Bayesian markets. People trade an asset whose value represents the proportion of affirmative answers to a question. Their trading position then reveals their own answer to the question. The results of this paper are based on a Bayesian setup in which people use their private information (their “type”) as a signal. Hence, beliefs about others’ types are correlated with one’s own type. Bayes