Squeezed K^+ K^- correlations in high energy heavy ion collisions

The hot and dense medium formed in high energy heavy ion collisions may modify some hadronic properties. In particular, if hadron masses are shifted in-medium, it was demonstrated that this could lead to back-to-back squeezed correlations (BBC) of particle-antiparticle pairs. Although well-established theoretically, the squeezed correlations have not yet been discovered experimentally. A method has been suggested for the empirical search of this effect, which was previously illustrated for phi-phi pairs. We apply here the formalism and the suggested method to the case of K^+ K^- pairs, since they may be easier to identify experimentally. The time distribution of the emission process plays a crucial role in the survival of the BBC's. We analyze the cases where the emission is supposed to occur suddenly or via a Lorentzian distribution, and compare with the case of a Levy distribution in time. Effects of squeezing on the correlation function of identical particles are also analyzed.Comment: 9 pages and 6 figures (figures 2 to 6 contain 4 plots each). Paragraph added to text, figures 2 to 6 revised for improving visualizatio

HBT Interferometry: Historical Perspective

I review the history of HBT interferometry, since its discovery in the mid 1950's, up to the recent developments and results from BNL/RHIC experiments. I focus the discussion on the contributions to the subject given by members of our Brazilian group.Comment: 32 pages, 42 figures; corrected typos, replaced corrupted figure

Convergence analysis of an Inexact Infeasible Interior Point method for Semidefinite Programming

In this paper we present an extension to SDP of the well known infeasible Interior Point method for linear programming of Kojima,Megiddo and Mizuno (A primal-dual infeasible-interior-point algorithm for Linear Programming, Math. Progr., 1993). The extension developed here allows the use of inexact search directions; i.e., the linear systems defining the search directions can be solved with an accuracy that increases as the solution is approached. A convergence analysis is carried out and the global convergence of the method is prove

DISCUSSION: LOCATION DETERMINANTS OF MANUFACTURING INDUSTRY IN RURAL AREAS

Community/Rural/Urban Development,

GREEN PAYMENTS AS FORESHADOWED BY EQIP

This paper addresses the potential of the Environmental Quality Incentives Program to become the first true green payment program, one which is not directly linked to farm income goals as all conservation programs have been in the past, even in contrast to the Conservation Reserve Program and the now obsolete Agricultural Conservation Program. EQIP is thus discussed as a new generation of conservation programs which are General Agreement on Tariffs and Trade-legal (no payments to farmers which may influence trade) and more targeted to actual agro-environmental problems than the traditional conservation programs. In the next sections, the paper raises two important questions: First, to what extent should green payments substitute for traditional commodity payments, as they are being phased out? If taking water quality problems into account, EQIP does not reach the geographic areas of the highest commodity program payments, although substitution was never intended and has inherent problems. The paper then looks at EQIP as a green payment program, discussing to what extent EQIP reflects the desired characteristics of a GATT-legal green payment program. Three such characteristics are discussed as hurdles for a successful EQIP implementation: a program has to be targeted, tailored and transparent. Additionally, rent-seeking by various private interests, lack of science-based data, agency and farmer inertia and the complexity of the program are all challenges which must be faced. The study concludes with a discussion of the future of green payments.Environmental Economics and Policy,

THE NEW ERA OF AMERICAN AGRICULTURE: UNCERTAINTIES AND CONSTRAINTS

Agricultural and Food Policy,

AGRICULTURE AS THE PROBLEM: NEW AGENDAS AND NEW OPPORTUNITIES

Agribusiness,