Recent Results from E877

Abstract

Relativistic heavy ion collisions at 10 A·GeV incident beam energy probe nuclear matter at high densities and temperatures. The experimental approach of E877 at the Brookhaven AGS is to measure the transverse energy E _T produced in these collisions in conjunction with the identification of single particles within a limited region of phase space. Among the major results for Au + Au collisions are the large degree of stopping deduced from E _T ¹ and the finding of an azimuthal anisotropy in the E _T production depending on centrality.^2–5 The latter can be interpreted as a signature for transverse energy flow. Particle spectra support the formation of a high density region at midrapidity and the existence of a reaction plane. A single particle analysis combined with the knowledge of the azimuthal E _T pattern opens up the unique opportunity to study the reaction geometry in detail for each particle species involved. The comparison of produced particles like π^±, K^±, $\bar p$ and Λ hyperons is of special interest in this context since their properties in nuclear matter, e.g. propagation, production and absorption cross sections, are very different.