Low-p{sub t} enhancement in meson spectra from relativistic heavy-ion collisions
Journal Article
·
· Bulletin of the American Physical Society
OSTI ID:387228
The collision of two large nuclei at high energies creates a zone of high energy density from which it has been postulated that a new state of matter (Quark-Gluon Plasma) might be formed. Studies of such collisions have been underway for several years at the Brookhaven National Laboratory AGS accelerator facility using beams of 14.6 GeV/nucleon {sup 28}Si and more recently using 11.4 GeV/nucleon {sup 197}Au. Enhanced meson production at low transverse momentum (p{sub t}) has been proposed as a signature of medium modifications and is generally quite sensitive to the collision dynamics. Proposed mechanisms for enhancement include the decay of baryon resonances, meson condensates or {open_quotes}liquids{close_quotes}, partial chiral symmetry restoration, and finite pion chemical potentials. Measurements of the pion spectrum using the E814 spectrometer indicate a strong low p{sub t} component at rapidities near that of the projectile. The contribution due to the {Delta}(1232) resonance is determined through reconstruction of the {Delta}{sup ++} decay in the p-{pi} invariant mass spectrum. The {Delta} is shown to account for the majority of the enhancement. These measurements suggest that the density of excited nucleons during the most compressed phase of the collision could exceed the density of nucleons in normal nuclear matter. Measurements of the Kaon spectrum at low p{sub t} will also be discussed.
- OSTI ID:
- 387228
- Report Number(s):
- CONF-931044--
- Journal Information:
- Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 9 Vol. 38; ISSN BAPSA6; ISSN 0003-0503
- Country of Publication:
- United States
- Language:
- English
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