Charged particle spectra in ³²S + ³²S interactions at 200 GeV/nucleon from CCD-imaged nuclear collisions in a streamer chamber

Thesis/Dissertation · Wed Apr 01 00:00:00 EST 1992

DOI:https://doi.org/10.2172/10103003· OSTI ID:10103003

Teitelbaum, Lawrence Paul ^[1]

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1. Univ. of California, Berkeley, CA (United States)

We have measured the transverse momentum spectra 1/p_T dN/dp_T and rapidity distributions dN/dy of negatively charged hadrons and protons for central ³²S + ³²S interactions at 200 GeV/nucleon incident energy. The negative hadron dN/dy distribution is too broad to be accounted for by thermal models which demand isotropic particle emission. It is compatible with models which emphasize longitudinal dynamics, by either a particle production mechanism, as in the Lund fragmentation model, or by introducing one-dimensional hydrodynamic expansion, as in the Landau model. The proton dN/dy distribution, although showing no evidence for a peak in the target fragmentation region, exhibits limited nuclear stopping power. We estimate the mean rapidity shift of participant target protons to be Δy ~ 1.5, greater than observed for pp collisions, less than measured in central pA collisions, and much less than would be observed for a single equilibrated fireball at midrapidity. Both the negative hadron and proton dN/dy distributions can be fit by a symmetric Landau two-fireball model. Although the spectrum possesses a two-component structure, a comparison to pp data at comparable center-of-mass energy shows no evidence for enhanced production at low p_T. The two-component structure can be explained by a thermal and chemical equilibrium model which takes into account the kinematics of resonance decay. Using an expression motivated by longitudinal expansion we find the same temperature for both the protons and negative hadrons at freezeout, T_f ~ 170 MeV. We conclude that the charged particle spectra of negative hadrons and protons can be accommodated in a simple collision picture of limited nuclear stopping, evolution through a state of thermal equilibrium, followed by longitudinal hydrodynamic expansion until freezeout.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 10103003
• Report Number(s): LBL-32812; ON: DE93002562
• Resource Relation: Other Information: TH: Thesis (Ph.D.); PBD: Apr 1992
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
SULFUR 32 TARGET
SULFUR 32 REACTIONS
TRANSVERSE MOMENTUM
CHARGE-COUPLED DEVICES
DATA ACQUISITION SYSTEMS
PROTON-PROTON INTERACTIONS
CROSS SECTIONS
PARTICLE RAPIDITY
STREAMER SPARK CHAMBERS
EXPERIMENTAL DATA
SPECTRA
663450
663530
HEAVY-ION-INDUCED REACTIONS AND SCATTERING
A = 20-38