Antiproton production in heavy ion collisions
In high energy p-p and {alpha} {minus} {alpha} collisions, baryons are observed predominantly at rapidities near those of target and projectile; the mean rapidity shift of projectile and target nucleons is approximately one unit. In the central rapidity region, the number of baryons is quite small. In fact, the number of baryons and antibaryons is rather similar, indicating that most of these baryons are CREATED particles rather than projectile and target fragments. Antibaryon production is of interest in heavy ion collisions as enhanced antiquark production has been predicted as a potential signature of quark-gluon plasma formation. Antibaryons also provide a sensitive probe of the hadronic environment, via annihilation and/or mean field effects upon their final distributions. However, the collision dynamics also affect the baryon and antibaryon distributions. Baryons are more shifted toward midrapidity in nucleus-nucleus and p-p nucleus collisions than in p-p collisions, increasing the probability of annihilating the antibaryons. The interpretation of antibaryon yields is further complicated by collective processes which may take place in the dense hadronic medium formed in nucleus-nucleus collisions. Jahns and coworkers have shown that multistep processes can increase antibaryon production near threshold. Antiproton production is clearly very interesting, but is sensitive to a combination of processes taking place in the collision. The final number of observed antiprotons depends on the balance between mechanisms for extra antiproton production beyond those from the individual nucleon-nucleon collisions and annihilation with surrounding bayrons. We can hope to sort out these things by systematic studies, varying the system size and beam energy. I will review what is known about antiproton production at both the AGS and SPS, and look at trends going from p-p to p-nucleus to nucleus-nucleus collisions.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 10129370
- Report Number(s):
- LA-UR-94-713; CONF-9310293-1; ON: DE94007552; TRN: 94:006441
- Resource Relation:
- Conference: NATO Advanced Study Institute on hot and dense nuclear matter,Bodrum (Turkey),5 Oct 1993; Other Information: PBD: [1993]
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTIPROTONS
PRODUCTION
HEAVY ION REACTIONS
PARTICLE RAPIDITY
TRANSVERSE ENERGY
QUARK MATTER
663450
662410
662230
HEAVY-ION-INDUCED REACTIONS AND SCATTERING
PROPERTIES OF BARYONS AND BARYON RESONANCES
QUANTUM CHROMODYNAMICS