Production of pions and light fragments at large angles in high-energy nuclear collisions

Journal Article · Tue Sep 01 04:00:00 EDT 1981 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.24.971· OSTI ID:6248972

Nagamiya, S; Lemaire, M; Moeller, E; Schnetzer, S; Shapiro, G; Steiner, H; Tanihata, I

Inclusive cross sections for production of ..pi../sup +/, ..pi../sup -/, p, d, /sup 3/H, /sup 3/He, and /sup 4/He have been measured at laboratory angles from 10/sup 0/ to 145/sup 0/ in nuclear collisions of Ne+NaF, Ne+Cu and Ne+Pb at 400 MeV/nucleon, C+C, C+Pb, Ne+NaF, Ne+Cu, Ne+Pb, Ar+KCl, and Ar+Pb at 800 MeV/nucleon, and Ne+NaF and Ne+Pb at 2.1 GeV/nucleon. The production of light fragments in proton induced collisions at beam energies of 800 MeV and 2.1 GeV has also been measured in order to allow us to compare these processes. For equal-mass nuclear collisions the total integrated yields of nuclear charges are well explained by a simple participant-spectator model. For 800 MeV/nucleon beams the energy spectra of protons at c.m. 90/sup 0/ are characterized by a ''shoulder-arm'' type of spectrum shape with an exponential fall off at high energies, whereas those of pions are of a simple exponential type. The inverse of the exponential slope, E/sub 0/, for protons is systematically larger than that for pions. This value of E/sub 0/ is larger for heavier-mass projectiles and targets. It also increases monotonically with the beam energy. The angular anisotropy of protons is larger than that of pions. The yield ratio of ..pi../sup -/ to total nuclear charge goes up with the beam energy, whereas the yields of composite fragments decrease. The ratio of low-energy ..pi../sup -/ to ..pi../sup +/, as well as that of /sup 3/H to /sup 3/He, is larger than the neutron to proton ratio of the system. The spectrum shape of the composite fragments with mass number A is explained very well by the A/sup th/ power of the observed proton spectra. The sizes of the interaction region are evaluated from the observed coalescence coefficients. The radius obtained is typically 3--4fm. The yield ratio of composite fragments to protons strongly depends on the projectile and target masses and the beam energy, but not on the emission angle of the fragments. These results are compared with currently available theoretical models.

• Research Organization: Lawrence Berkeley Laboratory and Department of Physics, University of California, Berkeley, California 94720
• OSTI ID: 6248972
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 24:3; ISSN PRVCA
• Country of Publication: United States
• Language: English

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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALI METAL COMPOUNDS
ANGULAR DISTRIBUTION
ARGON 40 REACTIONS
BARYON REACTIONS
BARYONS
BOSONS
CARBON
CARBON 12 REACTIONS
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
COPPER
CROSS SECTIONS
DEUTERONS
DISTRIBUTION
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FERMIONS
FLUORIDES
FLUORINE COMPOUNDS
FRAGMENTATION
GEV RANGE
HADRON REACTIONS
HADRONS
HALIDES
HALOGEN COMPOUNDS
HEAVY ION REACTIONS
HELIUM 3
HELIUM 4
HELIUM ISOTOPES
INCLUSIVE INTERACTIONS
INTERACTIONS
ISOTOPES
LEAD
LIGHT NUCLEI
MESONS
METALS
NEON 20 REACTIONS
NONMETALS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUCLEONS
PARTICLE INTERACTIONS
PARTICLE PRODUCTION
PIONS
POTASSIUM CHLORIDES
POTASSIUM COMPOUNDS
PROTON REACTIONS
PROTONS
PSEUDOSCALAR MESONS
SODIUM COMPOUNDS
SODIUM FLUORIDES
STABLE ISOTOPES
TRANSITION ELEMENTS
TRITONS