Subthreshold pion dynamics as a source for hard photons beyond proton-neutron Bremsstrahlung in heavy-ion collisions

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.76.2412· OSTI ID:286088

Gudima, K K; Matulewicz, T; Delagrange, H; Marques, F M; Martinez, G; Ostendorf, R W; Ploszajczak, M; Schutz, Y; Toneev, V D; Bozek, P; Hlavac, S ^[1]; Holzmann, R; Schubert, A; Simon, R S; Wagner, V ^[2]; Loehner, H; van Pol, J H; Siemssen, R H; Wilschut, H W ^[3]; Diaz, J ; Marin, A ^[4]

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1. Grand Accelerateur National d`Ions Lourds, F-14021 Caen (France)
2. Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany)
3. Kernfysisch Versneller Instituut, NL-9747 AA Groningen (The Netherlands)
4. Instituto de Fsica Corpuscular, E-46100 Burjassot (Spain)

We report on the first measurement in heavy-ion collisions of hard photons of extremely high energies that extend the photon spectrum to 5 times the beam energy per nucleon. The photon spectrum was measured for the systems {sup 86}Kr+{sup nat}Ni at 60 {ital A} MeV and {sup 181}Ta+{sup 197}Au at 40 {ital A} MeV. The data are interpreted using the Dubna cascade model. The radiative channel of pion-nucleon interaction {pi}+{ital N}{r_arrow}{ital N}+{gamma}, involving subthreshold pions produced in the nuclear medium, dominates all other processes considered for the production of the very energetic photons. This channel was never considered so far at beam energies below the pion threshold. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 286088
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 14 Vol. 76; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BREMSSTRAHLUNG
CASCADE THEORY
DYNAMICS
GAMMA SPECTRA
GEV RANGE 01-10
GOLD 197 TARGET
HEAVY ION REACTIONS
KRYPTON 86 REACTIONS
NICKEL
PHOTONS
PION-NUCLEON INTERACTIONS
PIONS
PROTON-NEUTRON INTERACTIONS
TANTALUM 181