Charged pions from Ni on Ni collisions between 1 and 2 AGeV

Abstract

Charged pions from Ni + Ni reactions at 1.05, 1.45 and 1.93 AGeV are measured with the FOPI detector. The mean ${\pi }^{\pm }$ multiplicities per mean number of participants increase with beam energy, in accordance with earlier studies of the Ar + KCl and La + La systems. The pion kinetic energy spectra have concave shape and are fitted by the superposition of two Boltzmann distributions with different temperatures. These apparent temperatures depend only weakly on bombarding energy. The pion angular distributions show a forward/backward enhancement at all energies, but not the $\Theta =90^0$ enhancement which was observed in case of the Au + Au system. These features also determine the rapidity distributions which are therefore in disagreement with the hypothesis of one thermal source. The importance of the Coulomb interaction and of the pion rescattering by spectator matter in producing these phenomena is discussed.

22 pages, Latex using documentstyle[12pt,a4,epsfig], to appear in Z. Phys.A

References in corpus (6)

• Thermal Equilibration and Expansion in Nucleus-Nucleus Collision at the AGS
• Central Collisions of Au on Au at 150, 250 and 400 A MeV
• Effects of Compression and Collective Expansion on Particle Emission from Central Heavy-Ion Reactions
• Azimuthal correlations of pions in relativistic heavy ion collisions at 1 GeV/nucl.
• Measurement of Pion Enhancement at Low Transverse Momentum and of the Delta-Resonance Abundance in Si-Nucleus Collisions at AGS Energy
• Bose-Einstein Correlations of Pion Wavepackets

Cited by in corpus (25)

• Systematics of pion emission in heavy ion collisions in the 1A GeV regime
• Influence of Impact Parameter on Thermal Description of Relativistic Heavy Ion Collisions at GSI/SIS
• Probing the equation of state with pions
• Cascade production in heavy-ion collisions at SIS energies
• Stopping and Radial Flow in Central 58Ni + 58Ni Collisions between 1 and 2 AGeV
• Hadronic Particle Production in Nucleus-Nucleus Collisions
• Probing the density dependence of the symmetry potential in intermediate energy heavy ion collisions
• Thermal Model Analysis of Particle Ratios at GSI Ni-Ni Experiments Using Exact Strangeness Conservation
• In-medium dependence and Coulomb effects of the pion production in heavy ion collisions
• $K^{-}/K^{+}$ ratios in relativistic heavy-ion collisions
• Quenching of resonance production in heavy-ion collisions at 1-2 A GeV
• Meson $m_T$-scaling in heavy-ion collisions at SIS energies
• Review of SIS Experimental Results on Strangeness
• Charged pion production in ${}_{44}^{96}$Ru+${}_{44}^{96}$Ru collisions at 400A and 1528A MeV
• Delta(1232) and Nucleon Spectral Functions in Hot Hadronic Matter
• Mapping out the QCD phase transition in multiparticle production
• Limits of complete equilibration of fragments produced in central Au on Au collisions at intermediate energies
• Photoproduction of $\eta$-mesons off C and Cu nuclei for photon energies below 1.1 GeV
• Role of isospin dependent mean field in pion production in heavy ion reactions
• Relativistic quantum transport theory of hadronic matter: the coupled nucleon, delta and pion system
• Wide acceptance measurement of the K${}^{-}$/K${}^{+}$ ratio from Ni+Ni collisions at 1.91A GeV
• Centrality dependence of subthreshold $\varphi$ meson production in Ni+Ni collisions at 1.9A GeV
• The Delta(1232) at RHIC
• On the exact conservation laws in thermal models and the analysis of AGS and SIS experimental results
• The Coulomb Interaction between Pion-Wavepackets: The piplus-piminus Puzzle