相关论文: Coherent Pion Pairs from Heavy-Ion Collisions
Based on the isospin dependent transport model IBUU, the pion production and its absorption are thoroughly studied in the central collision of $Au+Au$ at a beam energy of 400 MeV/nucleon. It is found that the pions are firstly produced by…
Multi-pion correlations and wavepacket size effects on the pion multiplicity distribution, pion momentum distribution and two-pion interferometry are studied. It is shown that multi-pion Bose-Einstein correlations and the wavepacket size…
A dynamical coupled-channel model is presented for investigating the nucleon resonances in the meson production reactions induced by pions and photons. The model is based on an energy-independent Hamiltonian which is derived from a set of…
Some recent theoretical results on coherent electromagnetic processes in ultrarelativistic heavy ion reactions are surveyed.
The strong electromagnetic fields present in ultra-peripheral collisions of heavy-ions offer a possibility to study two-photon and photonuclear collisions complementary to similar studies with lepton beams but over an increased photon…
The environment generated in the mid-rapidity region of a high-energy nuclear collision endows the pionic degrees of freedom with a time-dependent effective mass. Its specific evolution provides a mechanism for the production of…
Two-particle correlation functions for positive and negative pions have been measured in Au+Au collisions at 10.8~GeV/c per nucleon. The data were analyzed using one- and three-dimensional correlation functions. From the results of the…
Using an isospin-dependent transport model, we study isospin effects on two-nucleon correlation functions in heavy-ion collisions induced by neutron-rich nuclei at intermediate energies. We find that these correlation functions are…
The posibility of large charge and isospin fluctuations in high-energy heavy ion-collisions is studied within the framework of the nonlinear $\sigma $-model with quark degrees of freedom. The multipion exchange potential between two quarks…
Two-pion correlation functions, measured as a function of azimuthal emission angle with respect to the reaction plane, provide novel information on the anisotropic shape and orientation of the pion-emitting zone formed in heavy ion…
Recent experimental results show a large enhancement of the 2 pion emission on the scalar isoscalar channel, which had been predicted by some theoretical estimates. We present here a detailed calculation of the A(pi, 2pi)X process…
A meson exchange model of the $\pi\pi$ interaction which fits free $\pi\pi$ scattering data is used to calculate the interactions of pions in nuclear matter as a function of nuclear density. Polarization of the nuclear medium by the pions…
Relativistic heavy ions are copious sources of virtual photons. The large photon flux gives rise to a substantial photonuclear interaction probability at impact parameters where no hadronic interactions can occur. Multiple photonuclear…
The low-mass dielectron signal from heavy-ion collisions at the CERN--SPS reported by the {\em CERES} collaboration is in excess of estimated hadronic decays suggestive of possible contribution from two-pion annihilation or other hadronic…
Estimation of multiplicity of muons and pions production at high energy proton-nuclei collisions is given. Both QED and QCD contributions are considered for peripheral kinematics of muon pair and $\sigma$-meson production, keeping in mind…
The ABC effect -- an intriguing low-mass enhancement in the $\pi\pi$ invariant mass spectrum -- is known from inclusive measurements of two-pion production in nuclear fusion reactions. First exclusive measurements carried out at…
We show that the phenomenology of isospin effects on heavy ion reactions at intermediate energies (few AGeV range) is extremely rich and can allow a ``direct'' study of the covariant structure of the isovector interaction in the hadron…
Attention is paid to recent results from the ZEUS Collaboration on the photo- and electro- production of leading neutrons in e^+ p collisions at HERA. Some implications for the structure of the pion and the nucleon are discussed.
We estimate the cross sections for the production of resonances, pion pairs and a central cluster of hadrons in peripheral heavy-ion collisions through two-photon and double-pomeron exchange, at energies that will be available at RHIC and…
Precise measurements of neutrino oscillation parameters and of neutrino-nucleon cross-sections require a good understanding of neutrino beams: flux as a function of energy, transverse beam profile, and flavour composition. For this, hadron…