Neutron-proton interferometry in collisions (original) (raw)
Related papers
Two-neutron correlations at small relative momenta in 40Ar + 197Au collisions at 60 MeV/nucleon
The European Physical Journal A, 2000
Two-neutron correlation functions are measured in the 40 Ar + 197 Au reaction at 60 MeV/nucleon to study the space-time characteristics of neutron emitting sources. The source temperatures and velocities are deduced by fitting the single-neutron energy spectra with a three-source model. A comparison of the correlation data with the predictions of the model of moving sources and with the dynamical Landau-Vlasov model suggests the relevance of a multisource description. Particular care has been paid to the influence of the relative source abundance on the shape of the correlation function. PACS. 25.70.-z Low and intermediate energy heavy-ion collisions -25.75.Gz Particle correlations
Evidence for Strong Dominance of Proton-Neutron Correlations in Nuclei
Physical Review Letters, 2006
We analyze recent data from high-momentum-transfer (p, pp) and (p, ppn) reactions on carbon. For this analysis, the two-nucleon short-range correlation (NN-SRC) model for backward nucleon emission is extended to include the motion of the NN pair in the mean field. The model is found to describe major characteristics of the data. Our analysis demonstrates that the removal of a proton from the nucleus with initial momentum 275-550 MeV=c is 92 8 ÿ18 % of the time accompanied by the emission of a correlated neutron that carries momentum roughly equal and opposite to the initial proton momentum. This indicates that the probabilities of pp or nn SRCs in the nucleus are at least a factor of 6 smaller than that of pn SRCs. Our result is the first estimate of the isospin structure of NN-SRCs in nuclei, and may have important implication for modeling the equation of state of asymmetric nuclear matter.
Effects of correlations on the total neutron-Nucleus cross section at high energies
arXiv preprint arXiv:0705.3613, 2007
Abstract: The total neutron-Nucleus cross section has been calculated within an approach which takes into account nucleon-nucleon correlations, Glauber multiple scattering and inelastic shadowing corrections. Nuclear targets ranging from 4He to 208Pb and neutron incident momentum ranging from 3 to 300 GeV/c, have been considered. Correlations have been introduced by two different approaches leading to the same results. The commonly used approximation, consisting in treating nuclear effects only by a product of one-body ...
Physical Review C, 1992
Neutron-light-charged-particle (LCP) and LCP-LCP correlation functions were measured for the 215 MeV ' 0+ Al reaction, together with the neutron-proton correlation function for the ' 0+' C reaction at El,b =60.5 MeV. The np and pp correlation data are compared with the predictions of the Koonin model and a semiclassical evaporation model. Both models provide an excellent fit to the np data, while the pp data are not reproduced as well. Production yields of singlet deuterons, ground state 'He and 'Li, and Li nuclei in the 2.186 MeV state were obtained from the coincidence data, and a nuclear temperature of T=2.0+& 6 MeV for the ' 0+ Al compound system was determined from the ratio of singlet to ground state deuteron emission, after corrections for sequential emission and noncompound deuteron production. This temperature value is well below the Fermi gas model estimate, and a similar result is observed for the ' 0+ ' C compound system.
Nuclear Physics A, 2000
Two-neutron, two-proton and neutron-proton correlation functions have been measured simultaneously for the E/A = 45 MeV 58 Ni + 27 Al reaction. Calculations from a statistical model have been compared to singles energy spectra as well as to total and gated correlation functions. This imposes very strong constraints on the model parameters. The use of directionally gated correlation functions helps to disentangle space and time information. Values of Gaussian radii, emission lifetimes, initial temperatures, source velocities and flow velocities are extracted. Correlation functions gated on total momentum of the nucleon pairs suggest that more energetic particles are emitted on a fast time scale (< 100 fm/c) and that the fraction of pre-equilibrium to equilibrium emission is larger for protons than for neutrons.
Physics Letters B, 1988
Proton-proton small angle correlations have been measured in neon-nucleus collisions, using the 47r detector Diogene, at 400 and 800 MeV per nucleon incident energies. Values of the size of the emitting region are obtained by comparison with the Koonin formula, taking into account the biases of the apparatus. The dependence of the density on target mass and incident energy is also analysed.
Two-particle correlations from neutron–light-charged-particle coincidences
Physical Review Letters, 1990
The first correlation functions from a neutron-light-charged-particle small-angle coincidence measurement are reported for the ' 0+ "Al reaction at E(0) =215 MeV. Clear evidence for singletdeuteron and He production, and an anticorrelation of low-relative-momentum neutron-deuteron pairs, is observed. The nuclear temperature of 1. 6+'0. 3 MeV, calculated from the ratio of excited-state to ground-state deuteron emission and corrected for sequential emission, is considerably lower than expected.
T=0 Neutron-Proton Correlations at high angular momenta
AIP Conference Proceedings, 1999
The properties of T = 0 neutron-proton correlations are discussed within the framework of different model calculations. Single-j shell calculations reveal that the T = 0 correlations remain up to the highest frequencies. They are more complex than the T = 1 corrlations and cannot be restricted to L = 0 pairs only. Whereas it may be difficult to find clear evidence for T = 0 pairing at low spins, T = 0 correlations are found to induce a new excitation scheme at high angular momenta.