Progress in all-order breakup reaction theories

Progress in breakup reaction theories, like the distorted wave Born approximation, the continuum discretized coupled channels method and the dynamical eikonal approximation, is brought into focus. The need to calculate exclusive reaction observables and the utility of benchmark tests as arbitrators of theoretical models are discussed.     

Investigation of neutron-deuteron charge-exchange reaction at small transfer momentum

Analysis of the nd → p(nn) reaction in the GeV energy region is performed in the framework based on the multiple-scattering theory for a few-nucleon system. The special kinematic condition where momentum transfer from neutron beam to final proton is close to zero is considered. The possibility of extracting the spin-dependent term of the elementary np → pn amplitude from the nd breakup process is investigated. The energy dependence of the ratio R = is obtained taking account of the finalstate interaction of the two outgoing neutrons in the ¹ S ₀ state. The text was submitted by the author in English.     

Procedure for extracting the nn scattering length from data on the yield of the nd breakup reaction

A procedure for extracting the neutron-neutron scattering length a _nn from the nd breakup data obtained in an experimental investigation carried out in the neutron beam at the INR is described. Simulation of the experiment made it possible to choose the optimal experimental conditions, to optimize the method for determining the nn scattering length, and to evaluate the effect of various factors on the accuracy of the determination.     

Cross sections for the n+d breakup reaction

The n+d breakup cross section has been measured between 8 and 22 MeV by integrating the energy distributions of breakup protons and recoil deuterons observed in a deuterated scintillator. The results obtained deviate from the trend suggested by recent measurements of the cross section for proton-induced breakup and favour predictions based on a local N-N potential having a hard core in the singlet state.     

A possible approach to breakup in nuclear reaction calculations

It is proposed to use the multi-channel Kato identity for estimating breakup amplitudes when an approximate scattering wave function is known from a variational calculation. Lines of connection are drawn with more familiar expressions for the breakup amplitudes.     

Projectile breakup and total reaction strengths in Li-induced reactions

Spectra and angular distributions have been measured for the light particles emitted from the reactions induced by 36 MeV ⁶Li and ⁷Li ions on targets of ¹²C, ¹³C and ²⁷Al. Some measurements were also performed at beam energies of 28 and 32 MeV. The spectra are dominated by broad peaks centered at energies corresponding to the beam velocity, a characteristic of projectile breakup. A simple breakup model roughly reproduces the shapes of the measured spectra and angular distributions. The total cross sections observed for projectile breakup average about 600 mb and are almost as large as the fusion cross sections. The ⁷Li breakup yields are somewhat larger than those for ⁶Li, the same trend that was previously observed for the Li-induced fusion cross sections on C. As a result the measured total reaction cross sections induced by ⁷Li ions are about 200 mb larger than those of ⁶Li on the same targets. This difference is not predicted by conventional optical model calculations.     

Pion single charge-exchange reaction on nuclei near the (3, 3) resonance

Angle integrated cross-sections for the pion single charge-exchange reaction on¹³C and⁷Li have been calculated at several energies in the distorted wave impulse approximation employing the off-shell nature of the pion-nucleon scattering amplitude and using the Breit-Wigner formula for its energy dependence. Effect of the two nucleon correlations in the nucleus on the cross-section is also studied. Our results are in rough accord with the experimental data. The major part of this work was done while the author was at the University of Manitoba, Canada.     

The contribution of quasi-elastic processes to the totsal reaction cross section of heavy ions

A simple estimate of the ratio of the total quasi-elastic cross section to the total reaction cross section of heavy ions is made and compared to the experimentally deduced values for the system ${}^{16}\text{O}\text{+}{}^{27}\text{Al}$. The slow energy dependence of the ratio is stressed.     

Production of the neutron-rich hypernucleus 10LambdaLi in the (pi-,K+) double charge-exchange reaction

In order to produce a neutron-rich Lambda hypernucleus for the first time, we carried out an experiment by utilizing the (pi-,K+) double charge-exchange reaction on a 10B target. We observed the production of a 10LambdaLi hypernucleus. The cross section for the Lambda bound region was found to be 11.3+/-1.9 nb/sr with the 1.2 GeV/c incident momentum, which is compared with the 10LambdaB hypernucleus production cross section, 7.8+/-0.3 microb/sr, in the (pi+,K+) reaction with a 1.05 GeV/c incident momentum beam.     

Self-diffusion in liquid lithium and lead from coherent quasi-elastic neutron scattering data

The temperature dependence of the self-diffusion coefficient of liquid lithium in the temperature range of 500–830 K has been investigated using coherent quasi-elastic neutron scattering. Good agreement with the results obtained from incoherent quasi-elastic neutron scattering experiments traditionally used for this purpose has been achieved, as well as with the corresponding literature data. In addition, one temperature point (623 K) has been obtained for the self-diffusion coefficient of liquid lead, which is a pure coherent scatterer.     

Transverse enhancement model and MiniBooNE charge current quasi-elastic neutrino scattering data

Recently proposed Transverse Enhancement Model of nuclear effects in Charge Current Quasi-Elastic neutrino scattering (A. Bodek, H.S. Budd, M.E. Christy, Eur. Phys. J. C 71:1726, 2011) is confronted with the MiniBooNE high statistics experimental data.     

On a quasi-elastic mechanism of the reaction d(p, 2p)n

The problem on validity of quasi-elastic mechanism of the reaction d(p, 2p)n in the range of low energies (20–50 MeV) is studied. While estimating the effect of multiple scattering it is shown that the condition of quasi-elasticity holds sufficiently well in all the considered cases under the assumption on peripheral collision of counted particles (the cutoff method). The dependence of the cutoff radius R₀ on the energy of incident particles E₀ is discussed.     

Antisymmetrization effects in the spin-transverse quasi-elastic response

In the transverse spin-isovector channel a ρ-exchange force is compared to a realisticG-matrix interaction. An energy and momentum dependent g′ is extracted that can be used together with a ρ-exchange potential in ring approximation yielding for the collective response function in the quasi-elastic peak the same result as a fully antisymmetrizedG-matrix interaction.     

Measurement of the neutron-induced deuteron breakup reaction cross-section between 5 and 25 MeV

High-spin states in ¹⁸⁷Pt have been studied by means of ??-ray spectroscopy techniques. Known bands have been significantly extended and new bands have been found. The band structures are discussed in the framework of the cranking model and negative-parity states are compared with calculations performed with a semi-microscopic axial-rotor plus one-quasiparticle coupling model. Shape coexistence is observed from low excitation energy.