Deuteron-Photospaltung bei niedrigen Energien

Low energy photodisintegration of the deuteron is useful for obtaining information about mesonic corrections to the magnetic dipole operator. Therefore, on the basis of a phenomenological theory of the photodisintegration process, the differential cross section and the polarization of the final state nucleons are calculated. TheD-state admixture of the ground state is taken into account. Using information from neutron-proton scattering, the dependence of the magnetic dipole transition on the force parameters is investigated in detail.     

Proton-deuteron elastic scattering at medium energy and relativistic models of multiple scattering

We have constructed a simple model of proton-deutron elastic scattering which can incorporate either a two-dimensional Pauli matrix or four-dimensional Dirac matrix parametrization of the nucleon-nucleon scattering amplitude. The model includes the S-and D-wave components of the deuteron wave function but neglects interactions with the spins of the target nucleons and is intended to provide an estimate of the magnitude of the differences between relativistic and non-relativistic treatments. We find these differences to be quite large and attribute them primarily to the intermediate negative energy states which are present only in the relativistic calculation.     

原子核力场之研究

本篇应用王淦昌所建议之两个核子间之相互位能即V=V(r)=-Ae^klr在r≥α时;及V=V(α)在r<α时。以求下列数点:(1)重子在正常情形时之波函数,(2)中子与质子间之扩散断面值,及(3)重子被γ射线击破之断面值。本篇所计算得之各断面值之结果与实验所得者,颇相近似。     

Tensor Interaction Effect in Dibaryon

The gluon and Goldstone boson induced tensor interaction effect on the dibaryon mass and the D-wave decay width has been studied in the quark delocalization, color screening model. The effective S-D wave transition interactions induced by gluon and Goldstone boson exchanges decrease quickly as the increasing of the channel strangeness. The K and η meson tensor contribution is negligible in this model. No six-quark state in the light flavor world can become a bound one by the help of these tensor interactions except the deuteron. The partial D-wave decay width of IJ^p=\frac{1}{2}2⁺ NΩ state to spin 0, 1 ΛΞ final state is 20.7 keV and 63.1 keV respectively. It is a very narrow dibaryon resonance and might be detected in the relativistic heavy ion reaction by the existing RHIC detectors through the reconstruction of the ΛΞ vertex mass and the future COMPAS detector at CERN and FAIR project in Germany.     

Nucleon form factors for elastic electron-deuteron scattering at high momentum transfer

Elastic electron-deuteron scattering at high momentum transfer is investigated within the Bethe-Salpeter approach. The relativistic covariant Graz II separable kernel of nucleon-nucleon interactions is used to analyze the deuteron structure functions, form factors, and tensor of polarization components. The modern data for the electromagnetic structure of nucleons from the double polarization experiments, as well as some other models of the nucleon form factors, are considered.     

Neutrino disintegration and muon capture in the deuteron

Neutrino and antineutrino disintegration of the deuteron and muon capture in the deuteron are studied. The final-state interaction between the nucleons is considered. The two-nucleon final state is found for the realistic potentials suggested by Reid and Ulehla et al.     

General formulae for polarization observables in deuteron electrodisintegration and linear relations

Formal expressions are derived for all possible polarization observables in deuteron electrodisintegration with longitudinally polarized incoming electrons, oriented deuteron targets and polarization analysis of outgoing nucleons. They are given in terms of general structure functions which can be determined experimentally. These structure functions are Hermitean forms of theT-matrix elements which, in principle, allow the determination of allT-matrix elements up to an arbitrary common phase. Since the set of structure functions is overcomplete, linear relations among various structure functions exist which are derived explicitly.Supported by the Deutsche Forschungsgemeinschaft (SFB 201)     

Elementary particle component of the deuteron

The low energy nucleon-nucleon system is analyzed by means of a model interaction which includes coupling of the nucleons to an “elementary deuteron” state. The probability of the elementary particle component, or “elementarity”, of the physical deuteron is investigated. It is found that, contrary to earlier assertions, the low energy scattering parameters do not determine the elementarity of the deuteron in a model-independent way.     

The differential cross section and polarization in p + p → d + π+

A coupled-channels approach is used for incorporating NΔ configurations into the mechanism of the meson production reaction p + p → d + π⁺. The differential cross section and the polarization asymmetry are calculated for lab energies ranging from threshold to 750 MeV including the partial waves up to f-wave pions and ³F state nucleons. It is found that the pp state ³F₃ is important in obtaining a reasonable agreement with the existing experimental data. We find a remarkable insensitivity of the differential cross section to the D-state probability of the deuteron, whereas the polarization is somewhat dependent on this.     

Sum rule for bremsstrahlung cross section for 6Li in the resonating-group method

In the method of resonating-group structure, the wave function of ⁶Li is assumed to have a single channel of alpha and deuteron substructures in the ground state. It is shown that the intercluster exchange of nucleons is an important effect which causes significant change in the root mean square radius and the dipole transition cross section. Due to the lack of symmetry in space coordinates of ⁶Li, the dipole operator is not identical to the mean square radius operator for this sum rule calculation and is expected to display like behavior in similar systems. It is also shown that the deuteron substructure in this nucleus is substantially larger than the alpha substructure.     

Polarization of protons from the Be(d, p)Be reaction

The polarization of protons from the ⁹Be(d, p)¹⁰Be reaction has been measured for deuteron energies between 1 and 6 MeV. Angular distributions of the polarization for the ground state proton group (Q=4.59 MeV) have been measured for laboratory angles 10° and 135° at 2.5, 4.0 and 5.5 MeV. The polarization at a laboratory angle of 30° was measured in 0.2 MeV steps between 1 and 6 MeV. In addition the polarization of protons leaving ¹⁰Be in its first excited state (Q=1.22 MeV) was measured between 10° and 90° for a deuteron bombarding energy of 5.5 MeV. Measurements were made by conventional double-scattering techniques using elastic scattering from helium at 45° as the analyser. The results show a strong energy dependence contrary to what one might expect on the basis of the lack of structure in the cross section. The maximum polarization observed at each energy is about 0.35.     

The Pion-Recoil Current and Quark-Cluster Effects of Electromagnetic Form Factors of Deuteron

The electromagnetic form factors of deuteron are investigated on hybrid quarkhadron model, whexe meson exchange and six-quark clusters are taken into account. It is found that pion-recoil current and six-quark clusters have important effects on charge form factor, magnetic structure function and tensor polarization, which are all sensitive to the interaction between nucleons. The theoretical predictions agree well with new experimental data.     

ON THE CONTRACTION AND DEFORMATION OF DEUTERON CLUSTER IN 6Li

The ground state of ⁶Li is investigated by means of the projected variational method for double well-cluster shell model. The results of the variational calculation show that the root-mean-square radius of d-cluster in the ground state of ⁶Li is smaller than that of free deuteron and as the mean distance between the α-cluster and the d-cluster decreases there are two effects on the d-cluster, namely contraction effect in which the d-cluster contracts first and then makes a bit extension and deformation effect in which the d-cluster makes oblation first and then streteches.It is also demonstrated by the calculation that the repulsive component of the odd sytate of N-N force and the pauli exchange of the nucleons between the clusters play an important role not only on the cluster structure in the ground state of ⁶Li but also on the contraction and the deformation of d-cluster in ⁶Li.     

Polarization of protons from the Be(d,p)Be reaction at Ed = 12.0 MeV

The polarization of protons from the ⁹Be(d,p)¹⁰Be reaction at E_d = 12.0 MeV was measured for the ground state and first excited state transitions. The results obtained are compared with the predictions of DWBA theory. It was found that better fits to the experimental data can be obtained using volume absorption in the distorting potential of the deuteron elastic channel. A comparison of the present polarization data with the vector analysing power for the same reaction and the same incident deuteron energy has also been made.     

Radiative corrections to polarization observables in elastic electron-deuteron scattering in hadronic variables

Model-independent QED radiative corrections to polarization observables in the elastic scattering of unpolarized and longitudinally polarized electron beam by a deuteron target are calculated. Two experimental setups are considered: the deuteron target is arbitrarily polarized, or the vector and/or tensor polarization of the recoil deuteron is measured. The calculations are based on taking all essential Feynman diagrams into account and using the covariant parametrization of the deuteron polarization state. The radiative corrections are calculated for the hadronic variables using invariant integration of the leptonic tensor. Numerical estimates of the radiative corrections to the polarization observables are made for various values of the kinematical vari-ables.     

Sensitivity of T20 indA →PX to the reaction mechanism and relativistic effects

A method for the analysis of interactions between fast deuterons and nucleons is developed, taking into account both the relativistic effects in the deuteron and the mechanism of their interaction. The inclusive proton spectra and the polarisation characteristics are investigated, taking for instance the fragmentation type processes of deuterons on nucleons. A strong sensitivity of the deuteron polarisation tensor component T₂₀ both to the reaction mechanism and to the relativistic structure of the deuteron is shown. It is shown that there can't be a direct indication of the 6q-state existence in the deuteron from the T₂₀ experimental data.     

Polarization of protons from the C(d,p)C reaction

The polarization of protons from the ¹²C(d, p)¹³C reaction has been measured for deuteron bombarding energies between 3.9 and 5.8 MeV. Angular distributions of the polarization for protons leaving ¹³C in its ground state have been measured for laboratory angles between 10° and 135° at several energies in the vicinity of a resonance at 4 MeV in order to determine the effect of that resonance on the polarization. Additional measurements were made at 0.4 MeV intervals throughout the energy range. These measurements demonstrate that the compound-nuclear resonances observed in the cross section do not significantly alter the polarization angular distributions except at back angles. The shape of the observed polarization angular distributions at all energies is quite similar to previous results obtained for deuteron bombarding energies up to 15 MeV.     

J/Ψ suppression in relativistic heavy ion collisions through final state interactions with excited nucleons

TheJ/Ψ suppression in relativistic heavy ion collisions through final state interactions with excited state nucleons is estimated in a manner analogous to that of Gerschel and Hüfner for ground state nucleons. If excited state nucleons are larger in size than nucleons in their ground state, theJ/Ψ absorption cross section is increased. Because of relativistic time dilation this effect does not significantly alter theJ/Ψ suppression previously found.     

Annular effect in MHD — an example of a boundary value problem to be solved by Lie series formalism

The relation between the parameters of the optical potential of the deuteron and those of its constituent nucleons is investigated. An analytical expression for the real depth of the deuteron potential is derived, where it is represented as the sum of the proton and neutron real potentials minus a correction factor. Optical model analysis is carried out for deuteron and proton elastic scatterings in order to test the derived relation.     

Radiative corrections to polarization observables in elastic electron-deuteron scattering in leptonic variables

The model-independent QED radiative corrections to polarization observables in elastic scattering of unpolarized and longitudinally polarized electron beams by a deuteron target are calculated in leptonic variables. The experimental setup when the deuteron target is arbitrarily polarized is considered and the procedure for applying the derived results to the vector or tensor polarization of the recoil deuteron is discussed. The calculation is based on taking all essential Feynman diagrams into account, which results in the form of the Drell-Yan representation for the cross section, and the use of the covariant parameterization of the deuteron polarization state. Numerical estimates of the radiative corrections are given in the case where event selection allows undetected particles (photons and electron-positron pairs) and the restriction on the lost invariant mass is used.