Sensitivity of polarization observables in elastic ed scattering to the neutron form factors

The deuteron elastic form factors are calculated within the Bethe-Salpeter approach with separable interaction. The charge, quadrupole, and magnetic form factors [F _C(q ²), F _Q(q ²), and F _M(q ²), respectively]; the structure functions A(q ²) and B(q ²); and the tensor polarization components T ₂₀(q ², T ₂₁(q ²), and T ₂₂(q ²) are investigated up to ?q ²=50 fm^?2. The role of relativistic effects is discussed, and a comparison with nonrelativistic calculations is performed. The effect of the neutron form factors on the deuteron form factors and especially on tensor polarization components is discussed too.     

Pion exchange current effects inv μ +d→μ− +p+p

The differential cross sectiondσ/dq ² for the processv _μ +d→μ ^?+p+p is studied using realistic deuteron wave functions and closure over the dinucleon states. The effect of meson exchange currents is estimated using one-pion exchange diagrams in the static limit. Implications of our present results on the determination ofF _A (q ²) from neutrinodeuteron reaction experiments are discussed.     

Inelastic electron-deuteron scattering with final-state interactions

Measurements of the cross sectiond ² σ/dΩ dE′ for the inelastic electron-deuteron scattering processe+d→e+n+p have been used to determine the electromagnetic structure of the neutron. The effects on the theoretical cross section of the structure of the deuteron and of interactions between the outgoing nucleons are examined in detail. We start with the relativistic invariant expressions of the one-nucleon exchange diagram including deuteron structure to obtain the interaction Hamiltonian. For the disintegration near the quasi-elastic peak thed-n-p vertex function can be represented by nonrelativistic deuteron wave functions. The final state interaction is calculated from phenomenological nucleon-nucleon potentials. The rescattering corrections are found to lead to a decrease in the peak value of the cross section between ?6% and ?2% depending on the electron momentum transfer q² which has been varied between 2.5f ^?2 and 40f ^?2. These corrections are largest for smallq ²<5f ^?2. Furthermore the results show that the influence of our insufficient knowledge of the deuteron structure on the cross section is small.     

The deuteron wave function at short range and the triton

It is shown that if one assumes something between zero and the prediction of the scaling model with dipole fit for the neutron electric form factor, then a variety of short-range behaviour for the deuteron wave function is consistent with existing experimental data on the deuteron electric form factor. This still relatively wide latitude for the inner deuteron wave function, consistent with existing experimental electromagnetic data, gives rise to an off-shell variation of approximately 1.2 MeV in the triton binding energy with a fixed ¹S₀ interaction and a P_D varying from 4.5 to 6.5 %. Interactions with greater densities of matter at short range bind the triton more strongly and closer to the experimental value. An off-shell variation of 0.7 MeV is obtained with a fixed p_d and singlet interaction. However, a single measurement of the deuteron tensor polarization at about q² = 20 fm^?2 would severely restrict this variation.     

Exclusive deuteron electrodisintegration at high neutron recoil momentum

We have determined the ²H(e, e′p)n cross section for neutron recoil momenta between 295 and 500 MeV/c. In this region the ³D₁ state contribution is predominant in the deuteron wave function. The high excitation energy (E_cm^np = 179 MeV) and the small momentum transferred (|;q_cm|;² = 1.66 fm^?) emphasize the influence of isobar configurations (IC). Experimental data are compared with calculations including isobar contributions, mesonic exchange currents and final state interactions.     

Intermediate energy deuteron-nucleus diffraction interaction

On the basis of diffraction scattering theory, elastic and inelastic deuteron-nucleus scattering, deuteron dissociation and stripping reactions have been studied at intermediate deuteron energies. The finite value of the nuclear surface diffuseness, Coulomb deuteron-nucleus interaction and internal deuteron structure have been considered in the analysis of differential and integrated deuteron-nucleus cross sections. The theoretically calculated deuteron cross sections are in good agreement with the experimental data.     

Threshold electrodisintegration of the deuteron caused by backward scattering of electrons

Using a new relativistic integral representation for the matrix element of electromagnetic current in terms of experimental phase shifts alone (representation of Shirokov RS) the cross section of the threshold electrodisintegration of the deuteron caused by backward scattered electrons is calculated for the S-wave deuteron in the interval of the four-momentum transfers squared 0.16 ? q² ? 5 fm^?2. Nucleon-nucleon interaction in the deuteron and the final state interaction (FSI) are taken into account in a unified manner and exactly. The effects of the meson exchange currents (MEC) and the inelastic n-p channels are neglected. The calculated cross section coincides with the experimental one.     

The pd → tπ+ reaction in an isobar model: Angular distributions

Various wave function effects are studied in the differential cross section for the pd → tπ⁺ reaction. These include both S- and D-waves for the deuteron and the triton as well as the production of p-wave and d-wave pions. For the triton a parametrized Faddeev wave function is employed and for the deuteron a wave function of Hulthén or McGee type. The two-body correlations considered are NΔ(⁵S₂, ^5D₂, ⁵P₃) and NN(¹D₂) which are found to be the most important partial waves in the pp → dπ⁺ reaction.     

The 6Li(e,e′α) and 6Li(e,e′d) reactions at 520 MeV

The reactions ⁶Li(e,e′α) and ⁶Li(e,e′d) have been studied at T₀ ≈ 520 MeV and q ≈ 1.4 fm^?1, by coincidence measurements. The angular dependence of the cross sections is interpreted in the plane wave impulse approximation to obtain the momentum distribution of α-particle and deuteron clusters in ⁶Li. The amount of clustering of ⁶Li is also discussed.     

On the normalization of the Gamov resonant wave function in the configuration space

The regularization of the normalization integral for the resonant wave function, proposed by Zeldovich, is valid only when |Req _res| > |Imq _res|. A new normalization procedure is proposed and implemented, which is valid when this condition fails. First, an arbitrarily normalized vertex function g(k) is calculated using the formula with the potential V(r) in the integrand. This Fourier integral converges for a potential with the asymptotics V(r) → constr ^?n exp(?μr) if |Imq _res| < μ/2. Then the function g(k) is normalized using the generalized normalization rule, which is independent of the resonance pole position. The proposed method is approved by the example of calculation for a virtual triton.     

The process γγ → X by parton model and prediction of equivalent-photon method for ee → ee + X

A parton model for the virtual photon process γ → X is examined. It is assumed that a scaling property applies and the total cross section is σ_γγ→X = s^?1φ(ξ), where the function ? is dependent on the scaling variable ξ defined by ξ = s/(q²₁q²₂). The cross section for the process ee → + X is calculated using the equivalent-photon technique.     

Deuteron size effects on its elastic scattering from1H and4He

The effect of change in deuteron size on its elastic scattering from protons and alphas is investigated by varying the Hulthen parameters of the deuteron wave function in the scattering process. The cross sections forp-d scattering, calculated in the Born approximation, are found to increase substantially at backward angles even when the deuteron size is reduced by a small amount, whereas the shape of the angular distribution does not change significantly. For theα-d elastic scattering, interaction potential is obtained by folding the deuteron wave function and the optical potential for nucleon-scattering. The cross sections calculated atE _d = 13·7 MeV, shows that the first minimum around Θ_cm = 60° is deepend as the deuteron size is reduced, while at 52 MeV bombarding energy, the size effects are not very distinct. These observations are useful in the interpretation of deuteron cluster knockout reactions.     

An isobar model for the pd → tπ+ reaction

The differential cross section for the pd → tπ⁺ reaction is calculated at the three proton laboratory energies 400, 470 and 600 MeV. The triton wave function is taken to be of correlated Gaussian form, and the deuteron is one of the s-wave forms due to Hulthén, McGee and Paris. The pion production is considered to take place from intermediate states based on the five types of two-body correlations NΔ(⁵S₂, ⁵D₂, ⁵D₀) and NN(¹D₂, ¹S₀). The final cross sections are not in good agreement with experiment.     

Weitere Messungen zur Anisotropie der intermolekularen Wechselwirkung durch Streuung von Molekülen in definiertem Quantenzustand

The interaction between diatomic molecules and rare gas atoms can be described by the realistic, though simplified potentialV=?[(r_m/r)¹²(1 +q₁₂P₂(cosθ))?2(r_m/r)⁶(1+q₆P₂(cosθ))] The determination of the parameters?, r _m andq ₆has been treated in the two previous parts of this series. The present final paper describes the determination of the anisotropy parameter in the repulsive part of the potential, q₁₂, for the system CsF-He. Whileq ₆ could be derived using only the dependence of the total scattering cross section on the molecular rotational state, the determination ofq ₁₂ requires, in addition, knowledge of the velocity dependence. The comparison of the experimental data for CsF in the rotational states ¦J, M〉=¦1, 1〉 and ¦1, 0〉 with cross sections calculated by means of the “high energy” approximation yields the result:q ₁₂=0.9±0.2. The validity of the “high energy” approximation in the velocity range covered by the experiment is discussed.     

High energy muon-nucleon inelastic scattering at lowq 2

The inelastic interactions of 150 GeV positive muons produced at Fermi Laboratory have been studied in nuclear emulsion. Secondary particles produced in these interactions have been identified, the energy spectra and angular distributions for pions and protons are given. The inclusive pionproduction reaction is studied and the relative shape ofp _t ² distribution is discussed. The average charged multiplicity relations are determined as a function of different parameters and are compared with the multiplicities produced in pure hadronic interactions. The integral cross sections have been measured and are compared with the first and second powers of 1/(1+q ²/m _p ² ) forσ _exp(q ²,v), the quantity commonly called the “virtualphoton-nucleon total cross section”. The values of the structure function νW ₂ are calculated for 0.02≤q ²≤0.5. The present data are compared with other muon data at the same energy.     

The stripping cross section for He4 (d,p) He5 under the assumption of cluster structures in the final nucleus

The differential cross section for the reaction He₄(d, p)He₅ is calculated assuming cluster configurations in the residual nucleus. The processes leading to the ground state and to the second excited state of He₅ are studied. The former is described by anα-particle — neutron configuration the latter by a triton — deuteron structure. Complete antisymmetrization of the wave functions, and thus exchange terms in the stripping amplitude are taken into account. The computed cross sections in the two cases differ appreciably in magnitude as well as in the angular distribution from one another.     

Isoscalar electromagnetic form factors and the structure of the deuteron at high momentum transfer

We derive general expressions for isoscalar electromagnetic form factors of nuclei including meson-exchange processes such as π, ?, ω and ?πγ exchange. Meson-nucleon vertices for nonzero momentum transfer as well as the effect of the finite width of the ?-meson are taken care of. Specifically, the electromagnetic form factors of the deuteron are calculated up to a momentum transfer of q² ≈ 200 fm^?2. A detailed numerical discussion of the various effects on meson-exchange processes is given. The effect of different deuteron wave functions and two types of photon-nucleon form factors are also discussed.     

Deuteron formation in nuclear collisions

Deuteron production cross sections are calculated from an intranuclear cascade model for Ne + U and Ar + Ca at 400 MeV/A. In effect, there are no adjustable parameters in this calculation. The parameters of the cascade code are fixed by sum charged inclusive data. Furthermore, the high momentum deuteron inclusive distribution is found to be insensitive to the details of the deuteron wave function. This latter observation leads to a justification of a generalized coalescence formula involving both momentum and spatial coordinates. Satisfactory agreement is found between our calculations and both the untriggered and high multiplicity triggered inclusive spectra of deuterons with energies ?50 MeV/A.     

Would the peak value of the electromagnetic quadrupole form factor of the deuteron determine the percentageD-state?

It is shown that short range unitary transformations on the deuteron wave function of the super-soft-core potential of de Tourreil and Sprung, which fix the percentageD state of the deuteronP _D, do not simultaneously fix the peak valueM of the electromagnetic quadrupole form factor of the deuteron within small error bars, even when the transformed wave functions are required to fit the quadrupole moment and the electric form factor of the deuteron within narrow limits. However there is a strong correlation betweenP _D andM ² for realistic interactions whose deuteron wave functions are suppressed at short distances.     

A semirelativistic calculation of the deuteron electrodisintegration at the quasielastic peak

The cross section for inelastic electron deuteron scattering at the quasielastic peak is calculated in the laboratory system, using complete relativistic kinematics. The difference between the exact cross section formula andDurand's simple sum rule expression is found to be approximately 1.2% for 4-momentum transfers of 2.5 to 4f^?1 and the influence of the deuteron wave function on the final results to be smaller than 1% for reasonable deuteron models. Final state corrections are introduced through a simple correction term in the cross section formula.