[en] Measurements of angular distributions of the cross section, σ(θ), and vector and tensor analyzing powers have been obtained at E_d (lab) = 9.0 MeV and E_d (lab) = 2.0 MeV for the ⁶Li(rvec d,γ)⁸Be reaction. The measured analyzing powers include A_yy(θ) and A_y(θ) at E_d (lab) = 2.0 MeV and A_yy (θ), A_y (θ) and T₂₀(θ) at E_d (lab) = 9.0 MeV. Energy excitation functions of the differential cross section, σ(θ) at θ = 130 degrees were measured from E_d (lab) = 7.0 MeV to E_d (lab) = 14.0 MeV. Transition matrix element analyses of the angular distributions at E_d (lab) = 9.0 MeV and E_d (lab) = 2.0 MeV were performed. The results show the presence of 13% to 21% E1 radiation in addition to the dominant E2 radiation at E_d (lab) = 9.0 MeV and a dominant E1 radiation contribution, instead of dominant E2 radiation, of 57% at E_d (lab) = 2.0 MeV. The largest E1 component at both energies is the isospin forbidden E1 transition comprising 10% of the cross section at E_d (lab) = 9.0 MeV and 40% of the cross section at E_d (lab) = 2.0 MeV. The angular distributions at E_d (lab) = 9.0 MeV were compared to a simple direct capture (DC) calculation. The dominant E2 direct capture calculation gave a reasonable description of the tensor analyzing power A_yy (θ) but failed to reproduce the cross section σ(θ) and the vector analyzing power A_y(θ). This model leads to a D-state probability of P_D = 0.5% for the ground state of ⁸Be. A multichannel resonating group model (MCRGM) calculation was also performed. This calculation provided a fairly good representation of the data and predicts a D-state probability of P_D = 0.3% for the ground state of ⁸Be

[en] Electroproduction of the Δ isobar in C and Fe has been studied for incident electrons with energies between 0.6 and 1.6 GeV. A longitudinal-transverse decomposition of the inclusive cross section has been made for q²_μ = 0.1(GeV/c)². The residual longitudinal cross sections measured do not provide the additional strength needed above the quasifree region to satisfy the Coulomb sum rule. The transverse cross sections are in good agreement with data from photoabsorption

[en] Measurements of the ⁶Li(d vector, γ)⁸Be cross section, σ(θ), the vector analyzing power, A_y(θ) and the tensor analyzing powers, A_yy(θ) and T₂₀(θ), have been obtained at < E_dLab> = 9.0 MeV. A transition matrix element analysis was performed. A directcapture and a multichannel resonating group model (MCRGM) calculation indicated a ⁶Li + d D-state probability of (0.3-1.5)% in the ground state of ⁸Be. (orig.)

[en] The absolute differential cross section for the ³H(p,γ)⁴He reaction has been measured at θ_γ=90 degree for E_p=2.0--15.0 MeV, corresponding to photon energies E_γ=21.3--31.1 MeV. The present results are 35% lower than previously measured (p,γ) cross sections and are in excellent agreement with recent (γ,p) data obtained with monoenergetic photons. Comparing our results to current photoneutron cross sections gives a ratio σ(γ,p)/σ(γ,n)=1.09±0.17 for E_γ=24--31 MeV. This ratio is consistent with conventional theoretical predictions, indicating that no charge-symmetry violation in ⁴He is required

[en] The analysis of the cross section and analyzing power data of the ¹³C(rvec p,γ₀)¹⁴N reaction leads to two solutions for the E1 amplitudes and phases which contribute in the region of the giant dipole resonance. One of these solutions indicates that the reaction proceeds predominantly via d-wave capture while the other corresponds to predominant s-wave capture. In the present work, we have used the interference between the E_p=3.11 MeV M1 resonance and the E1-dominated background to determine which of the two off-resonance E1 solutions is the correct (physical) one. The results show that the dominant d-wave capture solution is the correct one in the region of this resonance, demonstrating that the low-energy off-resonance E1 strength has the same (dominant d-wave) structure as that expected from the giant dipole resonance

[en] Measurements of angular distributions of the cross section, vector and tensor analyzing powers have been performed at E_d(lab)=9.0 MeV and 2.0 MeV for the ⁶Li( vector d, γ)⁸Be reaction. Excitation functions were also measured for E_d(lab)=7.0-14.0 MeV at θ_lab=130 . Transition matrix element analyses of the angular distributions were performed at both energies. The results of these analyses at E_d(lab)=9.0 MeV show the presence of 13-21% E1 radiation in addition to the expected dominant E2 radiation. At E_d(lab)=2.0 MeV the reaction has a dominant E1 contribution comprising about 60% of the cross section. The largest E1 component at both energies is the isospin-forbidden E1 transition comprising 10% of the cross section at E_d(lab)=9.0 MeV and 40% of the cross section at E_d(lab)=2.0 MeV. The angular distributions at E_d(lab)=9.0 MeV were compared to a simple direct capture (DC) calculation, leading to a D-state probability of P_D=1.5% for the ⁶Li+d component of the D-state in the ground state of ⁸Be. A multichannel resonating group model (MCRGM) calculation was also performed and compared to the data. The MCRGM used an effective nucleon-nucleon two-body force and predicts a D-state probability of P_D=0.3% for the ⁶Li+d component of the D-state in the ground state of ⁸Be. ((orig.))

[en] Cross sections have been measured for 65 MeV π⁺ scattering to the ¹⁰B ground and first four excited states. The 1.74 MeV excited state results provide the first measurement of the energy dependence of the isovector spin-flip strength parameter. Our analysis indicates that the observed empirical enhancement of the isovector spin-flip strength has little or no dependence on energy at and below resonance. A mass dependence for the empirical enhancement factor may exist. copyright 1997 The American Physical Society