J.C. Hiebert

Neutron spectra at 0° from p—p and p—d collisions at 647 and 800 MeV incident energies

Abstract The p—d spectra show sharp high-energy peaks (≈ 15 MeV FWHM) with integrated yields of 30 and 31 mb/sr, respectively and with lower-energy bumps associated with pion production. The p—p spectra reflect the influence of the Δ(1232) resonance.

Single-proton transfer reactions on N = 50 nuclei

Abstract Deuterons accelerated to 30, 35.5 and 40 MeV were used to investigate 89Y(d, 3He)88Sr reactions. A detailed study of the 88Sr ground state was made using 88Sr(d, 3He)87Rb reactions at 35 MeV and 88Sr(3He, d)89Y reactions at 33.4 MeV. Angular distributions are compared with local zero-range DWBA calculations from which the transferred angular momenta and spectroscopic factors are deduced. The analysis indicates that the major proton configurations in the 88Sr ground state are 0.7 (2 p 1 2 ) −2 + 0.2 (2 p 3 2 ) −2 + 0.1 (1 f 5 2 ) −2 , in good agreement with recent theoretical calculations.

(α, 3He) and (α, t) reactions on 40Ca

Abstract Angular distributions have been measured for several levels excited in the 40 Ca(α, 3 He) 41 Ca and 40 Ca(α, t) 41 Sc reactions at 40 MeV bombarding energy. 3 He and triton groups corresponding to several known levels in 41 Ca and 41 Sc were observed, in addition to 41 Sc levels at 3.356±0.020 and 3.905±0.020 MeV excitation energy which have not been reported previously. DWBA calculations were performed in both the zero- and finite-range approximations, and spectroscopic factors are compared with the results of other reactions. The (α, 3 He) and (α, t) reactions appear to selectively excite analogue states in the 41 Ca- 41 Sc mirror nuclei, most of which correspond to an l = 3 or l = 4 angular momentum transfer.

Neutron spectra at 0° from (p, n) reactions on 9Be, 12C, and 27Al at 647 and 800 MeV

Abstract The measured cross sections show a narrow high-energy peak (20–30 MeV/ c FWHM ) and a broad bump at lower momenta associated with pion production. Comparison is made to an intranuclear cascade calculation.

The measurement of KNN,KLLINpd →nX and p9Be→nX at 800 MeV☆

Abstract The polarization transfer parameters,KNN and KLL, have been measured in p d→ n X and p 9Be→ n X at 0° and 800 MeV. The quasifree p d→ n X values for KNN and KLL are close to the free n-p measured values. The rather large values of KLL demonstrate that this transfer mechanism will provide a useful source of polarized neutrons at medium energies.

Neutron hole states in 138La and 140Pr

Abstract Protons accelerated to 30 MeV were used to investigate low-lying states in the odd-odd nuclei 138 La and 140 Pr with (p, d) reactions. The elastic scattering of 30 MeV protons and 23 MeV deuterons was also studied to determine optical potentials. Experimental angular distributions are compared with distorted-wave Born approximation calculations to extract spin, parity, and spectroscopic factors for levels up to 432 keV of excitation in 140 Pr and 530 keV in 138 La. Comparisons with the simple shell-model predictions and extended shell-model calculations are presented. The 140 Pr levels appear experimentally to have an almost pure particle-hole structure whereas the 138 La levels exhibit substantial mixing.

The measurement of KNN and KLL in at 800 MeV

Abstract The spin-transfer parameters K NN and K LL have been measured for at 0° and 800 MeV for neutron momenta between 700 and 1200 MeV c . Peak values of K NN and K LL are −0.30 ± 0.05 and −0.5 ± 0.1 respectively. These results are in substantial disagreement with VerWests field theoretic model.

Energy-dependent measurements of the pp elastic analyzing power and narrow dibaryon resonances

Abstract The energy dependence of the pp elastic analyzing power has been measured using an internal target during polarized beam acceleration. The data were obtained in incident-energy steps varying from 4 to 17 MeV over an energy range from 0.5 to 2.0 GeV. The statistical uncertainty of the analyzing power is typically less than 0.01. A narrow structure is observed around 2.17 GeV in the two-proton invariant mass distribution. A possible explanation for the structure with narrow resonances is discussed.

Differential cross-section for n p elastic scattering in the angular region 50-degrees < Theta* < 180-degrees at 459-MeV

The n-p elastic differential cross section in the angular range 51/sup 0/..d..pi../sup 0/). A monoenergetic neutron beam bombarded a liquid hydrogen target, and the protons and deuterons ejected from the target were detected by a multiwire proportional chamber spectrometer which measured their momentum, angle, and mass. The results resolve discrepancies between previous measurements of this observable, and are in reasonable agreement with Saclay data at large angles, and with a phase shift fit. Evidence for accuracy of the shape of the angular distribution is provided by the good value obtained for the pion-nucleon coupling constant (f/sup 2/ = 0.0759 +- 0.0030) when the pole-extrapolation method of Chew is used to extract f/sup 2/ from this shape.

Differential cross section for n − p elastic scattering in the angular range 51 ° θ * 180 ° at 647.5 MeV

The n-p elastic differential cross section in the angular range 51/sup 0/..d..pi../sup 0/). A monoenergetic neutron beam bombarded a liquid hydrogen target, and the protons and deuterons ejected from the target were detected by a multiwire proportional chamber spectrometer which measured their momentum, angle, and mass. The results resolve discrepancies between previous measurements of this observable, and are in reasonable agreement with Saclay data at large angles, and with a phase shift fit. Evidence for accuracy of the shape of the angular distribution is provided by the good value obtained for the pion-nucleon coupling constant (f/sup 2/ = 0.0759 +- 0.0030) when the pole-extrapolation method of Chew is used to extract f/sup 2/ from this shape.