By using a polarized deuteron target we have measured the asymmetry in the differential cross section for elastic scattering of protons on deuterons and for quasi-elastic scattering of protons on protons bound in deuterons between the two states of opposite polarization, normal to the scattering plane of the initial deuteron. The beam momentum was 1.21 GeV/ c . It is checked that the neutrons bound in the deuterons are polarized to approximately 20%.
NOT ALL DATA POINTS COMPILED.
Axis error includes +- 10/10 contribution (DS/DT DATA NORMALIZED TO THAT OF VINCENT 70).
Precise measurements of deuteron vector and tensor analyzing powers Ayd, Axx, Ayy, and Axz in d−p elastic scattering were performed via 1H(d→,d)p and 1H(d→,p)d reactions at three incoming deuteron energies of Edlab=140, 200, and 270 MeV. A wide range of center-of-mass angles from ≈10° to 180° was covered. The cross section was measured at 140 and 270 MeV at the same angles. These high precision data were compared with theoretical predictions based on exact solutions of three-nucleon Faddeev equations and modern nucleon-nucleon potentials combined with three-nucleon forces. Three-body interactions representing a wide range of present day models have been used: the Tucson-Melbourne 2π-exchange model, a modification thereof closer to chiral symmetry, the Urbana IX model, and a phenomenological spin-orbit ansatz. Large three-nucleon force effects are predicted, especially at the two higher energies. However, only some of them, predominantly dσ/dΩ and Ayd, are supported by the present data. For tensor analyzing powers the predicted effects are in drastic conflict to the data, indicating defects of the present day three-nucleon force models.
Angular distribution for DEUT P elastic scattering at EKIN of 140 MeV with the SMART spectrograph.
Angular distribution for DEUT P elastic scattering at EKIN of 270 MeV with the D-room polarimeter.
Angular distribution for DEUT P elastic scattering at EKIN of 270 MeV with the SMART spectrograph.
The angular distributions of the cross section, the proton analyzing power, and all proton polarization transfer coefficients of p→d elastic scattering were measured at 250 MeV. The range of center-of-mass angles was 10°–165° for the cross section and the analyzing power, and about 10°–95° for the polarization transfer coefficients. These are the first measurements of a complete set of proton polarization observables for p→d elastic scattering at intermediate energies. The present data are compared with theoretical predictions based on exact solutions of the three-nucleon Faddeev equations and modern realistic nucleon-nucleon potentials combined with three-nucleon forces (3NF), namely, the Tucson-Melbourne (TM) 2π-exchange model, a modification thereof (TM′) closer to chiral symmetry, and the Urbana IX model. Large effects of the three-nucleon forces are predicted. The inclusion of the three-nucleon forces gives a good description of the cross section at angles below the minimum. However, appreciable discrepancies between the data and predictions remain at backward angles. For the spin observables the predictions of the TM 3NF model deviate strongly from the other two 3NF models, which are close together, except for Kyy′. In the case of the analyzing power all 3NF models fail to describe the data at the upper half of the angular range. In the restricted measured angular range the polarization transfer coefficients are fairly well described by the TM′ and Urbana IX 3NF models, whereas the TM 3NF model mostly fails. The transfer coefficient Kyy′ is best described by the Urbana IX but the theoretical description is still insufficient to reproduce the experimental data. These results call for a better understanding of the spin structure of the three-nucleon force and very likely for a full relativistic treatment of the three-nucleon continuum.
Cross section and analyzing power measurements.
Proton polarization transfer coefficients.
The differential cross sections and vector analyzing powers for nd elastic scattering at En=248 MeV were measured for 10°–180° in the center-of-mass (c.m.) system. To cover the wide angular range, the experiments were performed separately by using two different setups for forward and backward angles. The data are compared with theoretical results based on Faddeev calculations with realistic nucleon-nucleon (NN) forces such as AV18, CD Bonn, and Nijmegen I and II, and their combinations with the three-nucleon forces (3NFs), such as Tucson-Melbourne 99 (TM99), Urbana IX, and the coupled-channel potential with Δ-isobar excitation. Large discrepancies are found between the experimental cross sections and theory with only 2N forces for θc.m.>90°. The inclusion of 3NFs brings the theoretical cross sections closer to the data but only partially explains this discrepancy. For the analyzing power, no significant improvement is found when 3NFs are included. Relativistic corrections are shown to be small for both the cross sections and the analyzing powers at this energy. For the cross sections, these effects are mostly seen in the very backward angles. Compared with the pd cross section data, quite significant differences are observed at all scattering angles that cannot be explained only by the Coulomb interaction, which is usually significant at small angles.
Cross section for N DEUT elastic scattering for data taken in 2003 in the backward direction in the centre-of-mass. Statistical errors only are given.
Cross section for N DEUT elastic scattering for data taken in 2000 in the backward direction in the centre-of-mass. Statistical errors only are given.
Cross section for N DEUT elastic scattering in the forward direction in the centre-of-mass. Statistical errors only are given.
The elastic scattering of 600-MeV protons from light nuclei has been studied at the National Aeronautics Space Administration Space Radiation Effects Laboratory (SREL) synchrocyclotron. Differential cross sections have been obtained for the scattering of protons from hydrogen, deuterium, helium-3, and helium-4. Polarization was measured for deuterium and He4 nuclei. The p−p cross-section data are in excellent agreement with the predictions from the Livermore phase shifts. Small-angle p−D, p−He3 elastic scattering data are compared with calculations based on the multiple-scattering theories of Watson and Glauber.
No description provided.
Differential cross section and polarization distributions are presented for elastic p p scattering at incident momenta of 1.73, 2.13, 2.37 and 2.97 GeV/ c . The data have been analysed in terms of a 5-parameter diffraction model. In terms of this model the difference in the shape of the differential cross sections for p p and pp elastic scattering is a result of the strong absorption in the p p system.
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Polarization and differential cross-section data for elastic scattering of negative kaons on polarized protons between 865 and 1330 MeV/ c are presented. Comparisons are made with predictions given by published energy dependent phase-shift analyses. The Legendre expansion coefficients characterizing the polarization distributions show remarkable structures resulting from excitation of Λ- and Σ-resonances. An analysis of the elastic and charge-exchange data in this region of momenta supports the assignments of J P = 3 2 + for the Λ(1870) resonance. The occurence of zero crossings in the polarization data is discussed.
No description provided.
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Polarization and differential cross-section data at 16 momenta between 0.86 and 2.74 GeV/ c are presented. (Preliminary data on some of the momenta have been published earlier.) In an energy-independent phase-shift analysis from threshold up to 2.5 GeV/ c , resonant-like as well as non-resonant solutions are found for the P 3 wave. An helicity flip-non-flip decomposition of the partial waves partly supports the indications found in the analyses of other reactions that the pomeron is built up mainly from s -channel helicity non-flip contributions.
No description provided.
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Polarization and differential cross-section data for elastic scattering of positive pions on protons between 0.82 and 2.74 GeV/ c are presented. A dip in the polarization, at constant u ≈ −0.65 GeV 2 , is observed. The data are compared with published phase-shift analyses.
No description provided.
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Proton elastic scattering off a polarized proton target has been measured at 150 GeV/ c , in the |; t |-range 0.2–3.0 GeV 2 . The results on polarization and differential cross section are presented.
No description provided.
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