The polarization transfer κ 0 and the tensor analyzing power T 20 for the 1 H d p)d reaction have been measured up to an internal momentum of k = 0.58 GeV/c. Comparison of the same observables obtained in recent studies for 1 H d p)d reaction, as a function of k , show different behavior. However the data from these two reactions are almost identical when compared in T 20 versus κ 0 correlation plots. We discuss similarities and differences observed in the two reactions.
The authors use the Infinite Momentum Frame variable K= M( proton) * sqrt(1/(4*a*(1-a)) - 1), where a = (E(proton)+P_long(proton))/(E(deut)+P(deut)).
The angular distributions of the analyzing power for the pp → dπ + reaction have been measured at seven energies T p = 1.2, 1.4, 1.6, 1.7, 1.8, 2.0 and 2.3 GeV. The data show a strong energy dependence with a structure centered at √ s π d = 2.66 GeV. Possible interpretations are presented in the frame of the OPE model and involving the question of the excitation of a dibaryon resonance.
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The total cross section of the pp -> pp eta' reaction has been measured at two energies near threshold by detecting the final protons in a magnetic spectrometer. The values obtained are about a factor of 70 less than for the corresponding eta production, in good agreement with the predictions of a one-pion-exchange model.
Axis error includes +- 10/10 contribution (Overall normalization error already included).
Axis error includes +- 10/10 contribution (Overall normalization error already included).
The polarization of the proton from the inclusive breakup reaction 1 H( d , p )X at 2.1 GeV was measured at 0°. The results are expressed as the ratio of the proton polarization, P p , to the deuteron beam polarization, P d , κ 0 = P p / P d . The measured values of κ 0 range from +0.983 to -0.305 and are in general agreement with the expected behavior arising from the D state in the deuteron wave function.
POL(C=DEUT) is the DEUT polarization, the P(P=3,RF=ANTILAB) is the proton momentum in DEUT rest frame.
The reaction p + d → π − + X has been studied at Saturne at 1.45, 2.10 and 2.70 GeV, using the spectrometer SPES III. The analysing power and the differential cross sections show no evidence for narrow structures which could be interpreted as a resonance in the three baryon system. At the lowest incident energy, the shapes of the experimental cross sections are well reproduced by phase-space distributions.
Axis error includes +- 0.0/0.0 contribution (?////).
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The total cross section for omega production in the pp -> pp omega reaction has been measured at five c.m. excess energies from 3.8 to 30 MeV. The energy dependence is easily understood in terms of a strong proton-proton final state interaction combined with a smearing over the width of the state. The ratio of near-threshold phi and omega production is consistent with the predictions of a one-pion-exchange model and the degree of violation of the OZI rule is similar to that found in the pi-p -> n omega/phi reactions.
Axis error includes +- 0.0/0.0 contribution (?////Not given separately).
The cross section and tensor analysing power t_20 of the d\vec{d}->eta 4He reaction have been measured at six c.m. momenta, 10 < p(eta) < 90 MeV/c. The threshold value of t_20 is consistent with 1/\sqrt{2}, which follows from parity conservation and Bose symmetry. The much slower momentum variation observed for the reaction amplitude, as compared to that for the analogous pd->eta 3He case, suggests strongly the existence of a quasi-bound state in the eta-4He system and optical model fits indicate that this probably also the case for eta-3He.
The spin-averaged amplitude squared is defined as follows: ABS(AMP)**2 = (P_deut/P_eta)*D(SIG)/D(OMEGA) and obtained by assuming the angular distributions to be isotropic. The errors in this quantity includes a contribution from Delta(P_eta). The statistical error of about 2% are added quadratically to the systemat ic error.
The reaction pp→pπ+N has been studied at three energies ( Tp=1520, 1805, and 2100 MeV) and six angles from 0° up to 17° (laboratory). Several narrow states have been observed in missing mass spectra at 1004, 1044, and 1094 MeV. Their widths are typically 1 order of magnitude smaller than the widths of N* or Δ. Possible biases are discussed. These masses are in good agreement with those calculated within a simple phenomenological mass formula based on color magnetic interaction between two colored quark clusters.
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The pp→ppη reaction is studied at energies near the η production threshold. The total cross sections at nominal machine energies of 1260, 1265, and 1300 MeV are 90±15, 790±120, and 3460±690 nb, respectively. None of the existing perturbative model calculations reproduces the energy dependence, which deviates strongly from phase space. This suggests that the cross section is enhanced in the near vicinity of the production threshold by a large η−pp scattering length.
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