Search

A polarized proton beam extracted from SATURNE II and the Saclay polarized proton target were used to measure the rescattering observables $K_{onno}$ and $D_{onon}$ at 26 energies from 1.94 to 2.80 GeV and at 0.80 GeV. The beam and target polarizations were oriented vertically and left-right as well as up-down asymmetries in the second scattering on carbon were measured. The present data, obtained in small energy steps, are practically constant as a function of energy at 90°CM, where $K_{onno} = D_{onon}$ . These data will bring about important modification to phase shifts and stabilize the solutions.

A polarized proton beam extracted from SATURNE II and the Saclay polarized proton target were used to determine the spin correlation parameter Aoosk and the rescattering observablesKos″ so; Dos″ok, Nos″sn, andNonsk at 1.80 and 2.10 GeV. The beam polarization was oriented perpendicular to the beam direction in the horizontal scattering plane and the target polarization was directed either along the vertical axis or longitudinally. Left-right and up-down asymmetries in the second scattering were measured. A check for the beam optimization with the beam and target polarizations oriented vertically provided other observables, of which results forDonon andKonno at 1.80, 1.85, 2.04, and 2.10 GeV are listed here. The new data at 2.10 GeV suggest a smooth energy dependence of spin triplet scattering amplitudes at fixed angles in the vicinity of this energy.

The angular dependece of the pp elastic scattering spin correlation parameter was measured in the angular range from 60° to 97° CM at 14 energies between 1.96 and 2.23 GeV. A rapid decrease of the energy dependence of this observable at 90° CM is observed around 2.11 GeV kinetic energy. This agrees with the behavior of Aoonn predicted on the basis of an exotic six-quark structure. The Aoonn (90° CM), together with the known differential cross section, allows the determination of the absolute value of the pure spin-singlet amplitude. The energy dependence of this amplitude shows a shoulder centered at 2.11 GeV, corresponding to a total mass of 2.735 GeV and an estimated width of 17 MeV.

The vector analyzing power [ital iT][sub 11] of the reaction [pi][ital d][r arrow][ital pp] was measured at [ital T][sub [pi]]=350, 400, and 450 MeV. The results obtained at [ital T][sub [pi]]=350 MeV are in agreement with earlier measurements of [ital iT][sub 11] at 325 MeV. With increasing energies our results show a marked increase in the vector analyzing power up to a value close to its theoretical limit at [ital T][sub [pi]]=450 MeV ([radical][ital s] =2.40 GeV). In this energy region broad structure has been found in earlier measurements of [ital d][sigma]/[ital d][Omega] and [ital A][sub [ital y]0].

A single-spin asymmetry in the inclusive π 0 production at small x F was measured. In the experiment 40 GeV/c π − mesons were incident on transversely polarized protons and deutrons. An asymmetry of (40–50)% has been revealed in the hard scattering region.

A new measurement ofΔσT for polarized neutrons transmitted through a polarized proton target at 16.2 MeV has been made. A polarized neutron beam was produced with the3H(d, n)4 He reaction; proton polarization over 90% was achieved in a frozen spin target of 20 cm3 volume. The measurement yields the valueΔσT=(−126±21±14) mb. The result of a simple phase shift analysis for the3S1−3D1 mixing parameter e1 is presented and compared with the theoretical potential model predictions.

Experimental results are presented for the $\mathrm{pp}$ elastic-scattering single spin observable ${A}_{\mathrm{oono}}{=A}_{\mathrm{ooon}}{=A}_{N}=P,$ or the analyzing power, at 19 beam kinetic energies between 1795 and 2235 MeV. The typical c.m. angular range is $60--100\ifmmode^\circ\else\textdegree\fi{}.$ The measurements were performed at Saturne II with a vertically polarized beam and target (transverse to the beam direction and scattering plane), a magnetic spectrometer and a recoil detector, both instrumented with multiwire proportional chambers, and beam polarimeters.

A new measurement of $\Delta\sigma_T$ for polarized neutrons transmitted through a polarized proton target at 16.2 MeV has been made. A polarized neutron beam was obtained from the $^{3}\rm{H}(d,\vec n)^{4}\rm{He}$ reaction; proton polarization over 90\% was achieved in a frozen spin target of 20 cm$^3$ volume. The measurement yielded the value $\Delta\sigma_T=(-126\pm21\pm14)$ mb. The result of a simple phase shift analysis for the $^3S_1-^3D_1$ mixing parameter $\epsilon_1$ is presented and compared with the theoretical potential model predictions., Comment: 17 pages, 8 ps figures, available at http://www.troja.mff.cuni.cz/~dolezal/dstprep.html

The paper presents results on measuring the polarization in the reaction π − p→ π 0 n at 40 GeV/ c in the 4-momentum transfer range 0 t |⩽2 (GeV/ c ) 2 . The results based on the statistics of about 2.2 million recorded events made it possible to observe a noticeable value and complex structure in the polarization behaviour up to | t |⩽2 (GeV/ c ) 2 .

The spin rotation parameter R has been measured for elastic π − p scattering at 40 GeV/ c , at four momentum transfers t ranging from −0.19 to −0.52 (GeV/ c ) 2 . The average value within this interval is R π − p = -0.200± 0.023. The resulting constraints on the πN scattering amplitudes are discussed. The experiments also yields an average value for K − p scattering, R K − p scattering, R K − p = -0.16±0.16.

The polarization parameter in the reactions π−p→ηn and π−p→η′n at 40 GeV/c with −t ranging from 0 to 2.6 (GeV/c)2 and 1.0 (GeV/c)2, respectively, was measured in experiments using a propanediol polarized target. Only gamma particles from the neutral meson decay were detected. The polarization parameter of the first reaction turns out to be negative in a widet interval (0.05

The polarization parameter P has been measured for elastic π + p, K + p and pp scattering at 45 GeV/c. Four-momentum transfer ranges from −0.08 to −1.1 (GeV/) 2 for pp, and from −0.08 to −0.9 (GeV/) 2 for π + p and K + p. The energy dependence of the polarization P ( t ) in π + p and in K + p above 6 GeV/c incident momentum is compatible with interference between pomeron and Regge poles. On the other hand, the polarization in p p elastic scattering decreases faster than ordinary Regge model predictions. This result can be explained by interference between non flip and flip amplitudes of the pomeron, leading to negative values for the polarization.

The spin rotation parameterR in pp and π+ p elastic scattering at 45 GeV/c has been measured at the Serpukhov accelerator, for ¦t¦ ranging from 0·2 to 0·5 (GeV/c)2. The results are presented, together with previousR measurements at lower energies, and are compared with the predictions of Regge pole models. The equality of the values forR in proton-proton and pion-proton scattering, within the experimental errors, is a test of factorization of the residues.

The polarization parameterP has been measured for elastic scattering on polarized protons, of π−, K− and ¯p at 40 GeV/c and of π+, K+ and p at 45 GeV/c. Four-momentum transfer ranges from −0·08 to −1·8 (GeV/c)2 for π−p, and from −0·08 to about −1sd0(GeV/c)2 for p, π+, K± and ¯p. The angular distribution of the polarization in π−p exhibits the well known non sense double zero att=−0·6 (GeV/c)2. The K−p and ¯pp results are compatible with exchange degeneracy for ¦t¦r

We report final results on the polarization parameter P in elastic scattering of π − , K − and antiprotons at 40 GeV/ c incident momentum. The energy dependence of P (t) in π − p above 10 GeV/ c is well fitted by P (t) α s αR(t)-α P (t) where α R (t) are the effective Regge and Pomeron trajectories respectively. The data in K − p are compatible with exchange degeneracy. The results inp¯p show an important structure for |t|> 0.3 (GeV/c) 2 demonstrating the existence of a large helicity flip amplitude.

The results of the measurements of the spin-spin correlation parameter CNN in the energy region 0. 69–0. 95 GeV are presented.

The main parts of an apparatus for simultaneous measurements of the polarization and spin-rotation parameters in high-energy elastic scattering on polarized protons are described, including the beam design, the polarized target, detectors, fast electronics, and the data acquisition. Measurements have been performed in 1972 to 1974 at the Serpukhov accelerator with π − , K − and p of 40 GeV/ c , and with p, π + and K + of 45 Ge V / c incident momentum. In addition to the results for P and R , the experiment also yields information on the unpolarized differential cross section.

A statistically satisfactory description (χ 2 / χ 2 = 0.94, C.L. = 69% of the known experimental data on backward πN scattering in the region −2.86 (GeV/c)2 ⩽ u ⩽ 0.06 (GeV/c)2 and pL ≳ 7.8 GeV/c is obtained in the framework of the quasipotential approach. The predictions for higher values of pL are also given.

Relativistic formulae are obtained, expressing the polarization of the initially unpolarized particle in the scattering of an unpolarized nucleon on a polarized one, in terms of the polarization transfer tensor and in terms of the scattering matrix elements.

The phase-shift analysis of nucleon-nucleon scattering data at energies near 400 MeV has been performed. A search for the solutions of the phase shifts has been carried out for the maximal orbital momentum lmax = 4. Only the 1D2 wave is assumed to have an imaginary part. Seven solutions have been obtained in the region χ 2 ≦ 1.5 χ 2 . A detailed investigation has shown that six of them can be rejected with a probability of type I error smaller than 0.59% Tables of phase shifts are given and the energy dependence of phase shifts in the region 10–700 MeV are shown in the graphs.

The triple scattering depolarization transfer parameterD t in elastic p-p scattering was measured at an energy of 660 MeV using a polarzied proton target. All measurements have been carried out with the help of an optical spark chamber.

The new results of phase-shift analysis at energies of 23·1 and 18·2 MeV are discussed. Two and three solutions remain at these energies respectively. The measurements of triple n-p scattering parameters are necessary for obtaining the unambiguity of the solutions. It is shown that the Berkeley p-p polarization data at 19·7 MeV are in disagreement with other results.

Experimental data on πN scattering in the momentum transfer region 0.01⩽| t |⩽1.0 (GeV/ c ) 2 and P L ≳10 GeV/ c are described in the framework of the quasipotential approach. The parameters of the quasipotential are found which allow the data to be described satisfactorily.

Phase-shift analysis at 210 MeV has been performed taking l max = 5. New data on the differential cross section, polarization and triple scattering parameters have been used and the procedure leads to a unique solution. The angular dependences of experimental quantities are shown in diagrams.

The spin rotation sf R in pp and π + p elastic scattering at 45 GeV/c has been measured at the Seppukhov accelarator, for z . sfnc ; t |; ranging from 0.2 to 0.5 (GeV/) 2 . The results are presented, together with previous R measurements at lower energies. The equality of the values for R in proton-proton and pion-proton scattering, within the experimental errors, is a test of factorization of the residues in the pomeron exchange.

The preliminary results of polarization measurements in reaction π−+p→η+n at 40 GeV/c for the 4‐momentum transfers up to 1 (GeV/c)2 are presented. Averaged blue of the polarization in the t‐range 0,5

First results on measuring polarization in π - p →π°n reaction at 40 GeV/c are presented for the 4-momentum transfer range from 0.05 up to 0.4 (GeV/c)2. The experiment was carried out at the IHEP 70 GeV accelerator on a polarized proton target. Polarization in this reaction was earlier studied at incident momentum below 11.2 GeV/c/1–4/. Comparison of the present data with the previous ones allows us to see the polarization effect decreases with energy growth.

The spin correlation parameter Cnn has been measured in elastic pp scattering at 610 MeV at CM angles of 40, 67, 78, 90°. A polarized proton beam (PmaxB=0.38±0.02) and a ’’frozen’’ polarize proton target (PmaxT=0.97±0.04) have been used in the experiment.

The inclusive production of π0’s in the interaction of unpolarized π−, k−, and antiproton beams with polarized proton and deuteron targets has been studied at IHEP. The absolute value of the asymmetry for π0 production in the polarized proton and deuteron targets is between zero and fiften percent for large x=P*/P* max and small Pt and independent on the quark flavor. Results are presented and compared with theoretical calculations. (AIP)The inclusive production of π0’s in the interaction of unpolarized π−, k−, and antiproton beams with polarized proton and deuteron targets has been studied at IHEP. The absolute value of the asymmetry for π0 production in the polarized proton and deuteron targets is between zero and fiften percent for large x=P*/P* max and small Pt and independent on the quark flavor. Results are presented and compared with theoretical calculations. (AIP)

A 40%‐asymmetry has been revealed in the hard scattering region at 40 GeV. Systematic errors in the experiment are noticeable. The observed effect requires detailed discussion of the production mechanisms.