Antiproton-proton elastic scattering has been measured at 100 GeV/c for 0.5<−t<2.5 (GeV/c)2 and at 200 GeV/c for 0.9<−t<4 (GeV/c)2. The data show that the −t≃1.4 (GeV/c)2 dip recently observed at 50 GeV/c persists to higher incident momenta. Proton-proton measurements made at the same beam momenta show similar structure.
CLEAR DIP OBSERVED AT -T=1.4 (GEV/C)**2.
Results are presented on π±p, K±p, and p±p elastic scattering measured with an apparatus having acceptance of 0.5<−t<2.5 (GeV/c)2 and 0.9<−t<11 (GeV/c)2 at 100 and 200 GeV/c, respectively. A diffractionlike dip is seen for the first time in the π−p t distribution at −t=4 (GeV/c)2. All meson-proton cross sections are found to be similar in the range 1<−t<2.5 (GeV/c)2, although some small systematic differences are observed. Cross sections for pp and p―p are compared with previous data.
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Proton-proton elastic scattering using 201- and 400-GeV/c extracted beams at Fermilab has been measured in the region 4.9<−t<14.4 GeV2. Contrary to predictions of diffraction models, there is no sign of a second dip or "break," and the slope A in the fit exp(At) is smaller than predicted. It drops from 1.5 to 0.8 GeV−2 over our t range. The shape of the t distribution can be fitted by the power law dσdt∝t−8.4 which is close to a quantum-chromodynamics (QCD) prediction of t−8. At fixed t the 201-GeV/c cross sections are about 2.3 times those at 400 GeV/c which is compatible with the QCD and constituent-interchange-model prediction that dσdt∝s−10 at fixed ts.
LOW T.
HIGH T.
LOW T.
Proton-proton elastic scattering has been measured over the angular range 7 to 16 mrad at centre-of-mass energies of 31, 45 and 53 GeV using the CERN Intersecting Storage Rings. The results indicate that the diffraction peak has continued to shrink with increasing energy, but not as fast as suggested by the results at lower energies.
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This work extends our previous investigations at the CERN Intersecting Storage Rings, with improved statistics at three different energies, wider angular range and a better control over systematic errors. Values for the (diffraction) shape parameter b are given.
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We have investigated the above processes at the CERN Intersecting Storage Rings (ISR). Results show a marked change of the slope parameter b ( t , s ) = (d/d t ) ln (d σ /d t ) around − t ≈ 0.10 GeV 2 . The s − and t − dependence of b ( t , s ) have been observed over the interval 460 GeV 2 < s < 2900 GeV 2 and 0.02 GeV 2 < t < 0.40 GeV 2 .
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A measurement of the polarization parameter P 0 in pp elastic scattering has been made at 24 GeV/ c over the range | t | = 0.1 to 0.9 (GeV/ c ) 2 , positive, falling to zero around | t | = 0.8 (GeV/ c ) 2 . For the range 0.1 ⪕ |t| ⪕ 0.4 GeV /c) 2 , P 0 is constant at about 0.03.
Axis error includes +- 5/5 contribution (SYS-ERR DUE MAINLY TO UNCERTAINTY IN KNOWLEDGE OF ABSOLUTE VALUE OF TARGET POLARIZATION).
The polarization parameter in proton-proton elastic scattering has been measured at an incident momentum of 7.9 GeV/ c and four-momentum transfers in the range 0.9 < | t | < 6.5 (GeV/ c ) 2 using a high intensity unpolarized proton beam incident on a polarized proton target. The angle and momentum of the forward scattered protons were measured with a magnet spectrometer and scintillation counter hodoscopes and the angle of the recoil proton was measured using similar hodoscopes. A clean separation between the elastic scattering from free hydrogen and that coming from inelastic interactions and from interactions with complex nuclei in the target was obtained. The polarization shows substantial structure rising from zero at | t | = 1.0 (GeV/ c ) 2 to a maximum at | t | = 1.7 (GeV/ c ) 2 and then falling to zero at | t | = 2.0 (GeV/ c ) 2 . There is evidence of a further peak at | t | = 2.8 (GeV/ c ) 2 . Above | t | = 3.25 (GeV/ c ) 2 the polarization is small and consistent with zero. A comparison of these data with data obtained at other beam momenta shows that the polarization parameter has a strong momentum dependence.
No description provided.
The pp analyzing power was measured using the SATURNE II polarized proton beam and the Saclay frozen spin polarized target. The measurements at 0.88 and 1.1 GeV were carried out in the angular region θ CM from 28° to ≅50° and complete our previous measurements from 45 ° to 90°. Above 1.1 GeV the measurements presented here cover both regions, extending from θ CM = 28° (at the lower energies) or θ CM = 18° (at the higher energies) to θ CM > 90°. The shape of the angular distribution A oono ( pp ) = ƒ(θ CM ) changes considerably with increasing energy. The new data show the onset of a characteristic t -dependence of the analyzing power, with a minimum at − t ≅ 1.0 (GeV/ c ) 2 followed by a second maximum at − t ≅ 1.5 (GeV/ c ) 2 . This structure is present at all energies, from kinematic threshold to 200 GeV.
Errors are statistical plus random-like instrumental uncertainties. Results using polarised target.
Errors are statistical plus random-like instrumental uncertainties. Results using polarised target.
Errors are statistical plus random-like instrumental uncertainties. Results using polarised target.
A measurement of the polarization parameter P 0 in pp elastic scattering has been made at 24 GeV/ c over the range of momentum transfer squared 0.7 < | t | < 5.0 (GeV/ c ) 2 . The structure of P 0 has changed compared to typical lower energy data. The second peak is suppressed and a dip has appeared at | t | = 3.6 (GeV/ c ) 2 .
No description provided.
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