M. Werlen

Spin dependence of the inclusive reaction p + p (polarized) → π0 + X at 24 GeV/c for high-pT π0 produced in the central region

Abstract The spin dependence of π 0 inclusive production by 24 GeV/ c protons has been measured using a polarized target for Fhe Feynman x near 0 in the transverse momentum range 1.0 p T c . The results indicate a negative updown asymmetry growing strongly with p T and greater than 50% in absolute value for p T greater than 2 GeV/ c .

Measurement of the polarization parameter in 24 GeV/c proton-proton elastic scattering at small momentum transfers

Abstract A measurement of the polarization parameter P0 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 , P0 is constant at about 0.03.

Measurement of the polarization parameter in 24|GeV/c pp elastic scattering at large momentum transfers

A measurement of the polarization parameter Po in pp elastic scattering has been made at 24 GeV/c over the four momentum transfer range .7 ≤ |t| ≤ 5.0 (GeV/c)2. The structure of Po 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

A new determination of αs using direct photon production cross sections in pp and p̄p collisions at s=24.3 GeV

CERN-PBAR/P accelerator. A NEW DETERMINATION OF ALPHA(S) USING DIRECT PHOTON PRODUCTION CROSS-SECTIONS IN P P AND ANTI-P P COLLISIONS AT S**(1/2) = 24.3-GEV.

A New determination of

CERN-PBAR/P accelerator. A NEW DETERMINATION OF ALPHA(S) USING DIRECT PHOTON PRODUCTION CROSS-SECTIONS IN P P AND ANTI-P P COLLISIONS AT S**(1/2) = 24.3-GEV.

\alpha_s

Abstract 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 | 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.

using direct photon production cross-sections in

The spin dependence of inclusive proton and pion production by 7.9 GeV/c protons has been measured using a polarized proton target, for nominal values of x = pLcm/pmaxcm = 0.7 in the transverse momentum range 0.4 GeV/c <ppt < 1.2 GeV/c, and for pt = 0.4 GeV/c in the range 0.1 < x < 0.96. The results indicate a positive asymmetry of +5% over this kinematic region, which corresponds to fragmentation of the unpolarized proton.

p p

Data are presented on the analyzing power A for p‐n elastic scattering at 24 GeV/c in the range 0.1?−t?0.8 (GeV/c)2.

and

The polarization parameter in pn elastic scattering has been measured at 24 GeV/c over the range of four-momentum transfer squared 0.1 < |t| < 1.25 (GeV/c)2, and found to be negative except for a zero at |t| = 0.65 (GeV/c)2.

\bar{p} p

The spin dependence of inclusive π0 production by 24 GeV/c protons has been measured using a transversely polarized proton target at 90° CM in the transverse momentum range 1 ≤ pt ≤ 2.5 GeV/c. The results indicate a negative up-down asymmetry growing strongly with pt (A = (-56 ± 32)%) at pt = 2. GeV/c.