An experiment performed at Fermilab used double-arm calorimeter triggers to study di-jet production by 400 GeV protons and 200 GeVπ− mesons incident on liquid hydrogen. The observed ratio of positive to negative leading particles in the jets was compared forpp andπp production using a tree level parton scattering model. The results are moderately sensitive to the form of the pion gluon distribution function and yieldx g(x)⋍(1−x)2.75±0.40±0.75.
One parameter function is used for gluon distribution: X*G(X) = C*(1-x)**POWER.
The analyzing power Ay for π+p→ scattering at 68.3 MeV has been measured at the Paul Scherrer Institut with the magnetic spectrometer LEPS. The measurements cover the angular range 40°≤θlab≤70°. The protons have been polarized in a butanol target, operated in frozen spin mode. The S31 phase shift comes out by about 1° smaller than the Koch-Pietarinen [Nucl. Phys. A 336, 331 (1980)] phase shift analysis, supporting the necessity of an alternative dispersion analysis of πN scattering to determine the σ term and the πN coupling constant. © 1996 The American Physical Society.
The two data sets correspond to measurements with two different target compositions (see text).
Compensation of transverse momentum is studied in π+p interactions at 250 GeV/c. SignificantpT-transfer is found between c.m.s. hemispheres. With respect to the beam axis transverse momentum is compensated over the whole event, with respect to the sphericity axis mainly within one hemisphere. The highestpT in the event is mainly compensated by increased multiplicity. The QGSM and FRITIOF models qualitatively reproduce these effects, but important differences are observed.
Mean value of total transverse VECTOR defined as sum over all charged particles in the forward or backward hemispheres was measured.
Mean value of total transverse VECTOR defined as sum over all charged particles in the forward or backward hemispheres was measured.
No description provided.
Inclusive production of ϕ,K*0, and\(\overline {K*^0 } \) mesons has been measured in γp, π±p andK± p collisions at beam energies of 65 GeV<Eγ<175 GeV andEπ/K =80 and 140 GeV. Cross sections have been determined over the range 0<xF<1.0 and 0<PT<1.8 GeV/c. Emphasis is put on the comparison of cross sections for different projectiles as a function ofxF so as to study the effects of common quarks between the beam particle and the detected ϕ,K*0 or\(\overline {K*^0 } \). The data are compared with a parton fusion model. Many features of the data are well explained. In detail the strange quark appears to carry a large fraction of the kaon momentum and the contribution of the valence quarks from the proton is small.
Statistical errors only.
Statistical errors only.
Statistical errors only.. An entry 0.00 indicates a statistical error of < 0.005.
Total cross sections for the π − p single charge exchange and 20° “partial-total” cross sections have been measured between 126 and 202 MeV pion energy. The former are about 4% below similar results of Bugg et al. and (5–10)% below predictions made with currently accepted phase shifts. The latter agree quite well with calculations.
No description provided.
Data of the ηπ − system were obtained in the reaction π − p → ηπ − p at 6.3 GeV/ c beam momentum. About 17 k events of ηπ − were collected in the mass range 0.8 ⩽ M ηπ - ⩽ 1.8 GeV/ c 2 and in the range of the momentum transfer squared 0.075 ⩽ | t ′| ⩽ 0.60 (GeV/ c ) 2 . A large forward-backward asymmetry was observed around 1.3 GeV/ c 2 in the Gottfried-Jackson frame of the ηπ − system. A partial wave analysis of the data was performed. A peak of the D + wave attributed to a 2 (1320) is clearly seen. An enhancement is observed around 1.3 GeV/ c 2 in the P + wave.
No description provided.
No description provided.
Total cross-section measurements of the π+p→π+π+n reaction at pion kinetic energies of 180, 184, 190, and 200 MeV are reported. The threshold value for the amplitude a(π+π+) as well as the s-wave, isospin 2, ππ scattering length a20 were determined. The results were found to be in agreement with chiral perturbation theory and inconsistent with the calculations of Jacob and Scadron and the model of dominance by quark loop anomalies.
No description provided.
The spin-rotation parameters A and R and the related spin-rotation angle β have been measured for π+p and π−p elastic scattering using protons polarized in the scattering plane. The pion-beam momenta are 427, 471, 547, 625, and 657 MeV/c and the angular range is −0.9≤cosΘc.m.≤0.3. The scattered pion and recoil proton were detected in coincidence, using a scintillator hodoscope for the pions, and the Large Acceptance Spectrometer combined with the JANUS polarimeter for the recoil protons. The results are compared with the four recent πN partial wave analyses (PWA's). Our data show that the major features of these PWA's are correct. The A and R measurements complete our program of pion-nucleon experiments, providing full data sets at three of the above beam momenta. Such sets can be used to test the constraints in the PWA's or to obtain a model-independent set of πN scattering amplitudes.
BETA is the spin-rotation angle.
BETA is the spin-rotation angle.
BETA is the spin-rotation angle.
Measurements are reported of inclusivef2(1270) andf0(975) production in γp, π±p andK±p collisions at photon beam energies of 65 to 175 GeV and hadron beam energies of 80 and 140 GeV. Thef2 andf0 mesons were found at masses of 1.250 GeV and 0.961 GeV respectively. Inclusivef2 production at lowxF was found to have a similarpT dependence for each beam type, whereas an additional pion-exchange contribution was found for production by pions at highxF. Cross sections are compared with those for ρ0 production and give no indication of a non-q\(\bar q\) component in eitherf-meson state.
No description provided.
No description provided.
No description provided.
Results on the multiplicity structure of diffractively excited meson and proton systems in À+/K+p interactions at 250 GeV/c are presented for diffractive masses up to about 9 GeV. The energy dependence of the average charge multiplicity and the shape of the multiplicity distribution in terms of KNO-scaling and negative binomial distribution are investigated. The diffractive systems are compared toe+e−,lh and non-diffractivehh final states as suggested by modern approaches of the Pomeron-hadron collision. Systematic differences are found between diffractive meson and proton systems but also between diffraction and the reactions compared to.
No description provided.
No description provided.
No description provided.
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