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.
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We report on a study of inclusiveπ0 and η meson production inπ+p andK+p interactions at 250 GeV/c beam momentum. The Feynman-x spectrum ofπ0 is very similar in shape and normalization to that of negatively charged particles produced in the same experiment. The results are compared with data at other energies and with FRITIOF model predictions. This model overestimates the η cross section by a factor of 2.5. It reproduces theπ0 cross section correctly, but predicts a too hardπ0x distribution.
Data from Gamma Detectors only.
Data from Gamma Detectors only.
Data from RCBC only.
Inclusive production of direct soft photons is studied inK+p andK+π interactions at 250 GeV/c. Total cross sections, Feynman-x and transverse momentum distributions of direct γ's are presented. The measured cross sections are several times larger than expected from QED inner bremsstrahlung, indicating the presence of an anomalous soft photon source. The model of Lichard and Van Hove, based on the “cold quark-gluon plasma” picture, agrees with the data.
Results extrapolated below p(gamma) = m(pi0)/2.
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We present inclusive ϱ ±,0 and ω cross sections in the beam fragmentation region of π + p interactions at 250 GeV/ c . The near equality of the ϱ + and ϱ 0 cross sections implies suppression of valence quark recombination in forward vector meson production.
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Cross sections and charged multiplicity distributions for π+p,K+p andpp interactions at 250 GeV/c are presented and compared to each other as well as to earlier (for π+p andK+p lower energy) data. Consistently, the meson-proton (M+p) data have narrower multiplicity distributions and higher average multiplicity thanpp data. Up to our energy, generalized KNO functions describe the energy dependence of the shape of the multiplity distribution with one parameter forM+p and one forpp collisions. If interpreted in terms of negative binomials, the parameter 1/k tends to be slightly lower forM+p than forpp data. For both types of hadron-hadron collision, 1/k is larger than fore+e− andlp collisions.
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A detailed study ofJ/ψ hadronic production has been performed in a high statistics experiment (more than 1.5 106J/ψ observed in their dimuon decay mode). Data have been taken with incident π±,K±,p±, on hydrogen and platinum targets, at 150, 200 and 280 GeV/c. We find from the observed nuclear dependance of the cross sections, that about 18% of theJ/ψ are produced diffractively. Using known structure functions of the quarks in the nucleon and in the pion, we derive estimations for the gluon structure functions.
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Differential cross sections for π − p and pp elastic scattering have been measured at incident momenta ranging from 30 to 345 GeV and in the t range 0.002 (GeV/ c ) 2 ⩽ | t | ⩽ 0.04 (GeV/ c ) 2 . From the analysis of the data, the ratio ϱ ( t = 0) of the real to the imaginary parts of the forward scattering amplitude was determined together with the logarithmic slope b of the diffraction cone.
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The differential cross section of π − p scattering has been measured in the energy region 100–345 GeV and in the t -range 0.002<| t |< 0.04 (GeV/ c ) 2 . The real part of the π − p scattering amplitude has been extracted from the data. The results show that the real part continues to increase with energy. The energy dependence of the slope parameter has also been determined. The shrinkage found expressed in terms of the slope of the pomeron trajectory is2 α ′ p =0.23±0.04 (GeV/ c ) −2 . This agrees with the energy dependence found at larger| t |-values.
RE(AMP)/IM(AMP) (REAL/IMAG) AND SLOPE PARAMETERS DEDUCED FROM A FIT TO D(SIG)/DT IN T HE COULOMB INTERFERENCE REGION (-T = 0.002 TO 0.04 GEV**2).
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