Inclusive ϱ 0 production has been investigated in p p reactions at 22.4 GeV/ c . The total cross section for ϱ 0 production is 8.1 ± 2.0 mb. The average ϱ 0 's per event is 0.17 ± 0.03. The average transverse momentum, as obtained by extrapolation of a fitted simple exponential to the p T 2 distribution, is 0.52 ± 0.12 GeV/ c . The Feynman x and c.m. rapidity distributions show ϱ 0 to be “centrally” produced.
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The mass spectrum of muon pairs in the range 5 to 15 GeV is studied in the inclusive reaction p+nucleus→μ++μ−+anything. The ϒ and continuum distribution are presented as is the A dependence of the continuum. Comparison with a parton-annihilation model yields a sea-quark distribution.
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Data are presented on the polarization parameter in pp and pn elastic scattering at 11.8 GeV/c for four-momentum transfers −t=0.15 to 0.9 GeV2. In contrast to lower energies where the pn polarization is positive, it is slightly negative at 11.8 GeV/c; averaging the data from −t=0.18 to 0.5 GeV2 we find P(pn)=(−0.9±0.5)%, to be compared with P(pp)=(5.6±0.8)%. These data, combined with our previous data at lower energies, show that the I=0 single-flip exchange amplitude has an anomalously rapid energy dependence.
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We present upper limits on the production of heavy leptons (L±) by neutrinos via the process νμ+Ne→L±+⋯, L±→e±+ν+ν¯. These limits imply that the L− and L+, if they couple in full strength to νμ, are heavier than 7.5 and 9 GeV, respectively. They also imply that the coupling strength νμ to the recently discovered 1.9-GeV heavy lepton τ is less than 0.025 of the normal νμ−μ coupling.
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Quasi-inclusive and total inclusive ϱ + , ϱ − and ϱ 0 cross sections have been studied, using data of a π + p and a pp bubble chamber experiment at 16 and 24 GeV/ c , respectively. In pp collisions it is found that the total inclusive cross sections for ϱ 0 , ϱ + and ϱ − production are about equal. This equality also holds for the differential cross sections d σ/ d y ∗ , all showing the characteristics of dominantly central production. In the π + p reactions the ϱ − are mainly produced centrally, whereas there are strong additional contributions in the beam fragmentation region for ϱ + and ϱ 0 mesons. In the central region, however, the cross sections for ϱ + , ϱ − and ϱ 0 production are almost equal within errors. All our findings agree with what is expected from quark model predictions.
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The inclusive production of resonances is systematically studied in K + p interactions at 32 GeV/ c . Total production cross sections are given for three baryon resonances, five vector and three 2 + tensor mesons. We also compare the central and fragmentation components of the total production cross sections with quark model predictions.
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We have measured the inclusive electroproduction of positive and negative hadrons in the quark fragmentation region using the streamer chamber at DESY. Data are presented in terms of the variable z p = p / v in the kinematic region 1.8 < W < 2.8 GeV and 0.3 < Q 2 < 1.4 GeV 2 . The positive hadron distributions contain a strong proton component. After subtraction of the proton component and elastic rho events, the distribution (1/ σ tot ) d σ /d z p for positive and negative hadrons agrees well with the corresponding distribution from e + e − annihilation (DORIS data). This behaviour supports the validity of the quark-parton model at surprisingly low Q 2 and W .
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We report results from a measurement of the inclusive processes pp→Xp and pd→Xd in the range 5<Mx2s<0.1, 0.01≲|t|≲0.1 (GeV/c)2, and incident proton momenta of 65, 154, and 372 GeV/c. Both pp and pd data show an exponential t dependence and a dominant 1Mx2 behavior for Mx2s≲0.05. By comparing pp and pd data we test factorization and, using the Glauber model, we measure the XN total cross section, σXN=43±10 mb.
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The cross section ratio of the elastic neutral current reaction ν p→ ν p to the quasi-elastic charged current reaction ν n→ μ − p has been measured in the kinematical region 0.3⩽ q 2 ⩽1.0 (GeV/ c ) 2 . The measured value is R M =0.17±0.08. Model dependent corrections are applied, especially for ν n→ ν n contamination, and the result is compared to various models.
(C=OBSERVED) and (C=CORRECTED) are the observed and corrected for the nuclear effects ratios.
The inclusive reactions pn → p s + x and π + n → p s + x at incident momentum of 195 GeV/ c have been studied in an exposure of the Fermilab 30 inch deuterium filled bubble chamber to a mixed ( π + , p) beam. Analysing the t and M 2 dependence of our data within the framework of triple-Regge models we conclude that pion exchange yields a dominating contribution. Comparing our data with the pp results we conclude that isoscalar Regge exchange, ω, is much larger than isovector, ϱ, Regge exchange. We observe significant leading π − emission from the recoiling mass x, comparable to that observed in on-mass-shell π − p → π − experiments. This verifies our conclusions about pion-exchange dominance in the above reactions.
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