Data on multiplicities of charged particles produced in proton-nucleus and nucleus-nucleus collisions at 200 GeV per nucleon are presented. It is shown that the mean multiplicity of negative particles is proportional to the mean number of nucleons participating in the collision both for nucleus-nucleus and proton-nucleus collisions. The apparent consistency of pion multiplicity data with the assumption of an incoherent superposition of nucleon-nucleon collisions is critically discussed.
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The excitation of theΔ resonance is observed in proton collisions on C, Nb and Pb targets at 0.8 and 1.6 GeV incident energies. The mass E0 and widthΓ of the resonance are determined from the invariant mass spectra of correlated (p, π±)-pairs in the final state of the collision: The mass E0 is smaller than that of the free resonance, however by comparing to intra-nuclear cascade calculations, this reduction is traced back to the effects of Fermi motion, NN scattering and pion reabsorption in nuclear matter.
WITHIN THE DETECTORS ACCEPTANCE RESULTS.
WITHIN THE DETECTORS ACCEPTANCE RESULTS.
WITHIN THE DETECTORS ACCEPTANCE RESULTS.
Theπ0 andη0 production is studied inπ−p interactions at 360 GeV/c. The cross section forπ0 production in the forward hemisphere (X>0) isσ(π0)=(49.7 ± 1.0 ± 1.1) mb and for η withX>0.1,Nch>2,σ(η0)=(3.1 ± 0.5) mb. The ratio of theπ0 toη0 cross section forX>0.1,Nch>2 isσ(π0)/σ(η0). Results on FeynmanX andpT distributions are presented. The data were obtained using the European Hybrid Spectrometer EHS and the bubble chamber LEBC at CERN.
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The inclusive π0 and γ production is studied in a\(\bar PP\) experiment at 32.1 GeV/c performed in the Mirabelle bubble chamber with a sensitivity of ∼2.7 events/μb. Total and topological π0 cross sections are presented. The π0 and γ longitudinal and transverse momentum distributions are obtained and compared with\(\bar PP\) data at 22.4 GeV/c andK ± P data at 32.1 GeV/c. The inclusive π0 distributions are also compared to those obtained for charged pions in the same experiment.
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Multiplicities of charged hadrons produced in deep inelastic muon scattering off a $^6$LiD target have been measured as a function of the DIS variables $x_{Bj}$, $Q^2$, $W^2$ and the final state hadron variables $p_T$ and $z$. The $p_T^2$ distributions are fitted with a single exponential function at low values of $p_T^2$ to determine the dependence of $\langle p_T^2 \rangle$ on $x_{Bj}$, $Q^2$, $W^2$ and $z$. The $z$-dependence of $\langle p_T^2 \rangle$ is shown to be a potential tool to extract the average intrinsic transverse momentum squared of partons, $\langle k_{\perp}^2 \rangle$, as a function of $x_{Bj}$ and $Q^2$ in a leading order QCD parton model.
PT dependences of the differential multiplicities for 0.0045 < x_Bjorken < 0.0060 and 1.00 < Q^2 < 1.25 GeV^2 for Positive hadrons.
PT dependences of the differential multiplicities for 0.0060 < x_Bjorken < 0.0080 and 1.00 < Q^2 < 1.30 GeV^2 for Positive hadrons.
PT dependences of the differential multiplicities for 0.0060 < x_Bjorken < 0.0080 and 1.30 < Q^2 < 1.70 GeV^2 for Positive hadrons.
We present final results on the inclusive production of the\(\bar K^{*0} (890)\),K*−(890),K*0(890),K*−(890),K*−(1420), and\(\bar K^{*0} (1420)\) resonances inK−p interactions at 32 GeV/c. Total cross sections and invariantx-distributions are determined. Inclusive cross sections of\(\bar K^{*\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{o} } (890)\) amount to ≃4 mb each, of\(\bar K^{*\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{o} } (1420)\) to ≃1 mb and ofK*0(890) to ≃0.8 mb. These values are in agreement with additive quark model predictions. All strangenessS=−1 resonances are predominantly produced in the forward hemisphere, the tensor mesons being more peripherally produced than the vector ones. The\(\bar K^{*\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{o} } (890)\) density matrix elements andt-distributions are obtained. The unnatural spin-parity exchange contribution to inclusive\(\bar K^{*\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{o} } (890)\) production amounts to ≳60% at |t|<0.4 GeV2 and decreases with increasing |t|. Whenever relevant, a comparison is also made with available data at other energies.
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A study of strange particle production in muon neutrino charged current interactions has been performed using the data from the NOMAD experiment. Yields of neutral strange particles K0s, Lambda, AntiLambda have been measured. Mean multiplicities are reported as a function of the event kinematic variables Enu, W2 and Q2 as well as of the variables describing particle behaviour within a hadronic jet: xF, z and pT2. Decays of resonances and heavy hyperons with identified K0s and Lambda in the final state have been analyzed. Clear signals corresponding to K*+-, Sigma*+-, Xi- and Sigma0 have been observed.
Measured yields of the neutral strange particles measured in this analysis.The second line (marked *) is a recalculation taking into account contributions from both primary and secondary V0. The values for K0 are the K0S rates multipl ied by 2.
Measured yields as a function of E, the neutrino energy.
Measured yields as a function of W**2.
We report the first precision measurements of the scaled momentum, the charge multiplicity, and the thrust of hadronic jets in the Breit frame in Deep Inelastic Scattering ν μ N and ν ̄ μ N charged current events over the Q 2 range from 1 to 100 GeV 2 . The neutrino data, obtained in the NOMAD experiment at the CERN SPS, extend the Q 2 -evolution of these parameters by two orders of magnitude, and with commensurate precision, when compared to those reported by the ep and e + e − experiments.
Average neutrino energy. Peak postion of distribution on log(1/z) is presented.
The problem of the nuclear matter jets in nucleus-nucleus collisions at 4.5 A GeV/c is discussed. The global analysis of experimental data, namely the sphericity tensor, is used to evidence such jets.
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