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 dissociation of virtual photons, $\gamma^{\star} p \to X p$, in events with a large rapidity gap between $X$ and the outgoing proton, as well as in events in which the leading proton was directly measured, has been studied with the ZEUS detector at HERA. The data cover photon virtualities $Q^2>2$ GeV$^2$ and $\gamma^{\star} p$ centre-of-mass energies $40<W<240$ GeV, with $M_X>2$ GeV, where $M_X$ is the mass of the hadronic final state, $X$. Leading protons were detected in the ZEUS leading proton spectrometer. The cross section is presented as a function of $t$, the squared four-momentum transfer at the proton vertex and $\Phi$, the azimuthal angle between the positron scattering plane and the proton scattering plane. It is also shown as a function of $Q^2$ and $\xpom$, the fraction of the proton's momentum carried by the diffractive exchange, as well as $\beta$, the Bjorken variable defined with respect to the diffractive exchange.
The differential cross section DSIG/DT for the LRG and the LPS data samples.
The fitted exponential slope of the T distribution as a function of X(NAME=POMERON).
The fitted exponential slope of the T distribution as a function of X(NAME=POMERON).
We present a measurement of the muon neutrino-nucleon inclusive charged current cross-section, off an isoscalar target, in the neutrino energy range $2.5 \leq E_\nu \leq 40$ GeV. The significance of this measurement is its precision, $\pm 4$% in $2.5 \leq E_\nu \leq 10$ GeV, and $\pm 2.6$% in $10 \leq E_\nu \leq 40$ GeV regions, where significant uncertainties in previous experiments still exist, and its importance to the current and proposed long baseline neutrino oscillation experiments.
Inclusive muon-neutrino charged current cross section.
Data on the measurement of the v μ N total cross section at 2–30 GeV are presented. The observed behavior does not contradict a linear dependence on neutrino energy with slope S =0.73 ± 0.08.
Measured charged current total cross section.
Average total cross sections are given for neutrino charged current interactions at neutrino energies of 2.87 GeV and 9.05 GeV. The ratios 〈σ〉 〈E〉 are 0.69 ± 0.05 and 0.61 ± 0.06 in units of 10 −38 cm 2 /GeV nucleon, respectively The errors include both statistical and systematic uncertainties.
Measured charged current total cross section.
Measured charged current total cross section.
This Letter compares neutral-current and charged-current scaling-variable distributions in neutrino-nucleon interactions induced by a narrow-band beam at Brookhaven National Laboratory; the x distribution of neutral-current events has been reported previously. The first measurement of flux-normalized neutrino cross sections from a narrow-band beam in the energy range Eν=3−9 GeV is also presented.
Measured charged current total cross section.
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.
The isoscalar structure functions $xF_3$ and $F_2$ are measured as functions of $x$ averaged over all $Q^2$ permissible for the range of 6 to 28 GeV of incident neutrino (anti-neutrino) energy at the IHEP-JINR Neutrino Detector. The QCD analysis of $xF_3$ structure function provides $\Lambda_{\bar{MS}}^{(4)} = (411 \pm 200)$ MeV under the assumption of QCD validity in the region of low $Q^2$. The corresponding value of the strong interaction constant $\alpha_S (M_Z) = 0.123^{+0.010}_{-0.013}$ agrees with the recent result of the CCFR collaboration and with the combined LEP/SLC result.
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We have measured inclusive electron production in multiprong events produced by e+e− annihilation in the center-of-mass energy range 3.9-7.4 GeV. We find the electron momentum spectra are consistent with the electrons coming mainly from decays of charmed particles, with a smaller contribution from decays of the τ lepton. From our data we calculate the average branching ratio for charmed particles to decay into an electron plus additional particles to be (8.2±1.9)%.
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The isoscalar structure functions xF_3 and F_2 are measured as functions of x averaged over all Q~2 permissible for the range 6 to 28 GeV of incident (anti)neutrino energy. With the measured values of xF_3, the value of the Gross-Llewellyn Smith sum rule is found to be $\int_{0}~{1}{F_3 dx} = 2.13\pm0.38 (stat)\pm 0.26 (syst)$. The QCD analysis of xF_3 provides $\Lambda_{\overline{MS}} =358 \pm 59 MeV$ . The obtained value of the strong interaction constant $\alpha_S (M_Z)=0.120~{+3}_{-4}$ is larger than most of the deep inelastic scattering results.
The value of F2 is extracted with R = 0. The difference F2(C=R=.1)-F2(C=R=0.) is also presented.
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