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1.
Backward proton and pion production is studied in ν and \(\bar v\) charged current interactions in neon. The results are compared with other experiments and theory. The complete backward proton data is compatible with protons produced by reinteractions in the nucleus. However in events with only one proton, muon variables appear correlated to those for the backward proton, as expected by the two-nucleon correlation model.  相似文献   
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The cross section for coherent production of a single π? meson in charged current antineutrino interactions on neon nuclei has been measured in BEBC to be (175±25) 10?40 cm2/neon nucleus, averaged over the energy spectrum of the antineutrino wide band beam at the CERN SPS; this corresponds to (0.9±0.1) % of the total charged current \(\bar v_\mu \) cross section. The distributions of kinematical variables are in agreement with theoretical predictions based on the PCAC hypothesis and the meson dominance model; in particular, theQ 2 dependence is well described by a propagator containing a massm=(1.35±0.18) GeV. The absolute value of the cross section is also in agreement with the model. This analysis thus provides a test of the PCAC hypothesis in the antineutrino energy range 5–150 GeV.  相似文献   
3.
Jones  G. T.  Jones  R. W. L.  Kennedy  B. W.  Klein  H.  Morrison  D. R. O.  Wachsmuth  H.  Miller  D. B.  Mobayyen  M. M.  Wainstein  S.  Aderholz  M.  Hantke  D.  Katz  U. F.  Kern  J.  Schmitz  N.  Wittek  W.  Borner  H. P.  Myatt  G.  Cooper-Sarkar  A. M.  Guy  J.  Venus  W.  Bullock  F. W.  Burke  S. 《Zeitschrift fur Physik C Particles and Fields》1994,63(4):601-609
Zeitschrift für Physik C Particles and Fields - A set of proton longitudinal polarized distributions, worked out under the assumption of small gluon polarization, is used to evaluate several...  相似文献   
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The average multiplicities of charged hadrons and of π+, π? and π0 mesons, produced in \(\bar v\) Ne and νNe charged current interactions in the forward and backward hemispheres of theW ±-nucleon center of mass system, are studied with data from BEBC. The dependence of the multiplicities on the hadronic mass (W) and on the laboratory rapidity (y Lab) and the energy fraction (z) of the pion is also investigated. Special care is taken to determine the π0 multiplicity accurately. The ratio of average π multiplicities \(\frac{{2\left\langle {n_{\pi ^O } } \right\rangle }}{{[\left\langle {n_{\pi ^ + } } \right\rangle + \left\langle {n_{\pi ^ - } } \right\rangle ]}}\) is consistent with 1. In the backward hemisphere \(\left\langle {n_{\pi ^O } } \right\rangle \) is positively correlated with the charged multiplicity. This correlation, as well as differences in multiplicities between \(\mathop v\limits^{( - )} \) and \(\mathop v\limits^{( - )} \) , \(\mathop v\limits^{( - )} \) scattering, is attributed to reinteractions inside the neon nucleus of the hadrons produced in the initial \(\mathop v\limits^{( - )} \) interaction.  相似文献   
6.
The isoscalar nucleon structure functionsF 2(x, Q 2) andxF 3(x, Q 2) are measured in the range 0<Q 2<64 GeV2, 1.7<W 2<250 GeV2,x<0.7 using ν and \(\bar v\) interactions on neon in BEBC. The data are used to evaluate possible higher twist contributions and to determine their impact on the evaluation of the QCD parameter Λ. In contrast to previous analyses reaching to such lowW 2 values, it is found that a low \(\Lambda _{\overline {MS} } \) value in the neighbourhood of 100 MeV describes the data adequately and that the contribution of dynamical higher twist effects is small and negative.  相似文献   
7.
Jones  G. T.  Jones  R. W. L.  Kennedy  B. W.  Klein  H.  Morrison  D. R. O.  Wachsmuth  H.  Miller  D. B.  Mobayyen  M. M.  Wainstein  S.  Aderholz  M.  Hantke  D.  Katz  U. F.  Kern  J.  Schmitz  N.  Wittek  W.  Borner  H. P.  Myatt  G.  Cooper-Sarkar  A. M.  Guy  J.  Venus  W.  Bullock  F. W.  Burke  S. 《Zeitschrift fur Physik C Particles and Fields》1994,63(4):575-579
The analytic expressions for the production cross sections of polarized bottom and top quarks ine * e annihilation are explicitly derived at the one-loop order of strong interactions. Chirality-violating mass effects will reduce the longitudinal spin polarization for the light quark pairs by an amount of 3%, when one properly considers the massless limit for the final quarks. Numerical estimates of longitudinal spin polarization effects in the processese * e b (g) ande * e t (g) are presented.supported in part by the BMFT, Germany under contract 06MZ730  相似文献   
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Sets of parton distribution functions (PDFs) of the proton are reported for the leading (LO), next-to-leading (NLO) and next-to-next-to-leading-order (NNLO) QCD calculations. The parton distribution functions are determined with the HERAFitter program using the data from the HERA experiments and preserving correlations between uncertainties for the LO, NLO and NNLO PDF sets. The sets are used to study cross-section ratios and their uncertainties when calculated at different orders in QCD. A reduction of the overall theoretical uncertainty is observed if correlations between the PDF sets are taken into account for the ratio of \(WW\) di-boson to \(Z\) boson production cross sections at the LHC.  相似文献   
10.
The coherent production of π+ mesons by charged current neutrino interactions on neon nuclei in BEBC is compared to the predictions of the PCAC hypothesis and the meson dominance model. Good agreement is observed.  相似文献   
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