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No description provided.
We have extracted the strong interaction form factors from K o e3 and K o μ3 data of our previously reported K o L experiment in a manner which does not assume an explicit q 2 = ( p K − p π ) 2 dependence. We present the unparameterized form factors ƒ + (q 2 ) from the K o L → πeν and K o L → πμν modes and ƒ o (q 2 ) and ξ ( q 2 ) from the K o L → πμν data. A comparison of these unparameterized results is made with the results of the Dalitz plot analyses.
The conventional form factor f+ is studied.
The v and v nucleon total cross-sections have been determined as a function of energy using a sample of 2500 v and 950 v event. The results are compared with predictions of scaling and charge symmetry hypotheses.
Measured charged current total cross section.
Measured charged current total cross section.
We have measured deep inelastic muon-deuteron scattering in the range 0.4<Q2<3.4 and 1.6<ν<5.6 GeV. We have extracted the neutron structure function and find that νW2n differs significantly from νW2p, as also found in e−d scattering. To compare μ−d and e−d scattering we form the ratio r(Q2)=(νW2)μd(νW2)ed=N(1+Q2Λ2)−2 and find N=0.925±0.038 and 1Λ2=−0.019±0.016.
No description provided.
In view of the possible production of heavy leptons or charmed states in e+e− collisions, we searched for anomalous muons with momenta pμ≳1 GeV/c. The inclusive cross section for nch>~3 has an upper limit of 96 pb (assuming isotropy). For nch=2 and noncoplanarity > 20°, an excess of muonic events is observed, corresponding to (dσdΩ)|90°=23−9+12 pb/sr; the probability that known processes produce the observed events is 2×10−4.
No description provided.
The charged-current cross sections for neutrinos and antineutrinos on nucleons in the energy range 20–200 GeV are given. Taken in conjunction with the previous Gargamelle results, they show that σ E is almost constant with energy for antineutrinos, and falls with energy for neutrinos. The value of 〈q 2 〉 E decreases with energy for both neutrinos and antineutrinos, and these deviations from exact Bjorken scaling are consistent with those observed in electron and muon inelastic scattering. We find no evidence for new heavy quark states with right-handed coupling.
Measured charged current total cross section.
Measured charged current total cross section.
We present results on charged multiplicity nch=2 and nch>2 muon events produced in e+e− collisions with 〈s12〉=7.3 GeV at 90° to the beams. The background-subtracted inclusive cross section for the nch=2 events is 10.2±5.4 pb/sr, in agreement with the expected contribution from the heavy lepton τ. The cross section for the nch>2 events is 19.0±6.5 pb/sr whereas we expect only 2.9 pb/sr from the τ, indicating that we may be seeing the weak decays of charmed mesons.
No description provided.
No description provided.
We present results for the differential cross sections of neutrinos and antineutrinos on nucleons in the energy range E = 2−200 GeV, from the BEBC and Gargamelle experiments. The structure functions F 2 , 2 χF 1 and χF 3 have been evaluated as a function of χ and q 2 . Deviations are observed from Bjorken scaling, which are very similar to those found in electron and muon inelastic scattering. For the Callan-Gross ratio, we find 2χF 1 F 2 = 0.80 ± 0.12 and the corresponding value for 〈R〉 = 〈 σ S σ T 〉 = 0.15 ± 0.10 . Our results are consistent with the Gross-Llewellyn-Smith sum rule; we measure ⩾2.5 ± 0.5 valence quarks per nucleon. Quark and antiquark distributions are given. The Nachtmann moments of F 2 and χF 3 are quantitatively consistent with the predictions from QCD. The value of the strong interaction parameter is λ = 0.74 ± 0.05 GeV without corrections, and 0.66 ± 0.05 GeV including α S 2 corrections. The moments of the gluon distribution are found to be positive and indicate an χ distribution of gluons which is comparable with that of the valence quarks.
No description provided.
No description provided.
We have measured the reactions e + e − → e + e − → μ + μ − and e + e − → γγ at c.m. energies between 12 and 31.6 GeV. Excellent agreement with the predictions of QED has been found, resulting in cut off parameters Λ + > 112 GeV and Λ − > 139 GeV for the first process and Λ + > 34 GeV and Λ − > 42 GeV (95% c.1.) for the last one. A limit on the Weinberg angle of sin 2 θ W < 0.55 (95% c.1.) has been obtained.
SIG(C=QED) QED predictions for the cross sections. Only statistical errors are given.
SIG(C=QED) QED predictions for the cross sections. Only statistical errors are given.
SIG(C=QED) QED predictions for the cross sections. Only statistical errors are given.
The average transverse momentum squared, 〈 p ⊥ 2 〉, of hadrons is studied as a function of W 2 and of Q 2 for ν and ν interactions on an isoscalar target. An increase of 〈 p ⊥ 2 〉 with W 2 is observed for the hadrons emitted forward in the hadronic c.m.s. The p ⊥ dependence of the fragmentation function is found to factorise from the structure function at fixed W , but does not factorise at fixed Q 2 . Unlike the case of forward-going particles, the 〈 p ⊥ 2 〉 of hadrons going backward in the c.m.s. shows no strong dependence on W 2 .
No description provided.
No description provided.
No description provided.
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