We report a precise measurement of the weak mixing angle from the ratio of neutral current to charged current inclusive cross-sections in deep-inelastic neutrino-nucleon scattering. The data were gathered at the CCFR neutrino detector in the Fermilab quadrupole-triplet neutrino beam, with neutrino energies up to 600 GeV. Using the on-shell definition, ${\rm sin ~2\theta_W} \equiv 1 - \frac{{\rm M_W} ~2}{{\rm M_Z} ~2}$, we obtain ${\rm sin ~2\theta_W} = 0.2218 \pm 0.0025 ({\rm stat.}) \pm 0.0036 ({\rm exp.\: syst.}) \pm 0.0040 ({\rm model})$.
The NuTeV experiment at Fermilab has used a sign-selected neutrino beam to perform a search for the lepton number violating process $\bar{\nu}_mu e^- \to \mu^- \bar{\nu}_e$, and to measure the cross-section of the Standard Model inverse muon decay process $\nu_{\mu} e^- \to \mu^- \nu_e$. NuTeV measures the inverse muon decay asymptotic cross-section $\sigma/E$ to be 13.8 $\pm$ 1.2 $\pm$ 1.4 x $10^{-42} cm^2$/GeV. The experiment also observes no evidence for lepton number violation and places one of the most restrictive limits on the LNV/IMD cross-section ratio at $\sigma (\bar{\nu}_{\mu} e^- \to \mu^- \bar{\nu}_e) /\sigma (\nu_{\mu}e^- \to \mu^- \nu_e$) $\le$ 1.7% at 90% C.L. for V-A couplings and $\le$ 0.6% for scalar couplings.
Using the Primakoff formalism, we have extracted the radiative decay width of the A + 2 (1310) produced in coherent interactions of 200 GeV/ c π + mesons in nuclear targets. The width obtained is 295 ± 60 keV, a value consistent with quark-model predictions.
Using the Primakoff formalism, we have extracted the radiative decay width of the K ∗+ (1430) produced in coherent interactions of 200 GeV/ c K + mesons in nuclear targets. The width obtained is 240 ± 45 keV, a value reasonably consistent with quark-model predictions.
Coherent production of Kπ systems observed in the excitation of 200-GeV/c positive kaons on nuclear targets has been analyzed, including both electromagnetic and strong contributions, to yield a new value for the radiative width for the process K*+(890)→K+γ of 51 ± 5 keV.
In an exposure of the 30-in. hydrogen bubble chamber to a 303−GeVc proton beam, 2245 interactions have been observed. The measured total cross section is 39.0±1.0 mb and the average charged particle multiplicity 〈nch〉=8.86±0.16.
We present evidence for the diffractive processes nu_mu Fe -> mu^- D_s^+ (D_s^*+) Fe and nubar_mu Fe -> mu^+ D_s^- (D_s^*-) Fe using the Fermilab SSQT neutrino beam and the Lab E neutrino detector. We observe the neutrino trident reactions nu_mu Fe -> nu_mu mu^- mu^+ Fe and nubar_mu Fe -> nubar_mu mu^+ mu^- Fe at rates consistent with Standard Model expectations. We see no evidence for neutral-current production of J/psi via either diffractive or deep inelastic scattering mechanisms.
The energy dependence of the cross section for neutrino- and antineutrino-nucleon charged-current interactions has been determined from data taken in Fermilab's dichromatic neutrino beam. σνE=(0.669±0.003±0.024)×10−38 cm2/GeV and σν¯E=(0.340±0.003±0.02)×10−38 cm2/GeV are found. These results are higher than some previous measurements.
Inclusive and semi-inclusive ρ 0 production are studied in 205 GeV/ c pp interactions. The number of ρ 0 per inelastic event is 0.33 ± 0.06, so that (13 ± 2)% of the π − are products of ϱ 0 decay. The ρ 0 are found to be produced mainly near y = 0 and tend to have larger average transverse momentum than do pions.
The ν¯μ charged-current total cross section has been measured with the Fermilab 15-ft bubble chamber plus the external muon identifier and internal "picket fence." Beam monitoring information used for the flux calculation was obtained from Blair et al., whose detector operated in the same dichromatic beam. The present result, averaged over ν¯μ energies from 5 to 250 GeV, is σE=(0.340±0.019±0.022)×10−38 cm2/(GeV nucleon) for an isoscalar target.