P. A. Rapidis

Evidence for ηη resonances in antiproton-proton annihilations at 2950 < s < 3620 MeV

Abstract We present the first high-statistics study of the ηη system over the mass range 1000–3000 MeV/c2. The experiment was performed at the Fermilab Antiproton Accumulator, and the data sample consists of six-photon final states produced in antiproton-proton annihilations at s in the range 2950–3620 MeV. We find evidence for three states with masses 1488 ± 10 MeV/c2, 1748 ± 10 MeV/c2 and 2104 ± 20 MeV/c2 respectively.

Study of the χ1 and χ2 charmonium states formed in pp annihilations

We report on a study of the χ1(3P1) and χ2(3P2) states of charmonium formed in antiproton-proton annihilations. An energy scan through the resonances, performed with a very narrow momentum-band beam of antiprotons intersecting a hydrogen jet target, enables us to perform very precise measurements of the mass and the total width of the two resonances. From a sample of 513 χ1 and 585 χ2 events we find Mχ1 = (3510.53±0.13) MeV/c2, Mχ2 = (3556.15±0.14) MeV/c2, Γχ1 = (0.88±0.14) MeV and Γχ2 = (1.98±0.18) MeV. From our measurement of the quantity Γ(R → pp) × BR(R → Jψ → e+ e−), using known branching ratios, we obtain Λ(χ1 → pp) = (69±13) eV and Λ(χ2 → pp) = (180±31) eV.

Study of the chi(1) and chi(2) charmonium states formed in anti-p p annihilations

We report on a study of the χ1(3P1) and χ2(3P2) states of charmonium formed in antiproton-proton annihilations. An energy scan through the resonances, performed with a very narrow momentum-band beam of antiprotons intersecting a hydrogen jet target, enables us to perform very precise measurements of the mass and the total width of the two resonances. From a sample of 513 χ1 and 585 χ2 events we find Mχ1 = (3510.53±0.13) MeV/c2, Mχ2 = (3556.15±0.14) MeV/c2, Γχ1 = (0.88±0.14) MeV and Γχ2 = (1.98±0.18) MeV. From our measurement of the quantity Γ(R → pp) × BR(R → Jψ → e+ e−), using known branching ratios, we obtain Λ(χ1 → pp) = (69±13) eV and Λ(χ2 → pp) = (180±31) eV.

Limits on D0-D0 mixing and bottom particle production cross section from hadronically produced same-sign dimuon events☆

Abstract The rates for same-sign and opposite-sign dimuon events with missing energy (indicative of final-state neutrinos) have been measured in 278 GeV π − -Fe and 350 GeV proton-Fe collisions. The main source of opposite-sign events is two semi-leptonic decays of hadronically produced charm states. The same-sign events are consistent with background from pion and kaon decays. We obtain a limit of 0.044 (90% CL) on the fraction of D 0 semileptonic decays that result in the wrong-sign muon and conclude that less than 9% (90% CL) of same-sign dimuon events produced in neutrino interactions can be attributed to D 0 - D 0 mixing. The data imply δm −4 eV and δλ λ for the difference in mass and inverse lifetime of the CP eigenstates of the D 0 . Limits on diffractive bottom production cross sections in proton and pion collisions are also presented.

Measurement of the inclusive charged-current cross section for neutrino and antineutrino scattering on isoscalar nucleons

AbstractThis paper reports on measurements of the total cross section for the inclusive reaction vμ+N, as a function of incident energy. Neutrinos and antineutrinos with energy in the range 30–300 GeV were produced in the 1982 Fermilab narrow-band neutrino beamline. A total of 35 000 neutrino and 7000 antineutrino interactions were recorded in the CCFR detector located in LabE. The incident neutrino flux was determined by methods similar to those used in previous experiments. The rate of increase with energy of the total cross section (σ/Ev) in the range 30 to 75 GeV was determined to be 0.659±0.005(stat)±0.039(syst)×10−38 cm2/GeV and 0.307±0.008(stat)±0.020(syst)×10−38 cm2/GeV for incident neutrinos and antineutrinos, respectively. The 5.9% systematic errors are due primarily to uncertainties in the flux intensity measurement. The energy dependence of the cross section in the regionEν=100–300 GeV was found to be linear, as determined by relative normalization techniques. A weighted average of our previous and present measurement for the total ν-N cross section yields:

The E760 lead-glass central calorimeter: design and initial test results

\begin{gathered} \sigma (vN) = 0.666 \pm 0.020(statistical \hfill \\ + systematic)E_v 10^{ - 38} cm^2 ; \hfill \\ \sigma (\bar vN) = 0.324 \pm 0.014(statistical \hfill \\ + systematic)E_v 10^{ - 38} cm^2 ; \hfill \\ \end{gathered}

Hadron shower punchthrough for incident hadrons of momentum 15, 25, 50, 100, 200 and 300 GeV/c

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Precision measurements of antiproton-proton forward elastic scattering parameters in the 3.7 to 6.2 GeV/c region

Abstract We describe a high statistics measurement from deep inelastic neutrino-nucleon scattering of the electroweak parameters ϱ and sin 2 θ w , performed in the Fermilab narrow-band neutrino beam. Our measurement uses a radius-dependent cut in y = E H / E v which reduces the systematic error in sin 2 θ w , and incorporates electromagnetic and electroweak radiative corrections. In a renormalization scheme where sin 2 θ w ≡ 1− m 2 W / m 2 Z , a value of sin 2 θ w = 0.242±0.011±0.005 is obtained fixing ϱ = 1. If both sin 2 θ w and ϱ are allowed to vary in a fit to our data, we measure ϱ = 0.991 ± 0.025 ± 0.009.