J. P. Berge

Measurement of Dijet Angular Distributions by the Collider Detector at Fermilab.

We have used 106 pb^-1 of data collected in proton-antiproton collisions at sqrt(s)=1.8 TeV by the Collider Detector at Fermilab to measure jet angular distributions in events with two jets in the final state. The angular distributions agree with next to leading order (NLO) predictions of Quantum Chromodynamics (QCD) in all dijet invariant mass regions. The data exclude at 95% confidence level (CL) a model of quark substructure in which only up and down quarks are composite and the contact interaction scale is Lambda_ud(+)<1.6 TeV or Lambda_ud(-)<1.4 TeV. For a model in which all quarks are composite the excluded regions are Lambda(+)<1.8 TeV and Lambda(-)<1. 6 TeV.

Measurement of bottom quark production in 1.8 TeV

We present a measurement of the [ital b]-quark cross section in 1.8 TeV [ital p]-[ital [bar p]] collisions recorded with the Collider Detector at Fermilab using muonic [ital b]-quark decays. In the central rapidity region ([vert bar][ital y][sup [ital b]][vert bar][lt]1.0), the cross section is 295[plus minus]21[plus minus]75 nb (59[plus minus]14[plus minus]15 nb) for [ital p][sub [ital T]][sup [ital b]][gt]21 GeV/[ital c] (29 GeV/[ital c]). Comparisons are made to previous measurements and next-to-leading order QCD calculations.

p\bar{p}

Abstract In this paper we discuss inclusive spectra of K0s and Λs produced in charged in charged-current ν μ N interactions in the Fermilab 15 ft bubble chamber filled with a 64% Ne-H2 mixture. Data presented in terms of the invariant cross section show, when compared with results from experiments with other incident beams, that the behavior of these distributions is approximately the same. The K0 and Λ fragmentation functions are presented and the shape of the K0 fragmentation function is found to be consistent with the parametrization of Field and Feynman. The average K0 and Λ transverse momentum squared as a function of Q2, W2, x and z is presented. Comparisons for the K0s produced in the current fragmentation region are in qualitative agreement with QCD predictions. The value of the Λ polarization is measured and a positive normal polarization PN = 0.34±0.18 is found.

collisions using semileptonic decay muons

Abstract We investigate properties of the hadron jets produced in deep inelastic antineutrino-nucleon charged current interactions in the Fermilab 15 foot bubble chamber. Our detailed analysis of the jet net charge provides evidence for the quark origin of the hadron jets. The factorization hypothesis for the inclusive one-particle cross section is found to be valid.

Properties of K0 and Λ inclusive production in charged-current antineutrino-nucleon interactions☆

The results of a study of strange particle production in charged current νμN interactions in the Fermilab 15 ft bubble chamber filled with a heavy NeH2 mixture are presented. Production rates and average multiplicities of K0s and Λs as functions of W2 and Q2 are given. The experimental data agree well with the quark-parton model predictions if a yield of 0.06 ± 0.02 of K0s and Λs from charm production is included. Upper limits for D-meson production are given and the shape of the charmed quark fragmentation function is discussed. Inclusive production of the K∗(890) and Σ(1385) resonances is measured and it is shown that only about 5% of the K0 mesons and Λ hyperons results from resonance decays. Relative production rates of neutral strange particles on proton and neutron targets are studied.

Quark jets from antineutrino interactions (I). Net charge and factorization in the quark jets

We present a measurement of jet shapes in [ital [bar p]p] collisions at [radical][ital s] =1.8 TeV at the Fermilab Tevatron using the Collider Detector at Fermilab (CDF). Qualitative agreement is seen with the predictions of recent next-to-leading [[ital O]([alpha][sub [ital s]][sup 3])] calculations and with leading logarithm QCD based Monte Carlo simulations. The dependence of the jet shape on transverse energy is studied.

Charged current events with neutral strange particles in high-energy antineutrino interactions

Abstract We investigate the net change in the current fragmentation region in antineutrino-nucleon charged current interactions in the Fermilab 15 ft bubble chamber. Support is presented for the d-quark origin of the forward hadrons in the hadron center-of-mass system. An extrapolation of the net charge to infinite center-of-mass energy is performed giving as a result 〈Q〈 v =− (0.44 ± 0.09) . Combining this result with the result obtained using our v events in the same experiment we obtain the value 0.98 ± 0.15 for the charge difference between the fragmenting quarks in v and v charged current events.

Measurement of jet shapes in p-barp collisions at sqrt s =1.8 TeV.

Abstract We have used the ratio between the production rates of K 0 s and π − s in antineutrino-nucleon interactions in the Fermilab 15 ft bubble chamber to measure the size of the SU (3) symmetry violation in the production of quark-antiquark pairs to be 0.27±0.04. This value is significantly larger than the value obtained from a recent ep experiment. There is no apparent dependence of the K 0 π − ratio with W 2 , Q 2 , x b or p T 2 .

Net charge in deep inelastic antineutrino-nucleon scattering

Abstract We present results on inclusive particle production in the antineutrino charged current induced hadron jets observed in the Fermilab 15 ft bubble chamber. Fractional energy distributions, particle ratios and average multiplicities of the hadrons in the jets are measured. Ratios between the inclusive production rates of different mesons in the jets are studied to seek evidence for the d-quark origin of the observed hadrons. Good over-all agreement with the hypothesis of d-quark fragmentation with universal fragmentation functions obeying isospin systematics is established.

Measurement of SU(3) symmetry violation in the quark jet

We report a measurement of the ratio of the bottom quark production cross section in antiproton-proton collisions at 630 GeV to 1800 GeV using bottom quarks with transverse momenta greater than 10.75 GeV identified through their semileptonic decays and long lifetimes. The measured ratio sigma(630)/sigma(1800) = 0.171 +/- .024 +/- .012 is in good agreement with next-to-leading order (NLO) quantum chromodynamics (QCD).