Jeff Tseng

Abstract:

The first observation of diffractive J/ψ(→μ+μ-) production in p̄p collisions at s√=1.8 TeV was presented. Events were selected with a pair of muon candidates using a three-level dimuon trigger system. The dimuon mass distribution was fitted with a sum of a Gaussian and a linear function to evaluate the fraction of background events in the signal region. A value of 0.59±0.15 for the gluon fraction of the diffractive structure function of the proton was extracted.

Abstract:

A study on searches for quark-lepton compositeness and a heavy boson at high electron-neutrino transverse mass was presented. The data collected in pp̄ collisions at √s=1.8 TeV was used for the analysis. The data obtained is found to be consistent with the standard model (SM) predictions.

Abstract:

We report on the first measurement of the rapidity distribution dσ/dy over nearly the entire kinematic region of rapidity for e + e - pairs in both the Z-boson region of 66116 GeV/c 2 . The data sample consists of 108 pb -1 of pp̄ collisions at √s = 1.8 TeV taken by the Collider Detector at Fermilab during 1992-1995. The total cross section in the Z-boson region is measured to be 252±11 pb. The measured total cross section and dσ/dy are compared with quantum chromodynamics calculations in leading and higher orders. ©2000 The American Physical Society.

Abstract:

The mean charged-particle multiplicity of jets in dijet events with dijet masses were analyzed using collider detectors. The jet energy and direction were measured in the central lead-scintillator electromagnetic (CEM) and iron-scintillator hadronic (CHA) calorimeters. It is shown that the fraction of gluon jets decreases to 23%-26% at 630 GeV/c² from 61%-63% of all jets at 80 GeV/c².

Abstract:

We present results of searches for diphoton resonances produced both inclusively and also in association with a vector boson (W or Z) using 100 pb-1 of pp̄ collisions using the CDF detector. We set upper limits on the product of cross section times branching ratio for both pp̄→γγ+X and pp̄→γγ+ W/Z. Comparing the inclusive production to the expectations from heavy sgoldstinos we derive limits on the supersymmetry-breaking scale √F in the TeV range, depending on the sgoldstino mass and the choice of other parameters. Also, using a NLO prediction for the associated production of a Higgs boson with a W or Z boson, we set an upper limit on the branching ratio for H → γγ. Finally, we set a lower limit on the mass of a "bosophilic" Higgs boson (e.g., one which couples only to γ, W, and Z bosons with standard model couplings) of 82 GeV/c2 at 95% confidence level. ©2001 The American Physical Society.