R. Vilar

Transverse Momentum and Total Cross Section of e{sup +}e{sup -} Pairs in the Z-Boson Region from pp Collisions at {radical}(s) = 1.8 TeV

The transverse momentum and total cross section of e{sup +}e{sup -} pairs in the Z-boson region of 66<M{sub ee}<116 GeV/c{sup 2} from p{ovr p} collisions at sqrt[s] = 1.8 TeV are measured using 110 pb{sup -1} of collisions taken by the Collider Detector at Fermilab during 1992-1995. The total cross section is measured to be 248{+-}11 pb. The differential transverse momentum cross section is compared with calculations that match quantum chromodynamics perturbation theory at high transverse momentum with the gluon resummation formalism at low transverse momentum.

Search for new particles decaying to tt in pp collisions at radicals = 1.8 TeV

We use 106 pb{sup -1} of data collected with the Collider Detector at Fermilab to search for narrow-width, vector particles decaying to a top and an antitop quark. Model independent upper limits on the cross section for narrow, vector resonances decaying to t{ovr t} are presented. At the 95% confidence level, we exclude the existence of a leptophobic Z boson in a model of top-color-assisted technicolor with mass M{sub Z}<480 GeV/c{sup 2} for natural width {Gamma} = 0.012M{sub Z}, and M{sub Z}<780 GeV/c{sup 2} for {Gamma} = 0.04M{sub Z}.

Measurement of b-quark fragmentation fractions in pp collisions at sqrt

We have studied the production of B hadrons in 1.8-TeV pp[over ¯] collisions. We present measurements of the fragmentation fractions, f_{u}, f_{d}, f_{s}, and f_{baryon}, of produced b quarks that yield B^{+}, B^{0}, B_{s}^{0}, and Λ[over ¯]_{b}^{0} hadrons. Reconstruction of five electron-charm final states yields f_{s}/( f_{u}+f_{d})=0.213±0.068 and f_{baryon}/( f_{u}+f_{d})=0.118±0.042, assuming f_{u}=f_{d}. If all B hadrons produced in pp[over ¯] collisions cascade to one of these four hadrons, we determine f_{u}=f_{d}=0.375±0.023, f_{s}=0.160±0.044, and f_{baryon}=0.090±0.029. If we do not assume f_{u}=f_{d}, we find f_{d}/f_{u}=0.84±0.16.

Search for scalar top quark production in pp collisions at sqrt

We have searched for direct production of scalar top quarks at the Collider Detector at Fermilab in 88 pb of pp collisions at √ s =1.8 TeV. We assume the scalar top quark decays into either a bottom quark and a chargino or a bottom quark, a lepton, and a scalar neutrino. The event signature for both decay scenarios is a lepton, missing transverse energy, and at least two b-quark jets. For a chargino mass of 90 GeV/c and scalar neutrino masses of at least 40 GeV/c, we find no evidence for scalar top production and present upper limits on the production cross section in both decay scenarios. Typeset using REVTEX

Production of Upsilon(1S) mesons from chi(b) decays in pp collisions at sqrt

We have reconstructed the radiative decays

Direct measurement of the W boson width in pp collisions at radicals = 1.8 TeV

chi_{b}(1P) to Upsilon(1S) gamma

Limits on light gravitino production and new processes with large missing transverse energy in pp collisions at sqrt

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Measurement of the decay amplitudes of B0 --> J/psiK*0 and B(s)(0) --> J/psistraight phi decays

chi_{b}(2P) to Upsilon(1S) gamma

Diffractive dijets with a leading antiproton in pp collisions at sqrt

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