Limits on extra dimensions and new particle production in the exclusive photon and missing energy signature in pp̄ collisions at √s = 1.8 TeV
Physical Review Letters 89:28 I (2002)
Abstract:
A search for new physics in the exclusive γ∄T channel was performed. Departure from the expected standard model cross section was found. Limits on two specific models of new physics were defined. Furthermore, the limit in a "pseudomodel-independent" manner was detailed.Comparison of the isolated direct photon cross sections in pp̄ collisions at √s = 1.8 TeV and √s = 0.63 TeV
Physical Review D 65:11 (2002)
Abstract:
We have measured the cross sections d2σ/d P Tdη) for production of isolated direct photons in pp̄ collisions at two different center-of-mass energies, 1.8 TeV and 0.63 TeV, using the Collider Detector at Fermilab. The normalization of both data sets agrees with the predictions of quantum chromodynamics for a photon transverse momentum (PT) of 25 GeV/c, but the shapes versus photon PT do not. These shape differences lead to a significant disagreement in the ratio of cross sections in the scaling variable xT(≡ 2PT/√s). This disagreement in the xT ratio is difficult to explain with conventional theoretical uncertainties such as scale dependence and parton distribution parametrizations. © 2002 The American Physical Society.Branching ratio measurements of exclusive B+ decays to charmonium with the collider detector at fermilab
Physical Review D - Particles, Fields, Gravitation and Cosmology 66:5 (2002) 520051-520057
Abstract:
We report on measurements of the branching ratios of the decays B+→Xcl0(1P)K+ and B+ →J/ψK+π+π-, where Xcl0(1P)→J/ψγ and J/ψ→μ+μ- in pp collisions at √s= 1.8 TeV. Using a data sample from an integrated luminosity of 110 pb-1 collected by the Collider Detector at Fermilab we measure the branching ratios to be BR(B+→Xcl0(1P) K+)=15.5±5.4(stat)±1.5(syst)±1.3(br)× 10-4 and BR(B+ →J/ψK+π+π-)=6.9 ±1.8(stat)±1.1(syst)±0.4(br)×10-4 where (br) is due to the finite precision on BR(B-→J/ψK+), BR(Xcl0(1P)→J/ψγ)is used to normalize the signal yield, and (syst) encompasses all other systematic uncertainties.Search for new physics in photon-lepton events in pp collisions at sqrt[s] = 1.8 TeV.
Phys Rev Lett 89:4 (2002) 041802
Abstract:
We present the results of a search in pp collisions at sqrt[s] = 1.8 TeV for anomalous production of events containing a photon and a lepton (e or mu), both with large transverse energy, using 86 pb(-1) of data collected with the Collider Detector at Fermilab during the 1994-1995 collider run at the Fermilab Tevatron. The presence of large missing transverse energy (E(T)), additional photons, or additional leptons in these events is also analyzed. The results are consistent with standard model expectations, with the possible exception of photon-lepton events with large E(T), for which the observed total is 16 events and the expected mean total is 7.6+/-0.7 events.Diffractive dijet production at sqrt[s] = 630 and 1800 GeV at the Fermilab Tevatron.
Phys Rev Lett 88:15 (2002) 151802