We report the observation and measurement of the mass of the bottom, strange baryon Xi-_b through the decay chain Xi-_b --> J/psi Xi-, where J/psi --> mu+ mu-, Xi- --> Lambda pi+-, and Lambda --> p ...pi+-, and Lambda --> p pi+-. Evidence for observation is based on a signal whose probability of arising from the estimated background is 6.6 x 10-15, or 7.7 Gaussian standard deviations. The Xi-_b mass is measured to be 5792.9 +/- 2.5 (stat.) +/-1.7 (syst.) MeV/c2.
This paper presents a study of the production of a single $W$ boson in association with one or more jets in proton-antiproton collisions at $\sqrt{s}=1.96$ TeV, using the entire data set collected in ...2001-2011 by the Collider Detector at Fermilab at the Tevatron, which corresponds to an integrated luminosity of $9.0$ fb$^{-1}$. The $W$ boson is identified through its leptonic decays into electron and muon. The production cross sections are measured for each leptonic decay mode and combined after testing that the ratio of the $W(\rightarrow \mu\nu)+$jets cross section to the $W(\rightarrow e\nu)+$jets cross section agrees with the hypothesis of $e$-$\mu$ lepton universality. The combination of measured cross sections, differential in the inclusive jet multiplicity ($W+\geqslant N$ jets with $N=1,\,2,\,3, \textrm{or }4$) and in the transverse energy of the leading jet, are compared with theoretical predictions.
CDF Central Outer Tracker Affolder, T; Allspach, D; Ambrose, D ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2004, Letnik:
526, Številka:
3
Journal Article
Recenzirano
The Central Outer Tracker is a large cylindrical drift chamber constructed to replace Collider Detector at Fermilab's original central drift chamber for the higher luminosity expected for Run 2 at ...the Fermilab Tevatron. The chamber's drift properties are described in the context of meeting the operating requirements for Run 2. The design and construction of the chamber, the front-end readout electronics, and the high-voltage system are described in detail. Wire aging considerations are also discussed.
Here, a search for the exotic meson X(5568) decaying into the B$0\atop{s}$π± final state is performed using data corresponding to 9.6 fb-1 from $p\bar{p}$ collisions at $\sqrt{s}$ = 1960 GeV recorded ...by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7% at the 95% confidence level is set on the fraction of B$0\atop{s}$ produced through the X(5568)→B$0\atop{s}$π± process.
We report on a measurement of the D+-meson production cross section as a function of transverse momentum (pT) in proton-antiproton (pp¯) collisions at 1.96 TeV center-of-mass energy, using the full ...data set collected by the Collider Detector at Fermilab in Tevatron Run II and corresponding to 10 fb−1 of integrated luminosity. We use D+→K−π+π+ decays fully reconstructed in the central rapidity region |y|<1 with transverse momentum down to 1.5 GeV/c, a range previously unexplored in pp¯ collisions. Inelastic pp¯-scattering events are selected online using minimally biasing requirements followed by an optimized offline selection. The K−π+π+ mass distribution is used to identify the D+ signal, and the D+ transverse impact-parameter distribution is used to separate prompt production, occurring directly in the hard-scattering process, from secondary production from b-hadron decays. We obtain a prompt D+ signal of 2950 candidates corresponding to a total cross section σ(D+,1.5<pT<14.5 GeV/c,|y|<1)=71.9±6.8(stat)±9.3(syst) μb. While the measured cross sections are consistent with theoretical estimates in each pT bin, the shape of the observed pT spectrum is softer than the expectation from quantum chromodynamics. The results are unique in pp¯ collisions and can improve the shape and uncertainties of future predictions.
A measurement of the inclusive production cross section of isolated prompt photons in proton-antiproton collisions at center-of-mass energy $ \sqrt{s}=1.96 $ TeV is presented. The results are ...obtained using the full Run II data sample collected with the Collider Detector at the Fermilab Tevatron, which corresponds to an integrated luminosity of 9.5 fb-1. The cross section is measured as a function of photon transverse energy, E γ T , in the range 30 < E γ T <500 GeV and in the pseudorapidity region |ηγ|<1.0. The results are compared with predictions from parton-shower Monte Carlo models at leading order in QCD and from next-to-leading-order perturbative QCD calculations. The latter show good agreement with the measured cross section.
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