73 research outputs found
Polarizations of J/psi and psi(2S) Mesons Produced in ppbar Collisions at 1.96 TeV
We have measured the polarizations of \jpsi and \psiprime mesons as
functions of their transverse momentum \pt when they are produced promptly in
the rapidity range with \pt \geq 5 \pgev. The analysis is performed
using a data sample with an integrated luminosity of about 800 \ipb collected
by the CDF II detector. For both vector mesons, we find that the polarizations
become increasingly longitudinal as \pt increases from 5 to 30 \pgev. These
results are compared to the predictions of nonrelativistic quantum
chromodynamics and other contemporary models. The effective polarizations of
\jpsi and \psiprime mesons from -hadron decays are also reported.Comment: 8 pages, 7 figures, published in Physical Review Letter
Observation and Mass Measurement of the Baryon
We report the observation and measurement of the mass of the bottom, strange
baryon through the decay chain , where
, , and .
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 mass is measured to be (stat.) (syst.) MeV/.Comment: Minor text changes for the second version. Accepted by Phys. Rev.
Let
Precise measurement of the top quark mass in the lepton+jets topology at CDF II
We present a measurement of the mass of the top quark from proton-antiproton
collisions recorded at the CDF experiment in Run II of the Fermilab Tevatron.
We analyze events from the single lepton plus jets final state (). The top quark mass is extracted
using a direct calculation of the probability density that each event
corresponds to the final state. The probability is a function of both
the mass of the top quark and the energy scale of the calorimeter jets, which
is constrained {\it in situ} by the hadronic boson mass. Using 167 events
observed in 955 pb of integrated luminosity, we achieve the single
most precise measurement of the top quark mass, 170.8 2.2 (stat.)
1.4 (syst.) GeV/.Comment: accepted by Phys. Rev. Let
Search for resonant ttbar production in ppbar collisions at sqrt{s}=1.96 TeV
We report on a search for narrow-width particles decaying to a top and
antitop quark pair. The data set used in the analysis corresponds to an
integrated luminosity of 680 pb^{-1} collected with the Collider Detector at
Fermilab in Run II. We present 95% confidence level upper limits on the cross
section times branching ratio. Assuming a specific topcolor-assisted
technicolor production model, the leptophobic Z' with width
\Gamma_{Z'}=0.012M_{Z'}, we exclude the mass range M_{Z'} < 725 GeV/c^2 at the
95% confidence level.Comment: 7 pages, 3 figures. submitted to Phys. Rev. Let
Search for the standard model Higgs boson decaying to a pair in events with no charged leptons and large missing transverse energy using the full CDF data set
We report on a search for the standard model Higgs boson produced in
association with a vector boson in the full data set of proton-antiproton
collisions at TeV recorded by the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45 fb. We
consider events having no identified charged lepton, a transverse energy
imbalance, and two or three jets, of which at least one is consistent with
originating from the decay of a quark. We place 95% credibility level upper
limits on the production cross section times standard model branching fraction
for several mass hypotheses between 90 and . For a Higgs
boson mass of , the observed (expected) limit is 6.7
(3.6) times the standard model prediction.Comment: Accepted by Phys. Rev. Let
Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data
collected with the CDF II detector at the Tevatron corresponding to an
integrated luminosity of 9.45 fb-1. In events consistent with the decay of the
Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a
neutrino, we set 95% credibility level upper limits on the WH production cross
section times the H->bb branching ratio as a function of Higgs boson mass. At a
Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times
the standard model value.Comment: Submitted to Phys. Rev. Lett (v2 contains clarifications suggested by
PRL
Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely-charged leptons using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a Z boson in data collected with the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events
consistent with the decay of the Higgs boson to a bottom-quark pair and the Z
boson to electron or muon pairs, we set 95% credibility level upper limits on
the ZH production cross section times the H -> bb branching ratio as a function
of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a
limit of 7.1 (3.9) times the standard model value.Comment: To be submitted to Phys. Rev. Let
Measurement of correlated jet cross sections in collisions at TeV
We report on measurements of differential cross sections,
where the muon is from a semi-leptonic decay and the is
identified using precision track reconstruction in jets. The semi-differential
correlated cross sections, d/d\Et^{{\bar b}}, d/d\pt^{{\bar
b}}, and d/d for \pt^{\mu}>~9 GeV/c,
~10 GeV, ~1.5, are
presented and compared to next-to-leading order QCD calculations.Comment: Uses Latex, Article 12 point, figures appended as uuencoded file The
full PostScript available via WWW at
http://www-cdf.fnal.gov/physics/pub95/cdf3164_mu_bbar_prd_final.p
Search for Doubly Charged Higgs Bosons with Lepton-Flavor-Violating Decays involving Tau Leptons
We search for pair production of doubly charged Higgs particles followed by
decays into electron-tau and muon-tau pairs using data (350 inverse picobarns)
collected from proton-antiproton collisions at 1.96 TeV by the CDF II
experiment. We search separately for cases where three or four final-state
leptons are detected, and combine results for exclusive decays to left-handed
electron-tau (muon-tau) pairs. We set a lower mass limit of 114 (112) GeV/cc at
the 95% confidence level for left-handed doubly charged Higgs
Measurement of the Inclusive Jet Cross Section at the Fermilab Tevatron p-pbar Collider Using a Cone-Based Jet Algorithm
We present a measurement of the inclusive jet cross section in p-pbar
collisions at sqrt{s}=1.96 TeV based on data collected by the CDF II detector
with an integrated luminosity of 1.13 fb^-1. The measurement was made using the
cone-based Midpoint jet clustering algorithm in the rapidity region of |y|<2.1.
The results are consistent with next-to-leading-order perturbative QCD
predictions based on recent parton distribution functions (PDFs), and are
expected to provide increased precision in PDFs at high parton momentum
fraction x. The results are also compared to the recent inclusive jet cross
section measurement using the k_T jet clustering algorithm, and we find that
the ratio of the cross sections measured with the two algorithms is in
agreement with theoretical expectations over a large range of jet transverse
momentum and rapidity.Comment: Phys. Rev. D 78, 052006 (2008). We are posting a new version of the
paper with corrections for minor errors in some of the figures and tables. It
should be noted that the data-theory comparison presented in the results
section (VIII) used the correct numbers, so the conclusions of the paper have
not changed. More details can be found in [1] of the pape
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