10 research outputs found
Measurements of the properties of Lambda_c(2595), Lambda_c(2625), Sigma_c(2455), and Sigma_c(2520) baryons
We report measurements of the resonance properties of Lambda_c(2595)+ and
Lambda_c(2625)+ baryons in their decays to Lambda_c+ pi+ pi- as well as
Sigma_c(2455)++,0 and Sigma_c(2520)++,0 baryons in their decays to Lambda_c+
pi+/- final states. These measurements are performed using data corresponding
to 5.2/fb of integrated luminosity from ppbar collisions at sqrt(s) = 1.96 TeV,
collected with the CDF II detector at the Fermilab Tevatron. Exploiting the
largest available charmed baryon sample, we measure masses and decay widths
with uncertainties comparable to the world averages for Sigma_c states, and
significantly smaller uncertainties than the world averages for excited
Lambda_c+ states.Comment: added one reference and one table, changed order of figures, 17
pages, 15 figure
Search for a New Heavy Gauge Boson Wprime with Electron + missing ET Event Signature in ppbar collisions at sqrt(s)=1.96 TeV
We present a search for a new heavy charged vector boson decaying
to an electron-neutrino pair in collisions at a center-of-mass
energy of 1.96\unit{TeV}. The data were collected with the CDF II detector
and correspond to an integrated luminosity of 5.3\unit{fb}^{-1}. No
significant excess above the standard model expectation is observed and we set
upper limits on . Assuming standard
model couplings to fermions and the neutrino from the boson decay to
be light, we exclude a boson with mass less than
1.12\unit{TeV/}c^2 at the 95\unit{%} confidence level.Comment: 7 pages, 2 figures Submitted to PR
Measurement of the Forward-Backward Asymmetry in the B -> K(*) mu+ mu- Decay and First Observation of the Bs -> phi mu+ mu- Decay
We reconstruct the rare decays , , and in a data sample
corresponding to collected in collisions at
by the CDF II detector at the Fermilab Tevatron
Collider. Using and decays we report the branching ratios. In addition, we report
the measurement of the differential branching ratio and the muon
forward-backward asymmetry in the and decay modes, and the
longitudinal polarization in the decay mode with respect to the squared
dimuon mass. These are consistent with the theoretical prediction from the
standard model, and most recent determinations from other experiments and of
comparable accuracy. We also report the first observation of the {\mathcal{B}}(B^0_s \to
\phi\mu^+\mu^-) = [1.44 \pm 0.33 \pm 0.46] \times 10^{-6}27 \pm 6B^0_s$ decay observed.Comment: 7 pages, 2 figures, 3 tables. Submitted to Phys. Rev. Let
Search for heavy bottom-like quarks decaying to an electron or muon and jets in collisions at TeV
We report the most sensitive direct search for pair production of
fourth-generation bottom-like chiral quarks () each decaying promptly to
. We search for an excess of events with an electron or muon, at least five
jets (one indentified as due to a or quark) and an imbalance of
transverse momentum using data from collisions collected by the CDF
II detector at Fermilab with an integrated luminosity of 4.8 fb. We
observe events consistent with background expectation and calculate upper
limits on the pair production cross section ( fb for 375 GeV/) and exclude \gevcc at 95%
confidence level.Comment: For submission to PR
Search for Randall-Sundrum gravitons in the diphoton channel at CDF RID G-1087-2011 RID E-4473-2011
We report on a search for new particles in the diphoton channel using a data sample of p (p) over bar collisions at root s = 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron, with an integrated luminosity of 5.4 fb(-1). The diphoton invariant mass spectrum of the data agrees well with the standard model expectation. We set upper limits on the production cross section times branching ratio for the Randall-Sundrum graviton, as a function of diphoton mass. We subsequently derive lower limits on the graviton mass of 459 GeV = c(2) and 963 GeV = c(2), at the 95% confidence level, for coupling parameters ( k/(M) over bar (Pl)) of 0.01 and 0.1, respectively
Measurement of tt̅ spin correlation in pp̅ collisions using the CDF II detector at the Tevatron
The tt̅ spin correlation at production is a fundamental prediction of QCD and a potentially incisive test of new physics coupled to top quarks. We measure the tt̅ spin state in pp̅ collisions at √s=1.96 [square root of s=1.96] TeV using 1001 candidate events in the lepton plus jets decay channel reconstructed in the CDF II detector. In the helicity basis, for a top-quark mass of 172.5 GeV/c2 GeV/c superscript 2], we find a spin correlation coefficient κ=0.60±0.50 (stat)±0.16 (syst), consistent with the QCD prediction, κ≈0.40.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
Search for New Dielectron Resonances and Randall-Sundrum Gravitons at the Collider Detector at Fermilab
A search for new dielectron-mass resonances using data recorded by the CDF II detector and corresponding to an integrated luminosity of 5.7 fb(-1) is presented. No significant excess over the expected standard model prediction is observed. In this data set, an event with the highest dielectron mass ever observed (960 GeV/c(2)) was recorded. The results are interpreted in the Randall-Sundrum (RS) model. Combined with the 5: 4 fb(-1) diphoton analysis, the RS-graviton lower-mass limit for the coupling k/(M) over bar (P1) = 0.1 is 1058 GeV/c(2), making it the strongest limit to date
Observation of B(s)(0) -> J/psi K*(892)(0) and B(s)(0) -> J/psi K(S)(0) decays RID G-1087-2011 RID E-4473-2011
We report the first observation of two Cabibbo-suppressed decay modes of the B(s)(0) meson. Using a sample of p (p) over bar collisions at root s = 1.96 TeV corresponding to 5: 9 fb(-1) of integrated luminosity collected with the CDF II, the collider detector at the Fermilab Tevatron, we search for new B(s)(0) decay modes in a sample of events containing J/psi -> mu(+)mu(-) decays. We reconstruct a B(s)(0) -> J/psi K*(892)(0) 0 signal with K*(892)(0) -> K(+) pi(-), observing a yield of 151 +/- 25 events with a statistical significance of 8.0 sigma. We also reconstruct a B(s)(0) -> J/psi K(s)(0) signal with K(s)(0) -> pi(+)pi(-) , observing a yield of 64 +/- 14 events with a statistical significance of 7.2 sigma. From these yields, we extract the branching ratios B(B(s)(0) -> J/psi K* (892)(0) = (8.3 +/- 3.8) X 10(-5) and B(B(s)(0) -> J/psi K(0)) = (3.5 +/- 0.8) X 10(-5), where statistical, systematic, and fragmentation-fraction uncertainties are included in the combined uncertainty
Measurements of Direct CP Violating Asymmetries in Charmless Decays of Strange Bottom Mesons and Bottom Baryons
We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb(-1) of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, A(CP)(B(s)(0)K(-)pi(+))=+0.390.15(stat)0.08(syst), and bottom baryons, A(CP)(Lambda(b)(0)ppi(-))=+0.030.17(stat)0.05(syst) and A(CP)(Lambda(b)(0)pK(-))=+0.370.17(stat)0.03(syst). In addition, we measure CP violation in B(0)K(+)pi(-) decays with 3.5sigma significance, A(CP)(B(0)K(+)pi(-))=-0.0860.023(stat)0.009(syst), in agreement with the current world average. Measurements of branching fractions of B(s)(0)K(+)K(-) and B(0)pi(+)pi(-) decays are also updated
Top quark mass measurement using the template method at CDF RID G-1087-2011 RID E-4473-2011
We present a measurement of the top quark mass in the lepton + jets and dilepton channels of t (t) over bar decays using the data sample corresponding to an integrated luminosity of 5.6 fb(-1) of p (p) over bar collisions at Tevatron with root s = 1.96 TeV, collected with the CDF II detector. We construct templates of two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W decays in the lepton + jets channel, and a reconstructed top quark mass and m(T2), a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton + jets and dilepton channels to the data yields a measured top quark mass of M(top) = 172.1 +/- 1.1(stat) +/- 0: 9(syst) GeV/c(2)