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DOE OSTI2010

Search for Randall-Sundrum Gravitons in the Diphoton Channel at CDF

We report on a search for new particles in the diphoton channel using a data sample of p{bar p} collisions at {radical}s = 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron, with an integrated luminosity of 5.4 fb{sup -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 482 GeV/c{sup 2} and 975 GeV/c{sup 2}, at the 95% confidence level, for coupling parameters (k/{bar M}{sub Pl}) of 0.01 and 0.1 respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2010

New Measurement of the Bs Mixing Phase at CDF

The CDF collaboration presents an updated measurement of the CP-violating parameter {beta}{sub s}{sup J/{Psi}{phi}} and of the decay width difference {Delta}{Lambda}{sub s} using approximately 6500 B{sub s} {yields} J/{Psi}{phi} decays collected by the dimuon trigger and reconstructed in a data sample corresponding to 5.2 fb{sup -1} of integrated luminosity. Besides exploiting the two-fold increase in the data sample with respect to the previous measurement, several improvements have been introduced in the analysis including a fully data-driven flavor tagging calibration and proper treatment of possible S-wave contributions. We find that the CP-violating phase is within the range {beta}{sub s}{sup J/{Psi}{phi}} {element_of} [0.02, 0.52] {union} [1.08, 1.55] at 68% C.L. The decay width difference is found to be {Delta}{Lambda}{sub s} = 0.075 {+-} 0.035 (stat) {+-} 0.01 (syst) ps{sup -1}. In addition, we present the most precise mean B{sub s} lifetime {tau}{sub s}, polarization amplitudes |A{sub 0}|{sup 2},|A{sub {parallel}}|{sup 2} and |A{sub {perpendicular}}|{sup 2}, as well as strong phase {delta}{sub {perpendicular}}: {tau}{sub s} = 458.6 {+-} 7.6(stat) {+-} 3.6(syst) {micro}m; |A{sub 0}|{sup 2} = 0.524 {+-} 0.013(stat) {+-} 0.015(syst); |A{sub {parallel}}|{sup 2} = 0.231 {+-} 0.014(stat) {+-} 0.015(syst); and {delta}{sub {perpendicular}} = 2.95 {+-} 0.64(stat) {+-} 0.07(syst).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2010

Charmless and Penguin Decays at CDF

Penguin transitions play a key role in the search of New Physics hints in the heavy flavor sector. During the last decade CDF has been exploring this opportunity with a rich study of two-body charmless decays of neutral B mesons into charged final-state particles. After briefly introducing the aspects of this physics peculiar to the hadron collision environment, I report on two interesting results: the first polarization measurement of the B{sub s}{sup 0} {yields} {phi}{phi} decay and the update of the B{sub (s)}{sup 0} {yields} h{sup +}h{prime}{sup -} decays analysis.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2010

CP violation in the D0 -> pi+ pi- decay at CDF

We report a measurement of the CP violating asymmetry in D{sup 0} {yields} {pi}{sup +}{pi}{sup -} decays using approximately 215,000 decays reconstructed in about 5.94 fb{sup -1} of CDF data. We use the strong D*{sup +} {yields} D{sup 0}{pi}{sup +} decay ('D* tag') to identify the flavor of the charmed meson at production time and exploit CP-conserving strong c{bar c} pair-production in p{bar p} collisions. Higher statistic samples of Cabibbo-favored D{sup 0} {yields} K{sup -}{pi}{sup +} decays with and without D* tag are used to highly suppress systematic uncertainties due to detector effects. The result, A{sub CP}(D{sup 0} {yields} {pi}{sup +}{pi}{sup -}) = [0.22 {+-} 0.24 (stat.) {+-} 0.11 (syst.)]%, is the world's most precise measurement to date and it is fully consistent with no CP violation.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Measurement of $\beta_s$ at CDF

The latest results for the measurement of the CP violating phase {beta}{sub s} in B{sub s}{sup 0} {yields} J/{Psi}{phi} decays, from 5.2 fb{sup -1} integrated luminosity of CDF data are presented. For the first time, this measurement includes the contribution of B{sub s}{sup 0} {yields} J/{Psi}K{sup +}K{sup -} or B{sub s}{sup 0} {yields} J/{Psi}f{sub 0} events to the signal sample, where the f{sub 0} and non-resonant K{sup +}K{sup -} are S-wave states. Additional improvements to the analysis include more than doubling the signal sample, improved selection and particle ID, and fully calibrated flavour tagging for the full dataset. Additionally, the world's most precise single measurements of the B{sub s}{sup 0} lifetime, {tau}{sub s}, and width difference, {Delta}{Gamma}{sub s} are given.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2010

Measurement of ttbar Spin Correlation in ppbar Collisions Using the CDF II Detector at the Tevatron

The t{bar t} 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 t{bar t} spin state in p{bar p} collisions at {radical}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/c{sup 2}, we find a spin correlation coefficient {kappa} = 0.60 {+-} 0.50 (stat) {+-} 0.16 (syst), consistent with the QCD prediction, {kappa} {approx} 0.40.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Suppressed $B_s$ decays at CDF

We review three recent results of the CDF collaboration on B{sub s}{sup 0} suppressed decays: the first search for CP-violation in the B{sub s}{sup 0} {yields} {phi}{phi} decay, where two CP-violating asymmetries expected to be zero in the Standard Model are measured, and the observation and the branching ratio measurements of B{sub s}{sup 0} {yields} J/{Psi} f{sub 0}(980) and B{sub s}{sup 0} {yields} J/{Psi} K{sup (*)} decays.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Searching for New Physics through Charm at CDF

We report a search for non-Standard Model physics through the measurement of CP-violating asymmetry in the Cabibbo suppressed D{sup 0} {yields} {pi}{sup +}{pi}{sup -} and D{sup 0} {yields} K{sup +}K{sup -} decays reconstructed in about 5.94 fb{sup -1} of CDF data. We use the strong D*{sup +} {yields} D{sup 0} {pi}{sup +} decay (D* tag) to identify the flavor of the charmed meson at production time and exploit CP-conserving strong c{bar c} pair-production in p{bar p} collisions. Large samples of Cabibbo favored D{sup 0} {yields} K{sup -}{pi}{sup +} decays with and without D* tag are used to highly suppress systematic uncertainties due to detector effects. The results are the world's most precise measurements to date.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Search for $B_s \to \mu^+\mu^-$ and $B_d \to \mu^+\mu^-$ Decays with CDF II

A search has been performed for B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} and B{sup 0} {yields} {mu}{sup +}{mu}{sup -} decays using 7 fb{sup -1} of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B{sup 0} candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of {Beta}(B{sup 0} {yields} {mu}{sup +}{mu}{sup -}) < 6.0 x 10{sup -9} at 95% confidence level. We observe an excess of B{sub s}{sup 0} candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expected standard model rate of B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} could produce such an excess or larger is 1.9%. These data are used to determine {Beta}(B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -}) = (1.8{sub -0.9}{sup +1.1}) x 10{sup -8} and provide an upper limit of {Beta}(B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -}) < 4.0 x 10{sup -8} at 95% confidence level.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Top Physics at CDF

We present the recent results of top-quark physics using up to 6 fb{sup -1} of p{bar p} collisions at a center of mass energy of {radical}s = 1.96 TeV analyzed by the CDF collaboration. Thanks to this large data sample, precision top quark measurements are now a reality at the Tevatron. Further, several new physics signals could appear in this large dataset. We will present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Evidence for $WZ/WW\to \ell \nu$ + Heavy Flavors Vector Boson Production in 7.5 fb$^{-1}$ of CDF Data

This contribution describes a search for the associated production of Standard Model vector bosons WZ where the W boson decays leptonically (W {yields} {ell}{nu}) and the Z boson decays to a heavy flavor quark pair (Z {yields} b{bar b}, c{bar c}). At least one identified ('tagged') heavy flavor jet in the final state is required. Given the small di-jet invariant mass separation between the W and the Z resonances, the production of WW events where one W decays leptonically and the second W decays into an heavy flavor jet (e.i. W{sup + {yields} c{bar s}) contributes to our the signal. This search uses data collected with the CDF II detector at the Tevatron Collider at Fermilab, and corresponding to an integrated luminosity of approximately 7.5 fb{sup -1}. Events consistent with the signature of a charged lepton (electron or muon), large missing transverse energy and exactly two jets, of which at least one is required to contain a secondary vertex displaced from the jet origin, are selected. A multivariate discriminant based on the Support Vector Machine algorithm is used to reduce greatly the multi-jet background contamination. We observe a signal of significance of 3.03{sigma} over the background only hypothesis. A cross section of 1.085{sub -0.40}{sup +0.26} times the expected Standard Model value for the combined WZ/WW production and decay into heavy flavors is measured, consistent with the Standard Model prediction.

43 PARTICLE ACCELERATORS↗

DOE OSTI2011

Search for RS-gravitons at CDF

We present a search for Randall-Sundrum (RS) gravitons decaying to diphotons or dielectrons or dimuons, performed with the CDF II detector and using up to 5.7 fb{sup -1} of integrated luminosity. The respective mass spectra are consistent with the ones expected by the standard model. For the RS-model parameter k/{bar M}{sub Pl} = 0.1, RS-gravitons with mass less than 1111 GeV/c{sup 2} are excluded at 95% CL.

43 PARTICLE ACCELERATORS↗

DOE OSTI2011

CDF Run-II Silicon Detector: Operations and Aging

The CDF Run-II silicon microstrip detector has seen almost 12 fb{sup -1} of proton-antiproton collisions over the last 10 years. It has shown remarkable performance, with 80% of its channels still operating error-free, and only one of its eight layers approaching the operational limits for full depletion. The measured depletion voltage and signal-to-noise ratio of these sensors give unique information about the behavior of sensors irradiated slowly over a long period of time. Data from heavily irradiated, double-sided sensors excludes a monotonic electric field inside the sensor and is instead consistent with a doubly-peaked field that is lower in the center of the sensor and higher at the edges.

43 PARTICLE ACCELERATORS↗

DOE OSTI2012

CP violation results from CDF

We present world-leading results on CP-violating asymmetries and branching fractions of several decay modes of B{sup 0}, B{sub s}{sup 0}, and {Lambda}{sub b} hadrons into charmless two-body, and of B{sup {+-}} into charm, final states collected by the CDF detector. We also report a new measurement of CP-violating asymmetries in D*{sup {+-}}-tagged D{sup 0} {yields} h{sup +}h{sup -} (h = K or {pi}) decays, where any enhancement from the Standard Model prediction would be unambiguous evidence for New Physics.

43 PARTICLE ACCELERATORS↗

DOE OSTI2011

Top quark physics at CDF

We present the recent results of top-quark physics using up to 6 fb{sup -1} of p{bar p} collisions analyzed by the CDF collaboration. The large number of top quark events analyzed, of the order of several thousands, allows stringent checks of the standard model predictions. Also, the top quark is widely believed to be a window to new physics. We present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.

43 PARTICLE ACCELERATORS↗

DOE OSTI2011

Measurement of the Top Quark Mass in the All-Hadronic Mode at CDF

A measurement of the top quark mass (M{sub top}) in the all-hadronic decay channel is presented. It uses 5.8 fb{sup -1} of p{bar p} data collected with the CDF II detector at the Fermilab Tevatron Collider. Events with six to eight jets are selected by a neural network algorithm and by the requirement that at least one of the jets is tagged as a b quark jet. The measurement is performed with a likelihood fit technique, which simultaneously determines M{sub top} and the jet energy scale (JES) calibration. The fit yields a value of M{sub top} = 172.5 {+-} 1.4 (stat) {+-} 1.0 (JES) {+-} 1.1 (syst) GeV/c{sup 2}.

43 PARTICLE ACCELERATORS↗

DOE OSTI2011

CP violation and suppressed $B_s$ decays at CDF

The study of heavy-quark decays continues to have wide interest as a possible avenue for the discovery of physics beyond the standard model. With data samples as large as 6 fb{sup -1}, the CDF collaboration is exploring new channels that will extend the reach of measurements in probing the CKM mechanism of CP violation. Several new measurements are presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Search for Standard Model Higgs Boson Production in Association with a $W$ Boson Using a Matrix Element Technique at CDF in $p\bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV

This paper presents a search for standard model Higgs boson production in association with a W boson using events recorded by the CDF experiment in a dataset corresponding to an integrated luminosity of 5.6 fb{sup -1}. The search is performed using a matrix element technique in which the signal and background hypotheses are used to create a powerful discriminator. The discriminant output distributions for signal and background are fit to the observed events using a binned likelihood approach to search for the Higgs boson signal. We find no evidence for a Higgs boson, and 95% confidence level (C.L.) upper limits are set on {sigma}(p{bar p} {yields} WH) x {Beta}(H {yields} b{bar b}). The observed limits range from 3.5 to 37.6 relative to the standard model expectation for Higgs boson masses between m{sub H} = 100 GeV/c{sup 2} and m{sub H} = 150 GeV/c{sup 2}. The 95% C.L. expected limit is estimated from the median of an ensemble of simulated experiments and varies between 2.9 and 32.7 relative to the production rate predicted by the standard model over the Higgs boson mass range studied.

43 PARTICLE ACCELERATORS↗