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Observation of Exclusive Electron-Positron Production in Hadron-Hadron Collisions

Description: We present the first observation of exclusive e{sup +}e{sup -} production in hadron-hadron collisions, using p{bar p} collision data at {radical}s = 1.96 TeV taken by the Run II Collider Detector at Fermilab, and corresponding to an integrated luminosity of 532 pb{sup -1}. We require the absence of any particle signatures in the detector except for an electron and a positron candidate, each with transverse energy E{sub T} > 5 GeV and pseudorapidity |{eta}| < 2. With these criteria, 16 events are observed compared to a background expectation of 1.9 {+-} 0.3 events. These events are consistent in cross section and properties with the QED process p{bar p} {yields} p + e{sup +}e{sup -} + {bar p} through two-photon exchange. The measured cross section is 1.6{sub -0.3}{sup +0.5}(stat) {+-} 0.3(syst) pb. This agrees with the theoretical prediction of 1.71 {+-} 0.01 pb.
Date: November 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Observation of B0(s) - anti-B0(s) Oscillations

Description: The authors report the observation of B{sub s}{sup 0}-{bar B}{sub s}{sup 0} oscillations from a time-dependent measurement of the B{sub s}{sup 0}-{bar B}{sub s}{sup 0} oscillation frequency {Delta}m{sub s}. Using a data sample of 1 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron, they find signals of 5600 fully reconstructed hadronic B{sub s} decays, 3100 partially reconstructed hadronic B{sub s} decays, and 61,500 partially reconstructed semileptonic B{sub s} decays. They measure the probability as a function of proper decay time that the B{sub s} decays with the same, or opposite, flavor as the flavor at production, and they find a signal for B{sub s}{sup 0}-{bar B}{sub s}{sup 0} oscillations. The probability that random fluctuations could produce a comparable signal is 8 x 10{sup -8}, which exceeds 5{sigma} significance. They measure {Delta}m{sub s} = 17.77 {+-} 0.10(stat) {+-} 0.07(syst) ps{sup -1} and extract |V{sub td}/V{sub ts}| = 0.2050 {+-} 0.0007(exp{sub -0.0060}{sup +0.0081})(theor).
Date: September 1, 2006
Creator: Abulencia, A.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Observation of B0 (s) ---> K+ K- and Measurements of Branching Fractions of Charmless Two-body Decays of B0 and B0(s) Mesons in anti-p p Collisions at s**(1/2) = 1.96-TeV

Description: The authors search for decays of the type B{sub (s)}{sup 0} {yields} h{sup +}h'{sup -} (where h,h' = K or {pi}) in 180 pb{sup -1} of data collected by the CDF II detector at the Fermilab Tevatron. They observe the new mode B{sub s}{sup 0} {yields} K{sup +}K{sup -} with a yield of 236 {+-} 32 events, corresponding to (f{sub s}/f{sub d}) x {Beta}(B{sub s}{sup 0} {yields} K{sup +}K{sup -})/{Beta}(B{sup 0} {yields} K{sup +}{pi}{sup -}) = 0.46 {+-} 0.08(stat.) {+-} 0.07(syst.), where f{sub s}/f{sub d} is the ratio of production fractions of B{sub s}{sup 0} and B{sup 0}. They find results in agreement with world averages for the modes B{sup 0} {yields} {pi}{sup +}{pi}{sup -} and B{sup 0} {yields} K{sup +}{pi}{sup -}, and set the following upper limits at 90% CL: {Beta}(B{sup 0} {yields} K{sup +}K{sup -}) < 1.8 x 10{sup -6}, {Beta}(B{sub s}{sup 0} {yields} K{sup -}{pi}{sup +}) < 5.6 x 10{sup -6}, and {Beta}(B{sub s}{sup 0} {yields} {pi}{sup +}{pi}{sup -}) < 1.7 x 10{sup -6}.
Date: July 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Precise measurement of the top quark mass in the lepton+jets topology at CDF II

Description: The authors 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. They analyze events from the single lepton plus jets final state (t{bar t} {yields} W{sup +}bW{sup -}{bar b} {yields} lvbq{bar q}{bar b}). The top quark mass is extracted using a direct calculation of the probability density that each event corresponds to the t{bar t} 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 in situ by the hadronic W boson mass. Using 167 events observed in 955 pb{sup -1} of integrated luminosity, they achieve the single most precise measurement of the top quark mass, 170.8 {+-} 2.2(stat.) {+-} 1.4(syst.) GeV/c{sup 2}.
Date: March 1, 2007
Creator: Abulencia, A.; /Illinois U., Urbana; Adelman, J.; U., /Chicago; Affolder, T.; /UC, Santa Barbara et al.
Partner: UNT Libraries Government Documents Department

Measurement of the helicity fractions of W bosons from top quark decays using fully reconstructed t anti-t events with CDF II

Description: The authors present a measurement of the fractions F{sub 0} and F{sub +} of longitudinally polarized and right-handed W bosons in top quark decays using data collected with the CDF II detector. The data set used in the analysis corresponds to an integrated luminosity of approximately 318 pb{sup -1}. They select t{bar t} candidate events with one lepton, at least four jets, and missing transverse energy. The helicity measurement uses the decay angle {theta}*, which is defined as the angle between the momentum of the charged lepton in the W boson rest frame and the W momentum in the top quark rest frame. The cos {theta}* distribution in the data is determined by full kinematic reconstruction of the t{bar t} candidates. They find F{sub 0} = 0.85{sub -0.22}{sup +0.15}(stat){+-}0.06(syst) and F{sub +} = 0.05{sub -0.05}{sup +0.11}(stat) {+-} 0.03(syst), which is consistent with the standard model prediction. They set an upper limit on the fraction of right-handed W bosons of F{sub +} < 0.26 at the 95% confidence level.
Date: December 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the t anti-t Production Cross Section in p anti-p collisions at s**(1/2) = 1.96-TeV using Lepton + Jets Events with Jet Probability b-tagging

Description: The authors present a measurement of the t{bar t} production cross section using events with one charged lepton and jets from p{bar p} collisions at a center-of-mass energy of 1.96 TeV. A b-tagging algorithm based on the probability of displaced tracks coming from the event interaction vertex is applied to identify b quarks from top decay. Using 318 pb{sup -1} of data collected with the CDF II detector, they measure the t{bar t} production cross section in events with at least one restrictive (tight) b-tagged jet and obtain 8.9{sub -1.0}{sup +1.0}(stat.){sub -1.0}{sup +1.1}(syst.) pb. The cross section value assumes a top quark mass of m{sub t} is presented in the paper. This result is consistent with other CDF measurements of the t{bar t} cross section using different samples and analysis techniques, and has similar systematic uncertainties. They have also performed consistency checks by using the b-tagging probability function to vary the signal to background ratio and also using events that have at least two b-tagged jets.
Date: July 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the t anti-t production cross section in p anti-p collisions at s**(1/2) = 1.96-TeV using missing E(T) + jets events with secondary vertex b-tagging

Description: The authors present a measurement of the t{bar t} production cross section in p{bar p} collisions at {radical}s = 1.96 TeV which uses events with an inclusive signature of significant missing transverse energy and jets. This is the first measurement which makes no explicit lepton identification requirements, so that sensitivity to W {yields} {tau}{nu} decays is maintained. Heavy flavor jets from top quark decay are identified with a secondary vertex tagging algorithm. From 311 pb{sup -1} of data collected by the Collider Detector at Fermilab they measure a production cross section of 5.8 {+-} 1.2(stat.){sub -0.7}{sup +0.9}(syst.) pb for a top quark mass of 178 GeV/c{sup 2}, in agreement with previous determinations and standard model predictions.
Date: March 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the tanti-t Production Cross Section in p anti-ptnipbar Collisions at s**(1/2) = 1.96-TeV

Description: The authors present a measurement of the top quark pair production cross section in p{bar p} collisions at {radical}s = 1.96 TeV using 318 pb{sup -1} of data collected with the Collider Detector at Fermilab. They select t{bar t} decays into the final states e{nu} + jets and {mu}{nu} + jets, in which at least one b quark from the t-quark decays is identified using a secondary vertex-finding algorithm. Assuming a top quark mass of 178 GeV/c{sup 2}, they measure a cross section of 8.7 {+-} 0.9(stat.){sub -0.9}{sup +1.1}(syst.) pb. They also report the first observation of t{bar t} with significance greater than 5{sigma} in the subsample in which both b quarks are identified, corresponding to a cross section of 10.1{sub -1.4}{sup +1.6}(stat.){sub -1.3}{sup +2.0}(syst.) pb.
Date: June 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the top-quark mass in all-hadronic decays in p anti-p collisions at CDF II

Description: We present a measurement of the top-quark mass, M{sub tpo}, in the all-hadronic decay channel t{bar t} {yields} W{sup +}bW{sup -}{bar b} {yields} q{sub 1}{bar q}{sub 2}bq{sub 3}{bar q}{sub 4}{bar b}. The analysis is performed using 310 pb{sup -1} of {radical}s = 1.96 TeV p{bar p} collisions collected with the CDF II detector using a multi-jet trigger. The mass measurement is based on an event-by-event likelihood which depends on both the sample purity and the value of the top-quark mass, using 90 possible jet-to-parton assignments in the six-jet final state. The joint likelihood of 290 selected events yields a value of M{sub top} = 177.1 {+-} 4.9(stat.) {+-} 4.7(syst.) GeV/c{sup 2}.
Date: December 1, 2006
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Abulencia, A.; /Illinois U., Urbana; Adelman, J.; U., /Chicago et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Top Quark Mass in p anti-p Collisions at s**(1/2) = 1.96-TeV using the Decay Length Technique

Description: We report the first measurement of the top quark mass using the decay length technique in p{bar p} collisions at a center-of-mass energy of 1.96 TeV. This technique uses the measured flight distance of the b hadron to infer the mass of the top quark in lepton plus jets events with missing transverse energy. It relies solely on tracking and avoids the jet energy scale uncertainty that is common to all other methods used so far. We apply our novel method to a 695 pb{sup -1} data sample recorded by the CDF II detector at Fermilab and extract a measurement of m{sub t} = 180.7{sub -13.4}{sup +15.5}(stat.) {+-} 8.6 (syst.) GeV/c{sup 2}. While the uncertainty of this result is larger than that of other measurements, the dominant uncertainties in the decay length technique are uncorrelated with those in other methods. This result can help reduce the overall uncertainty when combined with other existing measurements of the top quark mass.
Date: December 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Lambda0(b) Lifetime in Lambda0(b) ---> J/psi Lambda0 in p anti-p Collisions at s**(1/2) = 1.96-TeV

Description: The authors report a measurement of the {Lambda}{sub b}{sup 0} lifetime in the exclusive decay {Lambda}{sub b}{sup 0} {yields} J/{psi}{Lambda}{sup 0} in p{bar p} collisions at {radical}s = 1.96 TeV using an integrated luminosity of 1.0 fb{sup -1} of data collected by the CDF II detector at the Fermilab Tevatron. Using fully reconstructed decays, they measure {tau}({Lambda}{sub b}{sup 0}) = 1.593{sub -0.078}{sup +0.083}(stat.) {+-} 0.033(syst.) ps. This is the single most precise measurement of {tau}({Lambda}{sub b}{sup 0}) and is 3.2 {sigma} higher than the current world average.
Date: September 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the B0(s) - anti-B0(s) Oscillation Frequency

Description: The authors present the first measurement of the B{sub s}{sup 0}-{bar B}{sub s}{sup 0} oscillation frequency {Delta}m{sub s}. They use 1 fb{sup -1} of data from p{bar p} collisions at {radical}s = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. The sample contains signals of 3600 fully reconstructed hadronic B{sub s} decays and 37,000 partially reconstructed semileptonic B{sub s} decays. They measure the probability as a function of proper decay time that the B{sub s} decays with the same, or opposite, flavor as the flavor at production and they find a signal consistent with B{sub s}{sup 0}-{bar B}{sub s}{sup 0} oscillations. The probability that random fluctuations could produce a comparable signal is 0.2%. Under the hypothesis that the signal is due to B{sub s}{sup 0}-{bar B}{sub s}{sup 0} oscillations, they measure {Delta}m{sub s} = 17.31{sub -0.18}{sup +0.33}(stat.) {+-} 0.07(syst.) ps{sup -1} and determine |V{sub td}/V{sub ts}| = 0.208{sub -0.002}{sup +0.001}(exp.){sub -0.006}{sup +0.008}(theo.).
Date: June 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the top quark mass using template methods on dilepton events in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors describe a measurement of the top quark mass from events produced in p{bar p} collisions at a center-of-mass energy of 1.96 TeV, using the Collider Detector at Fermilab. They identify t{bar t} candidates where both W bosons from the top quarks decay into leptons (e{nu}, {mu}{nu}, or {tau}{nu}) from a data sample of 360 pb{sup -1}. The top quark mass is reconstructed in each event separately by three different methods, which draw upon simulated distributions of the neutrino pseudorapidity, t{bar t} longitudinal momentum, or neutrino azimuthal angle in order to extract probability distributions for the top quark mass. For each method, representative mass distributions, or templates, are constructed from simulated samples of signal and background events, and parameterized to form continuous probability density functions. A likelihood fit incorporating these parameterized templates is then performed on the data sample masses in order to derive a final top quark mass. Combining the three template methods, taking into account correlations in their statistical and systematic uncertainties, results in a top quark mass measurement of 170.1 {+-} 6.0(stat.) {+-} 4.1(syst.) GeV/c{sup 2}.
Date: February 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Analysis of the quantum numbers J**PC of the X(3872)

Description: The authors present an analysis of angular distributions and correlations of the X(3872) in the exclusive decay mode X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -} with J/{psi} {yields} {mu}{sup +}{mu}{sup -}. They use 780 pb{sup -1} of data from p{bar p} collisions at {radical}s = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. They derive constraints on spin, parity, and charge conjugation parity of the X(3872) by comparing measured angular distributions of the decay products with predictions for different J{sup PC} hypotheses. The assignments J{sup PC} = 1{sup ++} and 2{sup -+} are the only ones consistent with the data.
Date: December 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Polarization of J / psi and psi(2S) mesons produced in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors have measured the polarizations of J/{psi} and {psi}(2S) mesons as functions of their transverse momentum p{sub T} when they are produced promptly in the rapidity range |y| < 0.6 with p{sub T} {ge} 5 GeV/c. The analysis is performed using a data sample with an integrated luminosity of about 800 pb{sup -1} collected by the CDF II detector. For both vector mesons, they find that the polarizations become increasingly longitudinal as p{sub T} increases from 5 to 30 GeV/c. These results are compared to the predictions of non-relativistic quantum chromo-dynamics and other contemporary models. The polarizations of J/{psi} and {psi}(2S) mesons from B-hadron decays are also reported.
Date: April 1, 2007
Creator: Abulencia, A.; /Illinois U., Urbana; Adelman, J.; U., /Chicago; Affolder, T.; /UC, Santa Barbara et al.
Partner: UNT Libraries Government Documents Department

Search for V + A current in top quark decay in p anti-p collisions at s**(1/2) = 1.96 TeV

Description: The authors report an upper limit on the fraction of V + A current, f{sub V+A}, in top quark decays, using approximately 700 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV acquired by the upgraded Collider Detector at Fermilab. For the decay t {yields} Wb {yields} {ell}{nu}b (where {ell} = e or {mu}), the invariant mass of the charged lepton and the bottom quark jet is sensitive to the polarization of the W boson. They determine f{sub V+A} = -0.06 {+-} 0.25 given a top quark mass of 175 GeV/c{sup 2}. They set an upper limit on f{sub V+A} of 0.29 at the 95% confidence level, which represents an improvement by a factor of two on the previous best direct limit.
Date: September 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Search for V+A current in top quark decay in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors report an upper limit on the fraction of V + A current, f{sub V+A}, in top quark decays, using approximately 700 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV acquired by the upgraded Collider Detector at Fermilab. For the decay t {yields} wb {yields} {ell}vb (where {ell} = e or {mu}), the invariant mass of the charged lepton and the bottom quark jet is sensitive to the polarization of the W boson. They determine f{sub V+A} = -0.06 {+-} 0.25 given a top quark mass of 175 GeV/c{sup 2}. They set an upper limit on f{sub V+A} of 0.29 at the 95% confidence level, which represents an improvement by a factor of two on the previous best direct limit.
Date: August 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Search for W-prime boson decaying to electron-neutrino pairs in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors present the results of a search for W{prime} boson decaying to electron-neutrino pairs in p{bar p} collisions at a center-of-mass energy of 1.96 TeV, using a data sample corresponding to 205 pb{sup -1} of integrated luminosity collected by the CDF II detector at Fermilab. They observe no evidence for this decay mode and set limits on the production cross section times branching fraction, assuming the neutrinos from W{prime} boson decays to be light. If they assume the manifest left-right symmetric model, they exclude a W{prime} boson with mass less than 788 GeV/c{sup 2} at the 95% confidence level.
Date: November 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Top quark mass measurement from dilepton events at CDF II with the matrix-element method

Description: We describe a measurement of the top quark mass using events with two charged leptons collected by the CDF II detector from p{bar p} collisions with {radical}s = 1.96 TeV at the Fermilab Tevatron. The likelihood in top mass is calculated for each event by convoluting the leading order matrix element describing q{bar q} {yields} t{bar t} {yields} b{ell}{nu}{sub {ell}}{bar b}{ell}{prime} {nu}{sub {ell}}, with detector resolution functions. The presence of background events in the data sample is modeled using similar calculations involving the matrix elements for major background processes. In a data sample with integrated luminosity of 340 pb{sup -1}, we observe 33 candidate events and measure M{sub top} = 165.2 {+-} 6.1(stat.) {+-} 3.4(syst.) GeV/c{sup 2}. This measurement represents the first application of this method to events with two charged leptons and is the most precise single measurement of the top quark mass in this channel.
Date: May 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Ratios of Branching Fractions B(Bs -> Ds pi pi pi) / B(Bd -> Dd pi pi pi) and B(Bs -> Ds pi) / B(Bd -> Dd pi)

Description: Using 355 pb{sup -1} of data collected by the CDF II detector in p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron, they study the fully reconstructed hadronic decays B{sub (s)}{sup 0} {yields} D{sub (s)}{sup -}{pi}{sup +} and B{sub (s)}{sup 0} {yields} D{sub (s)}{sup -} {pi}{sup +}{pi}{sup +}{pi}{sup -}. They present the first measurement of the ratio of branching fractions {Beta}(B{sub s}{sup 0} {yields} D{sub s}{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -})/{Beta}(B{sup 0} {yields} D{sup -} {pi}{sup +}{pi}{sup +}{pi}{sup -}) = 1.05 {+-} 0.10(stat.) {+-} 0.22(syst.). They also update their measurement of {Beta}(B{sub s}{sup 0} {yields} D{sub s}{sup -} {pi}{sup +})/{Beta}(B{sup 0} {yields} D{sup -} {pi}{sup +}) to 1.13 {+-} 0.08(stat.) {+-} 0.23(syst.) improving the statistical uncertainty by more than a factor of two. They find {Beta}(B{sub s}{sup 0} {yields} D{sub s}{sup -} {pi}{sup +}) = [3.8 {+-} 0.3(stat.) {+-} 1.3(syst.)] x 10{sup -3} and {Beta}(B{sub s}{sup 0} {yields} D{sub s}{sup -} {pi}{sup +}{pi}{sup +}{pi}{sup -}) = [8.4 {+-} 0.8(stat.) {+-} 3.2(syst.)] x 10{sup -3}.
Date: October 1, 2006
Creator: Abulencia, A.; /Illinois U., Urbana; Adelman, J.; U., /Chicago; Affolder, T.; /UC, Santa Barbara et al.
Partner: UNT Libraries Government Documents Department

Precision measurement of the top quark mass from dilepton events at CDF II

Description: We report a measurement of the top quark mass, M{sub t}, in the dilepton decay channel of t{bar t} {yields} b{ell}{prime}{sup +} {nu}{sub {ell}}, {bar b}{ell}{sup -}{bar {nu}}{sub {ell}} using an integrated luminosity of 1.0 fb{sup -1} of p{bar p} collisions collected with the CDF II detector. We apply a method that convolutes a leading-order matrix element with detector resolution functions to form event-by-event likelihoods; we have enhanced the leading-order description to describe the effects of initial-state radiation. The joint likelihood is the product of the likelihoods from 78 candidate events in this sample, which yields a measurement of M{sub t} = 164.5 {+-} 3.9(stat.) {+-} 3.9(syst.) GeV/c{sup 2}, the most precise measurement of M{sub t} in the dilepton channel.
Date: December 1, 2006
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the B(c)+ meson lifetime using B(c)+ ---> J/psi e+ nu(e)

Description: The authors present a measurement of the B{sub c}{sup +} meson lifetime in the semileptonic decay mode B{sub c}{sup +} {yields} J/{psi}e{sup +}{nu}{sub e} using the CDF II detector at the Fermilab Tevatron Collider. From a sample of about 360 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV, they reconstruct J/{psi}e{sup +} pairs with invariant mass in the kinematically allowed range 4 < M{sub J/{psi}e} < 6 GeV/c{sup 2}. A fit to the decay-length distribution of 238 signal events yields a measured B{sub c}{sup +} meson lifetime of 0.463{sub -0.065}{sup +0.073}(stat) {+-} 0.036(syst) ps.
Date: March 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

A Search for scalar bottom quarks from gluino decays in anti-p p collisions at s**(1/2) = 1.96-TeV

Description: We searched for scalar bottom quarks in 156 pb{sup -1} of {bar p}p collisions at {radical}s = 1.96 TeV recorded by the CDF II experiment at the Tevatron. Scalar bottom quarks can be produced from gluino decays in R-parity conserving models of supersymmetry when the mass of the gluino exceeds that of the scalar bottom quark. Then, a scalar bottom quark can decay into a bottom quark and a neutralino. To search for this scenario, we investigated events with large missing transverse energy and at least three jets, two or more of which were identified as containing a secondary vertex from the hadronization of b quarks. We found four candidate events, where 2.6 {+-} 0.7 are expected from standard model processes, and placed 95% confidence level lower limits on gluino and scalar bottom quark masses of up to 280 and 240 GeV/c{sup 2} , respectively.
Date: December 1, 2005
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Search for new physics in lepton + photon + X events with 929 pb**(-1) of p anti-p collisions at s**(1/2) = 1.96-TeV

Description: The authors present results of a search at CDF in 929 {+-} 56 pb{sup -1} of p{bar p} collisions at 1.96 TeV for the anomalous production of events containing a high-transverse momentum charged lepton ({ell}, either e or {mu}) and photon ({gamma}), accompanied by missing transverse energy (E{sub T}), and/or additional leptons and photons, and jets (X). They use the same selection criteria as in a previous CDF Run I search, but with an order-magnitude larger data set, a higher p{bar p} collisions energy, and the CDF II detector. They find 163 {ell}{gamma}E{sub T} + X events, compared to an expectation of 150.6 {+-} 13.0 events. They observe 74 {ell}{ell}{gamma} + X events, compared to an expectation of 65.1 {+-} 7.7 events. They find no events similar to the Run II ee{gamma}{gamma}E{sub T} event.
Date: February 1, 2007
Creator: Abulencia, A.; /Illinois U., Urbana; Adelman, J.; U., /Chicago; Affolder, T.; /UC, Santa Barbara et al.
Partner: UNT Libraries Government Documents Department