Measurement of the kTk_{T} Distribution of Particles in Jets Produced in p\barp Collisions at s=1.96\sqrt{s}=1.96 TeV

Submitted to PRLWe present a measurement of the transverse momentum with respect to the jet axis ($k_{T}$) of particles in jets produced in $p\bar p$ collisions at $\sqrt{s}=1.96$ TeV. Results are obtained for charged particles within a cone of opening angle 0.5 radians around the jet axis in events with dijet invariant masses between 66 and 737 GeV/c$^{2}$. The experimental data are compared to theoretical predictions obtained for fragmentation partons within the framework of resummed perturbative QCD using the modified leading log and next-to-modified leading log approximations. The comparison shows that trends in data are successfully described by the theoretical predictions, indicating that the perturbative QCD stage of jet fragmentation is dominant in shaping basic jet characteristics

Measurement of the Single Top Quark Production Cross Section at CDF

submitted to Phys. Rev. Lett. 7 pages, two figuresWe report a measurement of the single top quark production cross section in 2.2 ~fb-1 of p-pbar collision data collected by the Collider Detector at Fermilab at sqrt{s}=1.96 TeV. Candidate events are classified as signal-like by three parallel analyses which use likelihood, matrix element, and neural network discriminants. These results are combined in order to improve the sensitivity. We observe a signal consistent with the standard model prediction, but inconsistent with the background-only model by 3.7 standard deviations with a median expected sensitivity of 4.9 standard deviations. We measure a cross section of 2.2 +0.7 -0.6(stat+sys) pb, extract the CKM matrix element value |V_{tb}|=0.88 +0.13 -0.12 (stat+sys) +- 0.07(theory), and set the limit |V_{tb}|>0.66 at the 95% C.L

Search for Technicolor Particles Produced in Association with a W Boson at CDF

submitted to Phys. Rev. LettInternational audienceWe present a search for the technicolor particles $\rho_{T}$ and $\pi_{T}$ in the process $p\bar{p} \to \rho_{T} \to W\pi_{T}$ at a center of mass energy of $\sqrt{s}=1.96 \mathrm{TeV}$. The search uses a data sample corresponding to approximately $1.9 \mathrm{fb}^{-1}$ of integrated luminosity accumulated by the CDF II detector at the Fermilab Tevatron. The event signature we consider is $W\to \ell\nu$ and $\pi_{T} \to b\bar{b}, b\bar{c}$ or $b\bar{u}$ depending on the $\pi_{T}$ charge. We select events with a single high-$p_T$ electron or muon, large missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with multiple $b$-tagging algorithms. The observed number of events and the invariant mass distributions are consistent with the standard model background expectations, and we exclude a region at 95% confidence level in the $\rho_T$-$\pi_T$ mass plane. As a result, a large fraction of the region $m(\rho_T) = 180$ - $250 \mathrm{GeV}/c^2$ and $m(\pi_T) = 95$ - $145 \mathrm{GeV}/c^2$ is excluded

Direct Measurement of the WW Production Charge Asymmetry in \ppbar Collisions at s=1.96\sqrt{s} = 1.96 TeV

submitted to Phys. Rev. LettWe present the first direct measurement of the $W$ production charge asymmetry as a function of the $W$ boson rapidity \yW in \ppbar collisions at $\sqrt{s} = 1.96$ \TeV. We use a sample of \wenu events in data from 1 \ifb of integrated luminosity collected using the CDF II detector. In the region |\yW| < 3.0, this measurement is capable of constraining the ratio of up and down quark momentum distributions in the proton more directly than in previous measurements of the asymmetry that are a function of the charged-lepton pseudorapidity

Inclusive Search for Squark and Gluino Production in ppbar Collisions at sqrt{s} = 1.96 TeV

Paper submitted to Phys. Rev. LettersWe report on a search for inclusive production of squarks and gluinos in ppbar collisions at sqrt{s}=1.96 TeV, in events with large missing transverse energy and multiple jets of hadrons in the final state. The study uses a CDF Run II data sample corresponding to 2 fb-1 of integrated luminosity. The data are in good agreement with the standard model predictions, giving no evidence for any squark or gluino component. In an R-parity conserving minimal supergravity scenario with A_0 = 0, mu < 0 and tanbeta = 5, 95% C.L. upper limits on the production cross sections in the range between 0.1 pb and 1 pb are obtained, depending on the squark and gluino masses considered. For gluino masses below 280 GeV/c2, arbitrarily large squark masses are excluded at the 95%C.L., while for mass degenerate gluinos and squarks, masses below 392 GeV/c2 are excluded at the 95% C.L

Clinical algorithms for the screening of Chlamydia trachomatis in Turkish women.

OBJECTIVE: To test the diagnostic validity of clinical algorithms for the detection of Chlamydia trachomatis in an urban population of married women in Turkey. DESIGN: Cross-sectional population-based survey. SUBJECTS: A systematic sample of 867 women who reported the use of contraceptive methods. MAIN OUTCOME MEASURES: Sensitivity, specificity and positive predictive value of clinical algorithms for the diagnosis of C trachomatis. RESULTS: C trachomatis was diagnosed in 4.89% of the women. The WHO algorithm for use in settings where no vaginal examination could be performed had a sensitivity of 9% and a specificity of 96%. The corresponding figures for the WHO algorithm incorporating the findings of a speculum examination were 47% and 56% respectively. Algorithms incorporating symptoms or signs other than those suggested by the WHO did not yield satisfactory standards of validity. CONCLUSIONS: The findings of this study do not support the widespread introduction of the use of clinical decision models for screening of women for chlamydia infection in primary health care settings such as family planning or antenatal clinics. The large number of false positive results with the use of the clinical algorithms tested in this study would cause unnecessary costs to the health system and unnecessary interventions to the women treated