Observation of Orbitally Excited B_s Mesons

We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let

Search for chargino-neutralino production in ppbar collisions at sqrt(s) = 1.96 TeV

We present the results of a search for associated production of the chargino and neutralino supersymmetric particles using up to 1.1 fb-1 of integrated luminosity collected by the CDF II experiment at the Tevatron ppbar collider at a center-of-mass energy of 1.96 TeV. The search is conducted by analyzing events with a large transverse momentum imbalance and either three charged leptons or two charged leptons of the same electric charge. The numbers of observed events are found to be consistent with standard model expectations. Upper limits on the production cross section are derived in different theoretical models. In one of these models a lower limit on the mass of the chargino is set at 129 GeV/c^2 at the 95% confidence level.Comment: To be submitted to Phys.Rev.Let

First Measurement of ZZ Production in ppbar Collisions at sqrt(s)=1.96 TeV

7 pages, 1 figure. Submitted to Phys. Rev. LettWe report the first measurement of the cross section for Z boson pair production at a hadron collider. This result is based on a data sample corresponding to 1.9 fb-1 of integrated luminosity from ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. In the llll channel, we observe three ZZ candidates with an expected background of 0.096^{+0.092}_{-0.063} events. In the llnunu channel, we use a leading-order calculation of the relative ZZ and WW event probabilities to discriminate between signal and background. In the combination of llll and llnunu channels, we observe an excess of events with a probability of $5.1\times 10^{-6}$ to be due to the expected background. This corresponds to a significance of 4.4 standard deviations. The measured cross section is sigma(ppbar -> ZZ) = 1.4^{+0.7}_{-0.6} (stat.+syst.) pb, consistent with the standard model expectation

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