22 research outputs found

    Measurement of correlated μoverlineb\mu - {overline b} jet cross sections in ppˉp {\bar p} collisions at s=1.8\sqrt{s}=1.8 TeV

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    We report on measurements of differential μbˉ\mu - {\bar b} cross sections, where the muon is from a semi-leptonic bb decay and the bˉ{\bar b} is identified using precision track reconstruction in jets. The semi-differential correlated cross sections, dσ\sigma/d\Et^{{\bar b}}, dσ\sigma/d\pt^{{\bar b}}, and dσ\sigma/dδϕ(μbˉ)\delta\phi(\mu - {\bar b}) for \pt^{\mu}>~9 GeV/c, ημ|\eta^{\mu}|~10 GeV, ηbˉ<|\eta^{{\bar b}}|<~1.5, are presented and compared to next-to-leading order QCD calculations.Comment: Uses Latex, Article 12 point, figures appended as uuencoded file The full PostScript available via WWW at http://www-cdf.fnal.gov/physics/pub95/cdf3164_mu_bbar_prd_final.p

    Measurement of the BB Meson Differential Cross Section, dσ/dpTd\sigma/dp_T, in ppˉp\bar{p} Collisions at s=1.8\sqrt{s} = 1.8 TeV

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    This paper presents the first direct measurement of the BB meson differential cross section, dσ/dpTd\sigma/dp_T, in ppˉp\bar{p} collisions at s=1.8\sqrt{s}=1.8 TeV using a sample of 19.3±0.719.3 \pm 0.7 pb1^{-1} accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region y6.0|y| 6.0 GeV/cc by fully reconstructing the BB meson decays B+J/ψK+B^{+}\to J/\psi K^{+} and B0J/ψK0(892)B^{0}\to J/\psi K^{*0}(892), where J/ψμ+μJ/\psi \to \mu^+\mu^- and K0K+πK^{*0} \to K^+ \pi^-. A comparison is made to the theoretical QCD prediction calculated at next-to-leading order.Comment: 14 pages. Submitted to Phys. Rev. Lett. The postscript file is at http://www-cdf.fnal.gov/physics/pub95/cdf2893_bexcl_xsection.p

    [Spectrum of laparoscopic surgery for gastric tumors]

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    Minimally invasive operative procedures are increasingly being used for treating tumors of the upper gastrointestinal tract. While minimally invasive surgery (MIS) has become established as a standard procedure for benign tumors and gastrointestinal stromal tumors (GIST) based on current studies, the significance of MIS in the field of gastric cancer is the topic of heated debate. Until now the majority of studies and meta-analyses on gastric cancer have come from Asia and these indicate the advantages of MIS in terms of intraoperative blood loss, minor surgical complications and swifter convalescence although without any benefits in terms of long-term oncological results and quality of life. Unlike in Germany, gastric cancer in Asia with its unchanged high incidence rate, 50\u2009% frequency of early carcinoma and predominantly distal tumor localization is treated at high-volume centres. Due to the proven marginal advantages of MIS over open resection described in the published studies no general recommendation for laparoscopic surgery of gastric cancer can currently be given

    eQTL Set–Based Association Analysis Identifies Novel Susceptibility Loci for Barrett Esophagus and Esophageal Adenocarcinoma

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    BACKGROUND: Over 20 susceptibility single-nucleotide polymorphisms (SNPs) have been identified for esophageal adenocarcinoma (EAC) and its precursor, Barrett's esophagus (BE), explaining a small portion of heritability. METHODS: Using genetic data from 4,323 BE and 4,116 EAC patients aggregated by international consortia including the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON), we conducted a comprehensive transcriptome-wide association study (TWAS) for BE/EAC, leveraging Genotype Tissue Expression (GTEx) gene expression data from six tissue types of plausible relevance to EAC etiology: mucosa and muscularis from the esophagus, gastroesophageal (GE) junction, stomach, whole blood, and visceral adipose. Two analytical approaches were taken: standard TWAS using the predicted gene expression from local expression quantitative trait loci (eQTLs), and set-based SKAT association using selected eQTLs that predict the gene expression. RESULTS: While the standard approach did not identify significant signals, the eQTL set-based approach identified eight novel associations, three of which were validated in independent external data (eQTL SNP sets for EXOC3, ZNF641 and HSP90AA1). CONCLUSIONS: This study identified novel genetic susceptibility loci for EAC and BE using an eQTL set based genetic association approach. IMPACT: This study expanded the pool of genetic susceptibility loci for EAC and BE, suggesting the potential of the eQTL set based genetic association approach as an alternative method for TWAS analysis

    MEASUREMENT OF THE RATIO SIGMA-B(W-]E-NU)/SIGMA-B(Z(0)-]E+E-) IN P(OVER-BAR)-P COLLISIONS AT ROOT-S=1.8-TEV

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    We present a measurement of the ratio sigmaB(W --> eupsilon)/sigmaB(Z0 --> e+e-) in ppBAR collisions at square-root s = 1.8 TeV. The data represent an integrated luminosity of 21.7 pb-1 from the 1992-1993 run of the Collider Detector at Fermilab. We find sigmaB(W --> eupsilon)/sigmaB(Z0 --> e+e-) = 10.90 +/- 0.32(stat) +/- 0.29(syst). From this value, we extract a value for the W width, GAMMA(W) = 2.064 +/- 0.061(stat) +/- 0.059(syst) GeV, and the branching ratio, GAMMA(W --> eupsilon)/GAMMA(W) = 0.1094 +/- 0.0033(stat) +/- 0.0031(syst), and we set a decay-mode-independent limit on the top quark mass m(top) > 62 GeV/c2 at the 95% C.L

    Measurement of the \u39bb0 Lifetime Using \u39bb0\u2192\u39bc+\u2113-\u3bd\uaf

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    The lifetime of Lambda(b)(0) is measured using the semileptonic decay Lambda(b)(0)-->Lambda(c)(+)l(-)nu(-), where the Lambda(c)(+) is reconstructed through its decay Lambda(c)(+) --> pK(-)pi(+). The data were collected by the CDF detector at the Tevatron Collider during 1992-1995 and correspond to an integrated luminosity of 110 pb(-1) of collisions at root s=1.8 TeV. From a fit to the decay length distribution of the Lambda(c)-lepton system from 197+/-25 signal events, the lifetime of Lambda(b)(0) is measured to be 1.32+/-0.15+/- 0.07 ps

    MEASUREMENT OF THE B+ AND B0 MESON LIFETIMES

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    The lifetimes of the B+ and B0 mesons have been measured using fully reconstructed decays. In a sample of approximately 49 600 J/psi --> mu+mu- decays recorded with the Collider Detector at Fermilab, 148 +/- 16 B+ and 121 +/- 16 B0 mesons have been reconstructed using the silicon vertex detector. Unbinned likelihood fits to the proper lifetime distributions of these B mesons give tau+ = 1.61 +/- 0.16 (stat) +/- 0.05 (syst) ps, tau0 = 1.57 +/- 0.18 (stat) +/- 0.08 (syst) ps, and tau+/tau0 = 1.02 +/- 0.16 (stat) +/- 0.05 (syst)

    Evidence for color coherence in pp\uaf collisions at 1as =1.8 TeV

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