1,653 research outputs found

    Using Feedback to Control Deadtime in the CDF Trigger System

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    The CDF experiment uses a three-level trigger system to select events produced during p{bar p} collisions. As the luminosity of the Tevatron accelerator falls by a factor of four over a 24 hour period, trigger selections are adjusted automatically in order to make full use of the data processing bandwidth. The selections are made to maximize high purity triggers and keep the deadtime as low as possible at any given luminosity throughout the entire course of a run. We describe the algorithms used to obtain these goals and how the changing conditions are accounted for in the analysis of the data

    TREATMENT OF CLASS I MALOCCLUSION WITH FRANKEL APPLIANCE

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    Aim. The aim of this paper is to evaluate the effect of the Frankel in child with class I malocclusion, maxillary and mandibular contraction, and anterior teeth crowding. Materials and methods. 5 patients with a class I division I malocclusion, maxillary and mandibular contraction and anterior crowding was enrolled in the present study. All patients presented with a stage CS2, CS3 or CS4. Patients with CS5 were not enrolled in the study. Before wearing the Frankel, on each patient head radiographs were taken in lateral plane with the head fixed in a cephalostat with a filmfocus distance of 4 m and a midsagittal-to-film distance of 0,1 m. Cephalometric analysis and casts analysis was performed before phase 1 treatment (T1), and immediately following phase 2 treatment (T2). In addition to standard cephalometric evaluation, another analysis, based on the distance of the basion, A and B to the T line, was done. Patients were instructed to wear the Frankel for 16 hours per day, during the night and afternoon, removing it only to eat and brush. Active treatment lasted 24 months for all patients. A statistical analysis of cephalometric and casts values before and after treatment was done.Results. After 24 months of treatment the cephalometric effects observed were: an increase of the anterior facial height (mean 3,8 mm), an increase of the distance of the basion to the T line (mean 3,6 mm), a incisors tip control (upper incisors mean 0°, lower incisors - 3,2°) and a sagittal maxillary growth control (the mean distance of A to T line was 0°, the mean distance of B to T line was of - 2,2 mm). On cast authors observed an expansion of the upper and lower arches (anterior upper arch expansion mean 2 mm, posterior upper arch expansion mean 2,5 mm; lower arch mean 1 mm) with anterior crowding resolution and incisors sagittal control. Conclusions. Authors evaluated that Frankel had a great repeal to control jaw growth, an increase of maxillary and mandibular expansion, an increase of the anterior facial height with a good control of incisors inclination

    Search for Second-Generation Scalar Leptoquarks in ppˉ\bm{p \bar{p}} Collisions at s\sqrt{s}=1.96 TeV

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    Results on a search for pair production of second generation scalar leptoquark in ppˉp \bar{p} collisions at s\sqrt{s}=1.96 TeV are reported. The data analyzed were collected by the CDF detector during the 2002-2003 Tevatron Run II and correspond to an integrated luminosity of 198 pb1^{-1}. Leptoquarks (LQ) are sought through their decay into (charged) leptons and quarks, with final state signatures represented by two muons and jets and one muon, large transverse missing energy and jets. We observe no evidence for LQLQ production and derive 95% C.L. upper limits on the LQLQ production cross sections as well as lower limits on their mass as a function of β\beta, where β\beta is the branching fraction for LQμqLQ \to \mu q.Comment: 9 pages (3 author list) 5 figure

    Study of CP violation in Dalitz-plot analyses of B0 --> K+K-KS, B+ --> K+K-K+, and B+ --> KSKSK+

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    We perform amplitude analyses of the decays B0K+KKS0B^0 \to K^+K^-K^0_S, B+K+KK+B^+ \rightarrow K^+K^-K^+, and B+KS0KS0K+B^+ \to K^0_S K^0_S K^+, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470×106470\times 10^6 BBˉB\bar{B} decays, collected with the BABAR detector at the PEP-II asymmetric-energy BB factory at the SLAC National Accelerator Laboratory. For B+K+KK+B^+ \to K^+K^-K^+, we find a direct CP asymmetry in B+ϕ(1020)K+B^+ \to \phi(1020)K^+ of ACP=(12.8±4.4±1.3)A_{CP}= (12.8\pm 4.4 \pm 1.3)%, which differs from zero by 2.8σ2.8 \sigma. For B0K+KKS0B^0 \to K^+K^-K^0_S, we measure the CP-violating phase βeff(ϕ(1020)KS0)=(21±6±2)\beta_{\rm eff} (\phi(1020)K^0_S) = (21\pm 6 \pm 2)^\circ. For B+KS0KS0K+B^+ \to K^0_S K^0_S K^+, we measure an overall direct CP asymmetry of ACP=(45+4±2)A_{CP} = (4 ^{+4}_{-5} \pm 2)%. We also perform an angular-moment analysis of the three channels, and determine that the fX(1500)f_X(1500) state can be described well by the sum of the resonances f0(1500)f_0(1500), f2(1525)f_2^{\prime}(1525), and f0(1710)f_0(1710).Comment: 35 pages, 68 postscript figures. v3 - minor modifications to agree with published versio

    Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s) = 1.96 TeV

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    We present a measurement of the top quark pair production cross section in ppbar collisions at sqrt(s)=1.96 TeV using 318 pb^{-1} of data collected with the Collider Detector at Fermilab. We select ttbar 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^2, we measure a cross section of 8.7 +-0.9 (stat) +1.1-0.9 (syst) pb. We also report the first observation of ttbar with significance greater than 5 sigma in the subsample in which both b quarks are identified, corresponding to a cross section of 10.1 +1.6-1.4(stat)+2.0-1.3 (syst) pb.Comment: Accepted for publication in Physics Review Letters, 7 page

    Combined search for the standard model Higgs boson decaying to a bb pair using the full CDF data set

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    We combine the results of searches for the standard model Higgs boson based on the full CDF Run II data set obtained from sqrt(s) = 1.96 TeV p-pbar collisions at the Fermilab Tevatron corresponding to an integrated luminosity of 9.45/fb. The searches are conducted for Higgs bosons that are produced in association with a W or Z boson, have masses in the range 90-150 GeV/c^2, and decay into bb pairs. An excess of data is present that is inconsistent with the background prediction at the level of 2.5 standard deviations (the most significant local excess is 2.7 standard deviations).Comment: To be published in Phys. Rev. Lett (v2 contains minor updates based on comments from PRL

    Measurement of CP-violation asymmetries in D0 to Ks pi+ pi-

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    We report a measurement of time-integrated CP-violation asymmetries in the resonant substructure of the three-body decay D0 to Ks pi+ pi- using CDF II data corresponding to 6.0 invfb of integrated luminosity from Tevatron ppbar collisions at sqrt(s) = 1.96 TeV. The charm mesons used in this analysis come from D*+(2010) to D0 pi+ and D*-(2010) to D0bar pi-, where the production flavor of the charm meson is determined by the charge of the accompanying pion. We apply a Dalitz-amplitude analysis for the description of the dynamic decay structure and use two complementary approaches, namely a full Dalitz-plot fit employing the isobar model for the contributing resonances and a model-independent bin-by-bin comparison of the D0 and D0bar Dalitz plots. We find no CP-violation effects and measure an asymmetry of ACP = (-0.05 +- 0.57 (stat) +- 0.54 (syst))% for the overall integrated CP-violation asymmetry, consistent with the standard model prediction.Comment: 15 page
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