3,522 research outputs found

    Measurement of Resonance Parameters of Orbitally Excited Narrow B^0 Mesons

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    We report a measurement of resonance parameters of the orbitally excited (L=1) narrow B^0 mesons in decays to B^{(*)+}\pi^- using 1.7/fb of data collected by the CDF II detector at the Fermilab Tevatron. The mass and width of the B^{*0}_2 state are measured to be m(B^{*0}_2) = 5740.2^{+1.7}_{-1.8}(stat.) ^{+0.9}_{-0.8}(syst.) MeV/c^2 and \Gamma(B^{*0}_2) = 22.7^{+3.8}_{-3.2}(stat.) ^{+3.2}_{-10.2}(syst.) MeV/c^2. The mass difference between the B^{*0}_2 and B^0_1 states is measured to be 14.9^{+2.2}_{-2.5}(stat.) ^{+1.2}_{-1.4}(syst.) MeV/c^2, resulting in a B^0_1 mass of 5725.3^{+1.6}_{-2.2}(stat.) ^{+1.4}_{-1.5}(syst.) MeV/c^2. This is currently the most precise measurement of the masses of these states and the first measurement of the B^{*0}_2 width.Comment: 7 pages, 1 figure, 1 table. Submitted to Phys.Rev.Let

    Measurement of the fraction of t-tbar production via gluon-gluon fusion in p-pbar collisions at sqrt(s)=1.96 TeV

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    We present a measurement of the ratio of t-tbar production cross section via gluon-gluon fusion to the total t-tbar production cross section in p-pbar collisions at sqrt{s}=1.96 TeV at the Tevatron. Using a data sample with an integrated luminosity of 955/pb recorded by the CDF II detector at Fermilab, we select events based on the t-tbar decay to lepton+jets. Using an artificial neural network technique we discriminate between t-tbar events produced via q-qbar annihilation and gluon-gluon fusion, and find Cf=(gg->ttbar)/(pp->ttbar)<0.33 at the 68% confidence level. This result is combined with a previous measurement to obtain the most precise measurement of this quantity, Cf=0.07+0.15-0.07.Comment: submitted to Phys. Rev.

    Exploring Entrepreneurial Skills and Competencies in Farm Tourism

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    Diversification to farm tourism is increasingly seen as a viable development strategy to promote a more diverse and sustainable rural economy and to counter declining farm incomes. However, our understanding of the dynamics of the modern farm tourism business and the entrepreneurial and competitive skills farmers require in making the transition from agriculture to a diversified - and service based - enterprise remains limited. Hence, the aim of this paper is to explore the range of skills and competencies that farmers in the North West of England identify as important when adopting a diversification strategy to farm tourism. With the findings indicating that that whilst a range of managerial skills are valued by farmers, they lack many of the additional business and entrepreneurial competencies required for success. Moreover, this paper acknowledges the need to generate consensus on the requisite skill-set that farm tourism operators require, along with a need for a currently fragmented rural tourism literature to acknowledge the significance of rural entrepreneurship and the characteristics of successful farmers and farm tourism ventures

    Occupational balance: What tips the scales for new students?

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    The open question, ‘What prevents you from reaching occupational balance?’, was posed within a questionnaire aimed at exploring the meanings of occupation, health and wellbeing with a cohort of first-year occupational therapy students during their initial few weeks at university. Their written responses to the question about occupational balance were analysed and are discussed in this paper. Not surprisingly, occupational balance appeared to be achieved by only a few and more by chance than design. People, time and money factors were identified as the main impediments to achieving occupational balance, with psychological and emotional pressures being at the forefront. Interestingly, despite these barriers, the overall educational benefit of considering the occupational balance question in this way raised the students’ awareness of its relationship to health and wellbeing. This increased awareness might have longer-term health benefits, both personally and professionally, which would be worthy of further research

    Revising acute care systems and processes to improve breastfeeding and maternal postnatal health: a pre and post intervention study in one English maternity unit

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    Background Most women in the UK give birth in a hospital labour ward, following which they are transferred to a postnatal ward and discharged home within 24 to 48 hours of the birth. Despite policy and guideline recommendations to support planned, effective postnatal care, national surveys of women’s views of maternity care have consistently found in-patient postnatal care, including support for breastfeeding, is poorly rated. Methods Using a Continuous Quality Improvement approach, routine antenatal, intrapartum and postnatal care systems and processes were revised to support implementation of evidence based postnatal practice. To identify if implementation of a multi-faceted QI intervention impacted on outcomes, data on breastfeeding initiation and duration, maternal health and women’s views of care, were collected in a pre and post intervention longitudinal survey. Primary outcomes included initiation, overall duration and duration of exclusive breastfeeding. Secondary outcomes included maternal morbidity, experiences and satisfaction with care. As most outcomes of interest were measured on a nominal scale, these were compared pre and post intervention using logistic regression. Results Data were obtained on 741/1160 (64%) women at 10 days post-birth and 616 (54%) at 3 months post-birth pre-intervention, and 725/1153 (63%) and 575 (50%) respectively postintervention. Post intervention there were statistically significant differences in the initiation (p = 0.050), duration of any breastfeeding (p = 0.020) and duration of exclusive breastfeeding to 10 days (p = 0.038) and duration of any breastfeeding to three months (p = 0.016). Post intervention, women were less likely to report physical morbidity within the first 10 days of birth, and were more positive about their in-patient care. Conclusions It is possible to improve outcomes of routine in-patient care within current resources through continuous quality improvement

    Search for a Higgs Boson Decaying to Two W Bosons at CDF

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    We present a search for a Higgs boson decaying to two W bosons in ppbar collisions at sqrt(s)=1.96 TeV center-of-mass energy. The data sample corresponds to an integrated luminosity of 3.0 fb-1 collected with the CDF II detector. We find no evidence for production of a Higgs boson with mass between 110 and 200 GeV/c^2, and determine upper limits on the production cross section. For the mass of 160 GeV/c^2, where the analysis is most sensitive, the observed (expected) limit is 0.7 pb (0.9 pb) at 95% Bayesian credibility level which is 1.7 (2.2) times the standard model cross section

    Top Quark Mass Measurement in the Lepton plus Jets Channel Using a Modified Matrix Element Method

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    46 pages, 16 figures. Edited in response to referee comments and resubmitted to Phys. Rev. DWe report a measurement of the top quark mass, m_t, obtained from ppbar collisions at sqrt(s) = 1.96 TeV at the Fermilab Tevatron using the CDF II detector. We analyze a sample corresponding to an integrated luminosity of 1.9 fb^-1. We select events with an electron or muon, large missing transverse energy, and exactly four high-energy jets in the central region of the detector, at least one of which is tagged as coming from a b quark. We calculate a signal likelihood using a matrix element integration method, with effective propagators to take into account assumptions on event kinematics. Our event likelihood is a function of m_t and a parameter JES that determines /in situ/ the calibration of the jet energies. We use a neural network discriminant to distinguish signal from background events. We also apply a cut on the peak value of each event likelihood curve to reduce the contribution of background and badly reconstructed events. Using the 318 events that pass all selection criteria, we find m_t = 172.7 +/- 1.8 (stat. + JES) +/- 1.2 (syst.) GeV/c^2.We report a measurement of the top quark mass, mt, obtained from pp̅ collisions at √s=1.96  TeV at the Fermilab Tevatron using the CDF II detector. We analyze a sample corresponding to an integrated luminosity of 1.9  fb-1. We select events with an electron or muon, large missing transverse energy, and exactly four high-energy jets in the central region of the detector, at least one of which is tagged as coming from a b quark. We calculate a signal likelihood using a matrix element integration method, where the matrix element is modified by using effective propagators to take into account assumptions on event kinematics. Our event likelihood is a function of mt and a parameter JES (jet energy scale) that determines in situ the calibration of the jet energies. We use a neural network discriminant to distinguish signal from background events. We also apply a cut on the peak value of each event likelihood curve to reduce the contribution of background and badly reconstructed events. Using the 318 events that pass all selection criteria, we find mt=172.7±1.8(stat+JES)±1.2(syst)  GeV/c2.Peer reviewe

    Search for Long-Lived Massive Charged Particles in 1.96 TeV \bar{p}p} Collisions

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    16 pages, 2 figures; Revision to fix PDF errors on some displays/printersWe performed a signature-based search for long-lived charged massive particles (CHAMPs) produced in 1.0 fb1\rm{fb}^{-1} of pˉp\bar{p}p collisions at s=1.96\sqrt{s}=1.96 TeV, collected with the CDF II detector using a high transverse-momentum (pTp_T) muon trigger. The search used time-of-flight to isolate slowly moving, high-pTp_T particles. One event passed our selection cuts with an expected background of 1.9±0.21.9 \pm 0.2 events. We set an upper bound on the production cross section, and, interpreting this result within the context of a stable scalar top quark model, set a lower limit on the particle mass of 249 GeV/c2c^2 at 95% C.L.We performed a signature-based search for long-lived charged massive particles produced in 1.0  fb-1 of pp̅ collisions at √s=1.96  TeV, collected with the CDF II detector using a high transverse-momentum (pT) muon trigger. The search used time of flight to isolate slowly moving, high-pT particles. One event passed our selection cuts with an expected background of 1.9±0.2 events. We set an upper bound on the production cross section and, interpreting this result within the context of a stable scalar top-quark model, set a lower limit on the particle mass of 249  GeV/c2 at 95% C.L.Peer reviewe

    Search for WW and WZ production in lepton plus jets final state at CDF

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    submitted to Phys. Rev. D (RC)We present a search for WW and WZ production in final states that contain a charged lepton (electron or muon) and at least two jets, produced in sqrt(s) = 1.96 TeV ppbar collisions at the Fermilab Tevatron, using data corresponding to 1.2 fb-1 of integrated luminosity collected with the CDF II detector. Diboson production in this decay channel has yet to be observed at hadron colliders due to the large single W plus jets background. An artificial neural network has been developed to increase signal sensitivity, as compared with an event selection based on conventional cuts. We set a 95% confidence level upper limit of sigma_{WW}* BR(W->lnu,W->jets)+ sigma_{WZ}*BR(W->lnu,Z->jets)We present a search for WW and WZ production in final states that contain a charged lepton (electron or muon) and at least two jets, produced in √s=1.96  TeV pp̅ collisions at the Fermilab Tevatron, using data corresponding to 1.2  fb-1 of integrated luminosity collected with the CDF II detector. Diboson production in this decay channel has yet to be observed at hadron colliders due to the large single W plus jets background. An artificial neural network has been developed to increase signal sensitivity, as compared with an event selection based on conventional cuts. We set a 95% confidence level upper limit of σWW×BR(W→ℓνℓ,W→jets)+σWZ×BR(W→ℓνℓ,Z→jets)<2.88  pb, which is consistent with the standard model next-to-leading-order cross section calculation for this decay channel of 2.09±0.12  pb.Peer reviewe
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