20,674 research outputs found

    Measurement of the Bs0J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction

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    The B 0 s → J/ψK 0 S branching fraction is measured in a data sample corresponding to 0.41 fb−1 of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin 2β measurement from B 0 → J/ψK 0 S . The time-integrated branching fraction is measured to be B(B 0 s → J/ψK 0 S ) = (1.83±0.28)×10−5 . This is the most precise measurement to date

    Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV

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    The prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region

    Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays

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    First observations of the B0s →ψ(2S)η, B0 →ψ(2S)π + π − and B0s →ψ(2S)π + π − decays are made using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in proton–proton collisions at a centre-of-mass energy of √ s = 7 TeV. The ratios of the branching fractions of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are B(B0s →ψ(2S)η) ÷ B(B0s →J/ψη) = 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B), ; B(B0→ψ(2S)π + π − ) ÷ B(B0→J/ψπ + π − ) = 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B), ; B(B0s →ψ(2S)π + π − ) ÷ B(B0s →J/ψπ + π − ) = 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B), where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ and ψ(2S) meson decays

    Measurement of prompt hadron production ratios in pppp collisions at s=\sqrt{s} = 0.9 and 7 TeV

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    The charged-particle production ratios pˉ/p , K −/K +, π −/π +, (p+pˉ)/(π++π−) , (K ++K −)/(π ++π −) and (p+pˉ)/(K++K−) are measured with the LHCb detector using 0.3 nb−1 of pp collisions delivered by the LHC at s√=0.9 TeV and 1.8 nb−1 at s√=7 TeV . The measurements are performed as a function of transverse momentum p T and pseudorapidity η. The production ratios are compared to the predictions of several Monte Carlo generator settings, none of which are able to describe adequately all observables. The ratio pˉ/p is also considered as a function of rapidity loss, Δy≡y beam−y, and is used to constrain models of baryon transport

    Agricultural Marketing Research Needs in the 1970's

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    CONTENTS : THE EMERGING FOOD AND FIBER SYSTEM: IMPLICATIONS FOR AGRICULTURE, by Marshall R. Godwin and Lonnie L. Jones; WHAT WE SHOULD HAVE LEARNED FROM THE RESEARCH PROGRAMS OF THE 1960'S, by Willard F. Mueller; MARKETING RESEARCH NEEDS IN THE 70'S,by W.O. Eikhoff; THE MORPHOLOGY OF LAND-GRANT UNIVERSITY AGRICULTURAL MARKETING RESEARCH AND ITS RELATIONSHIP TO DYNAMIC AGRICULTURE, by Thomas L. Sporleder and John P. Nichols; A UNIVERSITY ADMINISTRATOR'S VIEW FOR IMPLEMENTING EFFECTIVE MARKET RESEARCH, by Elmer R. Kiehl; EFFECTIVE MARKET RESEARCH - A PRIVATE CONSULTANT'S APPROACH, by R. E. Seltze

    Search for R-parity-violating supersymmetry in events with four or more leptons in root s=7 TeV pp collisions with the ATLAS detector

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    ATLAS Contributors: Paul Douglas Jackson and Nitesh Soni of School of Chemistry and Physics, University of Adelaide, Adelaide, Australia. Extent: 36p.A search for new phenomena in final states with four or more leptons (electrons or muons) is presented. The analysis is based on 4.7 fb⁻¹ of √s=7TeV proton-proton collisions delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in two signal regions: one that requires moderate values of missing transverse momentum and another that requires large effective mass. The results are interpreted in a simplified model of R-parity-violating supersymmetry in which a 95% CL exclusion region is set for charged wino masses up to 540 GeV. In an R-parity-violating MSUGRA/CMSSM model, values of m₁₍₂ up to 820 GeV are excluded for 10 < tan β < 40.The ATLAS collaboratio

    Efficient synthesis of an enantiopure thiasteroid by a double heck reaction

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    The thiaestrane 7 was synthesized by two sequential Heck reactions starting from the thiophene derivatives 8a - 8c, which contain a (Z)-halogenovinyl group, and the enantiopure hydrindene 2a. The first intermolecular Pd-catalyzed reaction leads to 11a and 11b in a highly regio- and diastereoselective manner. A subsequent intramolecular Heck reaction catalyzed by the palladacycle 4 then gave the thiasteroid 7 with an unusual cis-junction of the rings B and C

    Measurement of the differential cross-section of B+ meson production in pp collisions at root s=7 TeV at ATLAS

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    The production cross-section of B+ mesons is measured as a function of transverse momentum p T and rapidity y in proton-proton collisions at centre-of-mass energy root s = 7 TeV, using 2.4 fb(-1) of data recorded with the ATLAS detector at the Large Hadron Collider. The differential production cross-sections, determined in the range 9 GeV < p(T) < 120 GeV and vertical bar y vertical bar < 2.25, are compared to next-to-leading-order theoretical predictions

    Prompt charm production in pp collisions at &#8730;<span style="text-decoration:overline">s</span>=7 TeV

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    Charm production at the LHC in pp collisions at s√=7 TeV is studied with the LHCb detector. The decays D0→K−π+, D+→K−π+π+, D⁎+→D0(K−π+)π+, D+s→ϕ(K−K+)π+, Λ+c→pK−π+, and their charge conjugates are analysed in a data set corresponding to an integrated luminosity of 15 nb−1. Differential cross-sections dσ/dpT are measured for prompt production of the five charmed hadron species in bins of transverse momentum and rapidity in the region 0&#60;pT&#60;8 GeV/c and 2.0&#60;y&#60;4.5. Theoretical predictions are compared to the measured differential cross-sections. The integrated cross-sections of the charm hadrons are computed in the above pT-y range, and their ratios are reported. A combination of the five integrated cross-section measurements gives σ(cc¯)pT&#60;8 GeV/c,2.0&#60;y&#60;4.5=1419±12(stat)±116(syst)±65(frag) μb, where the uncertainties are statistical, systematic, and due to the fragmentation functions
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