263 research outputs found

    The effect of supplementing cereal straws with urea, trifolium hay and noug meal on feed intake and liveweight gain of growing crossbred heifers

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    Compares the effects of noug meal, Trifolium tembense hay and urea, fed in different combinations as supplements to wheat or teff straws, on feed intake and growth rate of crossbred heifers

    Observation of Scaling Violations in Scaled Momentum Distributions at HERA

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    Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of xx and Q2Q^2 using the ZEUS detector. The evolution of the scaled momentum, xpx_p, with Q2,Q^2, in the range 10 to 1280 GeV2GeV^2, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of Q2Q^2.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

    D* Production in Deep Inelastic Scattering at HERA

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    This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel D+(D0Kπ+)π+D^{*+}\to (D^0 \to K^- \pi^+) \pi^+ (+ c.c.) has been used in the study. The e+pe^+p cross section for inclusive D^{*\pm} production with 5<Q2<100GeV25<Q^2<100 GeV^2 and y<0.7y<0.7 is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {1.3<pT(D±)<9.01.3<p_T(D^{*\pm})<9.0 GeV and η(D±)<1.5| \eta(D^{*\pm}) |<1.5}. Differential cross sections as functions of p_T(D^{*\pm}), η(D±),W\eta(D^{*\pm}), W and Q2Q^2 are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and η\eta(D^{*\pm}), the charm contribution F2ccˉ(x,Q2)F_2^{c\bar{c}}(x,Q^2) to the proton structure function is determined for Bjorken xx between 2 \cdot 104^{-4} and 5 \cdot 103^{-3}.Comment: 17 pages including 4 figure

    Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

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    Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the γp\gamma p centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil

    Observation of Events with an Energetic Forward Neutron in Deep Inelastic Scattering at HERA

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    In deep inelastic neutral current scattering of positrons and protons at the center of mass energy of 300 GeV, we observe, with the ZEUS detector, events with a high energy neutron produced at very small scattering angles with respect to the proton direction. The events constitute a fixed fraction of the deep inelastic, neutral current event sample independent of Bjorken x and Q2 in the range 3 · 10-4 \u3c xBJ \u3c 6 · 10-3 and 10 \u3c Q2 \u3c 100 GeV2

    Measurement of the View the tt production cross-section using eμ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

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    This paper describes a measurement of the inclusive top quark pair production cross-section (σtt¯) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σtt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σtt¯ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented

    Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos, and b quarks

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    Measurement of the cross section for isolated-photon plus jet production in pp collisions at √s=13 TeV using the ATLAS detector

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    The dynamics of isolated-photon production in association with a jet in proton–proton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 fb−1. Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti- algorithm with radius parameter and required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements

    Search for high-mass new phenomena in the dilepton final state using proton–proton collisions at View the MathML sources=13TeV with the ATLAS detector

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    A search is conducted for both resonant and non-resonant high-mass new phenomena in dielectron and dimuon final states. The search uses View the MathML source3.2fb−1 of proton–proton collision data, collected at View the MathML sources=13TeV by the ATLAS experiment at the LHC in 2015. The dilepton invariant mass is used as the discriminating variable. No significant deviation from the Standard Model prediction is observed; therefore limits are set on the signal model parameters of interest at 95% credibility level. Upper limits are set on the cross-section times branching ratio for resonances decaying to dileptons, and the limits are converted into lower limits on the resonance mass, ranging between 2.74 TeV and 3.36 TeV, depending on the model. Lower limits on the ℓℓqqℓℓqq contact interaction scale are set between 16.7 TeV and 25.2 TeV, also depending on the mode

    A search for resonances decaying into a Higgs boson and a new particle X in the XH → qqbb final state with the ATLAS detector

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    A search for heavy resonances decaying into a Higgs boson (H) and a new particle (X) is reported, utilizing 36.1 fb−1 of proton–proton collision data at collected during 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. The particle X is assumed to decay to a pair of light quarks, and the fully hadronic final state is analysed. The search considers the regime of high XH resonance masses, where the X and H bosons are both highly Lorentz-boosted and are each reconstructed using a single jet with large radius parameter. A two-dimensional phase space of XH mass versus X mass is scanned for evidence of a signal, over a range of XH resonance mass values between 1 TeV and 4 TeV, and for X particles with masses from 50 GeV to 1000 GeV. All search results are consistent with the expectations for the background due to Standard Model processes, and 95% CL upper limits are set, as a function of XH and X masses, on the production cross-section of the resonance
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