6,248 research outputs found

    Quark resonances and high E_t jets

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    Possible spin-3/2 quark resonances would have a significant effect on high E_{\mbox{\rm t}} jet production through their contribution to the subprocess q+qˉg+gq+{\bar q}\rightarrow g+g. Such enhancements are compared to a, recently reported, anomaly in inclusive jet production at the CDF detector.Comment: 7 pages set in RevTex with four postscript figures appended- all uuencode

    Vector Boson Pair Production in Hadronic Collisions at Order αs\alpha_s: Lepton Correlations and Anomalous Couplings

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    We present cross sections for production of electroweak vector boson pairs, WWWW, WZWZ and ZZZZ, in ppˉp\bar{p} and pppp collisions, at next-to-leading order in αs\alpha_s. We treat the leptonic decays of the bosons in the narrow-width approximation, but retain all spin information via decay angle correlations. We also include the effects of WWZWWZ and WWγWW\gamma anomalous couplings.Comment: 23 pages, 8 figures, 3 table

    Higher-order QED corrections to W-boson mass determination at hadron colliders

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    The impact of higher-order final-state photonic corrections on the precise determination of the W-boson mass at the Tevatron and LHC colliders is evaluated. In the presence of realistic selection criteria, the shift in the W mass from a fit to the transverse mass distribution is found to be about 10 MeV in the WμνW \to \mu \nu channel and almost negligible in the WeνW \to e \nu channel. The calculation, which is implemented in a Monte Carlo event generator for data analysis, can contribute to reduce the uncertainty associated to the W mass measurement at future hadron collider experiments.Comment: 9 pages, 2 figures, 1 table, RevTe

    Effect of Carbohydrate Demand on the Remobilization of Starch in Stolons and Roots of White Clover (Trifolium repens L.) after Defoliation

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    White clover plants were grown from stolon tips in growth cabinets and then defoliated. Thereafter, changes in the contents of non-structural carbohydrates such as starch, sucrose, glucose, fructose, maltose, and pinitol in stolons and roots were monitored. Initial contents of carbohydrate reserves, photosynthetic supply of new carbohydrates and carbohydrate demand after defoliation were varied by growing the plants at various CO2 partial pressures, by varying the extent of defoliation and by removing either roots or stolon tips at the time of defoliation. Remobilization of carbohydrate reserves in stolons increased proportionally to their initial contents and was greater when plants had been severely defoliated, suggesting that carbohydrates were remobilized according to availability and demand. Starch was the predominant reserve carbohydrate. Starch degradation was associated with decreased contents of sucrose, glucose and fructose in young stolon parts and roots but not in old stolon parts suggesting that starch degradation was not strictly controlled by the contents of these sugars. A decrease in the demand for carbohydrates by removal of roots did not decrease starch degradation but increased the contents of sucrose, glucose, and fructose. Removal of stolon tips decreased starch degradation and contents of sucrose, glucose, and fructose. The results suggest that starch degradation was controlled by a factor other than sucrose, glucose, and fructose which was exported from stolon tips, e.g. gibberelli

    The Semiclassical Coulomb Interaction

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    The semiclassical Coulomb excitation interaction is at times expressed in the Lorentz gauge in terms of the electromagnetic fields and a contribution from the scalar electric potential. We point out that the potential term can make spurious contributions to excitation cross sections, especially when the the decay of excited states is taken into account. We show that, through an appropriate gauge transformation, the excitation interaction can be expressed in terms of the electromagnetic fields alone.Comment: 12 pages. Phys. Rev. C, Rapid Communication, in pres

    Two Photon Radiation in W and Z Boson Production at the Tevatron Collider

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    We present a calculation of two photon radiation in W and Z boson production in hadronic collisions, based on the complete matrix elements for the processes q\bar q'\to\ell^\pm\nu\gamma\gamma and q\bar q\to\ell^+\ell^-\gamma\gamma, including finite charged lepton masses. In order to achieve stable numerical results over the full phase space, multiconfiguration Monte Carlo techniques are used to map the peaks in the differential cross section. Numerical results are presented for the Fermilab Tevatron.Comment: Revtex, 28 pages, 3 figure

    Hadronic ZγZ\gamma Production with QCD Corrections and Leptonic Decays

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    The process ppZγ+X+γ+Xp p \to Z \gamma + X \to \ell^- \ell^+ \gamma + X, where \ell denotes a lepton, is calculated to order αs\alpha_s. Total and differential cross sections, with acceptance cuts imposed on the leptons and photon, are given for the Tevatron and LHC center of mass energies. In general, invariant mass and angular distributions are simply scaled up in magnitude by the QCD radiative corrections, whereas in transverse momentum distributions, the QCD radiative corrections increase with the transverse momentum.Comment: 16 pages + 9 figures, UCD-94-29. A postscript version and 9 postscript figures are available via anonymous ftp to UCDHEP.UCDAVIS.EDU in the directory [.ohnemus.ucd-94-29

    Electroweak-correction effects in gauge-boson pair production at the LHC

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    We have studied the effect of one-loop logarithmic electroweak radiative corrections on WZ and WγW\gamma production processes at the LHC. We present analytical results for the leading-logarithmic electroweak corrections to the corresponding partonic processes du -> WZ, Wgamma. Using the leading-pole approximation we implement these corrections into Monte Carlo programs for pplνlllˉ,lνlγpp\to l\nu_l l'\bar l', l\nu_l\gamma. We find that electroweak corrections lower the predictions by 5-20% in the physically interesting region of large transverse momentum and small rapidity separation of the gauge bosons.Comment: 28 pages, LaTex, 13 eps figures included; references added and corrected typo

    Top effective operators at the ILC

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    We investigate the effect of top trilinear operators in t tbar production at the ILC. We find that the sensitivity to these operators largely surpasses the one achievable by the LHC either in neutral or charged current processes, allowing to probe new physics scales up to 4.5 TeV for a centre of mass energy of 500 GeV. We show how the use of beam polarisation and an eventual energy upgrade to 1 TeV allow to disentangle all effective operator contributions to the Ztt and gamma tt vertices.Comment: LaTeX 13 pages. Typos corrected. Final version in JHE
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