882 research outputs found

    Z-prime Gauge Bosons at the Tevatron

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    We study the discovery potential of the Tevatron for a Z-prime gauge boson. We introduce a parametrization of the Z-prime signal which provides a convenient bridge between collider searches and specific Z-prime models. The cross section for p pbar -> Z-prime X -> l^+ l^- X depends primarily on the Z-prime mass and the Z-prime decay branching fraction into leptons times the average square coupling to up and down quarks. If the quark and lepton masses are generated as in the standard model, then the Z-prime bosons accessible at the Tevatron must couple to fermions proportionally to a linear combination of baryon and lepton numbers in order to avoid the limits on Z--Z-prime mixing. More generally, we present several families of U(1) extensions of the standard model that include as special cases many of the Z-prime models discussed in the literature. Typically, the CDF and D0 experiments are expected to probe Z-prime-fermion couplings down to 0.1 for Z-prime masses in the 500--800 GeV range, which in various models would substantially improve the limits set by the LEP experiments.Comment: 34 pages, 13 figure

    Threshold Corrections in Precision LHC Physics: QED otimes QCD

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    With an eye toward LHC processes in which theoretical precisions of 1 percent are desired, we introduce the theory of the simultaneous YFS resummation of QED and QCD to compute the size of the expected resummed soft radiative threshold effects in precision studies of heavy particle production at the LHC. Our results show that both QED and QCD soft threshold effects must be controlled to be on the conservative side to achieve such precision goals.Comment: 4 pages, no figures; presented by B.F.L. Ward in DPF200

    Gender differences in Parkinson's disease: A clinical perspective

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    Available data indicate that there are gender differences in many features of Parkinson's disease (PD). Precise identification of the gender differences is important to tailor treatment, predict outcomes, and meet other individual and social needs in women and men with PD. The aim of this study was to review the available clinical data on gender differences in PD. Original articles and meta‐analyses published between 1990 and 2016 systematically exploring gender differences in PD were reviewed. There is slight male preponderance in incidence and prevalence of PD. PD starts earlier in men. Women tend to be more prone to develop tremor‐dominant PD but are less rigid than men. Motor improvement after deep brain stimulation is equal in both sexes, but women tend to show better improvement in activities of daily living. Furthermore, women with PD show better results on tests for general cognitive abilities, outperform men in verbal cognitive tasks, show more pain symptoms, and score higher on depression scales. It seems, however, that the differences in cognition, mood, and pain perception are not disease specific as similar gender differences can be found in healthy subjects and in other neurological conditions. Despite PD being the most frequently studied movement disorder, studies investigating gender differences in PD are still scarce with most of the studies being cross‐sectional. Good‐quality, prospective, longitudinal studies analyzing gender differences in PD and comparing them to matched healthy controls are needed in order to properly address the issues of gender differences in PD

    Next-to-Next-to-Leading Order Higgs Production at Hadron Colliders

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    The Higgs boson production cross section at pp and p\bar{p} colliders is calculated in QCD at next-to-next-to-leading order (NNLO). We find that the perturbative expansion of the production cross section is well behaved and that scale dependence is reduced relative to the NLO result. These findings give us confidence in the reliability of the prediction. We also report an error in the NNLO correction to Drell-Yan production.Comment: 5 pages, 4 figures, minor change

    h→Ότh\to \mu\tau at Hadron Colliders

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    We study the observability for a lepton flavor-changing decay of a Higgs boson h→Ότh\to \mu\tau at hadron colliders. Flavor-changing couplings of a Higgs boson exist at tree level in models with multiple Higgs doublets. The hΌτh\mu\tau coupling is particularly motivated by the favorable intepretation of ΜΌ−Μτ\nu_\mu-\nu_\tau oscillation. We find that at the Tevatron Run II the unique Ότ\mu\tau signature could serve as the Higgs discovery channel, surpassing expectations for Higgs boson searches in the SM and in a large parameter region of the MSSM. The sensitivity will be greatly improved at the LHC, beyond the coverage at a muon collider Higgs factory.Comment: Version to appear in PR

    The Production of Zâ€ČZ' Associated With Photons or Jets as a Probe of New Gauge Boson Couplings

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    We examine the production of a new Zâ€ČZ' gauge boson in association with photons or jets at future hadron supercolliders as a probe of its couplings to fermions. Associated jet production is found to be rather insensitive to these couplings and suffers from large uncertainties as well as substantial backgrounds. On the other hand, the ratio of rates for associated photon Zâ€ČZ' production to that of conventional Zâ€ČZ' production has a rather clean signature (once appropriate cuts are made), and is found to be quite sensitive to the choice of extended electroweak model, while being simultaneously insensitive to structure function uncertainties and QCD corrections. Rates at both the SSC and LHC are significant for Zâ€ČZ' masses in the 1 TeV range.Comment: 14pp, 6 figs(not included), LaTex, ANL-HEP-PR-92-5

    Correction Factors for Reactions involving Quark-Antiquark Annihilation or Production

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    In reactions with qqˉq \bar q production or qqˉq\bar q annihilation, initial- and final-state interactions give rise to large corrections to the lowest-order cross sections. We evaluate the correction factor first for low relative kinetic energies by studying the distortion of the relative wave function. We then follow the procedure of Schwinger to interpolate this result with the well-known perturbative QCD vertex correction factors at high energies, to obtain an explicit semi-empirical correction factor applicable to the whole range of energies. The correction factor predicts an enhancement for qqˉq\bar q in color-singlet states and a suppression for color-octet states, the effect increasing as the relative velocity decreases. Consequences on dilepton production in the quark-gluon plasma, the Drell-Yan process, and heavy quark production processes are discussed.Comment: 25 pages (REVTeX), includes 2 uuencoded compressed postscript figure

    Drell-Yan forward-backward and spin asymmetries for arbitrary vector boson production at next-to-leading order

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    Longitudinally polarized, unpolarized and forward-backward mass differential cross sections for Drell-Yan lepton-pair production by arbitrary vector bosons are calculated in next-to-leading order (NLO) QCD. Analytical results are presented in a form valid for all consistent nn-dimensional regularization schemes, with the mass factorization scheme kept general. NLO predictions for all Drell-Yan type processes (W±W^\pm, ZZ and γ∗\gamma^*) at BNL's relativistic heavy ion collider (RHIC) are made using polarized parton distributions which fit the recent deep-inelastic scattering data. These are examined as tools in the determination of the polarized parton distributions and the unpolarized uˉ/dˉ\bar{u}/\bar{d} ratio. NLO predictions for the forward-backward lepton asymmetry at Fermilab are made and the precision determination of sin⁥2ΞW\sin^2 \theta_W from future runs is studied. In all the above, the QCD corrections are found to be significant. An introductory discussion is given of various theoretical issues, such as allowable factorization and regularization schemes, and scale dependences.Comment: 34 pages, figures included, revtex. Some discussions and references added/modified. In more compact form. To appear in Phys. Rev.

    Anomalous dimension of the gluon operator in pure Yang-Mills theory

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    We present new one loop calculations that confirm the theorems of Joglekar and Lee on the renormalization of composite operators. We do this by considering physical matrix elements with the operators inserted at non-zero momentum. The resulting IR singularities are regulated dimensionally. We show that the physical matrix element of the BRST exact gauge variant operator which appears in the energy- momentum tensor is zero. We then show that the physical matrix elements of the classical energy-momentum tensor and the gauge invariant twist two gluon operator are independent of the gauge fixing parameter. A Sudakov factor appears in the latter cases. The universality of this factor and the UV finiteness of the energy-momentum tensor provide another method of finding the anomalous dimension of the gluon operator. We conjecture that this method applies to higher loops and takes full advantage of the triangularity of the mixing matrix.Comment: submitted to Phys. Rev. D, 18 pages LaTEX uses psfig and revtex macros, figures appended as uuencoded Postscript file (complete Postsript version including figures available via anonymous ftp from ftp://max.physics.sunysb.edu/preprints/harris/paper.ps.Z), ITP-SB-94-3

    The impact of a 1-hour time interval between pazopanib and subsequent intake of gastric acid suppressants on pazopanib exposure

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    Co-treatment with gastric acid suppressants (GAS) in patients taking anticancer drugs that exhibit pH-dependant absorption may lead to decreased drug exposure and may hamper drug efficacy. In our study, we investigated whether a 1-hour time interval between subsequent intake of pazopanib and GAS could mitigate this negative effect on drug exposure. We performed an observational study in which we collected the first steady-state pazopanib trough concentration (C(min) ) levels from patients treated with pazopanib 800 mg once daily (OD) taken fasted or pazopanib 600 mg OD taken with food. All patients were advised to take GAS 1 hour after pazopanib. Patients were grouped based on the use of GAS and the geometric (GM) C(min) levels were compared between groups for each dose regimen. Additionally, the percentage of patients with exposure below the target threshold of 20.5 mg/L and the effect of the type of PPI was explored. The GM C(min) levels were lower in GAS users vs non-GAS users for both the 800 and 600 mg cohorts (23.7 mg/L [95% confidence interval [CI]: 21.1-26.7] vs 28.2 mg/L [95% CI: 25.9-30.5], P = .015 and 26.0 mg/L [95% CI: 22.4-30.3] vs 33.5 mg/L [95% CI: 30.3-37.1], P = .006). Subtherapeutic exposure was more prevalent in GAS users vs non-GAS users (33.3% vs 19.5% and 29.6% vs 14%). Sub-analysis showed lower GM pazopanib C(min) in patients who received omeprazole, while minimal difference was observed in those receiving pantoprazole compared to non-users. Our research showed that a 1-hour time interval between intake of pazopanib and GAS did not mitigate the negative effect of GAS on pazopanib exposure and may hamper pazopanib efficacy
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