122 research outputs found

    Next-to-leading order QCD predictions for the hadronic WHWH+jet production

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    We calculate the next-to-leading order(NLO) QCD corrections to the WH0WH^0 production in association with a jet at hadron colliders. We study the impacts of the complete NLO QCD radiative corrections to the integrated cross sections, the scale dependence of the cross sections, and the differential cross sections (dσdcos⁥Ξ\frac{d \sigma}{d\cos\theta}, dσdpT\frac{d \sigma}{dp_T}) of the final WW-, Higgs-boson and jet. We find that the corrections significantly modify the physical observables, and reduce the scale uncertainty of the LO cross section. Our results show that by applying the inclusive scheme with pT,jcut=20GeVp_{T,j}^{cut}=20 GeV and taking mH=120GeVm_H=120 GeV, ÎŒ=ÎŒ0≡12(mW+mH)\mu=\mu_0\equiv\frac{1}{2}(m_W+m_H), the K-factor is 1.15 for the process ppˉ→W±H0j+Xp\bar p \to W^{\pm}H^0j+X at the Tevatron, while the K-factors for the processes pp→W−H0j+Xpp \to W^-H^0j+X and pp→W+H0j+Xpp \to W^+H^0j+X at the LHC are 1.12 and 1.08 respectively. We conclude that to understand the hadronic associated WH0WH^0 production, it is necessary to study the NLO QCD corrections to WH0jWH^0j production process which is part of the inclusive WH0WH^0 production.Comment: 26 pages, 27 figures, accepted by Phys. Rev.

    Jet-veto in bottom-quark induced Higgs production at next-to-next-to-leading order

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    We present results for associated Higgs+n-jet production in bottom quark annihilation, for n=0 and n>=1 at NNLO and NLO accuracy, respectively. We consider both the cases with and without b-tagging. Numerical results are presented for parameters relevant for experiments at the LHC.Comment: 27 pages, 13 figures, 8 table

    The MSSM prediction for W+/- H-/+ production by gluon fusion

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    We discuss the associated W+/- H-/+ production in p p collision for the Large Hadron Collider. A complete one-loop calculation of the loop-induced subprocess g g -> W+/- H-/+ is presented in the framework of the Minimal Supersymmetric Standard Model (MSSM), and the possible enhancement of the hadronic cross section is investigated under the constraint from the squark direct-search results and the low-energy precision data. Because of the large destructive interplay in the quark-loop contributions between triangle-type and box-type diagrams, the squark-loop contributions turn out to be comparable with the quark-loop ones. In particular, the hadronic cross section via gluon fusion can be extensively enhanced by squark-pair threshold effects in the box-type diagrams, so that it can be as large as the hadronic cross section via the b b-bar -> W+/- H-/+ subprocess which appears at tree level.Comment: 35 pages, 7 figures, version to appear in Physical Review

    LeistungsfÀhigkeit von RettungsgerÀten der Feuerwehr bei der Rettung von Personen aus Obergeschossen baulicher Anlagen

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    Zur Ermittlung der „LeistungsfĂ€higkeit von RettungsgerĂ€ten der Feuerwehr bei der Rettung von Personen aus Obergeschossen baulicher Anlagen“ sollte ein Fragebogen erarbeitet und an 100 Feuerwehren ver-schickt werden. Aufgrund unklarer Formulierungen der Fragen waren auch die Antworten nicht eindeutig und somit konnte die Auswertung der ausgefĂŒllten Fragebögen keine nutzbaren Erkenntnisse bringen. Um dennoch verwertbare Erkenntnisse zu gewinnen, wurden Versuchsreihen mit verschiedenen Feuerweh-ren durchgefĂŒhrt, bei denen die Rettungszeiten adipöser Personen, mittels Krankentrage auf die Drehleiter, untersucht wurden

    MSSM Higgs bosons associated with high-pT jets at hadron colliders

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    The cross section for the production of the lightest neutral Higgs boson in association with a high-pT hadronic jet, calculated in the framework of the minimal supersymmetric standard model (MSSM), is presented. The expectations for the hadronic cross section at the Large Hadron Collider are discussed using reasonable kinematical cuts. In particular the contributions from superpartner loops to the cross section and their dependence on the parameters of the MSSM are investigated and found to be significant. Comparisons show that the production rate for h0 + jet in the MSSM can differ widely from the corresponding standard-model prediction.Comment: 20 page

    Gauge-independent MS‟\overline{MS} renormalization in the 2HDM

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    We present a consistent renormalization scheme for the CP-conserving Two-Higgs-Doublet Model based on MS‟\overline{MS} renormalization of the mixing angles and the soft-Z2Z_2-symmetry-breaking scale MsbM_{sb} in the Higgs sector. This scheme requires to treat tadpoles fully consistently in all steps of the calculation in order to provide gauge-independent SS-matrix elements. We show how bare physical parameters have to be defined and verify the gauge independence of physical quantities by explicit calculations in a general RΟR_{\xi}-gauge. The procedure is straightforward and applicable to other models with extended Higgs sectors. In contrast to the proposed scheme, the MS‟\overline{MS} renormalization of the mixing angles combined with popular on-shell renormalization schemes gives rise to gauge-dependent results already at the one-loop level. We present explicit results for electroweak NLO corrections to selected processes in the appropriately renormalized Two-Higgs-Doublet Model and in particular discuss their scale dependence.Comment: 52 pages, PDFLaTeX, PDF figures, JHEP version with Eq. (5.23) correcte

    Production of the neutral top-pion πt0\pi_{t}^{0} in association with a high-pTp_{T} jet at the LHCLHC

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    In the framework of the topcolor-assisted technicolor (TC2)(TC2) model, we study production of the neutral top-pion πt0\pi_{t}^{0} in association with a high-pTp_{T} jet at the LHCLHC, which proceeds via the partonic processes gg⟶πt0ggg\longrightarrow \pi_{t}^{0}g, gq⟶πt0qgq\longrightarrow \pi_{t}^{0}q, qqˉ⟶πt0gq\bar{q}\longrightarrow \pi_{t}^{0}g, gb(bˉ)⟶πt0b(bˉ)gb(\bar{b})\longrightarrow \pi_{t}^{0}b(\bar{b}), and bbˉ⟶πt0gb\bar{b}\longrightarrow \pi_{t}^{0}g. We find that it is very challenging to detect the neutral top-pion πt0\pi_{t}^{0} via the process pp⟶πt0+jet+X→ttˉ+jet+Xpp\longrightarrow \pi_{t}^{0}+jet+X\to t\bar{t}+jet+X, while the possible signatures of πt0\pi_{t}^{0} might be detected via the process pp⟶πt0+jet+X→(tˉc+tcˉ)+jet+Xpp\longrightarrow \pi_{t}^{0}+jet+X\to(\bar{t}c+t\bar{c})+jet+X at the LHCLHC.Comment: 13 pages, 4 figures; typos correcte

    Analytic Results for Higgs Production in Bottom Fusion

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    We evaluate analytically the cross section for Higgs production plus one jet through bottom quark fusion. By considering the small pT limit we derive expressions for the resummation coefficients governing the structure of large logarithms, and compare these expressions with those available in the literature.Comment: 14 pages, 7 figure

    Higgs-Boson Production Induced by Bottom Quarks

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    Bottom quark-induced processes are responsible for a large fraction of the LHC discovery potential, in particular for supersymmetric Higgs bosons. Recently, the discrepancy between exclusive and inclusive Higgs boson production rates has been linked to the choice of an appropriate bottom factorization scale. We investigate the process kinematics at hadron colliders and show that it leads to a considerable decrease in the bottom factorization scale. This effect is the missing piece needed to understand the corresponding higher order results. Our results hold generally for charged and for neutral Higgs boson production at the LHC as well as at the Tevatron. The situation is different for single top quark production, where we find no sizeable suppression of the factorization scale. Turning the argument around, we can specify how large the collinear logarithms are, which can be resummed using the bottom parton picture.Comment: 18 page

    Charged Higgs Boson Production in Bottom-Gluon Fusion

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    We compute the complete next-to-leading order SUSY-QCD corrections for the associated production of a charged Higgs boson with a top quark via bottom-gluon fusion. We investigate the applicability of the bottom parton description in detail. The higher order corrections can be split into real and virtual corrections for a general two Higgs doublet model and into additional massive supersymmetric loop contributions. We find that the perturbative behavior is well under control. The supersymmetric contributions consist of the universal bottom Yukawa coupling corrections and non-factorizable diagrams. Over most of the relevant supersymmetric parameter space the Yukawa coupling corrections are sizeable, while the remaining supersymmetric loop contributions are negligible.Comment: 18 pages, v2: some discussions added, v3: published versio
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