2,436 research outputs found

    Search for HZZâ€ČHZZ' couplings at the LHC

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    New physics models predict the possibility of extra neutral gauge bosons (Zâ€ČZ') associated with an extra U(1)â€ČU(1)' gauge symmetry. We study the couplings of the Higgs boson to the ZZ boson and Zâ€ČZ' boson predicted by the new physics models. The couplings of the Zâ€ČZ' boson to quarks can also be investigated through the Zâ€ČqqˉZ'q\bar{q} interactions. The accessible ranges of the parameter space have been searched for processes pp→HZXpp\rightarrow HZX and pp→HHZXpp\rightarrow HHZX at the LHC with s=14\sqrt{s}=14 TeV.Comment: 10 pages, 10 figure

    Resonant production of the fourth family slepton at the LHC

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    The resonant production of the fourth family slepton ~l_4 via R-parity violating interactions of supersymmetry at the Large Hadron Collider has been investigated. We study the decay mode of ~l_4 into the fourth family neutrino nu_4 and W boson. The signal will be a like-sign dimuon and dijet if the fourth family neutrino has Majorana nature. We discuss the constraints on the R-parity violating couplings lambda and lambda' of the fourth family charged slepton at the LHC with the center of mass energies of 7, 10 and 14 TeV.Comment: 8 pages, 4 figures, 4 table

    Projections for Neutral Di-Boson and Di-Higgs Interactions at FCC-he Collider

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    As a high energy e-p collider, FCC-he, has been recently proposed with sufficient energy options to investigate Higgs couplings. To analyse the sensitivity on the Higgs boson couplings, we focus spesifically on the CP-even and CP-odd Wilson coefficients with hhZZ hhZZ\:and hhγγ hh\gamma\gamma\: four-point interactions of Higgs boson with Effective Lagrangian Model through the process e−p→hhje−e^{-}p\to hhje^{-} . We simulate the related processes in FCC-he, with 60 GeV and 120 GeV e−e^{-} beams and 50 TeV proton beam collisions. We present the exclusion limits on these couplings both for 68% and 95% C.L. in terms of integrated luminosities.Comment: 18 pages, 20 figures, 3 table

    Probing Charged Higgs Boson Couplings at the FCC-hh Collider

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    Many of the new physics models predicts a light Higgs boson similar to the Higgs boson of the Standard Model (SM) and also extra scalar bosons. Beyond the search channels for a SM Higgs boson, the future collider experiments will explore additional channels that are specific to extended Higgs sectors. We study the charged Higgs boson production within the framework of two Higgs doublet models (THDM) in the proton-proton collisions at the FCC-hh collider. With an integrated luminosity of 500 fb−1^{-1} at very high energy frontier, we obtain a significant coverage of the parameter space and distinguish the charged Higgs-top-bottom interaction within the THDM or other new physics models with charged Higgs boson mass up to 1 TeV.Comment: 22 pages, 26 figures, 6 table

    Single Production of Fourth Family Sneutrino via RPV Couplings at Linear Colliders

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    The single production of fourth family sneutrino Îœ~4\tilde{\nu}_{4} via R-parity violating interactions in electron-positron collisions has been investigated. We study the decays of Îœ~4\tilde{\nu}_{4} into different flavor dilepton e±Ό∓e^{\pm}\mu^{\mp} via R-parity violation. It is shown that R-parity violating couplings (λ411,λ412)(\lambda_{411},\lambda_{412}) down to 0.001 will be reachable at future linear colliders which would provide better accuracy comparing to the indirect measurements as complementary to the LHC results.Comment: 11 pages, 6 figure

    The Observation of Jet Azimuthal Angular Decorrelation at FCC-ep

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    Higher collision energies at future colliders will eventually lead to the falsification of standard fixed-order perturbation theory and linear evolutions due to non-linear structure of QCD at small-x. New physics researches that is strictly based on accurate jet measurements will undoubtedly have this observation known as BFKL effect via angular jet decorrelations taking into account the Mueller-Navelet jets. As one of the frontier colliders, FCC-ep, has a great observation potential on parton densities through asymmetrical collisions. We aim to test the observability of azimuthal angular jet decorrelations with the recent event generators (HERWIG, PYTHIA) at the particle level for FCC-ep centre of mass energies 3.5 TeV in proton-electron collisions. Jets are reconstructed by the Anti-kT algorithm (R = 0.5), with p_{T} > 35 GeV and selected in the range of |y|<6. Relevant rapidity regions has been analyzed with the azimuthal-angle difference between Mueller-Navelet Jets ({\Delta}{\Phi}) in the rapidity seperation ({\Delta}y) and the distributions of cosn({\pi}-{\Delta}{\Phi}) are presented in comparison as the result.Comment: 11 pages, 15 figures, 2 table

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+→Ό+ÎœW^+ \rightarrow \mu^+\nu and W−→Ό−ΜW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13