Search for a Charged Higgs Boson in Pp Collisions at {u221A}s

Search for a Charged Higgs Boson in Pp Collisions at {u221A}s
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Total Pages: 62
Release: 2015
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Our search for a charged Higgs boson is performed with a data sample corresponding to an integrated luminosity of 19.7 ± 0.5 fb-1 collected with the CMS detector in proton-proton collisions at √s=8,TeV. The charged Higgs boson is searched for in top quark decays for m H± m t - m b, and in the direct production pp → t(b)Hsup± /supfor m H± m t - m born The H± → ? ± ? ? and H± → tb decay modes in the final states ? h+jets, ?? h, l+jets, and ll’ (l =e, ?) are considered in the search. No signal is observed and 95% confidence level upper limits are set on the charged Higgs boson production. Furthermore, a model-independent upper limit on the product branching fraction B(t→H±b)B(H±→?±??)=1.2-0.15% is obtained in the mass range m H± = 80–160 GeV, while the upper limit on the cross section times branching fraction ?(pp→t(b)H±)B(H±→ ?±??)=0.38-0.025 pb is set in the mass range m H+ = 180–600 GeV. Here, ?(pp → t(b)H±) stands for the cross section sum ?(pp→t¯(b)H+)+?(pp→t(b¯)H-). Assuming B(H±→tb)=1, an upper limit on ?(pp → t(b)H±) of 2.0–0.13 pb is set for m H± = 180–600 GeV. The combination of all considered decay modes and final states is used to set exclusion limits in the m H±-tan ? parameter space in different MSSM benchmark scenarios.

Search for a Charged Higgs Boson Produced in the Vector-boson Fusion Mode with Decay H± {u2192} W±Z Using pp Collisions at {u221A}s

Search for a Charged Higgs Boson Produced in the Vector-boson Fusion Mode with Decay H± {u2192} W±Z Using pp Collisions at {u221A}s
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Release: 2015
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A search for a charged Higgs boson, H±, decaying to a W± boson and a Z boson is presented. The search is based on 20.3 fb–1 of proton-proton collision data at a center-of-mass energy of 8 TeV recorded with the ATLAS detector at the LHC. The H± boson is assumed to be produced via vector-boson fusion and the decays W± → qq¯' and Z → e+e–/?+?– are considered. The search is performed in a range of charged Higgs boson masses from 200 to 1000 GeV. No evidence for the production of an H± boson is observed. Upper limits of 31–1020 fb at 95% C.L. are placed on the cross section for vector-boson fusion production of an H± boson times its branching fraction to W±Z. The limits are compared with predictions from the Georgi-Machacek Higgs triplet model.

Search for Associated Higgs Boson Production Using Like Charge Dilepton Events in P P Collisions at {u221A}s

Search for Associated Higgs Boson Production Using Like Charge Dilepton Events in P P Collisions at {u221A}s
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Total Pages:
Release: 2011
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We present a search for associated Higgs boson production in the process pp→ W/ZH → ell± ell± + X in ee, e?, and ?? final states. The search is based on data collected by the D0 experiment at the Fermilab Tevatron Collider at √s = 1.96 TeV corresponding to 5.3 fb-1 of integrated luminosity. We require two isolated leptons (electrons or muons) with the same electric charge and additional kinematic requirements. No significant excess above background is observed, and we set 95% C.L. observed (expected) upper limits on ratio of the production cross sectin to the standard model expectation of 6.4 (7.3) for a Higgs boson mass of 165 GeV and 13.5 (19.8) for a mass of 115 GeV.

Search for Higgs Bosons Decaying to aa in the ???? Final State in pp Collisions at {u221A}s

Search for Higgs Bosons Decaying to aa in the ???? Final State in pp Collisions at {u221A}s
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Release: 2015
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A search for the decay to a pair of new particles of either the 125 GeV Higgs boson (h) or a second charge parity (CP)-even Higgs boson (H) is presented. The data set corresponds to an integrated luminosity of 20.3 fb-1 of pp collisions at √s = 8 TeV recorded by the ATLAS experiment at the LHC in 2012. The search was done in the context of the next-to-minimal supersymmetric standard model, in which the new particles are the lightest neutral pseudoscalar Higgs bosons (a). One of the two a bosons is required to decay to two muons while the other is required to decay to two ? leptons. No significant excess is observed above the expected backgrounds in the dimuon invariant mass range from 3.7 to 50 GeV. Upper limits are placed on the production of h → aa relative to the standard model gg → h production, assuming no coupling of the a boson to quarks. The most stringent limit is placed at 3.5% for ma = 3.75 GeV. Upper limits are also placed on the production cross section of H → aa from 2.33 to 0.72 pb, for fixed ma = 5 GeV with mH ranging from 100 to 500 GeV.

Search for a CP-odd Higgs Boson Decaying to Zh in Pp Collisions at {u221A}s

Search for a CP-odd Higgs Boson Decaying to Zh in Pp Collisions at {u221A}s
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Total Pages: 21
Release: 2015
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A search for a heavy, CP-odd Higgs boson, A, decaying into a Z boson and a 125 GeV Higgs boson, h, with the ATLAS detector at the LHC is presented. The search uses proton–proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.3fb-1. Decays of CP-even h bosons to ?? or bb pairs with the Z boson decaying to electron or muon pairs are considered, as well as h → bb decays with the Z boson decaying to neutrinos. No evidence for the production of an A boson in these channels is found and the 95% confidence level upper limits derived for ?(gg → A) × BR(A → Zh) × BR(h → f¯f) are 0.098–0.013pb for f = ? and 0.57–0.014 pb for f = b in a range of mA=220–1000 GeV. The results are combined and interpreted in the context of two-Higgs-doublet models.

Search for a Heavy Gauge Boson Decaying to a Charged Lepton and a Neutrino in 1 Fb-1 of pp Collisions at {u221A}s

Search for a Heavy Gauge Boson Decaying to a Charged Lepton and a Neutrino in 1 Fb-1 of pp Collisions at {u221A}s
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Total Pages: 19
Release: 2011
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The ATLAS detector at the LHC is used to search for heavy charged gauge bosons (W'), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 1.04 fb−1. No excess beyond Standard Model expectations is observed. A W' with Sequential Standard Model couplings is excluded at the 95% confidence level for masses up to 2.15 TeV.