1,582 research outputs found

    The ATLAS discovery potential for a heavy charged Higgs boson in gg->tbH^{+-} with H^{+-}->tb

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    The feasibility of detecting a heavy charged Higgs boson, m(H^{+-})>m(t)+m(b), decaying in the H^{+-}->tb channel is studied with the fast simulation of the ATLAS detector. We study the gg->H^{+-}tb production process at the LHC which together with the aforementioned decay channel leads to four b-quarks in the final state. The whole production and decay chain reads gg->H^{+-}tb->t\bar{t}b\bar{b}->b\bar{b}b\bar{b}l\nu\bar{q}q'. Combinatorial background is a major difficulty in this multi-jet environment but can be overcome by employing multivariate techniques in the event reconstruction. Requiring four b-tagged jets in the event helps to effectively suppress the Standard Model backgrounds but leads to no significant improvement in the discovery potential compared to analyses requiring only three b-tagged jets. This study indicates that charged Higgs bosons can be discovered at the LHC up to high masses (m(H^{+-})>400 GeV) in the case of large tan(beta)

    Pair production of charged Higgs scalars from electroweak gauge boson fusion

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    We compute the contribution to charged Higgs boson pair production at the Large Hadron Collider (LHC) due to the scattering of two electroweak (EW) gauge bosons, these being in turn generated via bremsstrahlung off incoming quarks: q q --> q q V^*V^* --> q q H^+H^- (V=gamma,Z,W^{+/-}). We verify that the production cross section of this mode is tan beta independent and show that it is smaller than that of H^+H^- production via q q-initiated processes but generally larger than that of the loop-induced channel gg --> H^+H^-. Pair production of charged Higgs bosons is crucial in order to test EW symmetry breaking scenarios beyond the Standard Model (SM). We show that the detection of these kind of processes at the standard LHC is however problematic, because of their poor production rates and the large backgrounds.Comment: 22 pages, latex, 8 figures (largely revised version to appear in JPG

    ATLAS discovery potential for a heavy charged Higgs boson

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    The sensitivity of the ATLAS detector to the discovery of a heavy charged Higgs boson is presented. Assuming a heavy SUSY spectrum, the most promising channels above the top quark mass are H±tbH^\pm\to tb and H±τ±ντH^\pm\to\tau^\pm\nu_\tau which provide coverage in the low and high tanβ\tan\beta regions up to 600\sim 600 GeV. The achievable precisions on the charged Higgs mass and tanβ\tan\beta determination are also discussed. The H±W±h0H^\pm\to W^\pm h^0 channel, though restricted to a small MSSM parameter space, shows a viable signal in NMSSM where the parameter space is less constrained. The observation of the channel HτLντ+c.c.H^-\to\tau^-_L\nu_\tau + c.c. may constitute a distinctive evidence for models with singlet neutrinos in large extra dimensions.Comment: 18 page

    Discovery potential for a charged Higgs boson decaying in the chargino-neutralino channel of the ATLAS detector at the LHC

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    We have investigated charged Higgs boson production via the gluon-bottom quark mode, gb -> tH+, followed by its decay into a chargino and a neutralino. The calculations are based on masses and couplings given by the Minimal Supersymmetric Standard Model (MSSM) for a specific choice of MSSM parameters. The signature of the signal is characterized by three hard leptons, a substantial missing transverse energy due to the decay of the neutralino and the chargino and three hard jets from the hadronic decay of the top quark. The possibility of detecting the signal over the Standard Model (SM) and non-SM backgrounds was studied for a set of tanBeta and mA. The existence of 5-sigma confidence level regions for H+ discovery at integrated luminosities of 100 fb-1 and 300 fb-1 is demonstrated, which cover also the intermediate region 4 < tanBeta < 10 where H+ decays to SM particles cannot be used for H+ discovery

    A Nuclear Physics Program at the ATLAS Experiment at the CERN Large Hadron Collider

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    The ATLAS collaboration has significant interest in the physics of ultra-relativistic heavy ion collisions. We submitted a Letter of Intent to the United States Department of Energy in March 2002. The following document is a slightly modified version of that LOI. More details are available at: http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/SM/ionsComment: Letter of Intent submitted to the United States Department of Energy Nuclear Physics Division in March 2002 (revised version

    Possible improvements on the mass of the tau neutrino using leptonic Ds±D^\pm_s decays

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    We show how a very accurate measurement of the branching ratios of the leptonic decay modes of the Ds±D^\pm_s mesons can lead to a significant improvement in the mass limit for the tau neutrino.Comment: 1 typo in Eq.2 correcte

    Universality test of the charged Higgs boson couplings at the LHC and at B factories

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    Many extensions of the Standard Model (SM) of particle physics predict the existence of charged Higgs bosons with substantial couplings to SM particles, which would render them observable both directly at the LHC and indirectly at B-factories. For example, the charged Higgs boson couplings to fermions in two doublet Higgs models of type II, are proportional to the ratio of the two Higgs doublet vacuum expectation values (tan(beta)) and fermionic mass factors and could thus be substantial at large tan(beta) and/or for heavy fermions. In this work we perform a model-independent study of the charged Higgs boson couplings at the LHC and at B-factories for large values of tan(beta). We have shown that at high luminosity it is possible to measure the couplings of a charged Higgs boson to the third generation of quarks up to an accuracy of 10%. We further argue that by combining the possible measurements of the LHC and the B-factories, it is possible to perform a universality test of charged Higgs boson couplings to quarks.Comment: 20 pages, 7 figures, LaTeX (style changed to PRD format, text expanded, references added

    Production of the charged Higgs bosons at the CERN Large Hadron Collider in the left-right symmetric model

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    We study the production of the charged Higgs boson at the LHC in the left-right symmetric model. It is shown that there exists a lower bound of the cross section. We investigate that predicted cross sections of this model are generally larger than those of the two Higgs doublet model or the minimal supersymmetric model.Comment: The version which will appear in PRD. References are adde
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