| 1. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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| 2. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 3. |
- Akeroyd, A. G., et al.
(författare)
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Prospects for charged Higgs searches at the LHC
- 2017
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 77:5
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Forskningsöversikt (refereegranskat)abstract
- The goal of this report is to summarize the current situation and discuss possible search strategies for charged scalars, in non-supersymmetric extensions of the Standard Model at the LHC. Such scalars appear in Multi-HiggsDoublet models, in particular in the popular Two-HiggsDoublet model, allowing for charged and additional neutral Higgs bosons. These models have the attractive property that electroweak precision observables are automatically in agreement with the Standard Model at the tree level. For the most popular version of this framework, Model II, a discovery of a charged Higgs boson remains challenging, since the parameter space is becoming very constrained, and the QCD background is very high. We also briefly comment on models with dark matter which constrain the corresponding charged scalars that occur in these models. The stakes of a possible discovery of an extended scalar sector are very high, and these searches should be pursued in all conceivable channels, at the LHC and at future colliders.
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| 4. |
- Akeroyd, A. G., et al.
(författare)
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Slight excess at 130 GeV in search for a charged Higgs boson decaying to a charm quark and a bottom quark at the Large Hadron Collider
- 2022
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Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 49:8
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Tidskriftsartikel (refereegranskat)abstract
- Searches for a charged Higgs boson (H-+/-) decaying to a charm quark and a bottom quark (H +/- -> cb) have been carried out at the Large Hadron Collider (LHC) in the decay of top quarks (t -> H(+/-)b). In a recent search by the ATLAS collaboration (with all run II data, 139 fb(-1)) a local excess of around 3 sigma has been observed, which is best fitted by a charged Higgs boson with a mass (m(H)+/-) of around 130 GeV and a product of branching ratios (BRs) given by BR(t -> H(+/-)b) x BR(H-+/- -> cb) = 0.16% +/- 0.06%. In the context of two-Higgs-doublet models (2HDM) with independent Yukawa couplings for H-+/- we present the parameter space for which this excess (assuming it to be genuine) can be accommodated, taking into account the limits from LHC searches for H-+/- -> cs and H-+/- -> tau nu at m(H)+/- = 130 GeV and the constraint from b -> s gamma. It is then shown that such an excess cannot be explained in 2HDMs with natural flavour conservation, but can be accommodated in the flipped three-Higgs-doublet model (3HDM) and in the aligned 2HDM (A2HDM). Upcoming searches with 139 fb(-1) in the channels H-+/- -> cb (CMS), H-+/- -> cs (ATLAS/CMS) and H-+/- -> tau nu (ATLAS/CMS) will determine if the excess is the first sign of an H-+/- with m(H)+/- = 130 GeV.
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| 5. |
- Akeroyd, A. G., et al.
(författare)
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The decay A(0) -> h(0)Z(*) in the inverted hierarchy scenario and its detection prospects at the large hadron collider
- 2023
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Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 50:9
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Tidskriftsartikel (refereegranskat)abstract
- Searches are being carried out at the large hadron collider (LHC) for the decay of the CP-odd scalar (A(0)) in two-Higgs-doublet models (2HDMs) with natural flavour conservation (NFC) in the channel A(0) -> h(0)Z (with m(h)(0) = 125 GeV and Z on-shell). In the absence of any signal, limits on the parameter space of [tan beta, cos(beta - alpha), mA0] in each 2HDM are derived for m(A)(0) > 225 GeV. In this work, we consider the scenario of inverted hierarchy with m(h)(0) < 125 GeV and m(H)(0) = 125 GeV in which the decay A(0) -> h(0)Z(*) (i.e. including the case of an off-shell Z) can have a large branching ratio in the 2HDM (Type I) for m(A)(0) < 225 GeV. We calculate the signal cross section sigma(gg -> A(0)) ' BR(A(0) -> h(0)Z (*)) ' BR(h(0) -> b<(b)over bar>) in the 2HDM (Type I) with NFC and compare its magnitude with the cross section for the case of normal hierarchy (m(h)(0) = 125 GeV) that is currently being searched for at the LHC. For the experimentally unexplored region m(A)(0) < 225 GeV it is shown that the above cross section for signal events in the scenario of inverted hierarchy can be of the order of a few picobarns. Such sizeable cross sections are several orders of magnitude larger than the cross sections for the case of normal hierarchy, thus motivating an extension of the ongoing searches for A(0) -> h(0)Z(*) to probe the scenario of inverted hierarchy.
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