| 1. |
- Enberg, Rikard, et al.
(författare)
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Charged Higgs boson in the W± Higgs channel at the Large Hadron Collider
- 2015
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 893, s. 420-442
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Tidskriftsartikel (refereegranskat)abstract
- In light of the recent discovery of a neutral Higgs boson, Hobs, with a mass near 125 GeV, we reassess the LHC discovery potential of a charged Higgs boson, H±, in the W±Hobs decay channel. This decay channel can be particularly important for a H± heavier than the top quark, when it is produced through the pp→tH± process. The knowledge of the mass of Hobsprovides an additional handle in the kinematic selection when reconstructing a Breit-Wigner resonance in the Hobs→bb¯ decay channel. We consider some extensions of the Standard Model Higgs sector, with and without supersymmetry, and perform a dedicated signal-to-background analysis to test the scope of this channel for the LHC running at design energy (14 TeV), for 300/fb (standard) and 3000/fb (high) integrated luminosities. We find that, while this channel does not show much promise for a supersymmetric H± state, significant portions of the parameter spaces of several two-Higgs doublet models are testable.
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| 2. |
- Enberg, Rikard, et al.
(författare)
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H± in the W±h channel at the LHC Run 2
- 2015
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We analyse the discovery prospects of the charged Higgs boson, H±, via its decay in the W±h channel in the minimal supersymmetric Standard Model (MSSM) as well as several 2-Higgs Doublet Models (2HDMs). h, the lightest scalar Higgs boson in these models, is identified with the recently discovered ∼125 GeV state, Hobs, at the Large Hadron Collider (LHC). We find that, while it provides an important input in the kinematic selection of signal events, the measured Hobs mass renders this channel inaccessible in the MSSM. In the 2HDMs though, through a dedicated signal-to-background analysis for the pp→t(b¯)H−→ℓ±νℓjjbbb¯(b¯)+h.c process, we establish that some parameter space regions will be testable at the LHC with s√=14 TeV.
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| 3. |
- Enberg, Rikard, et al.
(författare)
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Higgs phenomenology in the Stealth Doublet Model
- 2015
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91
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Tidskriftsartikel (refereegranskat)abstract
- We analyze a model for the Higgs sector with two scalar doublets and a softly broken Z2 symmetry. One of the doublets breaks the electroweak symmetry and has tree-level Yukawa couplings to fermions. The other doublet has no vacuum expectation value and no tree-level couplings to fermions. Because the Z2 parity is broken the two doublets can mix, which leads to a distinct and novel phenomenology. This Stealth Doublet Model can be seen as a generalization of the Inert Doublet Model with a broken Z2 symmetry. We outline the model and present constraints from theory, electroweak precision tests and collider searches, including the recent observation of a Higgs boson at the LHC. The CP-odd scalar A and the charged scalar H± couple to fermions at one-loop level. We compute the decays of A and H± and in particular the one-loop decays A→ff¯, H±→ff¯′, H±→W±Z and H±→W±γ. We also describe how to calculate and renormalize such processes in our model. We find that if one of H± or A is the lightest scalar, H±→W±γ or A→bb¯ are typically their respective dominating decay channels. Otherwise, the dominating decays of H± and Aare into a scalar and a vector. Due to the absence of tree-level fermion couplings for H± and A, we consider pair production and associated production with vector bosons and scalars at the LHC. If the parameter space of the model that favors H±→W±γ is realized in Nature, we estimate that there should be a considerable amount of such events in the present LHC data.
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| 4. |
- Enberg, Rikard, et al.
(författare)
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Higgs properties in a broken Inert Doublet Model
- 2013
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Berlin/Heidelberg. - 1126-6708 .- 1029-8479. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- We consider a model for the Higgs sector with two scalar doublets and a softly broken Z2 symmetry, the Stealth Doublet Model. This model can be seen as a generalization of the Inert Doublet Model. One of the doublets is the Higgs doublet that participates in electroweak symmetry breaking and couples to fermions. The other doublet does not couple to fermions at tree level and does not acquire a vacuum expectation value. The broken Z2 symmetry leads to interesting phenomenology such as mixing between the two doublets and charged and CP-odd scalars that can be light and have unusual decay channels. We present theoretical and experimental constraints on the model and consider the recent observation of a Higgs boson at the LHC. The data on the H→ γγ channel can be naturally accommodated in the model, with either the lightest or the heaviest CP-even scalar playing the role of the observed particle.
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| 5. |
- Enberg, Rikard, et al.
(författare)
-
Higgs properties in a softly broken Inert Doublet Model
- 2013
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :8
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Tidskriftsartikel (refereegranskat)abstract
- We consider a model for the Higgs sector with two scalar doublets and a softly broken Z(2) symmetry, the Stealth Doublet Model. This model can be seen as a generalization of the Inert Doublet Model. One of the doublets is the Higgs doublet that participates in electroweak symmetry breaking and couples to fermions. The other doublet does not couple to fermions at tree level and does not acquire a vacuum expectation value. The broken Z(2) symmetry leads to interesting phenomenology such as mixing between the two doublets and charged and CP-odd scalars that can be light and have unusual decay channels. We present theoretical and experimental constraints on the model and consider the recent observation of a Higgs boson at the LHC. The data on the H -> gamma gamma channel can be naturally accommodated in the model, with either the lightest or the heaviest CP-even scalar playing the role of the observed particle.
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| 6. |
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| 7. |
- Enberg, Rikard, et al.
(författare)
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Search for Charged Higgs bosons via decays to W± and a 125 GeV Higgs at the Large Hadron Collider
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The recent observation of a 125 GeV neutral Higgs boson (Hobs) provides additional input for charged Higgs boson searches in the H±→W±Hobs decay channel at the Large Hadron Collider (LHC). We reassess the discovery potential in this channel, which is important for H± heavier than the top quark mass. When Hobs decays to a bb¯ pair, knowledge of the Higgs mass aids in the kinematic selection of signal events. We perform a signal-to-background analysis to demonstrate the LHC prospects for charged Higgs discovery in the resulting channel pp→t(b¯)H−→ℓ±νℓjjbbb¯(b¯)+h.c. for standard (300 fb−1) and high (3000 fb−1) luminosities at design energy, s√=14TeV. We find that regions of the parameter space of several two-Higgs doublet models, consistent with constraints from LHC Higgs searches and b-physics observables, are testable in this channel.
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| 8. |
- Wouda, Glenn, et al.
(författare)
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A light second Higgs doublet in light of LHC data
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We confront the general, CP-conserving, two-Higgs-doublet model (2HDM) with Yukawa couplings of Types I–IV with all the data present from run-I of the LHC. For the allowed regions of parameter space, we investigate to what extent there can still exist relatively light scalars, and under which conditions they may be within discovery reach for upcoming LHC runs.
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| 9. |
- Wouda, Glenn
(författare)
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Phenomenology of Higgs Bosons Beyond the Standard Model
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- After a long history of searches, a Higgs boson H was discovered by the ATLAS and the CMS experiments at the Large Hadron Collider (LHC) in 2012. Its properties fit well the ones predicted by the Standard Model (SM) of particle physics. However, the SM can not explain other established properties of Nature, such as the existence of Dark Matter. For this reason, models beyond the SM should be considered. Such models often predict the existence of several Higgs bosons and this thesis explores some of those models. In particular, the possibility to discover a charged Higgs boson, which would be a clear sign of physics beyond the SM, is studied.A commonly studied extension of the SM is the framework of two-Higgs-doublet models (2HDMs), where there are five Higgs bosons. By confronting the parameter spaces of some 2HDMs with publically available data from the LHC, the prospects for finding the 2HDM Higgs bosons is presented through the calculation of production cross sections and decay branching ratios in various channels.A new kind of 2HDM, called the Stealth Doublet Model is presented and the properties of the Higgs bosons are studied. In this model, it is shown that in particular the properties of the charged Higgs boson H± have new features not exhibited in earlier studied models. Within the parameter space compatible with the LHC results, the production cross section for H± can be sizeable enough to be experimentally observed.Finally, the discovery prospects at the LHC, for a H± in the pp → tH± process, with the decays H± → HW± and H → bb, is studied in various models beyond the Standard Model. It is shown that for the supersymmetric models, this channel is beyond the discovery reach of the LHC. In some of the other studied models, in particular the Aligned 2HDM, the situation is improved and the channel is feasible.
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