Diphoton and diboson probes of fermiophobic Higgs bosons at the LHC

With the Higgs search program already quite mature, there is the exciting possibility of discovering a new particle with rates near that of the SM Higgs. We consider models with a signal in γγ below the SM Higgs mass. We discuss singlet models with additional vectorlike matter, but argue that a Type-I two Higgs doublet model can more easily provide detectable rates. In such scenarios, in regions of moderate-to-strong fermiophobia, the enhanced γγ branching ratio allows signals from V H+VBF production to yield σ × BR γγ comparable to total SM rates and would thus be detectable. Light H production can be dominated via rare top decays t → bH + → bW * H, which provides an even more efficient means of production. We also consider this in the context of various Higgs anomalies, specifically the recent 2.9 σ (local) CMS excess at 95 GeV, the LEP Higgs excess near the same mass, and excesses in tth searches at Tevatron and LHC. We find regions of parameter space that can meet all simultaneously. An implication of the Type-I scenario is that any γγ excess should be associated with additional elements that could reduce background, including b-jets, forward jets or signs of vector boson production.

Section: Jhep08(2018)025mentioning

confidence: 99%

Light signals from a lighter Higgs

Fox

Weiner

2018

“…Since there is no coupling to SM fermions, there is no gluon fusion production available or corresponding decays. Thus, large branching ratios into electroweak gauge bosons, in particular photons, are a generic feature if they are the lightest new particle [15]. However, as we explore below, interference effects or if there is an exotic decay channel available, can dramatically alter this generic picture.…”

Section: Jhep06(2018)137mentioning

confidence: 99%

“…After briefly reviewing custodial fermiophobic Higgs bosons, following closely the discussion in [15], we then obtain limits from 8 and 13 TeV LHC inclusive diphoton searches [37,38] on the allowed branching ratio into photons in the mass range 45 − 160 GeV. We also estimate what size branching ratios are needed to explain the recent ∼ 95 GeV CMS diphoton excess [38].…”

Section: Diphoton Limits On Custodial Fermiophobic Higgs Bosonsmentioning

confidence: 99%

“…2 However, as shown in past [30][31][32][33][34][35] as well as more recent studies, diphoton [15,27] and multiphoton [29] searches can put robust constraints on these light, but otherwise difficult to detect Higgs bosons. This is especially true when combined with the universal Drell-Yan Higgs pair production mechanism [15,36] which dominates for small exotic Higgs VEV. Utilizing this, we combine Drell-Yan pair production with updated data from 1 We utilize the label Higgs boson for the neutral component which obtains a vacuum expectation value (VEV) as well as the charged components belonging to the same electroweak multiplet.…”

Section: Introductionmentioning

confidence: 99%

“…These custodial Higgs bosons 1 can have degenerate or compressed mass spectra, making them harder to detect due to soft decay products [11][12][13][14]. Furthermore, as emphasized in [15], if they have vanishing couplings to SM fermions (fermiophobic), and as measurements of the 125 GeV Higgs boson [4] are found to be more and more SM-like, previous searches which relied on single Higgs production mechanisms [16][17][18][19][20][21][22] become increasingly obsolete. Thus, even for masses well below the 125 GeV Higgs boson, many limits which typically apply to extended Higgs sectors, can be evaded.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Light (and darkness) from a light hidden Higgs

Vega

Vega-Morales

Xie

2018

Self Cite

We examine light diphoton signals from extended Higgs sectors possessing (approximate) fermiophobia with Standard Model (SM) fermions as well as custodial symmetry. This class of Higgs sectors can be realized in various beyond the SM scenarios and is able to evade many experimental limits, even at light masses, which are otherwise strongly constraining. Below the W W threshold, the most robust probes of the neutral component are di and multi-photon searches. Utilizing the dominant Drell-Yan Higgs pair production mechanism and combining it with updated LHC diphoton data, we derive robust upper bounds on the allowed branching ratio for masses between 45 − 160 GeV. Furthermore, masses 110 GeV are ruled out if the coupling to photons is dominated by W boson loops. We then examine two simple ways to evade these bounds via cancellations between different loop contributions or by introducing decays into an invisible sector. This also opens up the possibility of future LHC diphoton signals from a light hidden Higgs sector. As explicit realizations, we consider the Georgi-Machacek (GM) and Supersymmetric GM (SGM) models which contain custodial (degenerate) Higgs bosons with suppressed couplings to SM fermions and, in the SGM model, a (neutralino) LSP. We also breifly examine the recent ∼ 3σ CMS diphoton excess at ∼ 95 GeV.

The supersymmetric Georgi-Machacek model

Vega

Vega-Morales

Xie

2018

Self Cite

We show that the well known Georgi-Machacek (GM) model can be realized as a limit of the recently constructed Supersymmetric Custodial Higgs Triplet Model (SCTM) which in general contains a significantly more complex scalar spectrum. We dub this limit of the SCTM, which gives a weakly coupled origin for the GM model at the electroweak scale, the Supersymmetric GM (SGM) model. We derive a mapping between the SGM and GM models using it to show how a supersymmetric origin implies constraints on the Higgs potential in conventional GM model constructions which would generically not be present. We then perform a simplified phenomenological study of diphoton and ZZ signals for a pair of benchmark scenarios to illustrate under what circumstances the GM model can mimic the SGM model and when they should be easily distinguishable.2 In particular the SU (5)/SO(5) symmetry breaking pattern found in a number of composite Higgs scenarios [31,32], including certain Little Higgs [33] and the Littlest Higgs Model with T -Parity [34][35][36], contains within its coset the same SU (2) L ⊗ SU (2) R representations as the GM scalar sector.