Effects from new colored states and the Higgs portal on gluon fusion and Higgs boson decays

Kumar, K. Santhosh; Yu, Felix; Vega-Morales, Roberto

doi:10.1103/physrevd.86.113002

Cited by 26 publications

(15 citation statements)

References 73 publications

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“…The Manohar-Wise representation contains both a neutral scalar O 0 and a charged scalar O + ; assuming they have the same mass, as they do with this simplified set of interactions with the Higgs, one finds that they affect the Higgs decay widths as shown by the dashed purple curve in figure 2, which comes rather close to the best-fit point of our simplified χ 2 fit. Effects of such an octet scalar on the hGG amplitude were considered recently in [69][70][71] in the regime with relatively small corrections that would lead to a reduced gg → H cross section. The possibility that λ H O < 0 could lead to a reasonable fit of the data with enhanced diphoton rate was observed in [72].…”

Section: Inverting Hgg With Charged Scalar Color Octetsmentioning

confidence: 99%

Vacuum instabilities with a wrong-sign Higgs–gluon–gluon amplitude

Reece

2013

New J. Phys.

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The recently discovered 125 GeV boson appears very similar to a Standard Model (SM) Higgs, but with data favoring an enhanced h → γ γ rate. A number of groups have found that fits would allow (or, less so after the latest updates, prefer) that the htt coupling have the opposite sign. This can be given meaning in the context of an electroweak chiral Lagrangian, but it might also be interpreted to mean that a new colored and charged particle runs in loops and reinforces the W -loop contribution to h F F, while also producing the oppositesign hGG amplitude to that generated by integrating out the top. Due to a correlation in sign of the new physics amplitudes, when the SM h F F coupling is enhanced the hGG coupling is decreased. Thus, in order to not suppress the rate of h → W W and h → Z Z , which appear to be approximately SM-like, one would need the loop to 'overshoot', not only canceling the top contribution but producing an opposite-sign hGG vertex of about the same magnitude as that in the SM. We argue that most such explanations have severe problems with fine-tuning and, more importantly, vacuum stability. In particular, the case of stop loops producing an opposite-sign hGG vertex of the same size as the SM one is ruled out by a combination of vacuum decay bounds and Large Electron-Positron Collider (LEP) constraints. We also show that scenarios with a sign flip from loops of color octet charged scalars or new fermionic states are highly constrained.

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Section: Inverting Hgg With Charged Scalar Color Octetsmentioning

confidence: 99%

Vacuum instabilities with a wrong-sign Higgs–gluon–gluon amplitude

Reece

2013

New J. Phys.

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“…On the other hand, extensions of the SM with vector-like leptons which couple to the Higgs, can both enhance and suppress the h → γγ decay rate, because in contrast to chiral leptons, vector-like leptons can interfere also constructively with the W contribution. Colored new matter is additionally constrained by data, because it also affects the gluon fusion production cross section of the Higgs, which in turn leads to modifications of all Higgs signal strengths [7,9,14,25,26,28,[43][44][45][46][47].…”

Section: Models With Exotic Hyperchargesmentioning

confidence: 99%

Exotic leptons: Higgs, flavor and collider phenomenology

Altmannshofer

Bauer

Carena

2014

J. High Energ. Phys.

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We study extensions of the standard model by one generation of vector-like leptons with non-standard hypercharges, which allow for a sizable modification of the h → γγ decay rate for new lepton masses in the 300 GeV-1 TeV range. We analyze vacuum stability implications for different hypercharges. Effects in h → Zγ are typically much smaller than in h → γγ, but distinct among the considered hypercharge assignments. Nonstandard hypercharges constrain or entirely forbid possible mixing operators with standard model leptons. As a consequence, the leading contributions to the experimentally strongly constrained electric dipole moments of standard model fermions are only generated at the two loop level by the new CP violating sources of the considered setups. We derive the bounds from dipole moments, electro-weak precision observables and lepton flavor violating processes, and discuss their implications. Finally, we examine the production and decay channels of the vector-like leptons at the LHC, and find that signatures with multiple light leptons or taus are already probing interesting regions of parameter space.

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“…If there are new colored particles with mass not much larger than M h that couple to h 0 (such as a color-octet scalar [35][36][37][38]), then C g should be replaced by a function of M h . The only other Higgs couplings relevant here involve photons and arise also at one loop.…”

Section: Jhep02(2013)073mentioning

confidence: 99%

Coupling spans of the Higgs-like boson

Dobrescu

Lykken

2013

J. High Energ. Phys.

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Using the LHC and Tevatron data, we set upper and lower limits on the total width of the Higgs-like boson. The upper limit is based on the well-motivated assumption that the Higgs coupling to a W or Z pair is not much larger than in the Standard Model. These width limits allow us to convert the rate measurements into ranges for the Higgs couplings to various particles. A corollary of the upper limit on the total width is an upper limit on the branching fraction of exotic Higgs decays. Currently, this limit is 47% at the 95% CL if the electroweak symmetry is broken only by doublets.

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Effects from new colored states and the Higgs portal on gluon fusion and Higgs boson decays

Cited by 26 publications

References 73 publications

Vacuum instabilities with a wrong-sign Higgs–gluon–gluon amplitude

Vacuum instabilities with a wrong-sign Higgs–gluon–gluon amplitude

Exotic leptons: Higgs, flavor and collider phenomenology

Coupling spans of the Higgs-like boson

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