Four generations and Higgs physics

By G. Kribs, Tilman Plehn, Michael Spannowsky, T. Tait. 2007

278 citations recorded by the source corpus.

In the light of the LHC, we revisit the implications of a fourth generation of chiral matter. We identify a specific ensemble of particle masses and mixings that are in agreement with all current experimental bounds as well as minimize the contributions to electroweak precision observables. Higgs masses between 115-315 (115-750) GeV are allowed by electroweak precision data at the 68% and 95% C.L. Within this parameter space, there are dramatic effects on Higgs phenomenology: production rates are enhanced, weak-boson-fusion channels are suppressed, angular distributions are modified, and Higgs pairs can be observed. We also identify exotic signals, such as Higgs decay to same-sign dileptons. Finally, we estimate the upper bound on the cutoff scale from vacuum stability and triviality.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/cddb26c0712fab7f4e55f0d4aa6b6375980d1d6d

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In Nuclear and High Energy Physics

Citations in the corpus

Particle physics models for the 17 MeV anomaly in beryllium nuclear decays (2016, background): “Since these particles essentially form two additional families of leptons, the rate for Higgs boson decay to two photons decreases by ∼20% compared to the SM prediction [112], but this is still within the experimentally allowed region [113].”
Dark Matter Candidates from Particle Physics and Methods of Detection (2010, background): “The existence of 4th generation quarks and leptons is constrained by direct collider searches and also by precision electroweak measurements from LEP and the SLC, but is far from excluded (209).”
Vectorlike confinement at the LHC (2009, background): “nt for anomaly cancellation, and because mass generation via electroweak symmetry breaking generically leads to signiﬁcant oblique corrections to precision electroweak observables. (However, see Ref. [2] for discussion of the 4th generation model and viable regions of parameter space.) The advantage”
Patterns of flavour violation in the presence of a fourth generation of quarks and leptons (2010, methodology): “Indeed, from the tree level measurements of |Vud|, |Vus|, |Vub|, |Vcd|, |Vcs| and the unitarity of VSM4, we know already that cij ≈ 1 and that s14 and s24 are not larger than s12 [5].”