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Title: Masses of a Fourth Generation with Two Higgs Doublets

Journal Article · · Physical Review. D, Condensed Matter and Materials Physics

We use sampling techniques to find robust constraints on the masses of a possible fourth sequential fermion generation from electroweak oblique variables. We find that in the case of a light (115 GeV) Higgs from a single electroweak symmetry breaking doublet, inverted mass hierarchies are possible for both quarks and leptons, but a mass splitting more than MW in the quark sector is unlikely. We also find constraints in the case of a heavy (600 GeV) Higgs in a single doublet model. As recent data from the Large Hadron Collider hints at the existence of a resonance at 124.5 GeV and a single Higgs doublet at that mass is inconsistent with a fourth fermion generation, we examine a Type II two Higgs doublet model. In this model, there are ranges of parameter space where the Higgs sector can potentially counteract the effects of the fourth generation. Even so, we find that such scenarios produce qualitatively similar fermion mass distributions.

Research Organization:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
DOE Contract Number:
AC02-07CH11359
OSTI ID:
1049402
Report Number(s):
FERMILAB-PUB-12-251-PPD; arXiv eprint number arXiv:1205.5580; TRN: US1204825
Journal Information:
Physical Review. D, Condensed Matter and Materials Physics, Vol. 86, Issue 3; ISSN 1550-7998
Country of Publication:
United States
Language:
English