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Joint analysis of Higgs boson decays and electroweak precision observables in the standard model with a sequential fourth generation

Eberhardt, Otto; Herbert, Geoffrey; Lacker, Heiko; Lenz, Alexander; Menzel, Andreas; Nierste, Ulrich; Wiebusch, Martin

Authors

Otto Eberhardt

Geoffrey Herbert

Heiko Lacker

Alexander Lenz

Andreas Menzel

Ulrich Nierste

Martin Wiebusch



Abstract

We analyze the impact of LHC and Tevatron Higgs data on the viability of the standard model with a sequential fourth generation, assuming Dirac neutrinos and a Higgs mass of 125 GeV. To this end we perform a combined fit to the signal cross sections of pp→H→γγ, ZZ∗, WW∗ at the LHC, to pp¯→VH→Vbb¯ (V=W, Z) at the Tevatron and to the electroweak precision observables. Fixing the mass of the fourth-generation down-type quark b′ to 600 GeV we find best-fit values of mt′=632  GeV, ml4=113.6  GeV and mν4=58.0  GeV for the other fourth-generation fermion masses. We compare the χ2 values and pulls of the different observables in the three- and four-generation case and show that the data is better described by the three-generation standard model. We also investigate the effects of mixing between the third- and fourth-generation quarks and of a future increased lower bound on the fourth-generation charged lepton mass of 250 GeV.

Journal Article Type Article
Publication Date Jul 1, 2012
Deposit Date Nov 19, 2012
Publicly Available Date Jul 24, 2014
Journal Physical Review D
Print ISSN 1550-7998
Electronic ISSN 1550-2368
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 86
Issue 1
Article Number 013011
DOI https://doi.org/10.1103/physrevd.86.013011
Public URL https://durham-repository.worktribe.com/output/1470756

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