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

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.

Citation

Eberhardt, O., Herbert, G., Lacker, H., Lenz, A., Menzel, A., Nierste, U., & Wiebusch, M. (2012). Joint analysis of Higgs boson decays and electroweak precision observables in the standard model with a sequential fourth generation. Physical Review D, 86(1), Article 013011. https://doi.org/10.1103/physrevd.86.013011

• 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