Vacuum stability bounds on Higgs coupling deviations

Abstract

We analyze the constraints imposed by Higgs vacuum stability on models with new fermions beyond the Standard Model. We focus on the phenomenology of Higgs couplings accessible at the Large Hadron Collider. New fermions that affect Higgs couplings lead to vacuum instability of the Higgs potential. Above the scale of vacuum instability, bosonic states must stabilize the potential, implying a cut-off to the pure fermion model. Conservatively tuning the models to produce the maximal cut-off for a given Higgs coupling effect, we show that observing a deviation in the $Htt$, $H$-diphoton, or $H$-digluon coupling, larger than 20, would require that new bosons exist in order to stabilize the Higgs potential below about 100 TeV. For generic parameter configurations, and unless the new fermions are made as light as they can possibly be given current experimental constraints, observing a 10 deviation in any of these couplings would suggest an instability cut-off below 10-100 TeV. Similarly, if new bosons are absent up to a high scale, then a deviation in the $Hbb$ or $H\tau \tau$ coupling, larger than about 20, should be accompanied by a sizable deviation in the $Zbb$ or $Z\tau \tau$ couplings that can be conclusively tested with electroweak precision measurements at planned lepton colliders.

37 pages, 15 figures

References in corpus (22)

• PYTHIA 6.4 Physics and Manual
• FeynRules - Feynman rules made easy
• -- HATHOR -- HAdronic Top and Heavy quarks crOss section calculatoR
• The global electroweak fit at NNLO and prospects for the LHC and ILC
• Observation of the diphoton decay of the Higgs boson and measurement of its properties
• Threshold resummation for squark-antisquark and gluino-pair production at the LHC
• Soft gluon resummation for the production of gluino-gluino and squark-antisquark pairs at the LHC
• Search for direct production of charginos, neutralinos and sleptons in final states with two leptons and missing transverse momentum in pp collisions at sqrt(s) = 8 TeV with the ATLAS detector
• Measurement of Higgs boson production in the diphoton decay channel in $pp$ collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector
• Measurements of Higgs boson production and couplings in the four-lepton channel in $pp$ collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector
• Search for the $b\bar{b}$ decay of the Standard Model Higgs boson in associated $(W/Z)H$ production with the ATLAS detector
• The lifetime of the electroweak vacuum and sensitivity to Planck scale physics
• Vacuum Stability, Perturbativity, EWPD and Higgs-to-diphoton rate in Type II Seesaw Models
• Consistent Use of the Standard Model Effective Potential
• Search for anomalous production of events with three or more leptons in pp collisions at sqrt(s) = 8 TeV
• Search for pair-produced resonances decaying to jet pairs in proton-proton collisions at sqrt(s) = 8 TeV
• Search for pair and single production of new heavy quarks that decay to a $Z$ boson and a third-generation quark in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• Limits on Vectorlike Leptons from Searches for Anomalous Production of Multi-Lepton Events
• Vacuum Stability Constraints on the Enhancement of the Higgs to Diphoton Rate in the MSSM
• Probing anomalous $t\bar{t}Z$ interactions with rare meson decays
• $SU(2)\otimes SU(2)$ Gauge Extensions of the MSSM Revisited
• Standard Model with a distorted Higgs sector and the enhanced Higgs diphoton decay rate