Charged Higgs boson at the LHC 이강영 ( 건국대학교 연세대학교
Contents Introduction Theoretical background Present experimental constraints Light charged Higgs boson at the LHC Heavy charged Higgs boson at the LHC Summary
H + : singly charged scalar boson Exists when there is extra Higgs sector more than SM singlet. 2HD model MSSM and more extensions (NMSSM etc.) LR model Other GUT-based model Little Higgs model And others… Introduction
Charged Higgs boson in the 2HD model General Higgs potential with VEVs where and ~
Goldstone mode where the mass is Charged Higgs mode Note thatat tree level in the MSSM relevant tbH + couplings Phenomenology is governed byat tree level.
Higgs sector in the LR model Two triplets a bidoublet : breaking of SU(2) R and its L-R partner : electroweak symmetry breaking and fermion masses with VEVs Note that define
Charged Higgs boson in the LR model Mass matrix where Charged Higgs mass Diagonalization by
relevant tbH + couplings similarly for lepton sector
Light charged Higgs from t H b at Tevatron Light charged Higgs boson : Absence of observed charged Higgs boson Constrained by Present constraints on H
CDF collaboration, PRL 96, (2006)
Pair production of charged Higgs boson at LEP ALEPH collaboration, PLB 543, 1 (2002)
B and charged Higgs boson R. Barlow, ICHEP 2006
Charged Higgs boson in the LR model
allowed D.-W. Jung, K. Y. Lee., Phys. Rev. D 76, (2007)
top quark decay after tt pair production 10 8 top quarks produced More than 10 5 charged Higgs expected Full reconstruction is impossible due to many neutrinos. (M T 2?) Light charged Higgs production at the LHC
D.-W. Jung, K. Y. Lee., Phys. Rev. D 78, (2008)
in the LR model in the 2HD model ≫ 1 ( ) Decay of the light charged Higgs boson SUSY parameters : M h -max scenario
One lepton mode (2HD model) Standard model top pair production with two W bosons, one decaying into tau and one decaying into lepton. Standard model top pair production with two W bosons with misidentified tau-jets. Single top production W + jets production QCD processes : H + into tau associated with the leptonic W decays Thies Ehrich, ATLAS Collaboration Backgrouds
Single lepton triggers Tau triggers
Cut flow
Hadronic mode (2HD model) Similar to the previous case : Both tau from H + and W boson decay hadronically Elias Coniavitis, ATLAS Collaboration Backgrounds Triggers Trigger A : a tau and missing energy Trigger B : a tau, missing energy, and three jets Large cross section makes this channel promising in search of H +.
Selection cuts Cuts I : selecting events agreeing with the signal final state. Cuts II : reducing the QCD background by identifying the tt topology -
: discriminating between the signal and the SM-like tt background Likelihood discriminant Likelihood > 0.6 To reflect that the charged higgs is heavier than W boson.
Heavy charged Higgs production at the LHC dominant channel : K-factors for the NNLO QCD corrections considered N. Kidonakis, JHEP 05, 011 (2005).
D.-W. Jung, K. Y. Lee., Phys. Rev. D 78, (2008)
M. Flechl., ATLAS Collaboration, presented at Prospects for Charged Higgs Discovery at Hadron Collider, Uppsala, Sweden (2008)
D.-W. Jung, K. Y. Lee., Phys. Rev. D 78, (2008)
in the LR model in the 2HD model Decay of heavy charged Higgs boson ≪ 1
D.-W. Jung, K. Y. Lee., Phys. Rev. D 78, (2008)
Heavy charged Higgs with the tau mode in the 2HD model M. Flechl., ATLAS Collaboration, presented at Prospects for Charged Higgs Discovery at Hadron Collider, Uppsala, Sweden (2008)
Summary Discovery of the charged Higgs boson is a clear evidence of the new physics beyond the SM. Discovery potential of the light charged Higgs boson in the 2HD model has been studied. Discovery potential of the heavy charged Higgs boson in the 2HD model has been studied with tau mode. The charged Higgs boson in the LR model should be studied without tau mode.
Backup Slides
D0 collaboration, PRL 100, (2008) Transverse mass Edges of transverse mass distribution are crucially related to the mass of W’.
Trigger system for the charged Higgs at the LHC