Discovery of a standard model Higgs boson using vector boson fusion at the LHC
Charged Higgs boson at the LHC
description
Transcript of Charged Higgs boson at the LHC
Charged Higgs boson at the LHC
이강영 ( 건국대학교 )
@ 연세대학교 2009. 10. 29.
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 that at tree level in the MSSM
relevant tbH+ couplings
Phenomenology is governed by at 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 Hb at Tevatron
Light charged Higgs boson :
Absence of observed charged Higgs boson
Constrained by
Present constraints on H
CDF collaboration, PRL 96, 042003 (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
allowedallowed
D.-W. Jung, K. Y. Lee., Phys. Rev. D 76, 095016 (2007)
top quark decay after tt pair production
108 top quarks produced
More than 105 charged Higgs expected
Full reconstruction is impossible due to many neutrinos. (MT2?)
Light charged Higgs production at the LHC
D.-W. Jung, K. Y. Lee., Phys. Rev. D 78, 015022 (2008)
in the LR model
in the 2HD model
≫ 1
2
1
( )
Decay of the light charged Higgs boson
SUSY parameters : Mh-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
20tan
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, 015022 (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, 015022 (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, 015022 (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, 031804 (2008)
2 22 ( ) ( ) ( ) ( )
2 ( ) ( ) 1 cos
T T T T T
T T
M p e p p e p
p e p
Transverse mass
Edges of transverse mass distribution are crucially related to the mass of W’.
Trigger system for the charged Higgs at the LHC