Transcript Higgs Sector Beyond the Standard Model Sridhara Dasu University of Wisconsin - Madison With results from ATLAS & CMS Collaborations 11/5/2015 Sridhara Dasu (Wisconsin)

Higgs Sector
Beyond the Standard Model
Sridhara Dasu
University of Wisconsin - Madison
With results from
ATLAS & CMS Collaborations
11/5/2015
Sridhara Dasu (Wisconsin)
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Standard Model Scalar Sector
Generating masses for weak bosons and fermions
– Minimal model including one doublet of complex scalar fields
– Spontaneous symmetry breaking of electro-weak symmetry
– Provides masses for W and Z gauge bosons of weak sector
• Predicts single neutral scalar boson
– Yukawa coupling to fermions provides them masses
• Precise predictions of production and decays as a function of mass
Gluon Fusion
WZ
Fusion
WZt
Association
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Sridhara Dasu (Wisconsin)
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Beyond the Standard Model
There are many possibilities that change the precise predictions of
the minimal higgs sector of the Standard Model
– Fourth (heavy) generation of fermions modify H couplings
• Enhances SM4 higgs cross section over SM
• Already ruled out in entire parameter space with 2011 data
– Fermiophobic – fermion mass of different origin than higgs
• Changes low mass higgs production & decays dramatically
• Also ruled out for 126 GeV object
– Beyond minimal higgs doublet field
• Two higgs doublet model (2HDM)
– Multiple higgs bosons: 3 neutral and 2 charged
– Minimal Supersymmetric Model (MSSM) requires 2HDM
• NMSSM, triplets … have even more higgses
– Very light pseudoscalar higgs, Doubly charged …
– This talk focuses on these non-standard higgs bosons
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MSSM Higgs
• Higgs sector in SUSY theory is more complicated
• Need 2 higgs doublets each with 4 degrees of freedom
• Results in the Standard Model like Higgs (h0)
• Plus, two neutral higgs (A0, H0) and charged (H±)
• However, only 2 parameters (MA, tanβ – ratio of the two doublets)
• Masses of higgs and Z related
• Search in (MA, tanβ) plane
• Neutral Higgs
– Look for ϕ=(h0, A0, H0) in decays to tau-leptons
• Charged Higgs
– Look for H± in top decays
5-Nov-15
Sridhara Dasu (Wisconsin)
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MSSM ϕ(h, H, A)
• Use MHMAX Scenario
• Enhanced coupling to b-quarks and τ-leptons
• Production rate enhanced × tan2β
• Gluon fusion with b,t loops + associated b quark production
• Decays to b-quark and τ-lepton pairs enhanced at all masses
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Implications of SM Like H126
on MHMAX scenario
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Mass of ττ : 17 fb–1 Data
CMS HIG-12-051
Tau pairs reconstructed in decays to leptons (e or μ) + hadrons (1 or 3 prong) or two leptons (eμ)
Kinematic fit to obtain tau pair mass – used to search for H to ττ contribution
Two categories: non-b-tagged and b-tagged to enhance bbϕ
dN/dmtt [1/GeV]
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10
200
400
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10´f(160 GeV)®tt, tanb=8
observed
Z®tt
Z®mm
electroweak
tt
QCD
bkg. uncertainty
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500
1000
mtt [GeV]
800
10´f(160 GeV)®tt, tanb=8
observed
Z®tt
Z®mm
electroweak
tt
QCD
bkg. uncertainty
600
5-Nov-15
CMS Preliminary, s = 7-8 TeV, L = 17 fb-1tmtm
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200
CMS Preliminary, s = 7-8 TeV, L = 17 fb-1tmtm
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1
10-1
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mtt [GeV]
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dN/dmtt [1/GeV]
Sridhara Dasu (Wisconsin)
Mass of ττ : 17 fb–1 Data
CMS HIG-12-051
Tau pairs reconstructed in decays to leptons (e or μ) + hadrons (1 or 3 prong) or two leptons (eμ)
Kinematic fit to obtain tau pair mass – used to search for H to ττ contribution
Two categories: non-b-tagged and b-tagged to enhance bbϕ
dN/dmtt [1/GeV]
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200
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500
10´ f(160 GeV)®t t, tanb=8
observed
Z®tt
electroweak
tt
QCD
bkg. uncertainty
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1000
mtt [GeV]
800
10´ f(160 GeV)®t t, tanb=8
observed
Z®tt
electroweak
tt
QCD
bkg. uncertainty
600
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CMS Preliminary, s = 7-8 TeV, L = 17 fb-1tetm
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CMS Preliminary, s = 7-8 TeV, L = 17 fb-1tetm
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10-1
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0
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mtt [GeV]
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dN/dmtt [1/GeV]
Sridhara Dasu (Wisconsin)
Mass of ττ : 17 fb–1 Data
CMS HIG-12-051
Tau pairs reconstructed in decays to leptons (e or μ) + hadrons (1 or 3 prong) or two leptons (eμ)
Kinematic fit to obtain tau pair mass – used to search for H to ττ contribution
Two categories: non-b-tagged and b-tagged to enhance bbϕ
dN/dmtt [1/GeV]
10
200
400
400
500
10´f(160 GeV)®tt, tanb=8
observed
Z®tt
Z® ee
electroweak
tt
QCD
bkg. uncertainty
300
1000
mtt [GeV]
800
10´f(160 GeV)®tt, tanb=8
observed
Z®tt
Z® ee
electroweak
tt
QCD
bkg. uncertainty
600
5-Nov-15
CMS Preliminary, s = 7-8 TeV, L = 17 fb-1teth
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CMS Preliminary, s = 7-8 TeV, L = 17 fb-1teth
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mtt [GeV]
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dN/dmtt [1/GeV]
Sridhara Dasu (Wisconsin)
Mass of ττ : 17 fb–1 Data
CMS HIG-12-051
Tau pairs reconstructed in decays to leptons (e or μ) + hadrons (1 or 3 prong) or two leptons (eμ)
Kinematic fit to obtain tau pair mass – used to search for H to ττ contribution
Two categories: non-b-tagged and b-tagged to enhance bbϕ
dN/dmtt [1/GeV]
102
10
200
400
400
500
10´ f(160 GeV)®t t, tanb=8
observed
Z®tt
electroweak
tt
QCD
bkg. uncertainty
300
1000
mtt [GeV]
800
10´ f(160 GeV)®t t, tanb=8
observed
Z®tt
electroweak
tt
QCD
bkg. uncertainty
600
5-Nov-15
CMS Preliminary, s = 7-8 TeV, L = 17 fb-1tmth
100
200
CMS Preliminary, s = 7-8 TeV, L = 17 fb-1tmth
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10-1
10-2
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dN/dmtt [1/GeV]
Sridhara Dasu (Wisconsin)
Limit in mA-tanβ Plane
CMS HIG-12-051
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Charged Higgs Selection
CMS PAS HIG-11-019
ATLAS CONF 2012-11
Look for H± in top decays: τ+jets, eτ, μτ and eμ modes considered
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Sridhara Dasu (Wisconsin)
Event with
τ + MET from H±
2 b-jets,
2 jets from W or
e/μ + MET from W
Cut progression includes
MET, bTags
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Charged Higgs Limits
ATLAS CONF 2012-11
ATLAS Result
τj, eτ, μτ
4.6 fb–1
CMS PAS HIG-11-019
CMS Result
τj, eτ, μτ, eμ
2.2 fb–1
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MSSM Neutral Higgs to bb
• Three b-jet events
CMS PAS HIG-12-026
CMS PAS HIG-12-027
– More difficult to trigger
– Larger backgrounds than tau modes
– Mass resolution is a bit better
– Considered semi-leptonic and hadronic b tags
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ϕ(h, H, A) in bbBar Mode
mA-tanβ Limit
CMS PAS HIG-12-026
CMS PAS HIG-12-027
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MSSM Higgs Summary
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ATLAS CONF 2012-11
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100
300
400
500
-1
CMS Htt 17 fb
+
-1
CMS H 2.2 fb
CMS (b)bHbb 2.7-4.8 fb -1
-1
ATLAS Htt 4.7 fb
+
-1
ATLAS H 4.6 fb
-1
D0 7.3 fb
LEP
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MSSM mhmax scenario, MSUSY =1 TeV
CMS PAS HIG-12-026
CMS PAS HIG-12-027
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CMS PAS HIG-12-050
mA [GeV]
Sridhara Dasu
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CMS PAS HIG-11-019
tanb
H
aa 
γγ γγ
ATLAS CONF 2012-079
• Next-to-Minimal Supersymmetric Standard Model (NMSSM):
Adds singlet scalar field, thereby expanding the Higgs sector
to three CP-even (h1, h2 and h3), two CP-odd (a1, a2)
and two charged scalars (H+, H–)
• The lightest pseudo-scalar, if less massive than 3Mπ0, decays to γγ
• SM like Higgs can decays to four photons via an a-pair
Photon invariant mass has
broader peak than Hγγ
11/5/2015
Isolation provides separation
from prompt γ BG
Sridhara Dasu (Wisconsin)
Shower shape analysis
provides discrimination
from SM Hγγ
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H
aa
γγ γγ
ATLAS CONF 2012-079
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NMSSM: a1→μ+μ–
CMS PAS HIG-12-004
Events/[0.1 GeV]
• Next-to-Minimal Supersymmetric Standard Model (NMSSM):
Adds singlet scalar field, thereby expanding the Higgs sector
to three CP-even (h1, h2 and h3), two CP-odd (a1, a2)
and two charged scalars (H+, H–)
g
• A light (~10 GeV) boson produced
• Search for a1 in its decays to opposite sign di-muon pairs
g
– Di-tau BR is higher but is deemed impossible
• Analysis strategy
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– Chose isolated opposite sign
dimuons with
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pTμ > 4 GeV & pTμμ > 6 GeV
– Search above/below the upsilon
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peaks in dimuon invariant mass
• 5.5 < Mμμ < 9 GeV
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• 11.5 < Mμμ < 14 GeV
µ
a
µ
CMS
s = 7 TeV
L = 1.3 fb-1
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Barrel Data
Total Fit
7 GeV Signal x10
12 GeV Signal x10
Events/[0.1 GeV]
3
4
Endcap Data
Total Fit
7 GeV Signal x10
12 GeV Signal x10
3
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mmm [GeV]
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NMSSM: a1→μ+μ– Limits
CMS PAS HIG-12-004
Three parameters
ma , tan b , cosq A
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+
α
q
± ±→l±l±
Doubly
Charged
Φ
Z/ γ∗
Φ
+
β
++
• Models with tripletΦ−of
− higgs
q¯
−
fields,γ predict
CMS PAS HIG-12-005
doubly charged bosons
– Interestingly triplet models can include
− fermiophobic neutral higgs
δ
• Search for like-sign dilepton production
+
α
q
W∗
Φ+ +
Φ−
q¯
+
α
q
Z/ γ ∗
+
β
−
γ
νδ
Φ+ +
Φ− −
+
α
q
W∗
Φ+ +
Φ−
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−
γ
−
δ
q¯
q¯
+
β
+
β
−
γ
νδ
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Trilepton & Quadlepton Modes
CMS PAS HIG-12-005
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Doubly Charged Φ± ±→l±l±
Limits
CMS PAS HIG-12-005
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Summary
• MSSM higgs parameter space is being constrained
using modes with τ-leptons and b-jets
• No evidence for non-standard higgs production or
decay is found in several models
• It remains to be seen if the 125 GeV object has
partners lurking around the corner
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