Higgs effective potential in the warped Gauge-Higgs Unification
Looking through the Higgs portal with exotic Higgs …...Looking through the Higgs portal with...
Transcript of Looking through the Higgs portal with exotic Higgs …...Looking through the Higgs portal with...
Looking through the Higgs portal with exotic Higgs decays
Jessie SheltonUniversity of Illinois, Urbana-Champaign
Unlocking the Higgs Portal (U. Mass. Amherst)May 1, 2014
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]H
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LHC
HIG
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XS W
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�h(125 GeV) = 4.1 MeV
A light SM-like Higgs is narrow
A light SM-like Higgs is narrow
• Presence of new light degrees of freedom can distort Higgs Brs by O(1) even for small couplings
Simple example: one new scalar
z = 0.001
z = 0.005
z = 0.01z =ms2 ëv2
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ms HGeVL
BrHhÆ
ssLk
�L =⇣
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A light SM-like Higgs is narrow
Simple dim-5 interaction
• Exotic Higgs decay modes easily sensitive to new physics scales significantly above a TeV
M = 1 TeVM = 2.5 TeV
M = 5 TeV
M = 10 TeV
M = 20 TeV
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mcqHGeVL
BrHhÆccLk
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Exotic Higgs Decays at the LHC
Higgs production in gluon fusion (8 TeV): 20 pb
Accumulated data at 8 TeV: 20 ifb
If: order one acceptance, good S/B:statistics for branching fractions ~10-4
~400,000 Higgs bosons served
Exotic Higgs Decays at the LHC
BSMBR0.0 0.5 1.0
gκ
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ln L
Δ-2
02468101214161820
CMS Preliminary -1 12.2 fb≤ = 8 TeV, L s -1 5.1 fb≤ = 7 TeV, L s
CMS indirect limits on BSM Higgs width
Exotic Higgs Decays at the LHC
Unofficial combination of ATLAS and CMS (Giardino et al.);
(see also Ellis, You; Belanger et al.)
h
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bb
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Four soft b-jets:
pT . 30 GeV
A tough signal for a hadron machine like LHC:
...but also, many searches have not yet been done
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H+X
) [pb
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�(p
p �
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LHC
HIG
GS
XS W
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H (NNLO+NNLL QCD + NLO EW)
�pp
qqH (NNLO QCD + NLO EW)
�pp
WH (NNLO QCD + NLO EW)
�pp
ZH (NNLO QCD +NLO EW)
�pp
ttH (NLO QCD)
�pp
Exotic Higgs Decays at the LHC
D. Curtin, R. Essig, S. Gori, P. Jaiswal, A. Katz, T. Liu, Z. Liu, D. McKeen, JS, M. Strassler, Z. Surujon, B. Tweedie, Y-M. Zhong
Immense landscape of possibilities
Exotic Decays of the 125 GeV Higgs Boson, arXiv:1312.4992
• Higgs portal couplings:
• Signatures depend on how HS states decay: to further HS states, back to SM
• May be: NMSSM-like, semi-invisible, high multiplicity, displaced, ...
Lint =X
i
1
⇤di�2i
|H|2O(di)i + . . .
Theories for Exotic Higgs Decays
• Long-standing body of work on
exotic Higgs decays, much driven by
precision EW preference for a Higgs
below the LEP bound
• Many examples fall out naturally from extended Higgs
sectors: NMSSM, EW baryogenesis, ...
• Others come from DM model building
• Genericity of Higgs portal: what are light degrees of
freedom?
Theories for Exotic Higgs Decays
1. Higgs decay to scalars
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�L = V (a) +�
4a2|H|2
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ms!GeV"
BR
bbccss""##gg
$$
uudd
Singlet Br: SM Yukawas
Theories for Exotic Higgs Decays
1. Higgs decay to scalars
h
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�L = V (a) +�
4a2|H|2
Singlet pair Br: SM Yukawas
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ms!GeV"
BR#h"ss"XXYY$
4bbb##cc##4#
4ggg##bb$$4$##$$
gg$$
Theories for Exotic Higgs Decays
1. Higgs decay to scalars
Singlet pseudoscalar Br: SM Yukawas
Extended Higgs sectors alter Yukawas:
consider 2HDM + complex singlet S
Type 1: SM
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ma!GeV"
BR
Type I
bbccss""##gg
uudd$$
Theories for Exotic Higgs Decays
1. Higgs decay to scalars
Singlet pseudoscalar Br: Type II Yukawas
Extended Higgs sectors alter Yukawas:
consider 2HDM + complex singlet S
Type 1: SMType II: NMSSM-like
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ma!GeV"
BR
Tan "#5, TYPE II
bbccss$$%%gg
uudd&&
Theories for Exotic Higgs Decays
1. Higgs decay to scalars
Singlet pseudoscalar Br: Type III Yukawas
Extended Higgs sectors alter Yukawas:
consider 2HDM + complex singlet S
Type 1: SMType II: NMSSM-like
Type III: lepton-specific 1 2 5 10 20 50
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Tan "#5, TYPE III
bbccss$$%%gg
uudd&&
Theories for Exotic Higgs Decays
1. Higgs decay to scalars
Singlet pseudoscalar Br: Type IV Yukawas
Extended Higgs sectors alter Yukawas:
consider 2HDM + complex singlet S
Type 1: SMType II: NMSSM-like
Type III: lepton-specificType IV: flipped 1 2 5 10 20 50
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Tan "#5, TYPE IV
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Theories for Exotic Higgs Decays
2. Higgs decay to fermions
�L = ��HL �L =1
M�†�|H|2
Lepton number violation Nonrenormalizable
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L = 1 TeV
L = 2 TeV
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Chiral symmetry: can be effective dim-6
Theories for Exotic Higgs Decays
2. Higgs decay to fermions
Signatures depend on further fermion couplings: parameters largely independent of Higgs couplings
h
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h hh
invisible: DM, SUSY
light bosonic dofs?
flavored 3-body decays
Theories for Exotic Higgs Decays
3. Higgs decay to vectors
h
�L = V (S) +
4S2|H|2
+✏Bµ⌫Vµ⌫
•Photon and Higgs portal
couplings with independent
strengths
•Higgs mixing: ,
•Kinetic mixing:
h ! VDVD
h ! VDZ
h ! aa
Theories for Exotic Higgs Decays
3. Higgs decay to vectors
!!
!"
#!#"
c c
b b
light hadrons
$$
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mZD
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Relatively leptophilic!
Direct searches for exotic Higgs decays
• Each final state requires its own strategy.
• General observations:
• Leptonic resonances especially powerful
• Recast LHC8 analyses already place interesting limits on final states with multiple electroweak objects
• ...but results depend very sensitively on acceptance thresholds
• gluon fusion: powerful but limited
• A range of possibilities from spectacular to very hard
Direct searches for exotic Higgs decays
Example 1: .h ! VDVD ! 4`
h Resonant 4-lepton signal: spectacular ...just need to look for it!
• NMSSM-motivated 4-muon searches stop at 5 GeV
• Scrape data from Higgs searches, ZZ calibration regions
Direct searches for exotic Higgs decays
Example 1: .h ! VDVD ! 4`
CMS data, SM background: ZZ*
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m1 HGeVLm2HGe
VL
Exotic contribution
Direct searches for exotic Higgs decays
Example 1: .h ! VDVD ! 4`
CMS data, SM background: ZZ* Exotic contribution
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Direct searches for exotic Higgs decays
Example 1: .h ! VDVD ! 4`
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mZDqHGeVL
Brk HhÆ
Z DZ DL
95% CL limits
ATLAS ZZ control region
CMS Higgs
Direct searches for exotic Higgs decays
Example 1A: .
95% CL limits
h ! ZVD ! 4`
CMS 20 ! 5 fb"1ATLAS 20 ! 5 fb"1
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Direct searches for exotic Higgs decays
Example 1A: .h ! ZVD ! 4`
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mZD @GeVD
e
U70
PROMPT
NON-PROMPT
E141
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EWPM
am, 5s
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BaBarKLOE
WASA
APEXêMAMI
Orsay
BrHhÆZZD L=10 -6
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CMS
Further possibilities:
h ! ss ! 4ZD
more complicated HS cascades...
h ! ZDZD ! exotic
Direct searches for exotic Higgs decays
Example 2: . h ! aa ! 4⌧, 2⌧2µ
Exclusions from multilepton searches
Direct searches for exotic Higgs decays
Example 2: . h ! aa ! 4⌧, 2⌧2µ
Gain from sharp resonance in muons, despite lower BR [Lisanti & Wacker]
Direct searches for exotic Higgs decays
Example 2A: METh ! �2�2 ! 4`+
Best existing limits from inclusive many-bin CMS multi-lepton searches:
Br(h ! �2�2) < 12%
(SUS-12-027, SUS-13-010) (includes Z Br and is highly spectrum-dependent)
•Most multi-lepton analyses specialized for high-pT signals
•Can further target analyses to Higgs kinematics
30 GeV
40 GeV50 GeV
60 GeV
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Estimated 95% CL limits on allowed Br
Direct searches for exotic Higgs decays
Best limits: GMSB search (CMS SUS-12-018)
• 4 ifb, not optimized for Higgs signal
Example 2B: METh ! �2�2 ! 2�+
h
GMSB neutralinosextended DM sector with dipole
Estimated 95% CL reach
Direct searches for exotic Higgs decays
Example 3: .h ! ss ! 2b2µ
10 20 30 40 50 6010!4
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10!2
10!1
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ma !GeV"
Max.Br#h"aa"bb#$#!$
8 TeV LHC, L%25 fb!1
At least one b!tagTwo b!tagsNo b!tag
2m2µ
3m2b
= 4⇥ 10�4
Direct searches for exotic Higgs decays
LHC prospects for .h ! ss, aa
Direct searches for exotic Higgs decays
LHC prospects for .h ! ss, aa
Direct searches for exotic Higgs decays
LHC prospects for .h ! ss, aa
• The observed 125 GeV Higgs boson is highly sensitive to the potential existence of new light degrees of freedom
• Many interesting results/prospects at LHC8 already
• Light (pseudo-)scalars: still difficult
• Great statistical power from LHC 14: Higgs factory
• but reduced acceptance for low-pT objects may limit reach
• Important to remember for LHC 14: many physics opportunities at low pT
Summary and Conclusions