looking through the higgs portal with exotic higgs …...looking through the higgs portal with...
TRANSCRIPT
![Page 1: Looking through the Higgs portal with exotic Higgs …...Looking through the Higgs portal with exotic Higgs decays Jessie Shelton University of Illinois, Urbana-Champaign Unlocking](https://reader033.vdocuments.mx/reader033/viewer/2022050523/5fa719a25d46ab09e360567d/html5/thumbnails/1.jpg)
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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0.0
0.2
0.4
0.6
0.8
1.0
Br
h ! ff̄
h ! V V ⇤
h ! V V [GeV]HM100 200 300 1000
[GeV
]H
�
-210
-110
1
10
210
310
LHC
HIG
GS
XS W
G 2
010
500
�h(125 GeV) = 4.1 MeV
A light SM-like Higgs is narrow
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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
0 10 20 30 40 50 60
10-4
0.001
0.01
0.1
1
ms HGeVL
BrHhÆ
ssLk
�L =⇣
2s2|H|2
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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
0 10 20 30 40 50 600.0
0.2
0.4
0.6
0.8
1.0
mcqHGeVL
BrHhÆccLk
�L =1
M ̄ |H|2
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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
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Exotic Higgs Decays at the LHC
BSMBR0.0 0.5 1.0
gκ
0.0
0.5
1.0
1.5
2.0
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
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Exotic Higgs Decays at the LHC
Unofficial combination of ATLAS and CMS (Giardino et al.);
(see also Ellis, You; Belanger et al.)
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h
a
b
bb
b
a
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
[GeV] HM100 200 300 400 500 1000
H+X
) [pb
]
�(p
p �
-210
-110
1
10= 7 TeVs
LHC
HIG
GS
XS W
G 2
010
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
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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 + . . .
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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?
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Theories for Exotic Higgs Decays
1. Higgs decay to scalars
h
a
b
b
b
b
a
f
f
f
f
�L = V (a) +�
4a2|H|2
1 2 5 10 20 5010!4
0.001
0.01
0.1
1
ms!GeV"
BR
bbccss""##gg
$$
uudd
Singlet Br: SM Yukawas
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Theories for Exotic Higgs Decays
1. Higgs decay to scalars
h
a
b
b
b
b
a
f
f
f
f
�L = V (a) +�
4a2|H|2
Singlet pair Br: SM Yukawas
1 2 5 10 20 5010!4
0.001
0.01
0.1
1
ms!GeV"
BR#h"ss"XXYY$
4bbb##cc##4#
4ggg##bb$$4$##$$
gg$$
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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
1 2 5 10 20 5010!4
0.001
0.01
0.1
1
ma!GeV"
BR
Type I
bbccss""##gg
uudd$$
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Theories for Exotic Higgs Decays
1. Higgs decay to scalars
Singlet pseudoscalar Br: Type II Yukawas
Extended Higgs sectors alter Yukawas:
consider 2HDM + complex singlet S
Type 1: SMType II: NMSSM-like
1 2 5 10 20 5010!4
0.001
0.01
0.1
1
ma!GeV"
BR
Tan "#5, TYPE II
bbccss$$%%gg
uudd&&
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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
10!4
0.001
0.01
0.1
1
ma!GeV"
BR
Tan "#5, TYPE III
bbccss$$%%gg
uudd&&
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Theories for Exotic Higgs Decays
1. Higgs decay to scalars
Singlet pseudoscalar Br: Type IV Yukawas
Extended Higgs sectors alter Yukawas:
consider 2HDM + complex singlet S
Type 1: SMType II: NMSSM-like
Type III: lepton-specificType IV: flipped 1 2 5 10 20 50
10!4
0.001
0.01
0.1
1
ma!GeV"
BR
Tan "#5, TYPE IV
bbccss$$%%gg
uudd&&
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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
L = 0.5 TeV
L = 1 TeV
L = 2 TeV
0 10 20 30 40 50 6010-6
10-5
10-4
0.001
0.01
0.1
1
myHGeVL
BrHhÆyyLk
Chiral symmetry: can be effective dim-6
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Theories for Exotic Higgs Decays
2. Higgs decay to fermions
Signatures depend on further fermion couplings: parameters largely independent of Higgs couplings
h
X
X
h hh
invisible: DM, SUSY
light bosonic dofs?
flavored 3-body decays
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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
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Theories for Exotic Higgs Decays
3. Higgs decay to vectors
!!
!"
#!#"
c c
b b
light hadrons
$$
10 20 30 40 50 600.0
0.1
0.2
0.3
0.4
0.5
mZD
Br
Relatively leptophilic!
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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
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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
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Direct searches for exotic Higgs decays
Example 1: .h ! VDVD ! 4`
CMS data, SM background: ZZ*
mV = 20 GeVsmax = 7.3 fb
40 60 80 10010
20
30
40
50
60
m1 HGeVLm2HGe
VL
Exotic contribution
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Direct searches for exotic Higgs decays
Example 1: .h ! VDVD ! 4`
CMS data, SM background: ZZ* Exotic contribution
mV = 40 GeVsmax = 3.4 fb
40 60 80 10010
20
30
40
50
60
m1 HGeVLm2HGe
VL
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Direct searches for exotic Higgs decays
Example 1: .h ! VDVD ! 4`
10 20 30 40 50 600.0000
0.0002
0.0004
0.0006
0.0008
0.0010
mZDqHGeVL
Brk HhÆ
Z DZ DL
95% CL limits
ATLAS ZZ control region
CMS Higgs
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Direct searches for exotic Higgs decays
Example 1A: .
95% CL limits
h ! ZVD ! 4`
CMS 20 ! 5 fb"1ATLAS 20 ! 5 fb"1
15 20 25 300
5
10
15
mX
Br!h#ZX"$Br!X#
!!"$104
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Direct searches for exotic Higgs decays
Example 1A: .h ! ZVD ! 4`
10-3 10-2 10-1 1 10110-5
10-4
10-3
10-2
10-1
mZD @GeVD
e
U70
PROMPT
NON-PROMPT
E141
E774
EWPM
am, 5s
am,±2s favored
ae
BaBarKLOE
WASA
APEXêMAMI
Orsay
BrHhÆZZD L=10 -6
10 -510 -4
10 -3
CMS
Further possibilities:
h ! ss ! 4ZD
more complicated HS cascades...
h ! ZDZD ! exotic
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Direct searches for exotic Higgs decays
Example 2: . h ! aa ! 4⌧, 2⌧2µ
Exclusions from multilepton searches
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Direct searches for exotic Higgs decays
Example 2: . h ! aa ! 4⌧, 2⌧2µ
Gain from sharp resonance in muons, despite lower BR [Lisanti & Wacker]
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Direct searches for exotic Higgs decays
Example 2A: METh ! �2�2 ! 4`+
Best existing limits from inclusive many-bin CMS multi-lepton searches:
Br(h ! �2�2) < 12%
(SUS-12-027, SUS-13-010) (includes Z Br and is highly spectrum-dependent)
•Most multi-lepton analyses specialized for high-pT signals
•Can further target analyses to Higgs kinematics
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30 GeV
40 GeV50 GeV
60 GeV
20 GeV
0 10 20 30 40 50
0.02
0.05
0.10
0.20
0.50
1.00
mc1
Allo
wed
BR
Estimated 95% CL limits on allowed Br
Direct searches for exotic Higgs decays
Best limits: GMSB search (CMS SUS-12-018)
• 4 ifb, not optimized for Higgs signal
Example 2B: METh ! �2�2 ! 2�+
h
GMSB neutralinosextended DM sector with dipole
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Estimated 95% CL reach
Direct searches for exotic Higgs decays
Example 3: .h ! ss ! 2b2µ
10 20 30 40 50 6010!4
10!3
10!2
10!1
1
ma !GeV"
Max.Br#h"aa"bb#$#!$
8 TeV LHC, L%25 fb!1
At least one b!tagTwo b!tagsNo b!tag
2m2µ
3m2b
= 4⇥ 10�4
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Direct searches for exotic Higgs decays
LHC prospects for .h ! ss, aa
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Direct searches for exotic Higgs decays
LHC prospects for .h ! ss, aa
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Direct searches for exotic Higgs decays
LHC prospects for .h ! ss, aa
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• 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