Two Higgs Doublet Model:
Past and Future
February 21, 2014, EWSB-Flavours-LHC @ Guwahati
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
1
2HDM: Past & Future
EWSB-Flavour-LHC
• Intro:
Flav
H ➾ EWSB
Soni; H+; Enhanced “Murky”; Top-Higgs
➾
• Let’s Do H+: b → sg(g)
• “Murky Mode” @ 10%: b → ctn & b → sg
➥ B → D(*)tn; tn
• FCNH: Model III & t → ch0
• LHC
• Conclusion
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
2
The “God” Particle: the Origin of Mass
Fermion: Repeated Doublets
Higgs:
Flavour
Sector
Second Doublet
mF ~ lFυ
Weinberg, 1967
mV ~ gυ
(Agent of)
B.E.H., 1964
EWSB
VL “seen”
since 1983
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
3
2HDM
Will focus on Flavour Connection
p.s. parameters in Higgs sector always give me the shudders …
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
4
Thanks, Soni !
WSH, Soni, Steger,
b → sg
PLB’87
WSH, Soni, Steger,
b → sg*
PRL’87
WSH, Soni,
Bd & Bs Mixing
PLB’87
WSH, Willey, Soni,
b → sℓ+ℓ-
PRL’87
4G
Introduced me to B Physics.
But I missed “large QCD corrections”
by focusing too much on New Physcs…
Bertolini, Borzumati, Masiero,
PRL’87
Deshpande, Trampetic, Eilam, Singer, PRL’87
➥ Operator Analysis: Culmination in M. Misiak!
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
5
Thanks, Soni !
WSH, Soni, Steger,
b → sg
PLB’87
WSH, Soni, Steger,
b → sg*
PRL’87
WSH, Soni,
Bd & Bs Mixing
PLB’87
WSH, Willey, Soni,
b → sℓ+ℓ-
PRL’87
4G
Introduced me to B Physics.
Timelike
2HDM
Lightlike
George W.S. Hou (NTU)
Spacelike
Guwahati, 2/2014
6
Before summer 1987, before moving from Pitt to Munich, saw this paper
... and said to Ray Willey,
“We can easily do this, too.”
b → sg
Turned out they focus on large tanb
… and missed a crucial sign.
H+ effect
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
7
Usual 2HDM Framework: NFC
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
8
H+ Couplings in Model I/II
“SUSY”
(mindset: ~ mt/mb)
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
9
• Ca. 1990: Bs.l. (semileptonic BR) and NC (charm counting) problem.
Could there be Enhanced “Murky” Modes?
➥ Polish synergy:
B → D(*)tn; B → tn
• 1992: CDF bound of mt > 91 GeV
Could top be still lighter?
t → ch0
Non-NFC: Model III
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
10
2HDM: Past & Future
EWSB-Flavour-LHC
• Intro:
Flav
H ➾ EWSB
Soni; H+; Enhanced “Murky”; Top-Higgs
➾
• Let’s Do H+: b → sg(g)
• “Murky Mode” @ 10%: b → ctn & b → sg
➥ B → D(*)tn; tn
• FCNH: Model III & t → ch0
• LHC
• Conclusion
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
11
Let’s Do H+: b → sg(g)
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
12
b → sg(g)
logarithmic
2HDM
vs
power GIM suppression in SM
QCD corr. brings in large log
George W.S. Hou (NTU)
Guwahati, 2/2014
13
ξ2 = cot2b, ξξ′ = ξ2 (Model I), -1 (Model II)
why does ξ′ enter?
fig. stolen from Hermann, Misiak, Stenihauser
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
14
ξ2 = cot2b, ξξ′ = ξ2 (Model I), -1 (Model II)
why does ξ′ enter?
fig. stolen from Hermann, Misiak, Stenihauser
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
15
ξ2 = cot2b, ξξ′ = ξ2 (Model I), -1 (Model II)
NNLO
fig. stolen from Hermann,
2HDM
Misiak, Stenihauser, JHEP’12
George W.S. Hou (NTU)
Guwahati, 2/2014
16
State of the Art
Hermann, Misiak, Stenihauser, JHEP’12 [1208.2788]
Can be weakened by BSM
Exp 1s
SM 1s
WSH & Willey
NPB’89
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
17
“Murky Mode” @ 10%: b → ctn & b → sg
➥ B → D(*)tn; tn
2HDM
George W.S. Hou (NTU)
(mn
Guwahati, 2/2014
18
The Polish Connection/Synergy
b → ctn part based on Krawczyk and Pokorski, PRL’88
SM ~ 3%
2HDM
~ 0.2%
George W.S. Hou (NTU)
Guwahati, 2/2014
19
Sol. 1: b → sg @ 10%
ca. 1991
Sol. 2: b → ctn @ 10%
charm counting
~ SM
~ SM
Great Pheno If True !
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
20
PLB’92
7
s-wave
enhanced
5
3
Form Factors
tr. long.
2HDM
scalar
t polarization Flip
George W.S. Hou (NTU)
Kalinowski, PLB’90
Guwahati, 2/2014
21
ALEPH Exclusion of b → ctn @ 10%; and then …
b → tn + X = (4.08 ± 0.76 ± 0.62)%
(2.75 ± 0.30 ± 0.37)%
(2.43 ± 0.20 ± 0.25)%
PLB’93
PLB’95
EPJC’01
➙ SM-like, rule out enhanced b → ctn
= (1.05 ± 18)%
= (1.64 ± 15)%
saturate inclusive (PDG’13)
expected
a crisp result:
no new hadronic effect
beyond fB within SM
cf.
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
22
Crisp B → tn Surprise
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
23
anybody out there?
cottage industry
When First Evidence in 2006, citations soared.
A Driver for Super B Factory
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
24
An Illustration towards 2015+
No serious sign of Godot in FPCP ...
Roderjohann; Soni
• Old Tensions: e.g.
Or,
Lüth
Which One ?
But, B → mn
almost touched by BaBar/Belle.
Hara
Super B Factory (2015 for Belle 2) would unravel it “immediately”.
Totally different systematics!
Theory Summary
George W.S. Hou (NTU)
FPCP@USTC, Hefei 5/25/2012 25
FCNH: Model III & t → ch0
11/1991
Became relevant recently at the LHC
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
26
2HDM 2HDM
III: “Natural”
Framework:
FC Neutral
NFC Higgs
FCNH
from B Phys.
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
27
FCNH: t → ch0 & Model III
Thy Shall Not Mix
4G – 2HDM – FCNH !
“a3 ”
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
28
FCNH: t → ch0 & Model III
S/P
S/P
t → ch0 / t → bW*
h0 → tc / h0 → bb & tt
1% benchmark
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
29
Pro-found if Found
FCNH: verboten in SM
& 2HDM I/II
Glashow-Weinberg 1977
Outline
• BaBar Anomaly, 2HDM-III & tch0 Coupling
c
• B Physics & H → tt Constraints
• t → ch0 Search at LHC
h0
t
ZZ*
gg
WW*
bb
Fajfer, Kamenik, Nisandzic, Zupan, PRL 2012
Crivellin, Greub, Kokulu, PRD 2012; 1303.5877
t → ch @ LHC
CGK
KCHS
CHKK
George W.S. Hou (NTU)
Kao, Cheng, WSH, Sayre, PLB 2012
Chen, WSH, Kao, Kohda, 1304.8037
C.Kao
talk
EPSHEP@Stockholm 19/7/2013 30
BaBar “Anomaly”
BaBar,
PRL 2012
Very (too) Large !
t → ch @ LHC
George W.S. Hou (NTU)
EPSHEP@Stockholm 19/7/2013 31
2HDM-III (General) Yukawa Interactions
Crivellin, Greub, Kokulu, PRD 2012
[we use notation of Mahmoudi and Stal, PRD 2010
“Standard”
Exotic
23
To consider t → ch0 :
FCNH
• Need Nondecoupling:
h0 mixes in cos (b-a) frac. of H0
• Not only rbb, but rtt turn out small
 deviate from CGK
CGK considered Decoupling Limit:
SMH
t → ch @ LHC
(next page)
[left with mH+ pockets
• rct ~ 1,
implying
rtt and rcc need be considered!
George W.S. Hou (NTU)
EPSHEP@Stockholm 19/7/2013 32
With Regrets,
“detach” from
BaBar anomaly
B & H → tt
Constraints
mH+ pockets remain
t → ch0 Search at LHC
How large can B (t → ch0) be?
If rct ~ 1, what constraint we have on cos (b-a) ?
N.B. From stt(bar) measurement with dileptons, one
infers B (t → ch) cannot be larger than few %.
t → ch @ LHC
George W.S. Hou (NTU)
EPSHEP@Stockholm 19/7/2013 33
Summary of Constained 2HDM-III
rcc, rtt
rct
New Sector
to be probed
at the LHC
t → ch @ LHC
George W.S. Hou (NTU)
EPSHEP@Stockholm 19/7/2013 34
No Evidence of Excess Jets in ZZ* …
Any tt(bar) → chbW ?
Illustration
Simple CLs estimate
gives
(95% C.L.)
B (t → ch) < 1.5%
2.2%
Best done directly
by the Experiments
ATLAS 4ℓ + 4j evt (backup)
Craig et al., PRD 2012: < 2.7% (can improve)
KCHS’12: Can probe down to 1%
t → ch @ LHC
George W.S. Hou (NTU)
EPSHEP@Stockholm 19/7/2013 35
Comments
∙ gg + 4j, gg + jj + ln :
[gg in Higgs window]
Because
of background
evts perhaps
rejected
by EPS:
Dh (VBF)
ATLAS
announced atconcerns,
Higgs Hunting,
Orsay, week
after
 Even
of such BG
b/t tags if found.
t → the
cH study
< 0.83%
at 95may
C.L.be interesting;ATLAS-CONF-2013-081
gg
∙ WW* + jets, WW* + jets + W :
[no Higgs Mass]
Astounding: % level bound year after Higgs discovery !
CMS announced at SUSY2013:
t → chmult-ℓ
t → ch @ LHC
< 1.28% at 95 C.L.
George W.S. Hou (NTU)
Can
be
CMS PAS-SUS-13-002 Improved
EPSHEP@Stockholm 19/7/2013 36
2HDM H+ Search at LHC
LHC Search has Started !
a BaBar-centric View
Eli Ben-Haim @ EPSHEP2013
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
37
t → bH+ Search at LHC
ATLAS JHEP’12
CMS JHEP’12
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
38
t → bH+ & H+ → tb at LHC
ATLAS-CONF-2013-081
t → bH+:
getting there
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
39
finally getting there
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
40
Conclusion: 2HDM I, II & III
BaBar throws in
B → D(*)tn monkey wrench
➥ Rule out 2HDM II ?
Haisch 0805.2141
need Belle-II (2015+)
b → sg
FCNH t → ch0
Search Underway
2015+ Looks Bright
finally getting there
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
41
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
42
Outline
Is “the Higgs” the
Agent of BEH Mech.?
EWSB
12/2013
2HDM
Dilaton : Goldstone George
boson
of SSB of Scale Invariance
W.S. Hou (NTU)
Guwahati, 2/2014
43
υ /F
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
44
How does Dilaton fake Higgs ?
H → ZZ* → eemm
cg
Dilaton
υ /F
but, no convincing evidence
for VBF (Vector Boson Fusion)
or VH (Higgsstrahlung off V) so far
➙ Check Dilaton 2015+ !
cgυ /F ~ SM Higgs
cg cg ~ SM Higgs
Leading Processes
cg
fortuitous, maybe …
cg
Dilaton
H → gg
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
45
B → tn Satus
2HDM
George W.S. Hou (NTU)
Guwahati, 2/2014
46
Data-constrained 2HDM-III
Higgs → tt : rtt small
With Regrets,
“detach” from
BaBar anomaly
b → sg : rbb tiny
Because of chiral mt/mb
and KM enhancement, rbb tiny !
mH+ pockets remain
t → ch @ LHC
George W.S. Hou (NTU)
EPSHEP@Stockholm 19/7/2013 47
Example: Clean Sample of ZZ* → 4ℓ
Consistency of 15-20 evts
~ SM w/ little BG,
for both CMS/ATLAS
With 126 GeV dominantly SMH, i.e. sin(b-a) ≃ 1 (near Decoupling),
ZZ* (and WW*) Rate hard to change.
The width of 126 GeV Higgs can be enhanced by rcc as not measured.
Gluon Fusion can be enhanced by rtt , even though damped by cos (b-a).
Cf.: stt(bar) ~ 220 pb, if t → ch 2%,
then tt(bar) → chbW is at 9 pb !
t → ch @ LHC
George W.S. Hou (NTU)
Could we have
seen it already !?
EPSHEP@Stockholm 19/7/2013 48
One ATLAS eemm + 4j Event !
“Passed VBF Selection”
Is there bias even in ZZ*?
h = -2.20
h = 1.19
ATLAS-CONF-2013-013, (extra) Fig. 38
[thanks to Bill Murray
t → ch @ LHC
George W.S. Hou (NTU)
is there a b
EPSHEP@Stockholm 19/7/2013 49