higgs portal dark matter at lhc and other colliders...higgs portal dark matter at lhc and other...
TRANSCRIPT
Higgs portal Dark Matter
at LHC and other colliders
Abdelhak DJOUADI
(CNRS & LAPTh)
1. The Higgs portal to Dark Matter2. Invisible Higgs at the LHC
3. Higgs properties at e+e− colliders4. Comparison with astroparticle physics
5. Heavy DM states6. Conclusion
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.1/18
1. The Higgs portal to Dark Matter
1) Rotation curve of (clusters of) galaxiesDM indeed exists:
2) CMB and large scale structure formation
It is a new/unknown particle: no SM state (eg ν) can do the job.
A crucial hint for physics beyond the SM of strong+EW forces!
25% of energy budget of UniverseMakes
80% of total matter of Universe
PLANCK: ΩDMh2 = 0.1188± 0.0010
• Neutral particle and hence dark (a charged particle will shine...).
• Cold or not too warn and hence non-relativistic (ν do not work...).
• Very weakly interacting (reason why we did not observe it yet).
• Stable or at least very long lived particle: τDM ≫ 1017 s.
• Possibly a relic from the early Universe: a window to the origin.
In short, a WIMP. It worths the effort searching for it!
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.2/18
1. The Higgs portal to Dark Matter
WIMPS appear in models for naturalness/hierarchy problems:
– LSP: lightest neutralino of SUSY with Rp conserved
Examples: – LKP: lightest Kaluza-Klein state in extra-dimensions.
– LTP: lightest T-odd in Little Higgs/composite
We choose a different way: simply Agnosticism and Occam razor:
postulate the existence of a weakly interacting massive particle:
• a singlet particle but spin 0, 12
, 1 i.e. a scalar, vector or fermion
• QED neutral + isosinglet, no SU(2)xU(1) charge: no Z couplings
• Z2 parity for stability: no couplings or mixing with fermions
Hence, only couplings with the Higgs bosons: Higgs portal DM,
– annihilates into SM particles through s-channel Higgs exchange;
– can be produced in pairs via Higgs boson exchange or decays.
Again Occam razor: assume only the SM-like Higgs boson.
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.3/18
1. The Higgs portal to Dark Matter
Lagrangians:
∆LS = −12M2
SS2 − 1
4λSS
4 − 14λHSSΦ
†ΦS2
∆LV = 12M2
VVµVµ+ 1
4λV(VµV
µ)2+ 14λHVVΦ
†ΦVµVµ
∆Lχ = −12Mχχχ− 1
4
λHχχ
ΛΦ†Φχχ
EWSB: Φ → 1√2(v+H) with v=246 GeV and m2
S=M2S+
14λHSSv
2 ...
Two free parameters: DM mass mX and DM-Higgs coupling λHSS
Of course effective and even non-renormalisable models. EFT for:
• Scalars: inert Higgs doublet models (comes with others states).
• Vectors: may be related to a spontaneously broken U(1) symmetry.
• Fermions: fourth family, singlet-doublet or vector-like leptons?
All these are renormalisable, unitary, perturbative (up to cut-off) ...
But where are all the new (companion) states gone? Should have been seen?
– Z2 symmetry: all new particles decay at end into the DM state;
– eventually some mass degeneracy with the invisible DM particle.
⇒ missing energy and soft SM particle signature: very difficult!
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.4/18
1. The Higgs portal to Dark Matter
Direct Detection:
•SM
DM
SM
DM
scattering on nucl. target:XENON ⇒ LZ,DARWIN
Indirect Detection:
•DM
DM
SM
SM
annihilation products: γ, νHESS,;..⇒ CTA,HAWK,
Detection at colliders:
•SM
SM
DM
DM
missing energy signatureLHC ⇒ HL-LHC,e+e−,pp
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.5/18
2. Invisible Higgs at the LHC
For light DM states, only possible handle at colliders is Higgs decays:
Γinv(H → SS) =λ2HSS
v2βS
64πMH
Γinv(H → VV) =λ2HVV
v2M3HβV
256πM4V
(
1− 4M2
V
M2H
+ 12M4
V
M4H
)
Γinv(H → ff) =λ2Hff
v2MHβ3f
32πΛ2
Possible only for mX < 12MH ≈ 60 GeV; depends on mX, λHXX:
One has to check also the relic density/Planck: only one input...
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.6/18
2. Invisible Higgs at the LHC
A) Direct: measurement of total Higgs decay width via interference
ΓSMH =4.07MeV ⇒ too small to be resolved experimentally.
If MH>∼ 200GeV, ΓH>1GeV ⇒ possible in H → ZZ → 4ℓ
But in pp→H→ZZ→4f , about 20% are for MVV>∼ 2MV
Indirect measurement of ΓH via interference with pp→ZZ continuum
SMHΓ/HΓ
0 1 2 3 4 5
)λ2
ln(
0
2
4
6
8
10
12
14ExpectedStat. only
Expected
ObservedStat. only
Observed
ATLAS
ν 4l,2l2→ ZZ →H* 113 TeV, 36.1 fb
g/V, offshellκ = g/V, onshellκ
σ1
σ2
(MeV)HΓ0 20 40 60
ln L
∆-2
0
2
4
6
8
10
12
14 WW (observed)→H WW (expected)→H
ZZ (observed)→H ZZ (expected)→H
ZZ+WW (observed)→H ZZ+WW (expected)→H
CMS (7 TeV)-1 (8 TeV) + 5.1 fb-119.7 fb
68% CL
95% CL
But the constraints are too loose: ΓH/ΓSMH
<∼ 3−4 only.
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.7/18
2. Invisible Higgs at the LHC
B) Indirectly: measurements of the Higgs decay branching ratios
κ2X = σ(X)/σ(X)|SM = Γ(XX)/Γ(XX)|SM = g2HXX/g
2HXX|SM
Γ(VV)→κ2V, Γ(ff)→κ2f , σ(VH)→κ2V, σ(VBF)→0.74κ2W+0.26κ2ZΓ(γγ)→κ2γ=1.5κ2W+0.1κ2t−0.7κtκW, σ(ggH)→κ2g=1.06κ2t−0.07κtκb
Parameter value2− 1− 0 1 2 3
|µκ|
bκ
|τκ|
tκ
Wκ
Zκ
Run 1LHC
CMS and ATLAS ATLAS+CMS
ATLAS
CMS
intervalσ1
intervalσ2
fVκ
0 0.5 1 1.5 2
f Fκ
2−
1−
0
1
2
Combined γγ→H
ZZ→H WW→H
ττ→H bb→H
68% CL
95% CL
Best fit
SM expected
Run 1 LHC
CMS and ATLAS
κ2H=0.57κ2b+0.22κ2W+0.06κ2τ+0.03κ2Z+0.03κ2c+0.0023(κ2γ+ κ2Zγ)
Global ATLAS+CMS fit gives BR(H→ invisible) <∼ 20%@95%CL
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.8/18
2. Invisible Higgs at the LHC
C) Even more direct: search for Higgs decaying invisibly.
q
q
V
H
q
qH
g
g
t
H
qq→WH → ℓν+ET/ qq→qqH → jj+ET/ gg →Hg → j+ET/qq→ZH → ℓℓ+ET/ high-mass,pT, η jets also 2j, high rate.
Choudhury+Roy, ..., Eboli+Zeppenfeld AD,Falkowski,Mambrini...
inv)→B(H
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
1-E
xclu
sio
n C
L
-210
-110
1
Observed
Expected Median
σ 1 ±Expected
σ 2 ±Expected
95% CL
-1 = 13TeV, 36.1 fbsµµee+
ATLAS
[GeV]Hm100 150 200 250 300 350 400
(SM
)V
BF
σ inv)/
→ x
B(H
σ
0.5
1
1.5
2
2.5 invisible→CMS VBF H
-1 = 8 TeV, L = 19.5 fbs
95% CL limits
Observed limit
Expected limit
)σExpected limit (1
)σExpected limit (2
Combined VBF-tag Z(ll)H-tag V(qq')H-tag ggH-tag
SM
95%
CL u
pper
limit o
n σ
x B
(H →
inv)/
σ
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Observed
Median expected
68% expected
95% expected
(13 TeV)-1
35.9 fb
CMS
Here also ATLAS+CMS combo gives BR(H→invisible) <∼20%@95%CL
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.9/18
2. Invisible Higgs at the LHC
D) A combination of all these channels/possibilities
− −
Λ
s
ss
❱s ❱ s
s
❱s s
All in all at Run II LHC: BR(H → inv) < 20%.
This not very constraining after all. can this be improved? Of course!
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.10/18
3. Invisible Higgs in the future
High–Luminosity LHC:√s = 14 TeV and L = 3ab−1
Improve the sensitivity by factor of 2: BR(H→invisible) <∼10%
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.11/18
3. Invisible Higgs in the future
Higher energy pp colliders ⇒ √s = 100 TeV and L = a few ab−1
bb → H
qq/gg → ttH
qq → ZHqq′ → WH
qq′ → Hqq′gg → H
MH = 125 GeV
pp → H + X
√s [TeV]
σ(√
s)/
σ(√
s=
13TeV)
10075502513
100
10
1
Improve the sensitivity by another factor of 2: BR(H→invisible) <∼5%
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.12/18
3. Invisible Higgs in the future
Best deal ever a future e+e− machine:√s = 240 GeV and L = 1ab−1
e−
e+
Z∗
•
H
Z
•
e−
e+
V∗
V∗
H
νe/e−
νe/e+
•
e+
e−
H
t
t
•
e+
e−
H
H
Z
HHνν
HHZ
Htt
HZ
He+e−
Hνν
MH=125 GeV
σ(e+e− → HX) [fb]
√s [GeV]
200 350 500 700 1000 2000 3000
1000
100
10
1
0.1
0.01
Very precise measurements
mostly at√s≈250 GeV
and mainly in e+e− → ZH
gHWW ±0.01gHZZ ±0.01gHbb ±0.01gHcc ±0.03gHττ ±0.03gHtt ±0.05λHHH ±0.2MH ±0.0004ΓH ±0.05CP ±0.03
Improve the sensitivity very seriously: BR(H→invisible) <∼1%In fact: a BR(H→ inv) of 1% can be observed at the 5σ level
and a BR(H→ inv) of 5% can be measured with a 10% accuracy...Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.13/18
4. Comparison with astroparticle experiments
• Relic density ∝ 1/〈σ(XX → H → f f)vr〉 annihilation rate.
〈σXfermvr〉 = λ2
HXXm2
ferm
16π1
(4m2X−M2
H)2δX, δS = 1, δV = 1
3, δf =
12
v2r
Λ2
In principle needs to fit the Planck value: ΩDMh2=0.119±0.0010
• Spin–independent direct detection, simple for S, V, f DM states:
σSIX−N =
λ2HXX
16πM4H
m4Nf2N
(mX+mN)2δ′X, δS = δV = 1, δf =
4Λ2
BRinvX ≡ BR(H → inv) = Γ(H→XX)
ΓSMH
+Γ(H→XX)=
σSIXp
ΓtotH
/rX+σSIXp
Direct detection:
BRinvX ≃ (σSI
Xp/10−9pb)[δX + (σSI
Xp/10−9pb)]−1
δS = 400 (10 GeV/mS)2 , δV = 4× 10−2 (mV/10 GeV)2 , δf = 3.5
Indirect detection:
BRinvX ≃ (〈σvr〉/10−10GeV−1)[δX + (〈σvr〉/10−10GeV−1)]−1
δS = 2.4× 10−2δV = 1.3× 10−6 (mV/10GeV)4 δf = 3.9× 10−11 (mf/10
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.14/18
4. Comparison with astroparticle experiments
Arcadi,AD
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.15/18
5. Heavy DM states
Heavy DM states to be produced in pairs in continuum at pp colliders:
q
q
V
H
q
qH
g
g
t
H
• Exactly same channels as before but with and off-shell Higgs boson.
• Suppressed by the Higgs virtuality and small couplings to DM.
• Needs high energies, very high luminosities and some real efforts....
• Superseded by direct detection limits in all envisageable cases..
pp → FF + j
pp → SS + j
pp → VV + j
λhχχ = 1
√s = 14 TeV
.
mχ [GeV]
σ[fb]
550500450400350300250200150100
102
101
100
10−1
10−2
10−3
pp → FF + jj
pp → SS + jj
pp → VV + jj
λhχχ = 1
√s = 14 TeV
.
mχ [GeV]
σ[fb]
450400350300250200150100
101
100
10−1
10−2
10−3
pp → FF + Z
pp → FF + W±
pp → SS + Z
pp → SS + W±
pp → VV + Z
pp → VV + W±
λhχχ = 1
√s = 14 TeV
.
mχ [GeV]
σ[fb]
600500400300200100
100
10−1
10−2
10−3
10−4
10−5
AD,Quevillon
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.16/18
5. Heavy DM states
Heavy DM states to be produced in pairs in continuum at pp colliders:
q
q
V
H
q
qH
g
g
t
H
• Exactly same channels as before but with and off-shell Higgs boson.
• Suppressed by the Higgs virtuality and small couplings to DM.
• Needs high energies, very high luminosities and some real efforts....
• Superseded by direct detection limits in all envisageable cases..
pp → FF + j
pp → SS + j
pp → VV + j
λhχχ = 1
√s = 100 TeV
.
mχ [GeV]
σ[fb]
1000900800700600500400300200100
104
103
102
101
100
10−1
10−2
10−3
pp → FF + jj
pp → SS + jj
pp → VV + jj
λhχχ = 1
√s = 100 TeV
.
mχ [GeV]
σ[fb]
1000900800700600500400300200100
103
102
101
100
10−1
10−2
10−3
pp → FF + Z
pp → FF + W±
pp → SS + Z
pp → SS + W±
pp → VV + Z
pp → VV + W±
λhχχ = 1
√s = 100 TeV
.
mχ [GeV]
σ[fb]
1000900800700600500400300200100
101
100
10−1
10−2
10−3
10−4
10−5
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.17/18
6. Conclusions
• Dark matter exists, maybe only reachable sign of new physics?
• The Higgs portal to DM is one of the most minimal realizations.
• Even more minimal if only the SM–like Higgs state is considered.
• But scenario tested at LHC in Higgs searches/measurements:
– measurements of total Higgs width and various visible BRs;
– direct searches for missing energy signatures.
– possibility of going off-shell not that promising.
• Limits from LHC superseded by future astrophysics sensitivity.
• But I didn’t tell you the really interesting part of the story yet:
– concrete realizations of Higgs-DM and search for DM companions;
– extending the Higgs sector makes it even more interesting.
Needs further investigations at the LHC and also future ee and pp
colliders besides all experiments in astroparticle physics .
Valencia 14/12/2018 Higgs portal DM – A. Djouadi – p.18/18