at LEP, the (HL)LHC and future lepton colliders . Elina Fuchs - - PowerPoint PPT Presentation

Hunting relaxions and light (pseudo)scalars

at LEP, the (HL)LHC and future lepton colliders . Elina Fuchs

Weizmann Institute of Science, Israel

[1610:02025] Flacke, Frugiuele, EF, Gupta, Perez [1807.10842] Frugiuele, EF, Perez, Schlaffer

Beyond Standard Model: Where do we go from here? GGI Firenze, August 28, 2018

Challenges for naturalness at the TeV-scale

◮ symmetry-based theories of

naturalness: New Physics ∼ TeV

e.g. SUSY, composite Higgs

◮ under pressure by null-results at

LHC

how much tuning acceptable? still some blind spots survive

◮ novel ideas for naturalness with

light NP

instead of symmetry protection

• f Higgs mass:

dynamical evolution Relaxion

Elina Fuchs (Weizmann) | Relaxion at colliders | 1

Outline

1 Introduction: relaxion for naturalness 2 Relaxion phenomenology 3 Relaxion searches

Precision probes Direct searches

Elina Fuchs (Weizmann) | Relaxion at colliders | 1

• I. Brief introduction: relaxion for naturalness

Relaxion mechanism

[Graham, Kaplan, Rajendran ’15]

V (H) = µ2(φ)H†H + λ(H†H)2 V (φ) = rgΛ3φ + ...

µ2(φ) = −Λ2 + gΛφ scans mh during inflation

• 1. φ ≥ Λ/g ⇒ µ2 > 0, no vev
• 2. φ < Λ/g ⇒ µ2 < 0, sign flip, EWSB

Elina Fuchs (Weizmann) | Relaxion at colliders | 2

Relaxion mechanism

[Graham, Kaplan, Rajendran ’15]

V (H) = µ2(φ)H†H + λ(H†H)2 V (φ) = rgΛ3φ + ...

µ2(φ) = −Λ2 + gΛφ scans mh during inflation

• 1. φ ≥ Λ/g ⇒ µ2 > 0, no vev
• 2. φ < Λ/g ⇒ µ2 < 0, sign flip, EWSB
• 3. backreaction Vbr = Λ4

br cos

• φ

f

• 4. φց ⇒ |µ2(φ)|, v2ր

⇒ ∆Vbrր

• 5. until φ stopped by sufficient barrier

Elina Fuchs (Weizmann) | Relaxion at colliders | 2

Relaxion models (examples)

◮ minimal model: QCD (rel)axion,

Λ4

br = 4πf3 πyuv/

√ 2 θQCD ×

◮ non-QCD strong sector,

Λ4

br ≃ yv′3vH/

√ 2

◮ double-field mechanism (φ, σ)

[Espinosa, Grojean, Panico, Pomarol, Pujolas, Servant ’15]

◮ familon (PNGB of spontaneously broken

flavour symmetry) with vector-like leptons in the backreaction sector

[Gupta, Komargodski, Perez, Ubaldi ’15]

◮ friction via particle production

[Hook, Marques-Tavares ’16]

◮ ...

backreaction sector and scale Λbr model-dependent

Elina Fuchs (Weizmann) | Relaxion at colliders | 3

• II. Relaxion Phenomenology

Relaxion-Higgs mixing

[Flacke, Frugiuele, EF, Gupta, Perez ’16] [Choi, Im ’16]

considering Λ4

br = ˜

M4−jvj/ √ 2

j ≡ r4 brv4, here j = 2 (non-QCD)

minimum of V (φ, h): (φ0, v = 246 GeV), φ0: endpoint of rolling, s0 ≡ sin (φ0/f) can be O(1) or smaller Mixing term in the relaxion-Higgs potential V (φ, h) ⊃

˜ M4−jvj−1 √ 2

jf

sin

• φ0

f

• hφ → diagonalise

V (h, φ) ⊃ hφ : Measurable consequences of relaxion-Higgs mixing?

Elina Fuchs (Weizmann) | Relaxion at colliders | 4

Relaxion properties I: mass & mixing

f=103GeV 106GeV 109GeV 1012GeV 1015GeV 1018GeV M ˜ > M ˜

max

0.001 0.010 0.100 1 10 100 10-18 10-13 10-8 0.001 100.000 M ˜ [GeV] Mϕ [GeV]

Relaxion mass

mφ ≃ r2

brv2

f

• c0 − 16r4

brs2

sin θ ≃ 8r4

brs0

v f ≤ 2mφ v (for f ≫ r2

brv, 16 r4 brs2 0 ≪ c0)

Elina Fuchs (Weizmann) | Relaxion at colliders | 5

Relaxion properties I: mass & mixing

f=103GeV 106GeV 109GeV 1012GeV 1015GeV 1018GeV M ˜ > M ˜

max

0.001 0.010 0.100 1 10 100 10-18 10-13 10-8 0.001 100.000 M ˜ [GeV] Mϕ [GeV]

Relaxion mass

mφ ≃ r2

brv2

f

• c0 − 16r4

brs2

sin θ ≃ 8r4

brs0

v f ≤ 2mφ v (for f ≫ r2

brv, 16 r4 brs2 0 ≪ c0)

"Relaxion line": maximal mixing depends linearly on mass

Elina Fuchs (Weizmann) | Relaxion at colliders | 5

Relaxion properties II: lifetime

[Clarke, Foot, Volkas ’13] [Flacke, Frugiuele, EF, Gupta, Perez ’16]

e μ π had-pert c τ cτ=2m 1 s 106 s 1013 s 1017 s

sin2 θ 1 10-3 10-6 10-9 10-6 10-4 0.01 1 10-23 10-13 10-3 107 1017 mϕ [GeV] τϕ [s]

Relaxion lifetime

⊲ threshold effects ⊲ cτφ ∝ (sin θ)−2 ⊲ displaced vertex? ⊲ decay outside detector? ⊲ cosmological time scales? φ possibly long-lived

Elina Fuchs (Weizmann) | Relaxion at colliders | 6

Relaxion couplings to SM: CP-even and -odd

CP-even ghX = sin θ ghX, X = f ¯ f, V V Relaxion inherits SM Higgs couplings suppressed by mixing ⇔ Higgs portal (applicable to other light-scalar models) CP-odd L ⊃ φ 4π f ˜ cγγ 4 Fµν F µν + ˜ cZγ 2 Zµν F µν + ˜ cZZ 4 Zµν Zµν +˜ cWW 4 Wµν W µν + ˜ cGG 4 Gµν Gµν

• ˜

c model-dependent: backreaction sector

Elina Fuchs (Weizmann) | Relaxion at colliders | 7

• III. Relaxion Searches

Status (CP-even interaction)

C a s i m i r SN 1987A RG HB K→π+inv S H I P CHARM B→Kμμ LEP FCCee FCCee h→unt LHC1 max mix τ=1s τ

u n i v e r s e

τ = 1

2 6

s

2 4 6 8 10

• 12
• 10
• 8
• 6
• 4
• 2

Log10[mϕ/eV] Log10[sinθ]

5th force astro cosmo meson decays beam dump lepton collider LHC Relaxion mass and mixing span many orders of magnitude

Elina Fuchs (Weizmann) | Relaxion at colliders | 8

Precision probes

◮ Higgs couplings

sensitivity to BR(h → NP)? deviation from self-coupling λ?

◮ Z total width?

Elina Fuchs (Weizmann) | Relaxion at colliders | 9

New decay mode of the Higgs

invisible and untagged final states ΓNP

h

= Γinv

h

+ Γunt

h

total Higgs width Γh = κ2 ΓSM

h

+ ΓNP

h

h φ φ chφφ relaxion: 2 parameters → fit (as SM+singlet)

◮ BR(h → NP) = BR(h → unt) = BR(h → φφ)

(GeV-scale relaxion decays inside detector)

◮ κ ≡ cos θ: universal coupling modifier

Elina Fuchs (Weizmann) | Relaxion at colliders | 10

Triple-scalar coupling hφφ

cφφh = r4

brv3

f 2 c0c3

θ − 2r4 brv2

f s0c2

θsθ − r4 brv4

2f 3 s0c2

θsθ − 2r4 brv3

f 2 c0cθs2

θ + 3vλcθs2 θ + r4 brv2

f s0s3

θ θ→0

− → r4

brv3

f 2 c0c3

θ ≃ m2 φ

v

where s0, c0 ≡ sin, cos (φ0/f) Untagged Higgs decays

◮ Global Higgs coupling fits allow (under model assumptions) to bound

BR(h →NP), in particular h →untagged

◮ here h → φφ =

⇒ bound on ghφφ containing term ∝ cos3 θ does not vanish at θ → 0 expect sin θ-independent bound on mφ for θ → 0: relaxion-specific

Elina Fuchs (Weizmann) | Relaxion at colliders | 11

Upper bounds on BR(h → NP)

◮ BR(h → inv) available for all colliders ◮ BR(h → NP) often not available for suitable assumptions

Estimate via precision of couplings

◮ κZ most precise → approximation of global κ ◮ rates constrain combination of κ and BR(h → NP)

BR(h → NP) ≤ 1 − 1−n·δκ

κ

2 Conservative estimate; 2-parameter fit would be stronger than multi-κ

Elina Fuchs (Weizmann) | Relaxion at colliders | 12

Higgs self-coupling λ

λ ≃ f 2 − 4r4

br

• c0 + 16r4

brs2

• v2

8 (f 2 − 4c0 r4

brv2) [Di Vita, Durieux, Grojean, Gu, Liu, Panico, Riembau, Vantalon ’17]

◮ HL-LHC, FCCee, CLIC, ILC may reach a sensitivity of 10 − 50%

[Di Vita et al ’17, Abramowicz et al ’16]

◮ relaxion-induced deviations from SM prediction < 10% for sin2 θ < 0.1

= ⇒ too small to be resolved

Elina Fuchs (Weizmann) | Relaxion at colliders | 13

Z precision measurements

Precision measurements at the Z-pole

◮ relaxion opens NP contribution: ΓNP Z

= Γ(Z → φf ¯ f)

◮ bounded by δΓLEP1 Z

= 2.3 MeV → δΓTeraZ

Z

= 0.1 MeV

[Bicer et al ’14]

◮ theory improvement needed:

δΓth

Z = 0.5 MeV → δΓth,3loop Z

= 0.2 MeV

[Freitas ’14] Elina Fuchs (Weizmann) | Relaxion at colliders | 14

Resulting indirect bounds

◮ Z and Higgs precision

measurements

◮ lepton colliders

powerful h → untagged: bound on mass independent of sin θ for small mixing

Elina Fuchs (Weizmann) | Relaxion at colliders | 15

Direct probes: φ production as a light Higgs

Production at the LHC

◮ pp → φ (gg) ◮ pp → Zφ, Wφ ◮ pp → t¯

tφ, b¯ bφ

◮ pp → φjj (VBF)

Production at lepton colliders

◮ e+e− → Zφ ◮ Z → Z∗φ, Z∗ → ff

measurements at and above Z-pole

gg Wϕ Zϕ ttϕ bbϕ VBF 20 40 60 80 100 0.001 0.010 0.100 1 10 100 1000 mϕ [GeV] σ [pb]

Hadronic cross sections at 13 TeV (solid) and leptonic ones at 240 GeV (dashed) for sin2 θ = 1.

Elina Fuchs (Weizmann) | Relaxion at colliders | 16

Branching ratios

bb cc ττ μμ γγ 5 10 50 100 10-5 10-4 0.001 0.010 0.100 1 mϕ [GeV] BRϕ

exploit all final states: suitable at lepton/hadron colliders

Elina Fuchs (Weizmann) | Relaxion at colliders | 17

Searches for exotic Higgs decays

h → φφ → XXY Y

[e.g. CMS-PAS-HIG-17-024, ATLAS 1802.03388]

(GeV)

a

m

15 20 25 30 35 40 45 50 55 60

) (%) τ 2b2 → aa → B(h

SM

σ (h) σ 95% CL limit on

5 10 15 20 25

Observed Median expected 68% expected 95% expected Observed Median expected 68% expected 95% expected

CMS

Preliminary

Combined

(13 TeV)

• 1

35.9 fb ◮ BR(h → φφ → 4b) O(10−3) at CEPC with √s = 240 GeV

[Liu. Wang, Zhang ’17] Elina Fuchs (Weizmann) | Relaxion at colliders | 18

Comparison of direct and indirect bounds

◮ production at TeraZ, FCCee:

rough estimate by rescaling LEP1,2

◮ ILC: light Higgs study

applicable

[Drechsel, Moortgat-Pick, Weiglein ’18]

◮ ∆ΓZ not competitive

direct & indirect bounds complementary future colliders probe relevant mixing

Elina Fuchs (Weizmann) | Relaxion at colliders | 19

CP-violating nature of the relaxion

◮ so far: assumed dominating CP-even couplings (sin θ) ◮ constraints on CP-odd couplings:

f/˜ cγγ > 500 GeV from Pb-Pb collisions

[Knapen, Lin, Lou, Melia ’17]

f/˜ cZγ > 1 TeV from rare Z decays

[Bauer, Neubert, Thamm ’17]

f/˜ cγγ > 2.5 × 104 sin θ GeV from e-EDM

[Flacke, Frugiuele, EF, Gupta, Perez ’16]

◮ ALP at colliders studied, e.g.

[Bauer, Neubert, Thamm ’17] [Brivio et al ’17] [Buttazzo, Redigolo, Sala, Tesi ’18] ,... Elina Fuchs (Weizmann) | Relaxion at colliders | 20

CP-violating nature of the relaxion

◮ so far: assumed dominating CP-even couplings (sin θ) ◮ constraints on CP-odd couplings:

f/˜ cγγ > 500 GeV from Pb-Pb collisions

[Knapen, Lin, Lou, Melia ’17]

f/˜ cZγ > 1 TeV from rare Z decays

[Bauer, Neubert, Thamm ’17]

f/˜ cγγ > 2.5 × 104 sin θ GeV from e-EDM

[Flacke, Frugiuele, EF, Gupta, Perez ’16]

◮ ALP at colliders studied, e.g.

[Bauer, Neubert, Thamm ’17] [Brivio et al ’17] [Buttazzo, Redigolo, Sala, Tesi ’18] ,...

Possible hints of CP-violating interaction

◮ observation of φγ and φZ production

φγ loop-suppressed both for CP-even and -odd coupling possibly of similar order

◮ angular analyses of φ → f ¯

f decays which can be realised by CP-even and -odd couplings goal: distinction between pure H portal/ SM+singlet, pure axion-like and genuine relaxion signatures

Elina Fuchs (Weizmann) | Relaxion at colliders | 20

New bounds on ˜ cγZ and ˜ cZZ

Z Z∗ φ ℓ ℓ Z γ φ e+ e− Z∗ Z φ

5 10 15 20 25 30 35 0.1 1 10 100 mϕ [GeV] c ˜

γZ/f [1/TeV]

ϕℓℓ ϕγ Zϕ

L3 (LEP1) TeraZ ALEPH (LEP1) TeraZ LEP2 FCCee

5 10 15 20 25 30 35 0.1 1 10 100 mϕ [GeV] c ˜

ZZ/f [1/TeV]

{LEP1, LEP2} → strong bounds expected at {TeraZ, FCCee}

Elina Fuchs (Weizmann) | Relaxion at colliders | 21

Summary

scalar ALP relaxion

◮ relaxion attractive framework for naturalness without NP at TeV scale ◮ relaxion mass, mixing and lifetime: many orders of magnitude possible

searches via 5th force, astro, cosmo, flavour and colliders

◮ CP-violating relaxion-Higgs mixing close connection to Higgs physics ◮ CP-even and -odd couplings for model distinction ◮ LEP, LHC probe already “high-mass” region,

(future) colliders such as HL-LHC, FCCee/TLEP, ILC, CLIC: promising sensitivity esp. via φ-strahlung and Higgs couplings

Elina Fuchs (Weizmann) | Relaxion at colliders | 22

Outlook/discussion

◮ background studies for the proposed processes ◮ higher-order corrections ◮ systematic investigation of interplay of CP-even and -odd couplings ◮ further experimental searches for scalars of 5 − 35 GeV needed ◮ collider information for h → NP (in addition to h → inv)

Elina Fuchs (Weizmann) | Relaxion at colliders | 23

Outlook/discussion

◮ background studies for the proposed processes ◮ higher-order corrections ◮ systematic investigation of interplay of CP-even and -odd couplings ◮ further experimental searches for scalars of 5 − 35 GeV needed ◮ collider information for h → NP (in addition to h → inv)

pushing the low-mass collider frontier = high-mass relaxion region relaxion as a benchmark – applicable to other models

Elina Fuchs (Weizmann) | Relaxion at colliders | 23

Outlook/discussion

◮ background studies for the proposed processes ◮ higher-order corrections ◮ systematic investigation of interplay of CP-even and -odd couplings ◮ further experimental searches for scalars of 5 − 35 GeV needed ◮ collider information for h → NP (in addition to h → inv)

pushing the low-mass collider frontier = high-mass relaxion region relaxion as a benchmark – applicable to other models THANK YOU!

Elina Fuchs (Weizmann) | Relaxion at colliders | 23

APPENDIX

Low-energy: 5th force

C A S I M I R EqP ISqL

Λtp<2 TeV f>MPl f=MPl f=1014GeV Λbr=0.99 (Λbr)max Λbr=5 GeV

10-16 10-14 10-12 10-10 10-8

• 1. × 10-38
• 1. × 10-34
• 1. × 10-30
• 1. × 10-26
• 1. × 10-22

mϕ [GeV] sin2θ [Flacke, Frugiuele, EF, Gupta, Perez ’16]

◮ torsion balance

experiments:

weak equivalence principle (EqP) inverse square law (ISqL)

◮ Casimir force

re-interpreted from [Eöt-Wash group (Adelberger et al.)] [Bordag, Mohideen, Mostepanenko ’01] [Piazza, Pospelov ’10] [...] Elina Fuchs (Weizmann) | Relaxion at colliders | 1

Cosmological and astrophysical bounds

[Flacke, Frugiuele, EF, Gupta, Perez ’16]

BBN ηB SN1987a Neff EBL CMB-y CMB-μ GC-e GC-γ Λ

br

= . 9 9 ( Λ

br

)

max

f=10

1

GeV Pixie f=10

6

GeV f=m

h

Λ

br

= 1 G e V

10-7 10-6 10-5 10-4 0.001 0.01 0.1 10-23 10-21 10-19 10-17 10-15 10-13 10-11 10-9 mϕ [GeV] sin2θ some bounds re-interpreted from [Kolb, Turner] [Cadamuro, Redondo ’12] [Arias, Cadamuro, Goodsell, Jäckel, Redondo, Ringwald ’12] [...] Elina Fuchs (Weizmann) | Relaxion at colliders | 2

Meson decays (mass range of MeV – few GeV)

[Flacke, Frugiuele, EF, Gupta, Perez ’16] B→K+inv B0→K 0*μμ K→π+inv K→π+inv K→πμμ KL→π0ll B→K (*) ll Belle B→Kμμ LHCb B0→K 0* μμ LHCb CHARM SHiP Λbr=0.99 (Λbr)max f=106GeV f=104GeV f=mh cτ=2 m Λbr=10 GeV LEP hZ LHC h→ϕϕ→4μ SN1987a τ=1 s Neff ηB 2 mμ NA62 (our estimate) S e a Q u e s t

0.001 0.01 0.1 1 5 10-12 10-10 10-8 10-6 10-4 10-2 mϕ [GeV] sin2 θ

some bounds re-interpreted from [Clarke, Foot, Volkas ’13] [Schmidt-Hoberg, Staub, Winkler ’13]] [Dolan, Kahlhoefer, McCabe, Schmidt-Hoberg ’14] [Krnjaic ’15] Elina Fuchs (Weizmann) | Relaxion at colliders | 3

Relaxion parameter space

[Flacke, Frugiuele, EF, Gupta, Perez ’16] 5 t h f

• r

c e

• LHC
• LEP

K B SN η

B

N

e f f

BBN CMB G C e EBL Λbr > (Λbr)max

mϕ=μeV meV eV keV MeV GeV

CHARM

ΛtP = 1 4 5 G e V , Λcq = 1 07 G e V ΛtP = 2 T e V , Λcq = 1 08 G e V ΛtP = 1 T e V , Λcq = 1 09 G e V

100 101 102 103 106 109 1012 1015 1018 104 105 106 Λbr [GeV] f [GeV] Λ/3(N-30)/4 [GeV]

Elina Fuchs (Weizmann) | Relaxion at colliders | 4

Bounds on untagged/invisible Higgs decays

Collider √s [TeV] Lint [fb−1] BRinv [%] BRNP [%] LHC1 7, 8 22 37 20 LHC3 13 300 8.8 (68%) 7.6 (68%) HL-LHC 13 3 000 5.1 (68%) 4.3 (68%) CLIC 0.38 500 0.97 (90%) 3.1 CEPC 0.25 5 000 1.2 1.9 ILC 0.25 2 000 0.3 1.5 FCCee 0.24 10 000 0.19 0.64

Elina Fuchs (Weizmann) | Relaxion at colliders | 5

Searches for h → φφ → F at ATLAS and CMS

F exp. √s [TeV] Lint [fb−1] mφ [GeV] comment mHL

φ

[GeV] bbττ CMS 13 35.9 15-60 26 bbµµ CMS 8 19.7 15-62.5 27 ATLAS 13 36.1 20-60 30 ττµµ CMS 13 35.9 15-62.6

• 4τ

CMS 8 19.7 5-15

• 4µ

CMS 13 2.8 0.25-8.5 NMSSM, γD

• ATLAS

13 2.8 1-2.5, 4.5-8 2HDMS, ZD 4b ATLAS 13 36.1 20-60 Zh 27 Wh 29 γγgg ATLAS 13 36.7 20-60 VBF

• Elina Fuchs (Weizmann) | Relaxion at colliders | 6

Approximation of BR(h → NP)

Dilution of the BR of the h into SM: BR(h → F) = BRSM(h → F) · [1 − BR(h → NP)] SM-like at n σ: (1 − n · δκ)2 ≤ κ2 · [1 − BR(h → NP)] upper bound on BR(h → NP): BR(h → NP) ≤ 1 − 1 − n · δκ κ 2

Elina Fuchs (Weizmann) | Relaxion at colliders | 7

"Higgs portal" vs relaxion

translation (mφ, sθ) ← → ( ˜ M, f)

M ˜=M ˜

max

M ˜=10-3GeV f = M

P l

f = M

h

10-17 10-12 10-7 0.01 10-35 10-25 10-15 10-5 Mϕ [GeV] sin2θ given (mφ, f) − → 2 solutions of ˜ M

Elina Fuchs (Weizmann) | Relaxion at colliders | 8

"Higgs portal" vs relaxion

translation (mφ, sθ) ← → ( ˜ M, f)

M ˜=M ˜

max

M ˜=10-3GeV f = M

P l

f = M

h

10-17 10-12 10-7 0.01 10-35 10-25 10-15 10-5 Mϕ [GeV] sin2θ 5th given (mφ, f) − → 2 solutions of ˜ M

Elina Fuchs (Weizmann) | Relaxion at colliders | 8

"Higgs portal" vs relaxion

translation (mφ, sθ) ← → ( ˜ M, f)

M ˜=M ˜

max

M ˜=10-3GeV f = M

P l

f = M

h

10-17 10-12 10-7 0.01 10-35 10-25 10-15 10-5 Mϕ [GeV] sin2θ 5th cosmo given (mφ, f) − → 2 solutions of ˜ M

Elina Fuchs (Weizmann) | Relaxion at colliders | 8

"Higgs portal" vs relaxion

translation (mφ, sθ) ← → ( ˜ M, f)

M ˜=M ˜

max

M ˜=10-3GeV f = M

P l

f = M

h

10-17 10-12 10-7 0.01 10-35 10-25 10-15 10-5 Mϕ [GeV] sin2θ 5th cosmo collider given (mφ, f) − → 2 solutions of ˜ M

Elina Fuchs (Weizmann) | Relaxion at colliders | 8