Model Independent Constraints on Physics Beyond the Standard Model - - PowerPoint PPT Presentation

model independent constraints on physics beyond the
SMART_READER_LITE
LIVE PREVIEW

Model Independent Constraints on Physics Beyond the Standard Model - - PowerPoint PPT Presentation

Adam Falkowski (LPT Orsay) Model Independent Constraints on Physics Beyond the Standard Model Florence, 17 September 2015 Based on my 1505.00046, 1503.07872 with Aielet Efrati and Yotam Soreq, 1411.0669 with Francesco Riva, and 1508.00581


slide-1
SLIDE 1

Model Independent Constraints

  • n

Physics Beyond the Standard Model

Based on my 1505.00046, 1503.07872 with Aielet Efrati and Yotam Soreq, 1411.0669 with Francesco Riva, and 1508.00581 with Martín Gonzalez-Alonso, Admir Greljo, and David Marzocca

Florence, 17 September 2015 Adam Falkowski (LPT Orsay)

1 Thursday, September 17, 15

slide-2
SLIDE 2

Plan

Effective field theory approach to physics beyond the standard model Current precision constraints:

  • from LEP-1 pole observables
  • from LHC Higgs data and LEP-2 WW production
  • from LEP-2 ee->ll scattering (preview)

2 Thursday, September 17, 15

slide-3
SLIDE 3

Effective Field Theory approach to BSM physics

3 Thursday, September 17, 15

slide-4
SLIDE 4

SM is probably a correct theory the weak scale, at least as the lowest order term in an effective theory expansion If new particles are heavy, their effects can be parametrized by higher-dimensional operators added to the SM Lagrangian EFT framework offers a systematic expansion around the SM organized in terms of operator dimensions, with higher dimensional operator suppressed by the mass scale Λ of new physics

Premise

4 Thursday, September 17, 15

slide-5
SLIDE 5

Effective Theory Approach to BSM

New physics scale Λ separated from EW scale v, Λ >> v Linearly realized SU(3)xSU(2)xU(1) local symmetry spontaneously broken by VEV

  • f Higgs doublet field

Basic assumptions EFT Lagrangian beyond the SM expanded in operator dimension D Alternatively, non-linear Lagrangians with derivative expansion

5 Thursday, September 17, 15

slide-6
SLIDE 6

Effective Theory Approach to BSM

New physics scale Λ separated from EW scale v, Λ >> v Linearly realized SU(3)xSU(2)xU(1) local symmetry spontaneously broken by VEV

  • f Higgs doublet field

Basic assumptions EFT Lagrangian beyond the SM expanded in operator dimension D

X X X

Lepton number violating, hence too small to probe at LHC By assumption, subleading to D=6

6 Thursday, September 17, 15

slide-7
SLIDE 7

First attempts to classify dimension-6

  • perators back in 1986

First complete and non-redundant set of

  • perators explicitly written down only in 2010

Operators can be traded for other operators using integration by parts, field redefinition, equations of motion, Fierz transformation, etc Because of that, one can choose many different bases == non-redundant sets of

  • perators

EFT approach to BSM

Grządkowski et al. 1008.4884 see e.g. Grządkowski et al. 1008.4884 Giudice et al hep-ph/0703164 Contino et al 1303.3876 Buchmuller,Wyler pre-arxiv (1986)

7 Thursday, September 17, 15

slide-8
SLIDE 8

D=6 Basis

For D=6 Lagrangian several complete non-redundant set

  • f operators

(so-called basis) proposed in the literature

Grządkowski et al. 1008.4884

Warsaw Basis SILH basis

Giudice et al hep-ph/0703164 Contino et al 1303.3876

h basis

Gupta et al 1405.0181

HISZ basis Primary basis

LHCHXSWG-INT-2015-001

All bases are equivalent, but some may be more equivalent convenient for specific applications Physics description (EWPT, Higgs, RG running) in any of these bases contains the same information, provided all

  • perators contributing to that process are taken into

account

Hagiwara et al (1993)

8 Thursday, September 17, 15

slide-9
SLIDE 9

Example: Warsaw Basis

H4D2 and H6 OH ⇥ @µ(H†H) ⇤2 OT ⇣ H†← → DµH ⌘2 O6H (H†H)3 f2H3 Oe −(H†H − v2

2 )¯

eH†` Ou −(H†H − v2

2 )¯

u e H†q Od −(H†H − v2

2 ) ¯

dH†q V 3D3 O3G g3

sfabcGa µ⌫Gb ⌫⇢Gc ⇢µ

Of

3G

g3

sfabc e

Ga

µ⌫Gb ⌫⇢Gc ⇢µ

O3W g3✏ijkW i

µ⌫W j ⌫⇢W k ⇢µ

Og

3W

g3✏ijkf W i

µ⌫W j ⌫⇢W k ⇢µ

V 2H2 OGG

g2

s

4 H†H Ga µ⌫Ga µ⌫

Og

GG g2

s

4 H†H e

Ga

µ⌫Ga µ⌫

OWW

g2 4 H†H W i µ⌫W i µ⌫

O ]

WW g2 4 H†H f

W i

µ⌫W i µ⌫

OBB

g02 4 H†H Bµ⌫Bµ⌫

Og

BB g02 4 H†H e

Bµ⌫Bµ⌫ OWB gg0H†iH W i

µ⌫Bµ⌫

O g

WB

gg0H†iH f W i

µ⌫Bµ⌫

f2H2D OH` i¯ `µ`H†← → DµH O0

H`

i¯ `iµ`H†i← → DµH OHe i¯ eµ¯ eH†← → DµH OHq i¯ qµqH†← → DµH O0

Hq

i¯ qiµqH†i← → DµH OHu i¯ uµuH†← → DµH OHd i ¯ dµdH†← → DµH OHud i¯ uµd ˜ H†DµH f2V HD OeW g¯ `µ⌫eiHW i

µ⌫

OeB g0¯ `µ⌫eHBµ⌫ OuG gs¯ qµ⌫T au e H Ga

µ⌫

OuW g¯ qµ⌫ui e H W i

µ⌫

OuB g0¯ qµ⌫u e H Bµ⌫ OdG gs¯ qµ⌫T adH Ga

µ⌫

OdW g¯ qµ⌫diH W i

µ⌫

OdB g0¯ qµ⌫dH Bµ⌫ (¯ LL)(¯ LL) and (¯ LR)(¯ LR) O`` (¯ `µ`)(¯ `µ`) Oqq (¯ qµq)(¯ qµq) O0

qq

(¯ qµiq)(¯ qµiq) O`q (¯ `µ`)(¯ qµq) O0

`q

(¯ `µi`)(¯ qµiq) Oquqd (¯ qju)✏jk(¯ qkd) O0

quqd

(¯ qjT au)✏jk(¯ qkT ad) O`equ (¯ `je)✏jk(¯ qku) O0

`equ

(¯ `jµ⌫e)✏jk(¯ qkµ⌫u) O`edq (¯ `je)( ¯ dqj) ( ¯ RR)( ¯ RR) Oee (¯ eµe)(¯ eµe) Ouu (¯ uµu)(¯ uµu) Odd ( ¯ dµd)( ¯ dµd) Oeu (¯ eµe)(¯ uµu) Oed (¯ eµe)( ¯ dµd) Oud (¯ uµu)( ¯ dµd) O0

ud

(¯ uµT au)( ¯ dµT ad) (¯ LL)( ¯ RR) O`e (¯ `µ`)(¯ eµe) O`u (¯ `µ`)(¯ uµu) O`d (¯ `µ`)( ¯ dµd) Oqe (¯ qµq)(¯ eµe) Oqu (¯ qµq)(¯ uµu) O0

qu

(¯ qµT aq)(¯ uµT au) Oqd (¯ qµq)( ¯ dµd) O0

qd

(¯ qµT aq)( ¯ dµT ad)

59 different kinds of operators,

  • f which 17 are complex

Grządkowski et al. 1008.4884

2499 distinct operators, including flavor structure and CP conjugates

Alonso et al 1312.2014

9 Thursday, September 17, 15

slide-10
SLIDE 10

h-basis

Connection between operators and observables a bit obscured in Warsaw or SILH

  • basis. Also, in Warsaw basis EW precision constraints look complicated

h-basis proposed by LHCHXSWG2 to separate combinations of Wilson coefficients strongly constrained by EWPT from those relevant for LHC Higgs studies Rotation of any other D=6 basis such that one isolates linear combinations affecting Higgs observables and not constrained severely by precision tests LHCHXSWG-INT-2015-001

Similar “EFT Primaries” of Gupta et al 1405.0181

2499x2499 dimensional transformation matrix Linear transformation 2499 dimensional vector of Wilson coefficients 2499 parameters defining Higgs Basis

Relevant for LHC Higgs Very constrained parameters Irrelevant for LHC Higgs

10 Thursday, September 17, 15

slide-11
SLIDE 11

h-basis is defined via effective Lagrangian of mass eigenstates after electroweak symmetry breaking (photon,W,Z,Higgs boson, top). SU(3)xSU(2)xU(1) is not manifest but hidden in relations between different couplings Feature #1: In the tree-level Lagrangian, all kinetic terms are canonically normalized, and there’ s no kinetic mixing between mass

  • eigenstates. In particular, all oblique corrections from new physics

are zero, except for a correction to the W boson mass Feature #2: Tree-level relation between the couplings in the Lagrangian and SM input observables is the same as in the SM. In particular, photon and gluon couple as in SM, and there’ s no correction to Z mass term Features #1 and #2 can always be obtained without any loss of generality, via integration by parts, fields and couplings redefinition

h-basis Lagrangian

LHCHXSWG-INT-2015-001

11 Thursday, September 17, 15

slide-12
SLIDE 12

By construction, photon and gluon couplings as in the SM. Only W and Z couplings are affected Effects of dimension-6 operators are parametrized by a set of vertex corrections

h-Basis: Z and W couplings to fermions Dependent Couplings:

Relations enforced by linearly realized SU(3)xSU(2)xU(1) symmetry at the level of dimension-6 operators

12 Thursday, September 17, 15

slide-13
SLIDE 13

In HB, Higgs couplings to gauge bosons described by 6 CP even and 4 CP odd parameters that are unconstrained by LEP-1 D=6 EFT with linearly realized SU(3)xSU(2)xU(1) enforces relations between Higgs couplings to gauge bosons (otherwise, more parameters) Corrections to Higgs Yukawa couplings to fermions are also unconstrained by EWPT Apart from δm and δg, additional 6+3x3x3 CP-even and 4+3x3x3 CP-odd parameters to parametrize LHC Higgs physics

h-Basis: Higgs couplings to matter

relative correction to W mass

LHCHXSWG-INT-2015-001

13 Thursday, September 17, 15

slide-14
SLIDE 14

h-basis: Triple Gauge Couplings

SM predicts TGCs in terms of gauge couplings as consequence of SM gauge symmetry and renormalizability: In EFT with D=6 operators, new “anomalous”contributions to TGCs arise These depend on previously introduced h-basis parameters describing Higgs couplings to electroweak gauge bosons, and on 2 new parameters

14 Thursday, September 17, 15

slide-15
SLIDE 15

In the rest of the talk I will discuss constraints on the parameters in the h-basis For more details and the rest of the Lagrangian, see LHCHXSWG-INT-2015-001

15 Thursday, September 17, 15

slide-16
SLIDE 16

Model-independent precision constraints

  • n dimension 6 operators

16 Thursday, September 17, 15

slide-17
SLIDE 17

Analysis Assumptions

Working at order 1/Λ^2 in EFT expansion. Taking into account corrections from D=6 operators, and neglecting D=8 and higher

  • perators. (Only taking into account corrections to observables that

are linear in h-basis parameters, that is to say, only interference terms between SM and new physics. Quadratic corrections are formally of order 1/Λ^4, much as D=8 operators that are neglected.) Working at tree-level in EFT parameters (SM predictions taken at NLO

  • r NNLO, but only interference of tree-level BSM corrections with

tree-level SM amplitude taken into account) Except on las slide, restrict to observables that do not depend on 4- fermion operators (they are *not* neglected - just do not contribute at tree-level; constraints on 4-fermion operators left for future work) Allowing all dimension-6 operators to be present simultaneously with arbitrary coefficients (within EFT validity range). Constraints are

  • btained on all parameters affecting EWPT and Higgs at tree level,

and correlations matrix is computed. Unless otherwise noted, dimension-6 operators are allowed with arbitrary flavor structure

Han,Skiba hep-ph/0412166 Efrati,AA,Soreq 1503.07782

17 Thursday, September 17, 15

slide-18
SLIDE 18

Constraints

  • n Vertex Corrections

from Pole Observables

18 Thursday, September 17, 15

slide-19
SLIDE 19

For observables with Z or W bosons on-shell, interference between SM amplitudes and 4-fermion operators is suppressed by Γ/m and can be neglected Corrections from dimension-6 Lagrangian to pole observables can be expressed just by vertex corrections δg and W mass correction δm I will not assume anything about δg: they are allowed to be arbitrary, flavor dependent, and all can be simultaneously present

Pole observables (LEP-1 et al)

19 Thursday, September 17, 15

slide-20
SLIDE 20

Including leading order new physics corrections amount to replacing Z coupling to fermions with effective couplings These effective couplings encode the effect of vertex and oblique corrections Shift of the effective couplings in the presence of dimension-6 operators allows one to read off the dependence of observables on dimension-6 operators In general, pole observables constrain complicated combinations of coefficients of dimension-6 operators However, in h-basis, oblique corrections are absent (except for δm) thus δg directly constrained

On-shell Z decays: nuts and bolts

Lowest order: w/ new physics:

20 Thursday, September 17, 15

slide-21
SLIDE 21

Z-pole observables

Observable Experimental value Ref. SM prediction Definition ΓZ [GeV] 2.4952 ± 0.0023 [21] 2.4950 P

f Γ(Z → f ¯

f) σhad [nb] 41.541 ± 0.037 [21] 41.484

12π m2

Z

Γ(Z→e+e−)Γ(Z→q¯ q) Γ2

Z

Re 20.804 ± 0.050 [21] 20.743

P

q Γ(Z→q¯

q) Γ(Z→e+e−)

Rµ 20.785 ± 0.033 [21] 20.743

P

q Γ(Z→q¯

q) Γ(Z→µ+µ−)

Rτ 20.764 ± 0.045 [21] 20.743

P

q Γ(Z→q¯

q) Γ(Z→τ +τ −)

A0,e

FB

0.0145 ± 0.0025 [21] 0.0163

3 4A2 e

A0,µ

FB

0.0169 ± 0.0013 [21] 0.0163

3 4AeAµ

A0,τ

FB

0.0188 ± 0.0017 [21] 0.0163

3 4AeAτ

Rb 0.21629 ± 0.00066 [21] 0.21578

Γ(Z→b¯ b) P

q Γ(Z→q¯

q)

Rc 0.1721 ± 0.0030 [21] 0.17226

Γ(Z→c¯ c) P

q Γ(Z→q¯

q)

AFB

b

0.0992 ± 0.0016 [21] 0.1032

3 4AeAb

AFB

c

0.0707 ± 0.0035 [21] 0.0738

3 4AeAc

Ae 0.1516 ± 0.0021 [21] 0.1472

Γ(Z→e+

Le− L )−Γ(Z→e+ Re− R)

Γ(Z→e+e−)

Aµ 0.142 ± 0.015 [21] 0.1472

Γ(Z→µ+

Lµ− L )−Γ(Z→e+ µ µ− R)

Γ(Z→µ+µ−)

Aτ 0.136 ± 0.015 [21] 0.1472

Γ(Z→τ +

L τ − L )−Γ(Z→τ + R τ − R )

Γ(Z→τ +τ −)

Ab 0.923 ± 0.020 [21] 0.935

Γ(Z→bL¯ bL)−Γ(Z→bR¯ bR) Γ(Z→b¯ b)

Ac 0.670 ± 0.027 [21] 0.668

Γ(Z→cL¯ cL)−Γ(Z→cR¯ cR) Γ(Z→c¯ c)

As 0.895 ± 0.091 [22] 0.935

Γ(Z→sL¯ sL)−Γ(Z→sR¯ sR) Γ(Z→s¯ s)

Ruc 0.166 ± 0.009 [23] 0.1724

Γ(Z→u¯ u)+Γ(Z→c¯ c) 2 P

q Γ(Z→q¯

q)

µttZ 0.81 ± 0.24 [24,25] 1.00

(gZt

L )2+(gZt R )2

(gZu

L,SM)2+(gZu R,SM)2

Table 1: Z boson pole observables. The experimental errors of the observables between the double lines are correlated, which is taken into account in the fit. The results for Ae,µ,τ listed above come from the combination of leptonic polarization and left-right asymmetry measurements at the SLD; we also include the results Aτ = 0.1439± 0.0043, Ae = 0.1498± 0.0049 from tau polarization measurements at LEP-1 [21]. For the theoretical predictions we use the best fit SM values from GFitter [20]. We also include the model-independent measurement of on-shell Z boson couplings to light quarks in D0 [26].

21 Thursday, September 17, 15

slide-22
SLIDE 22

W-pole observables

Observable Experimental value Ref. SM prediction Definition mW [GeV] 80.385 ± 0.015 [27] 80.364

gLv 2 (1 + δm)

ΓW [GeV] 2.085 ± 0.042 [23] 2.091 P

f Γ(W → ff 0)

Br(W → eν) 0.1071 ± 0.0016 [28] 0.1083

Γ(W!eν) P

f Γ(W!ff0)

Br(W → µν) 0.1063 ± 0.0015 [28] 0.1083

Γ(W!µν) P

f Γ(W!ff0)

Br(W → τν) 0.1138 ± 0.0021 [28] 0.1083

Γ(W!τν) P

f Γ(W!ff0)

RWc 0.49 ± 0.04 [23] 0.50

Γ(W!cs) Γ(W!ud)+Γ(W!cs)

Rσ 0.998 ± 0.041 [29] 1.000 gWq3

L

/gWq3

L,SM

Table 2: W-boson pole observables. Measurements of the 3 leptonic branching fractions are

  • correlated. For the theoretical predictions of mW and ΓW, we use the best fit SM values from

GFitter [20], while for the leptonic branching fractions we take the value quoted in [28].

22 Thursday, September 17, 15

slide-23
SLIDE 23

Z coupling to charged leptons constrained at 0.1% level W couplings to leptons constrained at 1% level Some couplings to quarks (bottom, charm) also constrained at 1% level Some couplings very weakly constrained in a model-independent way, in particular Z couplings to light quarks (though their combination affecting *total* hadronic Z- width is strongly constrained) Some off-diagonal vertex corrections can also be constrained

Pole observables - constraints

All diagonal vertex corrections except for δgWqR and δgZtR simultaneously constrained in a completely model-independent way Efrati,AA,Soreq 1503.07872

m = (2.6 ± 1.9) · 10−4.

[δgW e

L ]ii =

  −1.00 ± 0.64 −1.36 ± 0.59 1.95 ± 0.79   × 10−2, [δgZe

L ]ii =

  −0.26 ± 0.28 0.1 ± 1.1 0.16 ± 0.58   × 10−3, [δgZe

R ]ii =

  −0.37 ± 0.27 0.0 ± 1.3 0.39 ± 0.62   × 10−3, [δgZu

L ]ii =

  −0.8 ± 3.1 −0.16 ± 0.36 −0.28 ± 3.8   × 10−2, [δgZu

R ]ii =

  1.3 ± 5.1 −0.38 ± 0.51 ×   × 10−2, [δgZd

L ]ii =

  −1.0 ± 4.4 0.9 ± 2.8 0.33 ± 0.16   × 10−2, [δgZd

R ]ii =

  2.9 ± 16 3.5 ± 5.0 2.30 ± 0.82   × 10−2.

23 Thursday, September 17, 15

slide-24
SLIDE 24

Full correlation matrix is also derived From that, one can reproduce full likelihood function as function of 21 parameters δg and δm If dictionary from h-basis to other bases exists, results can be easily recast to another form Similarly, when mapping to d=6 basis from (fewer) parameters of particular BSM models is given, results can be easily recast as constraints

  • n that model

Pole constraints - correlations

1σ Errors Correlation Matrix Central Values

24 Thursday, September 17, 15

slide-25
SLIDE 25

Pole constraints - recast to Warsaw basis

Dictionary Results

δgW ℓ

L

= c′

Hℓ + f(1/2, 0) − f(−1/2, −1),

δgZν

L

= 1 2 (c′

Hℓ − cHℓ) + f(1/2, 0),

δgZe

L

= −1 2 (c′

Hℓ + cHℓ) + f(−1/2, −1),

δgZe

R

= −1 2cHe + f(0, −1), f(T 3, Q) = I

  • −QcW B

g2

Lg2 Y

g2

L − g2 Y

+ (cT − δv)

  • T 3 + Q

g2

Y

g2

L − g2 Y

  • .

δgW q

L

= c′

HqV + f(1/2, 2/3)V − f(−1/2, −1/3)V,

δgW q

R

= cHud, δgZu

L

= 1 2

  • c′

Hq − cHq

  • + f(1/2, 2/3),

δgZd

L

= −1 2V † c′

Hq + cHq

  • V + f(−1/2, −1/3),

δgZu

R

= −1 2cHu + f(0, 2/3), δgZd

R

= −1 2cHd + f(0, −1/3).

[ˆ c′

Hℓ]ii =

  −1.09 ± 0.64 −1.45 ± 0.59 1.87 ± 0.79   × 10−2, [ˆ cHℓ]ii =   1.03 ± 0.63 1.32 ± 0.62 −2.01 ± 0.80   × 10−2, [ˆ cHe]ii =   0.22 ± 0.66 −0.6 ± 2.6 −1.4 ± 1.3   × 10−3, c′

ℓℓ = (−1.21 ± 0.41) × 10−2,

  • ˆ

c′

Hq

  • ii =

  0.1 ± 2.7 −1.2 ± 2.8 −0.7 ± 3.8   × 10−2, [ˆ cHq]ii =   1.8 ± 7.0 −0.8 ± 2.9 0.0 ± 3.8   × 10−2, [ˆ cHu]ii =   −3 ± 10 0.8 ± 1.0 ×   × 10−2, [ˆ cHd]ii =   −6 ± 32 −7 ± 10 −4.6 ± 1.6   × 10−2.

[ˆ c′

Hℓ]ij

= [c′

HL]ij +

  • g2

LcW B − g2 L

g2

Y

cT

  • δij,

[ˆ cHℓ]ij = [cHL]ij − cT δij, [ˆ cHe]ij = [cHE]ij − 2cTδij,

  • ˆ

c′

Hq

  • ij

=

  • c′

HQ

  • ij +
  • g2

LcW B − g2 L

g2

Y

cT

  • δij,

[ˆ cHq]ij = [cHQ]ij + 1 3cTδij, [ˆ cHu]ij = [cHU]ij + 4 3cTδij, [ˆ cHd]ij = [cHD]ij − 2 3cTδij.

Note in Warsaw basis only combinations of Wilson coefficients are constrained by pole observables

25 Thursday, September 17, 15

slide-26
SLIDE 26

Pole constraints - recast to SILH’ basis

Results

In SILH basis pole constraints look simpler, though important correlations remain, notably between cW+cB and leptonic couplings

[s``]1221 = (4.8 ± 1.6) × 102, sW + sB 2 = −0.43 ± 0.26, sT = (−1.03 ± 0.63) × 102, [s0

H`]ii =

@ −0.36 ± 0.92 3.0 ± 1.3 1 A × 102, [sH`]ii = @ 0.29 ± 0.95 −3.0 ± 1.3 1 A × 102, [sHe]ii = @ −2.0 ± 1.3 −2.1 ± 1.3 −2.2 ± 1.3 1 A × 102, ⇥ s0

Hq

ii =

@ 1.2 ± 2.8 −0.1 ± 2.9 0.4 ± 3.8 1 A × 102, [sHq]ii = @ 2.1 ± 7.1 −0.4 ± 2.9 0.3 ± 3.8 1 A × 102, [sHu]ii = @ −1 ± 10 2.2 ± 1.3 × 1 A × 102, [sHd]ii = @ −6 ± 32 −7 ± 10 −5.3 ± 1.7 1 A × 102, (

26 Thursday, September 17, 15

slide-27
SLIDE 27

All leptonic couplings constrained at per- mille level, all quark couplings constrained at 1% level or better Pole constraints - flavor blind

27 Thursday, September 17, 15

slide-28
SLIDE 28

Pole constraints - universal theories Oblique corrections:

Peskin Takeuchi pre-arxiv Barbieri et al hep-ph/0405040

Equivalent to restricted form of flavor-diagonal vertex corrections, W-mass corrections, and 4-fermion operators:

  • 0.3
  • 0.2
  • 0.1

0.0 0.1 0.2 0.3

  • 0.3
  • 0.2
  • 0.1

0.0 0.1 0.2 0.3

S T Pole observables

Same likelihood for pole observables can be used to constrain up to 3 oblique params

28 Thursday, September 17, 15

slide-29
SLIDE 29

Constraints from LHC Higgs data

29 Thursday, September 17, 15

slide-30
SLIDE 30

Higgs signal strength observables

Channel µ Production Ref.

  • 1.16+0.20

−0.18

2D [31] 1.0+1.6

−1.6

Wh [34] 0.1+3.7

−0.1

Zh [34] 0.58+0.93

−0.81

Vh [33] 1.30+2.62

−1.75 & 2.7+2.4 −1.7

tth [33, 34] Z 2.7+4.5

−4.3 & −0.2+4.9 −4.9

total [34, 35] ZZ∗ 1.31+0.27

−0.14

2D [31] WW ∗ 1.11+0.18

−0.17

2D [31] 2.1+1.9

−1.6

Wh [36] 5.1+4.3

−3.1

Zh [36] 0.80+1.09

−0.93

Vh [33] ⌧⌧ 1.12+0.25

−0.23

2D [31] 0.87+1.00

−0.88

Vh [33] bb 1.11+0.65

−0.61

Wh [32] 0.05+0.52

−0.49

Zh [32] 0.89+0.47

−0.44

Vh [33] 2.8+1.6

−1.4

VBF [37] 1.5+1.1

−1.1 & 1.2+1.6 −1.5

tth [38, 39] µµ −0.7+3.7

−3.7 & 0.8+3.5 −3.4

total [34, 40] multi-` 2.1+1.4

−1.2 & 3.8+1.4 −1.4

tth [41, 42]

Including 2D likelihoods from recent ATLAS+CMS combination

ATLAS-CONF-2015-044 CMS-PAS-HIG-15-002

30 Thursday, September 17, 15

slide-31
SLIDE 31

In Higgs basis, Higgs couplings to gauge bosons are described by 10 parameters These parameters are

  • bservables probed by

multiple Higgs production (ggF , VBF , VH) and Higgs decay (γγ, Zγ, VV^*→4f) processes Linearly realized SU(3)xSU(2)xU(1) with D=6

  • perators enforces relations

between Higgs couplings to gauge bosons (otherwise, 5 more parameters)

Higgs Basis: Higgs couplings to gauge bosons

31 Thursday, September 17, 15

slide-32
SLIDE 32

In Higgs basis, Higgs couplings to fermions are described by 3 general complex 3x3 matrices Here I will assume MFV couplings, thus reducing number

  • f parameters to 2x3

Without that assumption, couplings to light fermions are unconstrained, leading to flat directions; their effect on other parameters is similar to adding additional invisible width

Higgs Basis: Higgs couplings to fermions

∆LD=6

hff

= −h v

  • f∈u,d,e

δyf eiφf mff cf + h.c..

Other Higgs couplings to fermions (vertex-like, or dipole-like) are constrained to be small by precision

  • bservables and cannot affect LHC Higgs observables

given the current level of precision

32 Thursday, September 17, 15

slide-33
SLIDE 33

Higgs signal strength observables at linear level are

  • nly sensitive to CP even parameter (CP odd enter
  • nly quadratically and are ignored)

Only couplings unconstrained by precision tests can be relevant at the LHC Thus, assuming MFV couplings to fermions, only 9 EFT parameter affect Higgs signal strength measured at LHC Higgs observables in the Higgs basis

33 Thursday, September 17, 15

slide-34
SLIDE 34

→ σW h σSM

W h

≃ 1 + 2δcw +   6.39 6.51 6.96   cw +   1.49 1.49 1.50   cww → 1 + 2δcz +   9.26 9.43 10.08   cz +   4.35 4.41 4.63   czz −   0.81 0.84 0.93   czγ −   0.43 0.44 0.48   cγγ σZh σSM

Zh

≃ 1 + 2δcz +   5.30 5.40 5.72   cz +   1.79 1.80 1.82   czz +   0.80 0.82 0.87   cγ +   0.22 0.22 0.22   czγ, → 1 + 2δcz +   7.61 7.77 8.24   cz +   3.31 3.35 3.47   czz −   0.58 0.60 0.65   czγ +   0.27 0.28 0.30   cγγ. (4.7

→ σV BF σSM

V BF

≃ 1 + 1.49δcw + 0.51δcz −   1.08 1.11 1.23   cw − 0.10cww −   0.35 0.35 0.40   cz −0.04czz − 0.10cγ − 0.02czγ → 1 + 2δcz − 2.25cz − 0.83czz + 0.30czγ + 0.12cγγ.

Higgs production in the Higgs basis

− − × ≃ σggh σSM

ggh

≃ 1 + 237cgg + 2.06δyu − 0.06δyd.

→ σtth σSM

tth

≃ 1 + 2δyu.

7 8 13

( ) TeV

34 Thursday, September 17, 15

slide-35
SLIDE 35

Higgs decay in the Higgs basis

Γcc ΓSM

cc

≃ 1 + 2δyu, Γbb ΓSM

bb

≃ 1 + 2δyd, Γττ ΓSM

ττ

≃ 1 + 2δye,

Γ2ℓ2ν ΓSM

2ℓ2ν

≃ 1 + 2δcw + 0.46cw − 0.15cww → 1 + 2δcz + 0.67cz + 0.05czz − 0.17czγ − 0.05cγγ.

¯ Γ4ℓ ¯ ΓSM

4ℓ

≃ 1 + 2δcz +

  • 0.41

0.39

  • cz −
  • 0.15

0.14

  • czz +
  • 0.07

0.05

  • czγ −
  • 0.02

0.02

  • cγ +
  • < 0.01

0.03

  • cγγ

→ 1 + 2δcz + 0.35 0.32

  • cz −

0.19 0.19

  • czz +

0.09 0.08

  • czγ +

0.01 0.02

  • cγγ.

(4.13)

h h

ΓV V ΓSM

V V

  • 1 + ˆ

cvv cSM

vv

  • 2

, vv ∈ {gg, γγ, zγ}, ˆ cγγ = cγγ, cSM

γγ ≃ −8.3 × 10−2,

ˆ czγ = czγ, cSM

zγ ≃ −5.9 × 10−2,

Decays to 2 fermions Decays to 4 fermions Decays to 2 gauge bosons

2e2μ 4e

( )

35 Thursday, September 17, 15

slide-36
SLIDE 36

µX;Y = σ(pp → X) σ(pp → X)SM Γ(h → Y ) Γ(h → Y )SM Γ(h → all)SM Γ(h → all) .

Higgs observables in the Higgs basis

Signal strength

In EFT, assuming no other degrees of freedom, so total width is just sum of partial width into SM particle no invisible width in this analysis

One can express all measured signal strength in terms of the 9 EFT parameters Using available LHC signal strength data one can

  • btain constraints on most of these parameters

36 Thursday, September 17, 15

slide-37
SLIDE 37

Higgs constraints on EFT

Below is a comparison of the L (x0 ± 1 σ) δcz −0.12 ± 0.20 czz 0.6 ± 1.9 cz2 −0.25 ± 0.83 cγγ 0.015 ± 0.029 czγ 0.01 ± 0.10 cgg −0.0056 ± 0.0028 δyu 0.55 ± 0.30 δyd −0.42 ± 0.45 δye −0.18 ± 0.36 (I haven’t computed all t

Not all parameters yet constrained enough that EFT approach is valid Results sensitive to including corrections to Higgs observables quadratic in EFT parameters which are formally O(1/Λ^4). Thus, in general, results may be sensitive to including dimension-8 operators Flat direction Needs more data

  • n differential distributions

in h->4f decays

AA 1505.00046

37 Thursday, September 17, 15

slide-38
SLIDE 38

Combined Constraints from LEP-2 WW and LHC Higgs

Previously

Corbett et al 1304.1151 Dumont et al 1304.3369 Pomarol Riva 1308.2803 Masso 1406.6377 Ellis et al 1410.7703

Now

AA,Gonzalez-Alonso,Greljo,Marzocca 1508.00581

Consistent EFT analysis at O(1/Λ^2)

38 Thursday, September 17, 15

slide-39
SLIDE 39

In Higgs basis formalism, all but 2 TGCs are dependent couplings and can be expressed by Higgs couplings to gauge bosons Therefore constraints on δg1z and δκγ imply constraints on Higgs couplings But for that, all TGCs have to be simultaneously constrained in multi-dimensional fit, and correlation matrix should be given Note that c_zγ c_zz and c_zBox are difficult to access experimentally in Higgs physics Important to combine Higgs and TGC data!

TGC - Higgs Synergy

Linearly realized SU(3)xSU(2)xU(1) at D=6 level enforces relations between TGC and Higgs couplings in the Higgs basis Higgs TGC

39 Thursday, September 17, 15

slide-40
SLIDE 40

Higgs constraints on EFT

Flat direction between c_zz and c_zBox lifted to large extent by WW data! Much better constraints on some parameters. Most parameters (marginally) within the EFT regime Lower sensitivity to the quadratic terms (though still not completely negligible, especially for δcz and δyd)

               cz czz cz⇤ c cz cgg yu yd ye z                =                −0.07 ± 0.14 0.65 ± 0.42 −0.29 ± 0.21 −0.005 ± 0.014 −0.005 ± 0.095 −0.0053 ± 0.0027 0.55 ± 0.30 −0.44 ± 0.24 −0.22 ± 0.18 −0.152 ± 0.080                ,

Correlation matrix

40 Thursday, September 17, 15

slide-41
SLIDE 41

Corollary: constraints on TGCs

TGC Higgs TGC+Higgs 1.5 1.0 0.5 0.0 1.0 0.5 0.0 0.5 1.0 ∆g1,z ∆ΚΓ

LHC Higgs and LEP-2 WW data by itself do not constrain TGCs robustly due to each suffering from 1 flat direction in space of 3 TGCs However, the flat directions are orthogonal and combined constraints lead to robust O(0.1) limits on aTGCs

  δg1,z δκγ λz   =   0.037 ± 0.041 0.133 ± 0.087 −0.152 ± 0.080   , ρ =   1 0.62 −0.84 0.62 1 −0.85 −0.84 −0.85 1  

41 Thursday, September 17, 15

slide-42
SLIDE 42

42 Thursday, September 17, 15

slide-43
SLIDE 43

Non-trivial constraints at linear (1/Λ^2) level Quadratic (1/Λ^4) terms not completely negligible yet, but they do not change fit qualitatively

Combined WW+Higgs: robustness

43 Thursday, September 17, 15

slide-44
SLIDE 44

zz

mZh 200 300 400 500 600 700 800 900 0.00 0.05 0.10 0.15 mZh (pb/bin)

Combined WW+Higgs: robustness

For VH production, quadratic (1/Λ^4) contributions are comparable to linear (1/Λ^2)

  • nes

They are numerically important but don’ t change fit significantly because they constrain similar direction in parameter space as linear ones Sensitivity to 1/Λ^4 terms greatly reduced if VH signal strength with cut mVH<400 GeV was quoted

44 Thursday, September 17, 15

slide-45
SLIDE 45

Constraints

  • n 4 fermion operators

45 Thursday, September 17, 15

slide-46
SLIDE 46

Preview: 4-electron operators

1-by-1

[O``]1111 = (¯ `1¯ µ`1)(¯ `1¯ µ`1), [O`e]1111 = (¯ `1¯ µ`1)(ec

1µ¯

ec

1),

[Oee]1111 = (ec

1µ¯

ec

1)(ec 1µ¯

ec

1).

Simultaneous

1 10 10 2 10 3

  • 0.5

0.5 1 10 10 2 10 3

  • 0.5

0.5

3 3

LEP Averaged d σ / d cosθ (e+e-)

189 GeV

cosθe dσ/dcosθ (pb)

192 GeV

cosθe dσ/dcosθ (pb) (pb) (pb)

AA, Mimouni, to appear

46 Thursday, September 17, 15

slide-47
SLIDE 47

Take away

There are strong constraints on certain combinations of dimension-6 operators from the pole observables measured at LEP-1 and other colliders. These can be conveniently presented as correlated constraints on vertex corrections and W mass corrections. Assuming MFV , these constraints allow one to describe LO EFT deformations of single Higgs signal strength LHC observables by just 9 parameters There are non-trivial constraints on all of these 9 parameters from Higgs and WW data Synergy of TGC and Higgs coupling measurements is crucial for deriving meaningful bounds

47 Thursday, September 17, 15