Are there hidden scalars in the LHC Higgs results? BURI2014 - - - PowerPoint PPT Presentation

Rui Santos

13 February 2014

BURI2014 - University of Toyama ISEL & CFTC (Lisbon) with A. Arhrib and P. Ferreira

Are there hidden scalars in the LHC Higgs results?

LHC The Higgs One Higgs? Multi-”Higgs”?

What is this talk about?

Gluon fusion

;A

The SM-like Higgs decays are just the same (with different widths though)

h → γγ ; h → W +W − ; h → ZZ ; h → τ +τ − ; h → bb

H → hh A → hZ

h

Direct Chain (the two most relevant)

• A. Arhrib, P. Ferreira, RS

1311.1520 - to appear in JHEP

In which model?

SM + singlet SM +doublet ⎧ ⎨ ⎩

Z2 symmetric CP-conserving 2HDM (softly broken)

φ1 = 1 2 v1 ⎛ ⎝ ⎜ ⎞ ⎠ ⎟ ; φ2 = 1 2 v2 ⎛ ⎝ ⎜ ⎞ ⎠ ⎟

7 free parameters + MW:

ratio of vacuum expectation values tanβ = v2 v1 rotation angle neutral CP-even sector

2HDM Lagrangian

 scalars-gauge bosons couplings

 Yukawa couplings

sinα tanβ

gSM

hVV sin(β − α)

IV = II’ = X = Lepton Specific= … III = I’ = Y = Flipped=… for the lightest CP-even Higgs

cos(β − α)

for the heavier CP- even Higgs no FCNC at tree- level

The decoupling limit of the 2HDM

• J. Gunion, H. Haber, PRD67 (2003) 075019.
• S. Kanemura, Y. Okada, E. Senaha, C.-P. Yuan PRD70 (2004) 115002.
• I. Ginzburg, M. Krawczyk, PRD72 (2005) 115013.

Experimental and theoretical constraints

• Perturbative unitarity
• Potential is bounded from below
• Electroweak precision
• Constraints on the masses from LEP
• Constraints on the plane (mH+, tanβ) from Tevatron and LHC and B-physics
• LHC exclusion bounds on the heavy scalars

BR(H − →τν )

Corrected for

ATLAS-CONF-2013-090

I II Y X tanβ 4.3 6.4 3.2 5.2

mH + = 90 GeV

Vacuum structure of 2HDMs

Local minimum – NORMAL (VN) Global minimum – CHARGE BREAKING (VCB)

The tree-level global picture

• 1. 1. 2HDM have at most two minima
• 2. 2. Minima of different nature never coexist
• 3. Unlike Normal, CB and CP minima are uniquely determined
• 4. If a 2HDM has only one normal minimum then this is the absolute minimum – all other SP if

they exist are saddle points

• 5. If a 2HDM has a CP breaking minimum then this is the absolute minimum – all other SP if

they exist are saddle points

PLB603(2004), PLB632(2006), PLB652(2007) PRD75(2007)035001, PRD77(2008)15017

• I. Ivanov

EPJC48(2006)805

• M. Maniatis, A. von Manteuffel,
• O. Nachtmann and F. Nagel
• A. Barroso, P. Ferreira, RS

VG −VL = − 4.2 ×108 GeV

Two normal minima - potential with the soft breaking term mW = 80.4 GeV mW =107.5 GeV

• A. Barroso, P.M. Ferreira, I.P. Ivanov, RS, JHEP06 (2013) 045.
• A. Barroso, P.M. Ferreira, I.P. Ivanov, RS, J.P. Silva, Eur. Phys. J. C73 (2013) 2537.

Let

IF D < 0 PANIC

The vacuum is the global minimum of the potential if and only if D > 0.

Consequences of finding a ~125 GeV Higgs for 2HDMs

• Set mh = 125 GeV.
• Generate random values for potential’s parameters such that
• Impose all experimental and theoretical constraints previously

described.

• Calculate all branching ratios and production rates at the LHC.

Scan

• Impose ATLAS and CMS results.

• The function sin2(β – α) is very sensitive to deviations from 1 – large dispersion.
• For ATLAS RZZ is above 1 – 1σ (green) excluded; 2σ (blue) allowed.
• For CMS RZZ is below 1 – 1σ (green) away from SM limit but allowed; 2σ (blue)

allowed and with a large dispersion.

• Large positive values of sinα already excluded at 2σ.

SM-like limit sin(β - α) = 1

Green – ATLAS 1σ Blue – ATLAS 2σ Green – CMS 1σ Blue – CMS 2σ

sin(β + α) = 1 SM-like limit sin(β - α) = 1

• This function is not sensitive to deviations from 1 – small dispersion.
• In both cases we have 1σ (green) and 2σ (blue) allowed regions.
• For CMS they are mostly above the red lines (R’s below 1) and for ATLAS they are

mostly below the red lines (R’s above 1).

• Large positive values of sinα (and the ones close to -1) already excluded at 2σ.

Green – ATLAS 1σ Blue – ATLAS 2σ Green – CMS 1σ Blue – CMS 2σ

sin(β + α) = 1 SM-like limit sin(β - α) = 1

E X C L U D E D E X C L U D E D

Green – ATLAS 1σ Blue – ATLAS 2σ Green – CMS 1σ Blue – CMS 2σ

• sin(β – α) < 0.5 excluded at 2σ – deviations of the light Higgs couplings to gauge

bosons relative to the SM’s.

• For sin(β – α) < 0.8, tanβ < 4 – large tanβ only close to sin(β – α) = 1. This is a major

difference relative to type I models.

What is this talk about?

Gluon fusion

;A

The SM-like Higgs decays are just the same (with different widths though)

h → γγ ; h → W +W − ; h → ZZ ; h → τ +τ − ; h → bb

H → hh A → hZ

h

Direct Chain (the two most relevant)

• A. Arhrib, P. Ferreira, RS

1311.1520 - to appear in JHEP

Consequences of not finding other scalars for 2HDMs.

[GeV]

• m

100 150 200 250 300 350 400 450 500 ) [pb] ! ! /

• BR(

"

• 95% CL limit on
• 2

10

• 1

10 1 10

2

10

ATLAS

= 7 TeV s

• 1

Ldt = 4.7 - 4.8 fb

• !

!

• CLs
• Observed bb
• Expected bb

CLs

• Observed gg
• Expected gg
• bb
• 1

#

• bb
• 2

#

ATLAS, JHEP02(2013)095 These are the searches for taus in the final state. All other available searches were considered.

(a) predicted values for pp -> H -> ττ in type I; (b) predicted values for pp -> A -> ττ in type II. Green points include all constraints except the light Higgs ones. The black line is the ATLAS exclusion line. Excludes large tan beta in type II. Very important because couplings do not depend on alpha. Direct constraints on the (mA, tan β) plane. Comparison between 2HDM predictions and the LHC results.

RWW in type II with all constraints except for light Higgs measurements.

150 200 250 300 350 400 450 500 550 600 10

2

10

1

10

(b) mH RH

WW

Type II after imposing LHC h results

There are still points in parameter space that are excluded with this particular bound. All this is telling us is that H cannot couple very strongly to gauge bosons… … and that is to be expected: if h couples strongly to ZZ and WW, H must couple weakly: RWW in type II with all constraints.

Rγγ (for A production) in type II Comparison between 2HDM predictions and the LHC results. Cross section for A production times BR(A->γγ) in type II Increases until the opening of the A -> tt channel. It could improve our understanding of the models when combined with the A -> ττ results.

What if some of the h’s we are observing at the LHC are coming from the decays of the other heavy scalar states?

There are new contributions to the lightest Higgs rates This is the “usual” rate, which includes only “direct” production There are however “indirect” contributions as well: An H, an A or a H+ is produced first, and THEN decays to a light h – CHAIN HIGGS PRODUCTION.

All production processes considered

Gluon fusion

;A

Vector boson fusion Higgs-strahlung Associated production with

t t

The SM-like Higgs decays are just the same (with different widths though)

h → γγ ; h → W +W − ; h → ZZ ; h → τ +τ − ; h → bb

;A ;A

H → hh H → H +H − → hhW +W − H → AA → hhZZ ⎧ ⎨ ⎪ ⎩ ⎪ A → hZ A → H +W − → hW +W − ⎧ ⎨ ⎩ H → AZ → hZ H → H +W − → hW +W − ⎧ ⎨ ⎩

For instance, for H the new contribution would be given by With being the “expectation value of h’s produced in H decays”.

SM-like points can already come from chain decays.

Does it make any difference…?

Manage to get larger values of RZZ, which couldn’t occur for Type I… Also for Rγγ. Plenty of Green points in the middle of blue ones DIRECT + CHAIN PRODUCTION CAN YIELD PERFECTLY REASONABLE VALUES OF THE R’S!

HOW IMPORTANT CAN CHAIN PRODUCTION BE?

• Take all R’s of h within 20% of their SM values.
• Consider the ratio between the CHAIN cross sections and the

TOTAL.

• CHAIN PRODUCTION CAN BE UP TO ~25% OF THE TOTAL

PRODUCTION OF HIGGSES AT THE LHC. GREEN – before 20 %. BLUE – AFTER 20%.

Type II

Plots clearly shows that in both model types the enhancement reaches a maximum very close to sin (β-α) ≈ 1. GREEN – before 20 %. BLUE – AFTER 20%. WHERE ARE THESE POINTS IN PARAMETER SPACE?

Type II

GREEN – before 20 %. BLUE – AFTER 20%. Preferred values of tanβ are small - close to 1. Again this is valid for both model types. WHERE ARE THESE POINTS IN PARAMETER SPACE?

Type II

All constraints taken into account, including the 20 % one. Here we also show the sum of all contribution of the charged Higgs to chain decays which is clearly negligible (in BLUE). WHICH PROCESSES CONTRIBUTE THE MOST?

H → hh

A → hZ

Conclusions

We could already be seeing heavy scalars hidden in chain decays. Chain decays give also a larger range of variation for RXX. Searches for A -> hZ and H -> hh can improve our knowledge on extensions of the scalar sector of the SM. Now, dedicated analysis are needed. Wait, don’t go away. I still have two announcements: one short, and the other very short.

ScannerS, a tool for multi-Higgs calculations

with R. Coimbra and M. Sampaio

2-5 September 2014 Workshop on

Multi-Higgs Models

Lisbon - Portugal

International Advisory Committee: F.J. Botella G.C. Branco

• H. Haber
• M. Krawczyk
• P. Osland

, CFTC , ISEL and CFTC , ISEL and CFTC , ISEL and CFTP , CFTP Organizing Committee: Augusto Barroso Pedro Ferreira Rui Santos João P. Silva Luís Lavoura

This Workshop brings together those interested in the theory and phenomenology of Multi-Higgs models. The program is designed to include talks given by some of the leading experts in the field, and also ample time for discussions and collaboration between researchers. A particular emphasis will be placed on identifying those features of the models which are testable at the LHC. For registration and/or to propose a talk, send an email to: ferreira@cii.fc.ul.pt Web Page : http://www.ciul.ul.pt/~2hdmwork/

Third Edition of the workshop on Multi-Higgs Models

All Welcome!

The end – thank you for your attention!

What kind of A - > hZ?

• “A” mass close to maximum production rate (but can be higher);
• small tanβ, close to one;
• cos (β-α) ≈ 0; but A->hZ width is proportional to cos2(β-α) and so total width has

to be small as well.

What kind of A - > hZ?

Maximum enhancement for small values of the total width;

Experimental - not considered

SM – 3.4σ deviation Type II Type X,Y Type I For most of the parameter space 2HDM=SM

 LEP

(Model X)

 B factories H-

Models II and Y Best available bound on the charged Higgs mass

Experimental constraints on the charged Higgs mass

Any

Experimental (LHC)

pp →t t →b bW +H − mt tanβ mb tanβ BR(H − →τν )

Corrected for

ATLAS-CONF-2013-090

I II Y X tanβ 4.3 6.4 3.2 5.2

mH + = 90 GeV

All models

Experimental

Model II only

Vacuum Stability

Theoretical

Perturbative unitarity

Theoretical

• Trust perturbative calculations implies Higgs self-couplings λi

should not be too large.

• Simpler approach |λi| < λmax for i = 1, . . . , 5
• In this approach the most conservative choice is λmax = 4π

(|λiλj| < 16π2). Perturbativity

• O. Eberhardt, U. Nierste, M. Wiebusch, JHEP07(2013)118.

Estimate the dependence of the results on the “ultimately arbitrary upper limit λmax“ by showing results for λmax = 2π and λmax = 4π.

• D. Erikkson, J. Rathsman, O.Stahl, 2HDMC, Comput. Phys.
• Commun. 181 (2010) 189.

Perturbativity variants

Theoretical

0.2 0.4 0.6 0.8 1 sin(!-") 200 400 600 800 mH0 [GeV]

package

CKM

f i t t e r

• O. Eberhardt, U. Nierste, M.

Wiebusch (JHEP07(2013)118). Allowed region before the LHC

Theoretical

Allowed region before the LHC

Theoretical

No soft breaking term = strong constraint on tanβ

• B. Gorczyca, M. Krawczyk,

arXiv: 1112.5086, Z2 symmetric potential

• sin(β – α) < 0.5 excluded at 2σ – deviations of the light Higgs couplings to gauge

bosons relative to the SM’s.

• For sin(β – α) < 0.8, tanβ < 4 – large tanβ only close to sin(β – α) = 1. This is a major

difference relative to type I models.

• A zoom on the allowed region together with limits will again show the difference

between ATLAS and CMS.C

sin(β + α) = 1 SM-like limit sin(β - α) = 1

E X C L U D E D E X C L U D E D

Blue- passed all pre-LHC constraints Yellow – ATLAS 1σ Red – ATLAS 2σ Blue- passed all pre-LHC constraints Yellow – CMS 1σ Red – CMS 2σ

Resonant gg -> H -> H+H- Lines start and end abruptly due to the theoretical constraints – these do not change with time.

sin(β − α) ≈1

Fraction of points originating in chain that passed all constraints previously

• described. Besides we have forced the points to have values of total RXX (for

the lightest Higgs h) within 20% of SM prediction. The maximum fraction is mainly obtained for maximum values of A and H production.

H → hh

A → hZ

;A

Largest contributions comes from A -> hZ and H -> hh.

R

γγ = cosα

sinβ ⎛ ⎝ ⎜ ⎞ ⎠ ⎟

2 BR2HDM (h →γγ)

BRSM (h →γγ)

The simplest example is to take model type I and consider that the production

• ccurs only via gluon-gluon fusion

RZZ ≈ sin2(β − α)

RZZ → 1 SM - like limit

BR now depends on sinα, tanβ, charged Higgs mass and its coupling to neutral scalars. R

γγ =σ2HDM (pp →h) × BR2HDM (h →γγ)

σSM (pp →h) × BRSM (h →γγ) In type II even gluon fusion has a different factor in the top and in the bottom loop – with different QCD corrections. Higlu was used for gg and bb@nnlo for bb.

if h → bb dominates

What do we compare to data?

• sin(β – α) < 0.5 excluded at 2σ – deviations of the light Higgs couplings to gauge

bosons relative to the SM’s.

• As long as sin(β – α) is in the allowed region, large values of tanβ are also allowed.
• In type I, RXX tend to be close to or below 1. That is why there are no red points

in the ATLAS plot and the yellow points are the ones closer to the SM-like limit in the CMS plots.

SM-like limit sin(β - α) = 1

E X C L U D E D E X C L U D E D

Colour code changed Blue- passed all pre-LHC constraints Yellow – ATLAS 1σ Red – ATLAS 2σ Colour code changed Blue- passed all pre-LHC constraints Yellow – CMS 1σ Red – CMS 2σ