Lilith: A new tool for constraining new physics from Higgs...

Lilith:A new tool for constraining new physics

from Higgs measurements

1

Béranger Dumont(CTPU-IBS, Daejeon)

in collaboration with J. Bernon (LPSC Grenoble)

manual and download at: http://lpsc.in2p3.fr/projects-th/lilith/

manual has also been submitted to arXiv(will be announced on Tuesday)

February 14, 2015

http://lpsc.in2p3.fr/projects-th/lilith/

HPNP2015 Béranger Dumont February 14, 2015 2

Introductionin every Higgs search, ATLAS and CMS measure

if 1) signal is made of processes that exist for the SM Higgs, i.e. if II) acceptance times efficiency is the SM one: if II) (simple rescaling of the SM Higgs signal)

→ "signal strength framework"→ allows for a global fit to the Higgs data combining all measurements

our goal: constrain new physics from Higgs data using signal strength measurements

µ =� ⇥A⇥ "

[� ⇥A⇥ "]SM

Xµ Y µ

[courtesy of J. Bernon]

(A⇥ ")X,Y = [(A⇥ ")X,Y ]SM

� =X

X,Y

�(X)BR(H ! Y )

HPNP2015 Béranger Dumont February 14, 2015

ττ,ZZ*,WW*,γγ

ggF+ttHµ

-2 -1 0 1 2 3 4 5 6ττ

,ZZ*

,WW

*,γγ VB

F+VH

µ-2

0

2

4

6

8

10 Standard ModelBest fit68% CL95% CL

γγ →H 4l→ ZZ* →H

νlν l→ WW* →H ττ →H

PreliminaryATLAS -1Ldt = 4.6-4.8 fb∫ = 7 TeV s

-1Ldt = 20.3 fb∫ = 8 TeV s

= 125.5 GeVHm

3

Higgs signal strengths

µ =X

X,Y

e↵X,Y�(X)B(H ! Y )

�SM(X)BSM(H ! Y )

µ0 5 10 15

8 Te

V7

TeV

H multijetttH leptonttVH dijetVH MET

VH loose lVH tight l

VBF dijet 2VBF dijet 1VBF dijet 0

Untagged 4Untagged 3Untagged 2Untagged 1Untagged 0

H tagsttVH dijetVH MET


VBF dijet 1VBF dijet 0

Untagged 3Untagged 2Untagged 1Untagged 0

0.23−0.26+ = 1.14

combinedµ

= 124.7 GeV ]H

[ m

(7 TeV)-1 (8 TeV) + 5.1 fb-119.7 fbCMS γγ →H

σ 1 ±combined

σ 1 ±per-channel

VS

µ(X,Y ) ⌘ �(X)B(H ! Y )

�SM(X)BSM(H ! Y )

μ category per category fundamental production modesunfolded from the results

requires information on efficienciesand individual μ for each category

takes all correlations into accountfor a given decay mode

HPNP2015 Béranger Dumont February 14, 2015

ττ,ZZ*,WW*,γγ

ggF+ttHµ

-2 -1 0 1 2 3 4 5 6ττ

,ZZ*

,WW

*,γγ VB

F+VH

µ-2

0

2

4

6

8

10 Standard ModelBest fit68% CL95% CL

γγ →H 4l→ ZZ* →H

νlν l→ WW* →H ττ →H

PreliminaryATLAS -1Ldt = 4.6-4.8 fb∫ = 7 TeV s

-1Ldt = 20.3 fb∫ = 8 TeV s

= 125.5 GeVHm

3

Higgs signal strengths

µ =X

X,Y

e↵X,Y�(X)B(H ! Y )

�SM(X)BSM(H ! Y )

µ0 5 10 15

8 Te

V7

TeV

H multijetttH leptonttVH dijetVH MET


VBF dijet 2VBF dijet 1VBF dijet 0

Untagged 4Untagged 3Untagged 2Untagged 1Untagged 0

H tagsttVH dijetVH MET


VBF dijet 1VBF dijet 0

Untagged 3Untagged 2Untagged 1Untagged 0

0.23−0.26+ = 1.14

combinedµ

= 124.7 GeV ]H

[ m

(7 TeV)-1 (8 TeV) + 5.1 fb-119.7 fbCMS γγ →H

σ 1 ±combined

σ 1 ±per-channel

VS

µ(X,Y ) ⌘ �(X)B(H ! Y )

�SM(X)BSM(H ! Y )

μ category per category fundamental production modesunfolded from the results

requires information on efficienciesand individual μ for each category

takes all correlations into accountfor a given decay mode

primary input in Lilith


Overview of Lilith

Lilith is a new, user-friendly public tool made in Pythonfor constraining BSM scenarios from Higgs measurements

manual and download at: http://lpsc.in2p3.fr/projects-th/lilith/(light likelihood fit for the Higgs)

‣ experimental results are stored in a flexible XML database, easy to modify and extend. can take any Higgs results given in terms of signal strengths as input

‣ model can be parametrized in terms of reduced couplings or signal strengths directly

‣ evaluation of the Higgs likelihood can be done using1. the Python interface,2. the command-line interface, or3. the C/C++/ROOT interface



XML experimental input

WHµ

-1 0 1 2 3 4

ZHµ

-1

0

1

2

3

4Best Fit68% CL95% CLSM Higgs boson

CMS-1 = 7 TeV, L = 5.0 fbs

-1 = 8 TeV, L = 18.9 fbs=125 GeVH, mb b→ VH; H →pp

[CMS-HIG-13-012, arXiv:1310.3687]

parametrization of thebivariate normal distribution

‣ all available ATLAS and CMS results are included in the database of experimental resultsfor H→ɣɣ, H→ZZ→4ℓ𝓁, H→WW→2ℓ𝓁2ν, H→𝜏𝜏, H→bb (incl. all searches for ttH prod.) also VBF→invisible and ZH→invisible (and Tevatron VH→bb)

‣ database of results made of XML files. one example:


XML user input: reduced couplingsL = g

CWmWWµWµ + CZ

mZ

cos ✓WZµZµ

�H

+ g

�Ct

mt

2mWt¯t� Cb

mb

2mWb¯b� Cc

mc

2mWcc̄� C⌧

m⌧

2mW⌧ ⌧̄

�H

(multi-particle labels can also be defined: "VV" for "WW" and "ZZ", etc.)

to compute scaling factors forgg→H, H→ɣɣ, etc. incl. QCD corrections (using HIGLU & HDECAY)

in order to treat gg→H, H→ɣɣ, etc. as free parameters(if BSM particles enter the loop process)

in order to specify invisible/undetected decays(invisible = MET undetected = simply missed by searches)also:

‣ CP-violating fermion couplings can be defined‣ a arbitrary number of Higgs states can be defined (if more than one Higgs around 125 GeV)


XML user input: signal strengths

µ(X,Y ) ⌘ �(X)B(H ! Y )

�SM(X)BSM(H ! Y )

=�(X)

�SM(X)Binvisible

("VVH" is a shortcut for "VBF", "WH", "ZH")


How to run Lilith‣ Python interface:‣ we provide and document

a series of methodsto perform all tasks

‣ can easily be used in anyPython script

‣ Command-line interface:‣ simple way to run Lilith

from a shell

‣ we provide XML and SLHA output of the results

‣ C/C++/ROOT interface:‣ we provide and document a series of functions to perform the common tasks‣ a simple working example is shipped with Lilith


Validation: ATLAS‣ need to validate the approximate Higgs likelihood used in Lilith

‣ we perform the same coupling fits as ATLAS and CMS and compare the results


Validation: CMS‣ need to validate the approximate Higgs likelihood used in Lilith

‣ we perform the same coupling fits as ATLAS and CMS and compare the results


Example 1: coupling fits‣ a full example of coupling fit is shipped with Lilith: (CV,CF) benchmark scenario

‣ very little effort using‣ the Python interface of Lilith‣ the Python version of MINUIT (iminuit)‣ matplotlib for plotting


Example 2: constraints on staus‣ SUSY partners of the tau lepton

can change the H→ɣɣ rate, if light

‣ we use the full 1-loop formula:

‣ this full example is shipped with Lilith

‣ for just above the LEP limit: Higgs results comparable with theconstraint from vacuum metastability

⌧̃1

C� =|MSM

H�� +M⌧̃H��(m⌧̃1 ,m⌧̃2 , ✓⌧̃ , tan�)||MSM

H�� |

[Endo, Kitahara,Yoshinaga '14]


Conclusions

‣ Lilith is a new public tool for applying the Higgs constraintson a wide class of new physics modelswritten in Python, interface with C/C++/ROOT

‣ you can download the code and the manual at http://lpsc.in2p3.fr/projects-th/lilith/(to appear on Tuesday on arXiv) several examples are shipped with the code

‣ more information will be needed from ATLAS and CMS at Run II:- correlations between systematic uncertainties will be a more pressing issue- multi-dimensional (> 2D) likelihood information will become necessary- communication with experimental collaborations is essential



backup slides


Status as of today

‣ excellent agreement with the SM predictions(both ATLAS and CMS H→ɣɣ results moved towards the SM)

[Bernon, BD, Kraml,arXiv:1409.1588]

global coupling fit using the latest results

CU

CV

Lilith 1.0 CU, CD, CV

mH=125.5 GeV 0.6

0.8

1

1.2

1.4

0.6 0.8 1 1.2 1.4

includes all resultsas of September

CU

CD


mH=125.5 GeV 0.6

0.8

1

1.2

1.4

0 0.5 1 1.5 2

Cg

Ca


mH=125.5 GeV 0.6

0.8

1

1.2

1.4

0.6 0.8 1 1.2 1.4

PhD thesis defense Béranger Dumont September 24, 2014 16

Status as of today: invisible decays

‣ global fit with invisible decays, under different assumptionson the couplings

‣ width effects in global fit more constraining than direct searchesfor invisible decays(if CV<1, i.e. no flat direction)

2σ

‣ if i. invisible = dark matterii. dark matter interacts only

via the Higgs (Higgs portal)

‣ then: upper bound on invisible decays⇔ upper bound on σSI

10 20 30 40 50 6010

−46

10−45

10−44

10−43

XENON100

LUX

0.6

0.4

0.2

0.1

mχ (GeV)

σSI(cm

2)

10 20 30 40 50 6010

−46

10−45

10−44

10−43

0.6

0.4

0.2

0.1

mφ (GeV)σSI(cm

2)

Majorana DM real scalar DM

[Bernon, BD, Kraml, arXiv:1409.1588; Bélanger, BD, Ellwanger, Gunion, Kraml,

arXiv:1302.5694, arXiv:1306.2941]

๏ SM ๏ CU,CD,CV<1

๏ Cg,Cɣ ๏ CU,CD,CV

๏ CU,CD,CV,Cg,Cɣ

PhD thesis defense Béranger Dumont September 24, 2014 17

Extended Higgs sectors

tan(`)

cos(`-_)

Lilith 1.0 Type II 2HDM

mh=125.5 GeV

0.1

1

10

-0.2 0 0.2 0.4 0.6

tan(`)

cos(`-_)

Lilith 1.0 Type I 2HDM

mh=125.5 GeV

0.1

1

10

-1 -0.5 0 0.5 1

one example: Two Higgs Doublet Models of Type I and IIsimple 2D parameterization (α,β) of the couplings

Type I and II Type I Type IIHiggs CV CU CD CU CD

h sin(� � ↵) c↵/s� c↵/s� c↵/s� �s↵/c�H cos(� � ↵) s↵/s� s↵/s� s↵/s� c↵/c�A 0 cot� � cot� cot� tan�

[Bernon, BD, Kraml,arXiv:1409.1588]

‣ Type I: large deviations froman SM-like Higgs are possible for tan(β)≳1

‣ Type II: 2nd branch with CD≈−1 is still allowed[see also Ferreira, Santos, Gunion, Haber, arXiv:1403.4736]

CD≈−1

(h is assumed to bethe observed Higgs boson)

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