Higgs & BSM: Lessons from lHC so far ... -...

BSM & Higgs: Lessons from lHC so far?. Rohini M. Godbole

Higgs & BSM: Lessons from lHC so far!

Rohini M. Godbole

Centre for High Energy Physics, IISc, Bangalore, India

CHEP, IISc, Bangalore March 10, 2012


1 Introduction

2 Expectations for the Standard Model (SM) Higgs.

3 Experimental reasons and Theoretical motivations for

going beyond the SM (BSM).

4 Two ways of being BSM:SUSY and Extra Dimensions

5 What does the current information (from 7 TeV

lHC) tell us? Subtle is the Nature! Is she Malicious ?

We dont know yet!

6 Search for BSM through the Higgs,flavour portal?!.



Refs.:

1)R.M. Godbole and A. Djouadi, hep-ph/0901.2030, in ’Physics at the LHC’

2)S. Dittmaier et al., “Handbook of LHC Higgs cross sections”, arXiv:1101.0593[hep-ph], arXiv:1201.3084[hep-ph]

3)Implications of BSM for Higgs searches at the LHC: D. Vasquez et al, In lesHouches report (to be uploaded in a day or two on the arxives) and referencestherein.

4)D. Albornoz Vasquez, G. Belanger, R. M. Godbole and A. Pukhov, hep-ph/1112.2200.

5)D. Choudhury, R. M. Godbole and P. Saha, arXiv:1111.1054 [hep-ph]

—————————

6)J. Elias-Miro, J. R. Espinosa, G. F. Giudice, G. Isidori, A. Riotto and A. Strumia,

[arXiv:1112.3022 [hep-ph]].


BSM & Higgs: Lessons from lHC so far?. State of play in HEP (pre) LHC.

The field of High Energy Physics (HEP) had been in a strange situ-

ation.

The usual road through which Science progresses:

Existing Theory and Unexplained Phenomena ⇒New Theoretical developments ⇒ Predictions ⇒

Testing in Experiments.

State in HEP for the past decade or so

Existing Theory No Unexplained Phenomena!,

demands made by the Community on the properties

of a theory ⇒ New Theoretical Developments ⇒Predictions ⇒ Testing in Experiments.



We have had strong theoretical reasons to believe that

there is new physics at ∼ TeV scale, Did not have any

strong experimental evidence indicating its need AT THE

TEV SCALE.

The track record of particle physicists had been pretty

good so far and theoretical developments based on de-

mands of aesthetics alone have been fruitful at getting at

the root of fundamental questions.

BUT



The gap between theory and experiment had never been

so large!

When we said we expected new physics at the TeV scale

how sure could we theorists be of the prefactor before the

TeV. How big or small can it be?.

We expected the world from LHC: (a multi TeV collider)

would help unravel the mystery.

Data from LHC have started coming, time of reck-

oning has arrived!CHEP, IISc, Bangalore March 10, 2012


Generalities:

The SM Lagrangian consists of ’proved’ gauge sector and

yet to be proved scalar sector:

L = − 1

4F aµνF

aµν + iψ 6Dψ+ ψTλψh+ h.c.

+ |Dµh|2 − V (h)

Gauge sector in good shape.CHEP, IISc, Bangalore March 10, 2012

BSM & Higgs: Lessons from lHC so far?. Gauge sector

The beginning of the spell of the gauge principle cast

by QED is made much stronger with Non Abelian Gauge

Field Theories with Spontaneous Symmetry Breaking and

without symmetry breaking

But no direct evidence yet exists for the last piece of

the Gauge Paradigm : the scalar sector! What is the

experimental information on it?


BSM & Higgs: Lessons from lHC so far?. Reminder of things old

Unitarity:

The existence of the Higgs boson with precisely the same

interactions as predicted in the SM can also be inferred

by simply demanding that the scattering amplitudes for

W+W− → W+W− etc. satisfy unitarity. (Tiktopoulos,

Cornwall; Joglekar..)

The arguments simply tell that there should be a ’S-wave’

contribution to the scattering amplitude which will tame

the bad high energy behaviour and hence restore unitarity.


BSM & Higgs: Lessons from lHC so far?. Reminder of things old

Only a rough idea on the scale of this high energy ULTRA-

violet ’completion’ of the theory.

Some of the modern ’avatar’s of these ideas :

Dynamical Symmetry breaking: running technicolour, Non-linearly realised symmetry breaking , unitarisation via spin1 particles.


BSM & Higgs: Lessons from lHC so far?. SU(2) × U(1) directly tested!

Direct ’Proof’ of Symmetry and Symmetry breaking!!

√s

[GeV]

σ(e

+ e− →

W+ W

− (γ))

[

pb

] LEP

only νe exchange

no ZWW vertex

GENTLE

YFSWW3

RACOONWW

Data

√s

≥ 189 GeV: preliminary

0

10

20

160 170 180 190 200

Proof that electroweak symmetry

exists and that it is broken.

The triple gauge boson ZWW

coupling tames the bad high

energy behaviour of the cross-

section caused by the t-channel

diagram. Direct proof for the

ZWW coupling.

This and precision testing, con-

firm basics of the SM


BSM & Higgs: Lessons from lHC so far?. Constraints from EWPT

Measurement Fit |Omeas−Ofit|/σmeas

0 1 2 3

0 1 2 3

∆αhad(mZ)∆α(5) 0.02750 ± 0.00033 0.02759

mZ [GeV]mZ [GeV] 91.1875 ± 0.0021 91.1874

ΓZ [GeV]ΓZ [GeV] 2.4952 ± 0.0023 2.4959

σhad [nb]σ0 41.540 ± 0.037 41.478

RlRl 20.767 ± 0.025 20.742

AfbA0,l 0.01714 ± 0.00095 0.01645

Al(Pτ)Al(Pτ) 0.1465 ± 0.0032 0.1481

RbRb 0.21629 ± 0.00066 0.21579

RcRc 0.1721 ± 0.0030 0.1723

AfbA0,b 0.0992 ± 0.0016 0.1038

AfbA0,c 0.0707 ± 0.0035 0.0742

AbAb 0.923 ± 0.020 0.935

AcAc 0.670 ± 0.027 0.668

Al(SLD)Al(SLD) 0.1513 ± 0.0021 0.1481

sin2θeffsin2θlept(Qfb) 0.2324 ± 0.0012 0.2314

mW [GeV]mW [GeV] 80.385 ± 0.015 80.377

ΓW [GeV]ΓW [GeV] 2.085 ± 0.042 2.092

mt [GeV]mt [GeV] 173.20 ± 0.90 173.26

March 2011

see http://lepewwg.web.cern.ch

• All the current experiments

have tested the perturbative pre-

dictions of the Standard Model

(SM) to an unprecedented

accuracy.

• May be holds also some clues

of Physics beyond the SM

• Meaning for the Higgs?


BSM & Higgs: Lessons from lHC so far?. Meaning for the Higgs?

[GeV]HM

50 100 150 200 250 300

2χ

∆

0

1

2

3

4

5

6

7

8

9

10

LE

P 9

5%

CL

Tevatr

on

95%

CL

σ1

σ2

σ3

Fit and theory uncertainty

Fit including theory errors

[GeV]HM

50 100 150 200 250 300

2χ

∆

0

1

2

3

4

5

6

7

8

9

10

G fitter SM

No

v 1

0

0

1

2

3

4

5

6

10040 200

mH [GeV]

∆χ2

LEPexcluded

LHCexcluded

∆αhad =∆α(5)

0.02750±0.00033

0.02749±0.00010

incl. low Q2 data

Theory uncertaintyMarch 2012 mLimit = 152 GeV



MH [GeV]

March 2012

ΓZΓZ

σhadσ0

RlR0

AfbA0,l

Al(Pτ)Al(Pτ)

RbR0

RcR0

AfbA0,b

AfbA0,c

AbAb

AcAc

Al(SLD)Al(SLD)

sin2θeffsin2θlept(Qfb)

mWmW

ΓWΓW

QW(Cs)QW(Cs)

sin2θ−−(e−e−)sin2θMS

sin2θW(νN)sin2θW(νN)

gL(νN)g2

gR(νN)g2

10 102

103



W-Boson Mass [GeV]

mW [GeV]80 80.2 80.4 80.6

χ2/DoF: 0.1 / 1

TEVATRON 80.387 ± 0.017

LEP2 80.376 ± 0.033

Average 80.385 ± 0.015

NuTeV 80.136 ± 0.084

LEP1/SLD 80.362 ± 0.032

LEP1/SLD/mt 80.363 ± 0.020

March 2012

80.3

80.4

80.5

155 175 195

LHC excluded

mH [GeV]114 300 600 1000

mt [GeV]

mW

[G

eV] 68% CL

∆α

LEP1 and SLD

LEP2 and Tevatron

March 2012


BSM & Higgs: Lessons from lHC so far?. Theory limits on the mH ?

Does the SM have anything to say

about what the Higgs mass should

be?

Theory predicts the interactions of

the Higgs boson, BUT is completely

silent about its mass.

Note : Just the mass of the Higgs

when observed can give nontrivial

indication on the BSM physics!

A heavy Higgs ( >∼ 300 GeV) would

have meant new physics around a

few TeV.

A ’light’ higgs hope for BSM?Riessleman and Hambye



GeV) / Λ(10

log4 6 8 10 12 14 16 18

[G

eV

]H

M

100

150

200

250

300

350

LEP exclusionat >95% CL

Tevatron exclusion at >95% CL

Perturbativity bound Stability bound Finite-T metastability bound Zero-T metastability bound

error bands, w/o theoretical errorsσShown are 1

π = 2λπ = λ

GeV) / Λ(10

log4 6 8 10 12 14 16 18

[G

eV

]H

M

100

150

200

250

300

350

G. Giudice et al. (Giudice et al updated after December 13: 1112.3022)



What does it all mean for the Higgs?

If all the current information is put together the Higgs mass should

be less than 152 GeV. (indirect experimental limit!)

• Direct limit on the SM higgs mass is 114 GeV.

• ’Indirect limit’ in the SM is 152 GeV.

In the SM, 115 < mH < 150 GeV. (Experimental limits: 95% C.L.)

• If SM is all that we have all the way to the Planck scale, 130 <

mh < 180 GeV (theoretical)


BSM & Higgs: Lessons from lHC so far?. What do we learn?

Lessons:

• The EW precision data like a light higgs.

• ANY discussion of alternate scenarios of symmetry break-

ing MUST always pass the precision test.

• Various theoretical considerations bound the Higgs mass.

• If mh > 700/800 GeV then our understanding of EWsymmetry breaking, based on perturbative ideas is not cor-rect.


BSM & Higgs: Lessons from lHC so far?. Lessons slide: pre LHC!

• Models where the direct and indirect experimental Higgs mass bound

can be violated quite often predicts new particles which should have

shown OR still may show up at the LHC. Interplay between interpre-

tation of Higgs and BSM searches.

• Need to keep an open mind and open eye.


BSM & Higgs: Lessons from lHC so far?. LHC mission?

LHC mission is to understand the mechanism of the EWSB.

Various BSM ideas have been suggested to address what we think are

esthetically nonpleasing issues.

Direct searches for this BSM physics have been on & with neagtive

results so far!

Recall: The properties of Higgs sector can get affected by the

BSM physics.

May be the clues to BSM physics are to be had more subtly (indi-

rectly)than through direct searches?

After all recall flavour physics K-meson mixing or B-meson mixing

gave clues of higher scale physics!


BSM & Higgs: Lessons from lHC so far?. Flavour sector

Last decade great progress in the flavour sector:

The correctness of CKM picture, Excellent results from B-factories

now augmented with LHCb, ν oscillations...

SM needs to be augmented by

L′ =1

MLiλ

νijLjh

2 and/orLiλνijNjh+ h.c. (1)

Neutrinos are special in that they are neutral and many new physics

ideas have implications for neutrino mass generation which can in

principle be different from other fermions. (Beyond standard model..)


BSM & Higgs: Lessons from lHC so far?. Observational motivations for BSM?

1] Neutrinos have nonzero masses and the fermion masses have a

huge hierarchy

SM has bearing on issues cosmological and needs BSM physics as

well.

2]. The contents of our periodic table seem to account for ONLY

4% of the matter in the Universe! Astrophysical evidence pretty con-

vincing. Dark Matter: exptal information indicates a BSM particle

3] A qualitative explanation of the Baryon-Antibaryion asymme-

try in the Universe, in terms of known CP violation in the SM,

measured in laboratory, is possible. A quantitative explanation indi-

cates need of BSM physics.


BSM & Higgs: Lessons from lHC so far?. Esthetic/theoretical reasons!

Then there are esthetic/theoretical reasons motivated by the experi-

mental information on the Higgs mass!

The fact that SM works so well means

1) a Higgs OR a look alike must exist and data tell us it must be

light!

2) We should also understand why it is light!! Loop corrections will

always push it to the maximum mass in the theory.

This is one reason for expecting physics beyond the Standard Model!!


BSM & Higgs: Lessons from lHC so far?. Why light elementary Higgs means BSM?

The hierarchy problem:

The EW theory has been tested at 1-loop level. The Higgs mass which

is a free parameter in the SM, receives large quantum corrections and

the mass will approach the cutoff scale of the theory.

If, m2h = m2

bare + δm2h the top loop (e.g.) gives

δm2h|top ∼ − 3GF

2√

2π2m2t Λ

2 ∼ −(0.2Λ)2.

The light higgs is ’natural’ then only if Λ ∼ TeV.


BSM & Higgs: Lessons from lHC so far?. Other than keeping Higgs light??

A little more ’experimen-

tally’ motivated hint for

BSM?:

• Do strengths of all the

interactions unify at some

high energy?

• with Supersymmetry (still

to be discussed) there is

some evidence that they

might.

• Models to explain observed

mass patterns, all like uni-

fied models.


BSM & Higgs: Lessons from lHC so far?. Is SM the whole truth?

Is that the whole truth? Is this a time for a paradigm shift?

Are Quantum Field Theories sort of a ’low energy’ paradigm?. Can

we combine gravity somewhere in the picture?


BSM & Higgs: Lessons from lHC so far?. Reasons for BSM

• Dark Matter makes up 23% of the Universe.!

• Direct evidence for the nonzero ν masses

• Quantitative explanation of the Baryon Asymmetry in the Universe!

—————————————————————————–

• Instability of the EW scale under radiative correc-tions.

• Need to get a basic understanding of the flavour Issue

• Unification of couplings

• Inclusion of Gravity in the picture?


BSM & Higgs: Lessons from lHC so far?. Keep the Higgs light?

We know at present two ways to keep the Higgs ’naturally’ light:

1] Introduce a symmetry:

Supersymmetry : cancel the large top loop contribution by contribu-

tions from scalars. There exist host of new particles which we should

see at the colliders, around TeV scale.

OR

Little Higgs models: The Higgs mass is small because its mass is pro-

tected as it is a pseudo goldstone boson. There exist many additional

fermions, gauge bosons in the theory at the TeV scale.


BSM & Higgs: Lessons from lHC so far?. Cutoff theories!

2] The cutoff is lowered to TeV:composite models and brane-worlds.

Brane Worlds postulate behaviour of the space and time different

from what we understand, such as additional compactified dimen-

sions! new developments: String theories havegs begun to make

some statements about such models!

3]Higgsless models/Light composite Higgs?

Little Higgs or Higgsless models can have problem passing the

acid test of LEP precision measurements and one has to work

hard. Issues of ultraviolet completions are sometimes solved by

reintroducing a high scale (much above a TeV scale) Super-

symmetry.


BSM & Higgs: Lessons from lHC so far?. Superparticles

Associated with every particle

there is a supersymmetric partner!

For it to solve the problems we

need the partners to have a mass

M such that Mc2 < 1000 GeV We

see no evidence for superpart-

ners in current experiments!

No clue for SUSY breaking mech-

anisms and scale! String theory

based ideas might give some di-

rections!

Combining SUSY with unification

is the most natural and also nec-

essary.


BSM & Higgs: Lessons from lHC so far?. Virtues of SUSY!

Theoretically extremely elegant and attractive: Spacetime symmetry,

finite ultraviolet behaviour.

Eqally important: As we saw the data seem to like a light Higgs.

But the Higgs is not ’soo’ naturally light unless sparticle masses

are small.

A ready made DM candidate in case of R-parity conservation.


BSM & Higgs: Lessons from lHC so far?. BUT....

However:

It is clearly broken. ALL the experiments have so far only given

NEGATIVE results, giving LOWER limits on sparticle masses.

The symmetry is beautiful, the ideas of how to break it are mostly

not!


BSM & Higgs: Lessons from lHC so far?. Score card for SUSY?

Keeps the Higgs light ’naturally’ ! But sparticle should not be too

heavy. What is ’too heavy’? When should we be worried?

Predictive: Higgs mass limits, quite robust with respect to SUSY

breaking parameters.

WIMP miracle happens easily. Ready made DM candidate. But in

CMSSM again it is now under great scrutiny. Good point: predictive

in a given model.

Baryogenesis works. Requires NMSSM and/or additional CP viola-

tion.


BSM & Higgs: Lessons from lHC so far?. Score card for SUSY?

Can address ν masses, but requires R-parity violaton.

Flavour physics: SUSY has no neat solution. B physics measurements

put it under strain in fact.

Local supersymmetry : Supergravity contains automatically Einstein

Gravity.

String theory requires Supersymmetry, BUT REMEMBER NOT TEV

scale Supersymmetry.


BSM & Higgs: Lessons from lHC so far?. Questions to SUSY?

Question:

1)Should we be worried now with the newer exclusions from CMS/ATLAS?

Is it still ’natural’? In T. Huxley’s words will SUSY be a great

tragedy of science: ’A beautiful theory slain by an ugly fact?’

2) Consistency between the DM experiments and LHC experiments?

3) What are the best ways of proving/disproving the idea given the

current CMS/ATLAS results?


BSM & Higgs: Lessons from lHC so far?. Xtra dim : questions

a How many extra dimensions?

b What is the size of the Xtra dimensions? What is the ’size’ of

the bulk? (’large’ extra dimesions, TeV−1 dimensions)

c What is the geometry of the additional dimensions? (warped or

otherwise?) (Randall Sundrum and many variations thereof)

d Which particles propagate into the bulk?

e Symmetries that the KK spectrum has (Universal Extra Dimen-

sion: UED)


BSM & Higgs: Lessons from lHC so far?. The good and the bad

• Interesting flavour physics model building possible in RS picture.

• KK parity gives DM candidate.

• None of the models is completely free from fine-tuning. RS the best

and hence the template of almost all the ED phenomenology these

days.

• Predictions for collider signals in some cases depend on the Ultra-

violet completion of the theories. Counterpart of uncertainties about

SUSY breaking (to some extent). In general less predictive than

SUSY.

• EWPT not always easy.

• Does not address the different reasons for BSM as well as SUSY.


BSM & Higgs: Lessons from lHC so far?. Experimental info?

Currently we only have limits on sparticle masses (for givenSUSY breaking scenarios) or on the scale Λ of the extradimensional theories.


BSM & Higgs: Lessons from lHC so far?. Higgs and BSM searches at the LHC

Few facts about the Higgs.


BSM & Higgs: Lessons from lHC so far?. Production processes

(p)p

(p)p

Hg

g

H1

H2

q

q(q′)Z∗(W ∗)

Z(W )

H

H1

H2

q q′

q q′W

Wh

H1

H2

q q

q q

Z

Zh


BSM & Higgs: Lessons from lHC so far?. Effect of SUSY

Effects of SUSY on h decay and production

• Sfermions: squarks and sleptons. again the most relevant are the t1, t2

• The chargino and neutralinos: χ±l , χ

0l .

• SUSY changes the couplings of the h with matter fermions and gauge bosonsmostly upto mixing angles.

• The sfermion loops give additional contributio to ggh and γγh coupling. Themixing between L–R stops and interference between the t–t loops can affect ggh,γγh coupling substantially.

• The LEP limits on sfermion masses ⇒ tree level decays of h into sfermions andchargino pairs not possible.

• MSSM assumes unification of gaugino masses. If it is relaxed no strong LEP limit

on χ01 mass. and h→ χ0

1χ01 is possible. χ0

1 is LSP and is ’invisible’ to our detectors.

Thus can decrease B.R. (h→ γγ) AND have ’invisible decay modes.


BSM & Higgs: Lessons from lHC so far?. Cross sections

pp! ttHqq ! ZHqq !WHqq ! Hqqgg ! H mt = 178 GeVMRST/NLOps = 14 TeV(pp! H +X) [pb

MH [GeV 1000100100

101

0.1At the LHC the most dominant

is the gg fusion, followed byHqq

production via V V fusion and

then the associated WH/ZH.

General wisdom:

Lower energies (14 to 10)

means losss of gg luminosity by

1/2. Increase from 7 to 8,

means 20% increase in cross-

section

In the low luminosity and low

energy option, only the heavier

higgs with detection in V V (V ∗)final state possible.


BSM & Higgs: Lessons from lHC so far?. Profile of the SM higgsZ

ttZZWW

ggss

bb

BR(H)

MH [GeV 10007005003002001601301001

0.10.01

0.0010.0001

MH<∼ 130 GeV, ΓH → bb ≃ 90%,

for cc , τ+τ− and gg ≃ 5% with

γγ ≃ 10−3. For ”higher” mass

case WW and ZZ dominant decay

modes sharing 2/3 and 1/3 width.

General wisdom: For light Higgs

use γγ mode and for heavier Higgs

use V V (V ∗) mode. Recently

methods using jet substructure

(Butterworth et al) mean bb

mode usable for a light Higgs.

Width: The total width is about 1

GeV at ZZ threshold and becom-

ing ≃MH at large MH.


BSM & Higgs: Lessons from lHC so far?. Higgs and BSM searches at LHC.


BSM & Higgs: Lessons from lHC so far?. A typical process


BSM & Higgs: Lessons from lHC so far?. What did theorists do?

A lot of work over the past decades done by a lot of people:

1) Hpw to predict reliably what the detectors should see and make

sure we dont calibrate away the signal!

1)How to compute the expected particle spectra for a given SUSY

breaking scenario

2) How to compute expected cross-sections for sparticle production

3)What are ’tell tale’ final states and signatures for different SUSY

models. That needs to be used once the experimentalists tell us if

they have seen any events above the background.


BSM & Higgs: Lessons from lHC so far?. Lessons from LHC so far?

First the Higgs, pre December 13!


BSM & Higgs: Lessons from lHC so far?. What does it tell already?


BSM & Higgs: Lessons from lHC so far?. The latest from LHC?


BSM & Higgs: Lessons from lHC so far?. Zoomed in ’low’ region


BSM & Higgs: Lessons from lHC so far?. More about data






BSM & Higgs: Lessons from lHC so far?. My take

Only concentrating on the low mass range:

Higgs mass range beyond 127 GeV is excluded for the SM at 95%

C.L. CMS CERN Seminar.

For smaller higgs masses exclusion not possible as there seems

to be ’some’ excess beyond the SM expectations.

Is it the Higgs? : Perhaps

Is it the statistical flctuation? : Possibility can not be ruled out with

the current luminosity.


BSM & Higgs: Lessons from lHC so far?. My take

1)Higgs heavier than 600(525) GeV allowed by lHC at 99%(99%) c.l.

still but in conflict with implications of EWPT.

2) Light Higgs : Situation tantalising. Not enough to claim a 5σ

signal, but still... Can we already take this to be ’indication’ for

BSM?

3) Theorists already started asking: Is this the SM Higgs?

4)What is the effect of BSM on Higgs production and decay?

Can one probe then the BSM through the ’Higgs’ portal?


BSM & Higgs: Lessons from lHC so far?. Next year

Experiments: Clear the picture for the Higgs

Theorists: Probe the BSM through the Higgs window!

Already within two weeks of CERN seminar there were at least two

dozen papers exploring this. Two ways:

One way: Through the mass value itself: MSSM, CMSSM, .., Giudice

: vacuum instability bounds

Second way: effect on production and decays.

Some of us wrote the papers BEFORE the CERN results were out ,


BSM & Higgs: Lessons from lHC so far?. Higgs mass and MSSM

Higgs mass in MSSM is bounded, bound increasing due to radiative

corrections mainly coming from top. (Is there anything else that can

rleax this bound: NMSSM, BMSSM?)

MZ

MZ

mH>

mh<

mh<

Am

mH>


BSM & Higgs: Lessons from lHC so far?. Higgs mass and MSSM


BSM & Higgs: Lessons from lHC so far?. Higgs searches hold the key!

So really if the Higgs searches should rule out Existence of a light

Higgs below 125 GeV or so we would have ruled out a large number

of simple implementations of SUSY and SUSY breaking!

But ruling out a Higgs with mass above 130 GeV could be taken as

a weak indication of BSM, not necessarily at low scale!


BSM & Higgs: Lessons from lHC so far?. What are constraints on SUSY?

From the talk by Paul de Jong at APPS, Amsterdam, Dec. 2, 2011.


BSM & Higgs: Lessons from lHC so far?. What does this imply?

Theorists have

i) Analysed the effect of these data for the best fit to a variety of

all the other data such as (g − 2)µ, B → sγ, requiring that SUSY

gives the right amount of DM and analysed what region gives the

best fit to define the ’corner’ arund which SUSY is hiding once

again. (1109.3859v2, S. Sekmen et al: 1109.5119, A. Fowlie et

al: 1111.6098)

Will not discuss details of this.

ii) Discussed how much worse the fine tuning problem has become

Strumia: 1101.2195v1, Ellwanger et al.arXiv: 1107.2471

How significant is this? Will discuss later.



iii)What are ’natural’ sparticle mass spectra in light of new LHC ex-

clusion? Since the t1t1 x.section is much smaller than the first two

generation squarks, constraints are indeed weaker.

Lighter third generation squarks, lighter EWinos, 1.5 TeV g. In-

deed the ’corner’ where one should look for SUSY has changed.

After all ’naturalness’ requires only the third generation squarks

to be light and ’EW’inos to be light. (light means ∼< 1 TeV),

a few hundred GeV. Barbieri: talk at HCP, L. Hall

http://indico.cern.ch/getFile.py/access?contribId=7

&sessionId=2&resId=0&materialId=slides&confId=157244

For this particular spectra multi top final states can be a signal. Inci-

dentally such a scenario had meritted a page in ’good’ textbooks on

sparticles (,), So this is clearly not ’desperation days’



A nice analysis by B.Allanach and Ben Gripaios: With R parity vio-

lation (particularly Baryon number violating, the current data imply

only a limit of about 550 GeV on gluinos.

hep-ph/1202.6616v1

Also important to realise that we have looked under the lamp post

i.e. production of strongly interacting sparticles which is the highest

rate.

More dedicated searches for EW sparticles necessary.



My take: if one is very agnostic, take a view that SUSY spec-

tra has only those features which we require to ’address’ the

observational issues.

Check whether we have

1)a light neutralino, (one needs a chargino along with it), and 2)one

light stop state.

Handles the matter-antimatter asymmetry, as well as DM.

Is not sooo inconsistent with ’naturalness’ and keeps the Higgs light

without too much fine tuning, if the stop less than few hundred GeV.

With current data and that of 2012 (with 8 TeV) may be possible to

answer such questions as well.



iv) Effects of SUSY on Higgs searches:

Different production and decay modes get affected differently. As one

goes away from cMSSM the effects of SUSY on Higgs phenomenology

can be varied.

Obvious question: How will these effects change the strength of

’Higgs’ signal and what would be associated sparticle phenomenol-

ogy?

Utilise the correlation between ’diect’ searches and this ’indirect’ ef-

fect on Higgs sector to either rule out SUSY or find it !


BSM & Higgs: Lessons from lHC so far?. BMSSM

The new heavy supersymmetric spectra means that perhaps one

should consider an effective theory where these sparticles have been

integrated out. The higher order operators will improve fine tuning.

So essentially additional contribution to the Lagrangian. A special

case will be for example, NMSSM.

(Carena et al: Phys. Rev. 82, 1111.2049, Boudjema, G. Drieu la

Rochelle: 1112.1434)

Upper limit on the light higgs is relaxed from 131 GeV. Analysis where

the constraints from EWPT, experimental searches at Teavtron and

LHC, allow for light Higgs mass upto 150 GeV, for some points in

the scan going upto 180-200 GeV, but with reduced production!.

There can be regions with large ’invisible’ branching ratio for the

Higgs.


BSM & Higgs: Lessons from lHC so far?. Effects of SUSY.

Effects of SUSY

Three production channels:gg → h can be affected by SUSY strongly.gg → tth, qq′ → V h is not affected drastically.

Effects on decays:Γ(h→ γγ) not affected strongly.Decay into a LSP pair, when possible, can affect the B.R.(h→ bb) and B.R.(h→ γγ)strongly.

Define

Rggγγ = ΓSUSY (h→gg)×BRSUSY (h→γγ)ΓSM(h→gg)×BRSM(h→γγ)

.

Choose (M1/M2)EW = 1/5. Lighter χ01 than usually taken.

Define Bχχ = B.R.(h→ χ01χ

01)

Rbb, Rγγ are defined as ratios of the branching ratios for SUSY to that in the SM.

Rbb = Rγγ = 1 − Bχχ


BSM & Higgs: Lessons from lHC so far?. Effects of SUSY.

What does this mean for the discovery of h at the LHC

For mt ≃ mt the production c.section can become dangerously small to lose (signif-icance of) the h signal in γγ channel.

Even for large mt, for nonuniversal gaugino masses, large b.r. into ’invisible’ LSP’s

is possible.


BSM & Higgs: Lessons from lHC so far?. Invisible Higgs decays.

F. Boudjema and G. Drieu la Rochelle (1112.1434).


BSM & Higgs: Lessons from lHC so far?. MSSM

Albornoz Vasquez, Belanger, R.G.: (arXiv: 1112.2200 (Dec.9, 2011)

(Update of R.G., G. Belanger, F. Boudjema et al: NPB 581, 2000,

3)

Looked effects in MSSM, with reduced parameters.

Mi, i = 1,3, µ, tanβ,MA,MlR,MlL

,Mq1,2,Mq3 and At.

Characterised by light neutralino Dark Matter.

Light MA and light neurtalino can affect the B.R. (h → γγ) and gg

fusion rate.

Loop couplings changed by sparticle loops.


BSM & Higgs: Lessons from lHC so far?. MSSM

1112.2200: The effect on production in gg fusion and decay into γγ

channel, relative to the SM.


BSM & Higgs: Lessons from lHC so far?. Bs → µ+µ−

1112.2200


BSM & Higgs: Lessons from lHC so far?. Invisible Higgs decays

1112.2200


BSM & Higgs: Lessons from lHC so far?. How to ’see’ invisible Higgs?

VBF.

For invisible Higgs: O. Eboli and

D. Zeppenfeld, PLB 495 (2000)

147. Works with 30 fb−1, at 14

TeV.

R.G., Guchait et al.PLB 571

(2003) 184 Works for a light

Higgs upto invisible branching ra-

tio 0.3, with 30 fb−1, at 14 TeV.

1

10

10 2

10 3

0 100 200 300 400 500

Missing pT(GeV)

Num

ber o

f eve

nts


BSM & Higgs: Lessons from lHC so far?. Higgs and fourth generation

[GeV]Hm

100 200 300 400 500 600

TH

σ/σ

95

% C

L L

imit o

n

-110

1

10

Observed PCLObserved, before PCLExpected PCL

PCLσ 1± PCLσ+ 2

Observed CLsExpected CLsCMS exclusionTevatron exclusion

generation modelth4

=7 TeVs-1

L dt ~ 35 pb∫Excluded

ATLAS


BSM & Higgs: Lessons from lHC so far?. What can we conclude?

Mt′ −Mb′ > mW allowed for MH.

(Amold Dighe, RG, V. Arunprasath, Diptimoy Ghosh)

Why is this important?


BSM & Higgs: Lessons from lHC so far?. Search for fourth generation

Searches at present use a final state t′ → bW as the channel t′ → b′Wwas not expected to be open. So the search strategies might have to

be revisited! Nontrivial interplay between different search groups!

Also between theory and experimentalists!


BSM & Higgs: Lessons from lHC so far?. Naturalness?

In CMSSM:

M2Z ≃ 0.2m2

0 + 0.7M23 − 2µ2

One can define fine tuning measures depending on the level of can-

cellation required to get the correct mass MZ.


BSM & Higgs: Lessons from lHC so far?. Naturalness?

For CMSSM for M3 > 650 GeV it is about 1 part in 35.

Green points correspond to allowed regions accroding to fine tuning

criterion.

Plotted in the second graph is the naturalness probability. In the

allowed regions fine tuning is about one part in 100..


BSM & Higgs: Lessons from lHC so far?. Results on ED searches

In RS models one has resonances which would decay into γγ and/or

µ+µ− . Already surpassing Tevatron constraints.

Implications for, for example, tt physics.


BSM & Higgs: Lessons from lHC so far?. Results on ED searches

In fact dijet channel used to obtain hig mass-exclusions.

One needs to be careful while analysing these very high mass dijet

resonances.

These are necessarily wide and intereference effects with the back-

ground need to be taken into account

D. Choudhury, P. Saha, R.M. Godbole: JHEP, 2012.


BSM & Higgs: Lessons from lHC so far?. Interplay of the Cosmology and LHC results

Many extensions of the SM have a neutral, stable particle with all the

properties needed for it to be an ideal candidate for the dark matter.

The suggested solutions to cosmological questions can be tested in

HEP experiments and Physics Beyond the SM can be constrained by

Cosmological connections.

Does the DM need to be coming from TeV scale BSM: not necessarily!

lHC and Direct detection making inroads into answering this question.

Ruchaskiy has painted a picture where LHC will have not much to

say. Answers to the riddles may not be provided by LHC at all !


BSM & Higgs: Lessons from lHC so far?. Interplay of the Cosmology and LHC results

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

m0 [GeV]

100

150

200

250

300

350

400

450

500

m1/

2 [G

eV]

ATLAS - jetsATLAS - jets+1lCMS - jetsCMS - OS dilepton

0.095<Ωχh2<0.13

Ωχ h

2=0.5

Ωχ h

2=1.0

Ωχ h

2=10.

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

m0 [GeV]

100

150

200

250

300

350

400

450

500

m1/

2 [G

eV]

CDMS II (curr. sens.)Xenon 100 (curr. sens.)Xenon100 (10x sensitivity)

ATLAS

σχp=10

-44 cm

2σχp

=4x10-45

cm2

σχp=2x10

-45 cm

2

σχp=2x10

-45 cm

2

CMS

excluded by CDMS II

excluded by Xenon100

excluded by CDMS II

(As an example Profumo: 1105.5162)


BSM & Higgs: Lessons from lHC so far?. Conclusions

LHC has cornered TeV scale BSM through direct searches and both

the SM and BSM, through the Higgs and data from LHCb.

For TeV scale Supersymmetry the year 2012 will be critical. The

small hierarchy problem (that is a fine tuning to about a one part in

10-100 for the Higgs mass) has got accentuated. Higgs sector can

provide nontrivial cross-checks.

For theories with extra dimension new paramter regions begin to be

explored.

Is there TeV scale BSM? . At least it has not been realised in the

most obvious ways. May be ’subtle’ is the nature



1) 2012 is the crucial year for the SM Higgs and SUSY.

2)For SUSY Not just direct searches but Higgs physics (just its

mass), results from LHCb as well as direct/indirect DM detection

from XENON, CoGent putting SUSY under a scanner.

3)Extra dimensions: ideas interesting..but not predicitve enough to

be pushed to wall. In principle these ideas do not necessarily address

the different observational facts which indicate BSM.

4) What if we have only strongly interacting WW sector? No el-

ementary Higgs? Need 14 TeV, 100 fb−1. But difficult. (Classic:

Butterworth, Foreshaw: Nucl. Phys. B). Discription depends on the

unitarisation scheme. The typical scale estimated to unitarise the

WW amplitude is rather high.



5)A recent analysis: Addition of a spin 1 resonance in a controlled

fashion, to extend the validity of perturbative analysis. Estimate the

onset of strong dynamics, which is lower than the earlier one and

investigate LHC phenomenology. (Falkowski et al,arXiv:1108.1183.)

6)We should be in fact be prepared that we are completely wrong and

none of the ideas are right!

8)Let us hope that nature is ’kind’ even though itmay not be ’natural’ !

Exciting Times ahead for sure!


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