New BSM Status Report and remaining hopes for LHC 2. Rohini M. … · 2019. 12. 24. · BSM status report and remaining hopes for LHC 2. LHC paradox! SM rocks but BSM does not / LHC

BSM status report and remaining hopes for LHC 2. Rohini M. Godbole

BSM Status Report and remaining hopes for LHC 2.

Rohini M. GodboleCentre for High Energy Physics, IISc, Bangalore, India

Nov. 23, 2017 NISER, Bhubaneswar

BSM status report and remaining hopes for LHC 2. Plan

Warning: Expanded version of a talk given at Blois, 2017 in June

2017.

1. Some generalities.

2. BSM: reasons

3. BSM: status

4. Remaining hopes for LHC-II:

i) Examples from the Known unknowns ! SUSY, 2HDM, Extra

Dimensions + Composite Higgs (In the context of particular BSM

models)

ii)Example from the Unknown unknowns! New Physics Model In-

dependent: Effective Theories, Pseudo observables.


BSM status report and remaining hopes for LHC 2. Particle Physics today

Particle physics finds itself in a very peculiar place.

To steal from ’A tale of two cities’: (Apologies to Charles

Dickens!)

It is the best of times , it is the worst of times

It is the epoch of belief , it is the epoch of incredulity

It is the season of ’Light’ , it is the season of Darkness


BSM status report and remaining hopes for LHC 2. Particle Physics today

It is the spring of hope, it is the winter of despair

We have everything before us, we have nothing before us.

We have found the SM Higgs, proved the SM, wehave no glimmer of BSM that the Higgs propertiespromises!


BSM status report and remaining hopes for LHC 2. Observational reasons for BSM!

• Dark Matter makes up 27% of the Universe.!

• We have direct evidence for the nonzero ν masses

• Need quantitative explanation of the Baryon Asymmetry in the Uni-

verse!

• We have found a light Higgs boson at the LHC!

• We feel the force of gravity but do NOT have a QUANTUM de-

scription!

• Cosmic Acceleration.


BSM status report and remaining hopes for LHC 2. Asthetical reasons for BSM!

• To cure instability of the EW scale under radiative

corrections and to keep the Higgs light!.

• Need to get a basic understanding of the flavour issue:

why the masses of fermions span at least 15 orders of

magnitude!

• Unification of couplings

• Inclusion of Gravity in the picture?

• Dark Energy!Nov. 23, 2017 NISER, Bhubaneswar

BSM status report and remaining hopes for LHC 2. Which BSM in this talk?


BSM status report and remaining hopes for LHC 2. CMS/SM


BSM status report and remaining hopes for LHC 2. ATLAS and SM

∫L dt

[fb−1]Reference

WZjj EWK 20.3 PRD 93, 092004 (2016)

W±W±jj EWK 20.3 arXiv: 1611.02428 [hep-ex]

Wγγ 20.3 PRL 115, 031802 (2015)

Zγγ 20.3 PRD 93, 112002 (2016)

Zjj EWK 20.3 JHEP 04, 031 (2014)

Wjj EWK4.7 arXiv:1703.04362 [hep-ex]mjj > 500GeV

20.2 arXiv:1703.04362 [hep-ex]mjj > 1TeVt̄tγ 4.6 PRD 91, 072007 (2015)

t̄tZ 20.3 JHEP 11, 172 (2015)

3.2 EPJC 77 (2017) 40

t̄tW 20.3 JHEP 11, 172 (2015)

3.2 EPJC 77 (2017) 40

Zγ4.6

PRD 87, 112003 (2013)arXiv:1407.1618 [hep-ph]

20.3PRD 93, 112002 (2016)arXiv:1407.1618 [hep-ph]

Wγ 4.6PRD 87, 112003 (2013)arXiv:1407.1618 [hep-ph]

ts−chan 20.3 PLB 756, 228-246 (2016)

ZZ4.6 JHEP 03, 128 (2013)

20.3 JHEP 01, 099 (2017)

3.2 PRL 116, 101801 (2016)

WZ4.6 EPJC 72, 2173 (2012)

20.3 PRD 93, 092004 (2016)

3.2 PLB 762 (2016) 1

Wt2.0 PLB 716, 142-159 (2012)

20.3 JHEP 01, 064 (2016)

3.2 arXiv:1612.07231 [hep-ex]

γγ 4.9 JHEP 01, 086 (2013)

WW4.6 PRD 87, 112001 (2013)

20.3 PLB 763, 114 (2016)

3.2 arXiv: 1702.04519 [hep-ex]

tt−chan4.6 PRD 90, 112006 (2014)

20.3 arXiv:1702.02859 [hep-ex]

3.2 arXiv:1609.03920 [hep-ex]

t̄t4.6 EPJC 74: 3109 (2014)

20.2 EPJC 74: 3109 (2014)

3.2 PLB 761 (2016) 136

Z4.6 JHEP 02 (2017) 117

20.2 JHEP 02 (2017) 117

3.2 JHEP 02 (2017) 117

W4.6 arXiv:1612.03016 [hep-ex]

0.081 PLB 759 (2016) 601

γ

4.6 PRD 89, 052004 (2014)pT > 100 GeV

20.2 JHEP 06 (2016) 005pT > 25 GeV

3.2 arXiv: 1701.06882 [hep-ex]pT > 125 GeV

Dijets R=0.4 4.5 JHEP 05, 059 (2014)0.3 < mjj < 5 TeVJets R=0.4 4.5 JHEP 02, 153 (2015)0.1 < pT < 2 TeV

pp8×10−8 Nucl. Phys. B, 486-548 (2014)

50×10−8 PLB 761 (2016) 158

σ [pb]10−4

10−3

10−2

10−1 1 10

110

210

310

410

510

610

11

data/theory0.5 1 1.5 2 2.5

Theory

LHC pp√s = 7 TeV

Datastatstat ⊕ syst

LHC pp√s = 8 TeV


LHC pp√s = 13 TeV


Standard Model Production Cross Section Measurements Status: March 2017

ATLAS Preliminary

Run 1,2√s = 7, 8, 13 TeV


BSM status report and remaining hopes for LHC 2. Higgs in the PDG!

Next steps: couplings and CP! Still not in the PDG!


BSM status report and remaining hopes for LHC 2. Higgs is at the right place!

SM rocks! At LOOP levelNov. 23, 2017 NISER, Bhubaneswar

BSM status report and remaining hopes for LHC 2. Three lessons!

Three lessons to be learnt from the plot

1) SM works really spectacularly!

2) Space allowed for new physics contributions very limited. But this

can be indeed the way to probe new physics! Recall after all there

was a time when top was not found and the mass was ’predicted ’

from the same precision studies!

3) We know the Higgs mass as well (or better) as we will ever need

for this exercise! Need to focus on strength AND tensor structure of

the coupling!


BSM status report and remaining hopes for LHC 2. Higgs mass and BSM

Observed Higgs mass is small enough to believe in SUSY miracle.

It also implies that Sparticle masses need to be large ! Which is

consistent with the fact that we have not seen any so far!

Extended Higgs sector: additional doublets/singlets preferred but

doublets have to be ’aligned’ ! This comes NOT from higgs mass

but its couplings! 2HDM. Perhaps one model under the least ten-

sion!

In composite Higgs models (SILH)JHEP 0706 (2007) 045, the ob-

served Higgs mass implies lower scales for BSM, but nothing seen at

that scale. The basic idea under tension and needs extension!

Some of the ideas can be completely tested at the LHC run II. Will

give examples.


BSM status report and remaining hopes for LHC 2. All ideas under strain!

All BSM ideas under different amount of strains just like the

’wimp’ miracle itself is! We were all very happy that for generic

masses and weak interactions of the DM one got the ’right’ relic

density. That was the miracle! Now it is getting strained!

Ideas like sequential chiral fourth generation were ruled out the day

Higgs was discovered! However vector like fermions are still very

much allowed. Vector like Fermions: BSM that is present quite often

in Brane world models.


BSM status report and remaining hopes for LHC 2. LHC paradox!

SM rocks but BSM does not /

LHC Seems to have found the light Higgs consistent with

the top mass implied by EW precision tests

BUT So far no evidence/indication for the different BSM

particles that one expected IF the Higgs was light!


BSM status report and remaining hopes for LHC 2. Intermezzo

Luckily there are some indications of flavour non universality.

That is exciting but situation needs to settle down. Also right now

analyses first only in terms of effective operators. Experts are working!

Next step would be to construct models which will give rise to these

effective operators.

Would be then a big step to look at phenomenology of the ’com-

pletons’ : particles predicted to exist in UV completions of models

suggested to explain these observations.

Dust needs to settle down!


BSM status report and remaining hopes for LHC 2. What are the anomalies?

B-decays particularly b → s transitions show anomalies with SM pre-

dictions.

We expectNP in flavour changing NC ,

Most recently the decays B → K and B → K∗ have shown evidence

of flavour non universality.

I will summarize only the results and touch in the end briefly on

implications for NP!


BSM status report and remaining hopes for LHC 2. BSM status report

Status report!


BSM status report and remaining hopes for LHC 2. ATLAS SUSY limits: simplified models

Simplififed models


BSM status report and remaining hopes for LHC 2. CMS: SUSY

Simplified models.


BSM status report and remaining hopes for LHC 2. PMSSM

Attempts to quantify results against the ’branching ratio’ warning!

Analysis in PMSSM: more about this later.


BSM status report and remaining hopes for LHC 2. Limits, limits


BSM status report and remaining hopes for LHC 2. What about heavy Higgses?

A. Ferrari: Higgs couplings 2016. Will gain from full lump of Run II.


BSM status report and remaining hopes for LHC 2. What about heavy Higgses?

A. Ferrari, Higgs couplings 2016. Will gain from full Lumi of Run II.


BSM status report and remaining hopes for LHC 2. Higgs BSM decay modes

Limits on BSM decay branching ratios of the Higgs from the Higgs

rates typically ∼ 10%. Indirect and ambiguous.

Limits on invisible branching ratio for the Higgs possible from direct

searches via VBF, VH and Higgs + jet production:

CMS: 24 % EPJC 74, 2980, 2014; JHEP02, 135, 2017

ATLAS: 28% JHEP11, 206, 2015;JHEP01,172, 2016.


BSM status report and remaining hopes for LHC 2. Flavour physics

Am going to copy from a talk by D. Guadagnoli at ALPS 2017 and

a talk by him published in conference proceedings: ‘Strategies for

Lepton Flavour Violation in B decays“: Nuclear and Particle Physics

Proceedings 285-286 (2017) 87-92

LHCb paper : 1705.05802

A good EFT analysis: W. Altsmanhofer, P. Stangl and D.M. Straub,

1704.05435.

Nardeccia et al, 1704.05438.

An older paper: D. Ghosh, M. Nardecchia and S. A. Renner, “Hint of

Lepton Flavour Non-Universality in B Meson Decays,” JHEP 1412,

131 (2014) [arXiv:1408.4097 [hep-ph]].

Implications of the new data for NP scale: 1706.01868


BSM status report and remaining hopes for LHC 2. What are the data?


BSM status report and remaining hopes for LHC 2. Bto K






BSM status report and remaining hopes for LHC 2. What are the hopes for LHC-II


BSM status report and remaining hopes for LHC 2. Higgs-flavour-DM

Peeping at the BSM through the known Higgs and Top/bottom

and through the unknown: DM if it has anything to do with particle

physics. Look for the ’unknown’ through the ’known’ or ’unknown’.

Absence of Evidence is not Evidence of Absence!


BSM status report and remaining hopes for LHC 2. mh in SUSY

In SUSY the scalar potential involves only gauge couplings! The

lightest higgs mass is bounded from above!.

mh < MZ at tree level.

Radiative corrections raise the upper bound in MSSM to 132 GeV

Observed mass requires that the radiative corrections change it from

MZ to 125. So about 30 − −40% correction. The corrections are

coming from sparticle loops. So large corrections mean high SUSY

scale. Can be seen explicitly by looking at corrections caused by top

and stop loops.


BSM status report and remaining hopes for LHC 2. Little hierarchy?

Implications of observed Higgs mass for natural/unnatural

SUSY.

Generally, in SUSY models there is a relation between the

EW symmetry breaking and SUSY. This means a relation-

ship between MZ and other SUSY parameters, masses.

With sparticles as heavy as required to satisfy the Higgs

mass limit, a fine tuning of a percent or more is required

to satisfy this relation. Naturalness may be lost?


BSM status report and remaining hopes for LHC 2. Some results

For high MS typical mixing possible, for low MS only maximal mixing

possible. Gives some indication of the character of stop. (From

Mahamoudi, Arbey, DJouadi) Xt = At − µ cotβ


BSM status report and remaining hopes for LHC 2. Need to take care!

Lot of scalar fields. The scalar

potential may have charge and

color breaking minima which can

destabilize the vacuum away from

the EW minimum.

Red : Unstable,

Green: metastable: tunneling

time > life time of the Universe!

Blue: stable.

We can get mh = 125 with ’light’ (800 GeV to 1 TeV) stop but

with large At. But with large At the Higgs potential develops charge

and color breaking minima making vacuum unstable! So need to be

careful!

JHEP 14 (2014) 110 (R.G. + K.Mohan, S. Vempati, D. Chowdhury)


BSM status report and remaining hopes for LHC 2. Light Higgs and heavy SUSY

So the fact that Higgs is light ’smells’ of SUSY.

Its mass close to the upper limit of 132 GeV in MSSM means larger

values of MS!

It is the latter which people feel indicates ’unnaturalness’ !

For example Dine: “Naturalness Under Stress”

(On a lighter note: who are we to tell ’Nature’ what is ’natural!’)


BSM status report and remaining hopes for LHC 2. Light Higgs and heavy SUSY

Much agonisation over the loss of naturalnesss.

Much water has flown under that bridge now!

Achilee’s heel of SUSY theories: SUSY breaking mechanism?

Basically this is where we theorists are ignorant. We have different

biases , pointers.

Eg. GMSB is nice since it solves FCNC problem naturally.

But now in view of the Higgs mass the particle spectrum it produces

is ’unnatural’ !


BSM status report and remaining hopes for LHC 2. Measures of naturalness

Relation that follows from requiring conditions for EWSB.

|µ|2 = (cos 2β)−1(m22 sin2 β −m2

1 cos2 β)− 1

2M2Z .

One measure, ∆BG defined it in terms of max(pi/M2Z ∂M2

Z/∂pi) where

pi are the MSSM parameters! If this is large then naturalness is lost!

(Berbieri and Giudice, Nanopolous and J. Ellis.)

Large gluino mass and large stop mass means that naturalness is

lost! For ’natural’ spectrum we should have at least one light stop.

Is possible when mixing (Xt) is large. TeV gluinos and ’lightish’ stop!



X. Tata et al: Our measures of naturalness have high

values as we see it now. But it is possible that correla-

tions among parameters of the SUSY models can make

the value of the measure small for the same particle

spectrum!.PRD87, 115028, 2013

So they construct a measure, which if large definitely

points towards losing naturalness!



They consider the relation between M2Z, µ

2 and the Higgs mass pa-

rameters in scalar potential M21 ,M

22 at weak scale.

12M

2Z =

(m21+Σ1

1)−(m22+Σ2

2) tan2 β

tan2 β−1− µ2 .,Σ′s are one loop corrections.

So they construct another measure, out of each of the two terms in

the numerator compared to M2Z.

Find parameter range in NUHM case where theory ’could’ be ’natural’

with heavy gluinos and not so heavy electrowikinos.


BSM status report and remaining hopes for LHC 2. PMSSM and ∆EW

1612.06333v1: a light EW sector is ’natural’ in this sense. 1612.06333v1:

M. van Beekveld, W. Beenakker, Caron, Peeters and Austri


BSM status report and remaining hopes for LHC 2. PMSSM and ∆EW

A light EW sector is ’natural’ in this sense in PMSSM.


BSM status report and remaining hopes for LHC 2. Baysian approach

Let the (lack) of evidence tell us where we expect to find the evidence!

E. Bagnaschi et al., Eur. Phys. J. C 77, no. 4, 268 (2017),

P. Athron et al. [GAMBIT Collaboration],arXiv:1705.07917 [hep-ph].


BSM status report and remaining hopes for LHC 2. Light DM

A light LSP is still allowed in PMSSM, along with the relic con-

straints. For example, see R.K. Barman, G. Belanger, B. Bhattachar-

jee, R.G., D. Sengupta, G. Mendiratta,: PRD 95, 095018. Difft. from

1612.06333v1, considered non thermal DM as well.


BSM status report and remaining hopes for LHC 2. Light electroweakinos

From a talk by G. Belanger, Odense, 2017.


BSM status report and remaining hopes for LHC 2. Light LSP: further

This light LSP will mean invisible decay of the Higgs.

Possible to probe it at LHC and future colliders. For example, D.Ghosh,

R.G., M. Guchait and K. Mohan, PLB 725, 344, 2013 .

Projection for 13/14 TeV:

1310.8361 + HL LHC

CMS/ATLAS studies:

300 1/fb, 0.15; 3000 1/fb, 0.06

Searches for invisibly decaying

Higgs hold promise. Needs addi-

tional component for DM.

Green(orange) (dis)allowed by

LUX.


BSM status report and remaining hopes for LHC 2. Light stop ruled out?


BSM status report and remaining hopes for LHC 2. Light stop ruled out?

stop-LSP coannihilation region means very small mass differences be-

tween stop and Neutralino. E.g. G. Belanger, D. Ghosh, R.G. and S. Kulkarni, JHEP

1509, 214 (2015).

Search for c-tagged jet + LSP. Right now carried out using ’mono

jet’. Limits in simplified models, assuming 100 % branching ratios.

Certainly things should be clearer by end of LHC run II.


BSM status report and remaining hopes for LHC 2. Run-II, SUSY

As far as sparticles are concerned, Run -II has still three potentials:

Light electroweakinos, light(Ish) stop, invisibly decaying Higgs.

So as the experimentalists say: stay tuned

This is only for sparticles.

What about the Higgs sector?

Discuss examples of possibilities of the SUSY Higgs sector, generic

2HDM and composite Higgs.


BSM status report and remaining hopes for LHC 2. Extra/composite Higgs.

The Heavier Higgs in MSSM: Couplings to fermions depend on µ, tanβ.

Allowed values different in PMSSM than in CMSSM. For example G.

Belanger, D. Ghosh, R.G. and S. Kulkarni, JHEP 1509, 214 (2015)

Remember: Higgs decays into fermions coming of age and will really

gain from full luminosity of Run 2.


BSM status report and remaining hopes for LHC 2. Extra/composite Higgs.

Interesting: decays into electroweakinos large too. This comes di-

rectly from requiring that the DM satisfies constraints from Direct

Detection and provide right relic density. JHEP 1509, 214 (2015)

Can be accessed at 300 1/fb. R.K. Barman, B. Bhattacharjee, A. Chakraborty, A.

Choudhury,Phys. Rev. D 94, 075013 (2016).


BSM status report and remaining hopes for LHC 2. NMSSM/2DHM

Phys.Rev. D90 (2014) no.9, 095014 e-Print: arXiv:1408.1120 [hep-ph]

NMSSM: 2HDM + singlet. Small tanβ : tt̄ decays will be important.


BSM status report and remaining hopes for LHC 2. Heavy Higgs further

In NMSSM possible to have decays of the h and H/A into other

Higgses. A. Djouadi, M. Drees, R.G., U. Ellwanger and D. Moretti et al, JHEP 0807 (2008)

002

A light A is a clear possibility in NMSSM. Anlaysed, for example, by

Guchait et al, 1705.06275. h → A1A1 followed by A1 → γγ β =net

branching ratio.


BSM status report and remaining hopes for LHC 2. Pseudoscalar mediators!

In the context of DM, pseudo scalar mediators are postulated and are

still allowed over a considerable mass range. For example as in:

M. Dolan, F. Kahlhoefer, C. McCabe and K. Schmidt-Hober JHEP 1503,

171 (2015)

More about it later.


BSM status report and remaining hopes for LHC 2. Dihiggs and composite Higgs

Extended SILH : works even with higgs mass. Maximally composite

Higgs models have the SILH as the low energy limits.

Analysed in specific UV completed models by R. Grober, M. Muhlleitner and

M. Spira, at NLO.

Some possibilities of BSM showing up in Dihiggs only if there are

also heavy fermions in the reach of LHC run-II. Needs to be studied

further.


BSM status report and remaining hopes for LHC 2. Moving away from models

Even the DM results are throwing results at us which are at variance

with ’wisdom’ till now.

Analysis of B physics anomalies

Analysing anomalous tt̄φ vertex is also something to look while study-

ing the tt̄h production.

DM sector too is analyzed now in terms of effective models. DM

Group report contains a lot of work. Example in this context : analysis

for pseudo scalar mediator, for example: G. Belanger et al, 1705.02327. They

assume enhanced couplings of their pesudoscalar to top pair.

In general tt̄X: M. J. Dolan, M. Spannowsky, Q. Wang and Z. H. Yu,Phys.

Rev. D 94, no. 1, 015025 (2016)

Will discuss these one after another.


BSM status report and remaining hopes for LHC 2. Summary B-phys


BSM status report and remaining hopes for LHC 2. Summary B-phys


BSM status report and remaining hopes for LHC 2. Anom. top-Higgs coupling

Lttφ = att̄γµtφ+ btt̄γµγ5tφ

F. Boudjema et al, Phys.Rev. D92 (2015) no.1, 015019 All the other

couplings other than the t are taken to be SM couplings.

Rates are more sensitive to the pseudo scalar part bt than at Does

allow bt 6= 0 and will continue for a while!


BSM status report and remaining hopes for LHC 2. th/tth production

th cross-section:

α measures the CP admixture: X0 a scalar with indeterminate CP.

F. Demartin et al, Eur.Phys.J. C75 (2015) no.6, 267. Use of top

polarisation can improve this further! (Rindani et al)


BSM status report and remaining hopes for LHC 2. Distributions

F. Boudjema et al, Phys.Rev. D92 (2015) no.1, 015019


BSM status report and remaining hopes for LHC 2. Anom. hV V vertex

pVT spectrum for the V produced in association with the Higgs, harder

for anom. vertices: V. Sanz, J. Ellis and T. You, EPJC 73,2507,2013

Use jet substructure analysis to study the Anom. hV V vertex. R.G.,

D. Miller, K. Mohan and C. White,JHEP 1504 (2015) 103, PLB 730 (2014) 275. Idea is to

use jet substructure for both the W and the h. Modest reach for 300

1/fb.


BSM status report and remaining hopes for LHC 2. Pseudoscalar DM

S. Banerjee et al, JHEP 1707 (2017) 080


BSM status report and remaining hopes for LHC 2. May be

Some of this stories may be in the end for HL LHC, but some inroads

will be made already by LHC run II Lumi. In summary the spots towatch out:

1) Light electro weakinos,

2) Stop NLSP and degenerate stop-LSP,

3) Heavy Higgses decaying into b̄b, t̄t , electroweakinos and into lighter

(pseudo)scalar Higgs.

4) Composite higgses: hh the best standard candle. May not be the

first signature of BSM here. Heavy fermions should be seen beforethat.

5) Model independent study of the tt̄h (tt̄X) vertex from cross-section

measurements.

Studies with distributions will require HL.


BSM status report and remaining hopes for LHC 2. Blois-2011


BSM status report and remaining hopes for LHC 2. Blois-2011


BSM status report and remaining hopes for LHC 2. New paradigm for collider physics!

To quote Michelangelo Mangano


BSM status report and remaining hopes for LHC 2. New paradigm for collider physics!

BACKUP


BSM status report and remaining hopes for LHC 2. Composite W’

S.D. Chiara et al, JHEP 03, 2017,009


BSM status report and remaining hopes for LHC 2. Composite Z’


Documents

New BSM Status Report and remaining hopes for LHC 2. Rohini M. … · 2019. 12. 24. · BSM status report and remaining hopes for LHC 2. LHC paradox! SM rocks but BSM does not / LHC