+ All Categories
Home > Documents > 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems...

1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems...

Date post: 04-Jan-2016
Category:
Upload: christopher-joseph
View: 215 times
Download: 1 times
Share this document with a friend
28
1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES • “Big” and “little” hierarchy problems • Supersymmetry • Little Higgs • Extra dimensions G.F. Giudice CERN
Transcript
Page 1: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

1

THEORETICAL

PREDICTIONSFOR COLLIDER

SEARCHES

THEORETICAL

PREDICTIONSFOR COLLIDER

SEARCHES• “Big” and “little” hierarchy problems

• Supersymmetry

• Little Higgs

• Extra dimensions

G.F. Giudice CERN

Page 2: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

2

HIERARCHY PROBLEMHIERARCHY PROBLEM

2

22222

2

2

GeV200TeV 0.7

123624

SM

tHZWSMF

H mmmmG

m

nofine-tuning SM < TeV

“Big” hierarchy between SM and MPl

Cosmological constant

Cut off of quartic divergences at <10-3 eV

Page 3: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

3

LITTLE HIERARCHY LITTLE HIERARCHY

10

5.6

9.2

9.7

4.6

7.3

6.1

4.3

4.5

3.2

6.4

9.3

5.0

12.4

FqdH

qq

bbee

ee

LLHDiH

HDH

BWHH

LuudR

uuL

aa

2

55

2

2

1

LEP1

LEP2

MFV

Bounds on LH

LH > 5-10 TeV

+

O2LH

1L

Page 4: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

4

SM<1 TeV, LH>5-10 TeV

“Little” hierarchy between SM and LH

•New physics at SM is weakly interacting

•No (sizable) tree-level contributions from new physics at SM

•Strongly-interacting physics can only occur at scales larger than LH

•Successful new physics at SM has to pass non-trivial tests

Page 5: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

5

SUPERSYMMETRYSUPERSYMMETRY

mH2 =

H H+

t~

exp

Ghilencea-Ross

t

can be extended to MPl

-Link with quantum gravity

-Successful scenario for GUTexp

Page 6: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

6

UNIFICATION WITHOUT DESERTUNIFICATION WITHOUT DESERT

• Accelerated running from extra dimensions• or from gauge group replication• Different tree-level expression for sin2W

GUT: trace over GUT irrep

Little running needed

4

1sin~~,~for

8

3

QTr

Tr sin

2312

12123

2

232

W

W

ggg

USUUSUSU

I

Dienes-Dudas-Gherghetta

Arkani Hamed-Cohen-Georgi

Dimopoulos-Kaplan

Page 7: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

7

SUPERSYMMETRYSUPERSYMMETRY

• Gauge-coupling unification• Radiative EW breaking• Light Higgs

• Satisfies “little” hierarchy LH~4SM

• Dark matter

• Sparticles have not been observed• Susy-breaking sector unspecified

Page 8: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

8

Degrassi-Heinemeyer-Hollik-Slavich-Weiglein

MGeV

Page 9: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

9

Giusti-Romanino-Strumia

%3sun

moonsun

Page 10: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

10

Supersymmetry-breaking sector unspecified

Susy flavour violations gauge, gaugino mediation

Connection with gravity supergravity, anomaly mediation

problem supergravity

Predictivity gauge, gaugino, anomaly med.

Scenarios with different spectra and different experimental signals

Page 11: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

11

y

R

NEW INGREDIENTS FROM EXTRA DIMENSIONSNEW INGREDIENTS FROM EXTRA DIMENSIONS

Scherk-Schwarz breaking

symmetry -R is Q If

)(),(

conditionsboundary with expansion KK

),()2,(

2

22//

2

R

Qnmxeeyx

yxeRyx

nnn

RinyRyiQ

iQ

Supersymmetry is broken

Non-local susy breaking involves global structure

At short distances (<R), susy-breaking effects are suppressed

Page 12: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

12

y

R yZ2

NEW INGREDIENTS FROM EXTRA DIMENSIONSNEW INGREDIENTS FROM EXTRA DIMENSIONS

Orbifold projection

R 0

n=1

n=2

0

n=0n=1

n=2

R

Z2 : y y cos(ny/R) sin(ny/R)

Chiral theories

Page 13: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

13

5D SUSY SM compactified on S1/(Z2×Z2)

•Different susy breaking at each boundary

effective theory non-susy

(susy recovered at d<R)

• Higgs boson mass (rather) insensitive to UV

mH = 127 ± 10 GeV

Large corrections to ?

UV completion at ~ 5 TeV ?

AN INTERESTING EXAMPLEAN INTERESTING EXAMPLE

Barbieri-Hall-Nomura

Barbieri-Hall-Marandella-Nomura-Okui-Oliver-Papucci

Page 14: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

14

Mass spectrum is non-supersymmetric

• one Higgs and two sparticles for each SM particle

• LSP stable stop with mass 210 GeV

Page 15: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

15

USING WARPED DIMENSIONSUSING WARPED DIMENSIONS•Susy-breaking in Higgs sector is non-local finite effects

•AdS/CFT SM non-susy

Higgs sector: susy bound states of spontaneously broken CFT

•Light Higgs & higgsino

•New CFT states at L-1 ~ TeV

•Considerable fine tuning

states bound of size 4

1 11 LLmEW

Susy breaking

Higgs sector

SM

Gherghetta-Pomarol

Page 16: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

16

SUPERSYMMETRY:

CONCLUSIONS

SUPERSYMMETRY:

CONCLUSIONSSusy at EW scale can be realized in very different ways:

•ETmiss

• ETmiss +

•ETmiss + ℓ

•Stable charged particle

•Nearly-degenerate

•Stable stop

•Partial susy spectrum

0~ W

Page 17: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

17

HIGGS AS PSEUDOGOLDSTONE BOSON

HIGGS AS PSEUDOGOLDSTONE BOSON

22

/

forbids

symmetry realizedlinearly -Non

:

2

hmahh

ae

fef

ia

fi

Gauge, Yukawa and self-interaction are large non-derivative couplings

Violate global symmetry and introduce quadratic div.

Page 18: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

18

A less ambitious programme:

Explain only little hierarchy

At SM new physics cancels one-loop power divergences

LITTLE HIGGSLITTLE HIGGS

LH

224

4

22

222

2

TeV10 loops Two

TeV loop One

SMFSM

FH

F

SMSMSMF

H

mGm

Gm

Gm

Gm

“Collective breaking”: many (approximate) global symmetries preserve massless Goldstone bosonℒ1ℒ

2

H2

222

44

Hm

ℒ1 ℒ2

Arkani Hamed-Cohen-Georgi

Page 19: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

19

It can be achieved with gauge-group replication

•Goldstone bosons in

• gauged subgroups, each preserving a non-linear global symmetry

• which breaks all symmetries

Field replication Ex. SU2 gauge with doublets such that V(

) and

spontaneously break SU2

Turning off gauge coupling to

Local SU2(2) × global SU2() both spont. broken

HG /

21 GGG

21SM GG

loops two

42

4

42

gmH

Kaplan-Schmaltz

Page 20: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

20

Realistic models are rather elaborate

Effectively, new particles at the scale f ~ SM

canceling (same-spin) SM one-loop divergences with couplings related by symmetry

Typical spectrum:

Vectorlike charge 2/3 quark

Gauge bosons EW triplet + singlet

Scalars (triplets ?)

Arkani Hamed-Cohen-Georgi-Katz-Nelson-Gregoire-Wacker-Low-Skiba-Smith-Kaplan-Schmaltz-Terning…

Page 21: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

21

tuning-fine %1.0TeV 5

TeV 1422

ff

v

mm t

t

Bounds from: Tevatron limits on new gauge bosons

EW data ( from new gauge and top)

In minimal model:

Variations significantly reduce the fine tuning

Csaki-Hubisz-Kribs-Meade-Terning

Page 22: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

22

HIGGS AS EXTRA-DIM COMPONENT

OF GAUGE FIELD

HIGGS AS EXTRA-DIM COMPONENT

OF GAUGE FIELDAM = (A,A5), A5 A5 +∂5 forbids m2A5

2

gauge HiggsHiggs/gauge unification as graviton/photon unification in Kaluza-Klein

Higgs/gauge unification as graviton/photon unification in Kaluza-Klein

Correct Higgs quantum numbers by projecting out unwanted states with orbifold

•Yukawa couplings

•Quartic couplings

•Do not reintroduce quadratic divergences

Csaki-Grojean-Murayama

Burdman-Nomura

Scrucca-Serone-Silvestrini

Page 23: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

23

EXTRA DIMENSIONSEXTRA DIMENSIONSForget about symmetries, about little hierarchy

cut off at SM Any short-distance scale < SM

-1 explained by geometry

42/12/ DMRM DPl

KRPl eMM 5

FLAT Arkani Hamed-Dimopoulos-Dvali

WARPED Randall-Sundrum

Page 24: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

24H

QUANTUM GRAVITY AT LHCQUANTUM GRAVITY AT LHC

Graviton emissionMissing energy (flat)

Resonances (warped)

TT

4

1

252

1ff

Contact interactions (loop dominates over tree if gravity is strong)

Higgs-radion mixing

Page 25: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

25

Graviton emission

Tree-level graviton

exchange

Graviton loops

Gauge/graviton loop

G.G.-Strumia

Page 26: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

26

√As s approaches MD, linearized gravity breaks down

underlying quantum gravity (strings?)

TRANSPLANCKIAN REGIMES>>MD RS>>Pl and (semi)classical effects dominate

over quantum-gravity effects

b > RS

b < RS

Gravitational scatteringG.G.-Rattazzi-Wells

Black-hole productionGiddings-Thomas, Dimopoulos-Landsberg

Page 27: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

27

SM PARTICLES IN EXTRA DIMENSIONS

SM PARTICLES IN EXTRA DIMENSIONS

Gauge bosons in 5D: Direct + indirect limits Mc > 6.8 TeV Cheung-Landsberg

At LHC up to 13-15 TeV

Weaker bounds in universal extra dimensions After compactification, momentum conservation in

5th dim KK number conserved KK particles pair produced; no tree-level exchange Mc > 0.3 TeV Appelquist-Cheng-Dobrescu

Page 28: 1 THEORETICAL PREDICTIONS FOR COLLIDER SEARCHES “Big” and “little” hierarchy problems Supersymmetry Little Higgs Extra dimensions G.F. Giudice CERN.

28

CONCLUSIONSCONCLUSIONS

• Many open theoretical options for new physics at EW scale

• Direct searches + precision measurements no existing theory is completely free of fine-tuning

EWSUSY

GUT

E

Connection with MPl

Gauge coupling unification

Connection with MPl

Gauge coupling unification

LH orSM Need for UV

completion at


Recommended