of neutrino mass - PowerPoint Presentation

Slide1

of neutrino mass

R

e

l

d

The

d

i

A. Yu. Smirnov

Max-Planck Institute

for Nuclear Physics,

Heidelberg, Germany

NOW 2014

September 8– 13, 2014 Slide2

The riddle of neutrino mass:

strongly suppresses

There is something hidden and beyond the standards which

badly confuses and mixes

violates the law or maybe, does not violate the law

which is difficult to prove and probably the first and the second are because of the third

What is this?Slide3

Version adapted to physicist:

Smallness of neutrino mass in comparison to masses of the charged leptons and quarks

what is behind of

2. “Unusual” lepton mixing pattern with two large mixing

angles (one is close to maximal) and one small which differs from the quark mixing3. Weaker (or no) mass hierarchy than the hierarchy of charged leptons and quarks

In general, what is the type of mass spectrum and mass ordering?New physics?Slide4

and connected questions:

are they of Dirac or

Majorana

type?are they “hard” or “soft” (medium dependent)?

Does the nature of neutrino mass differ from the nature of the quarks and charged lepton masses?Are sterile neutrinos (if exist) relevant for the solution ?Nature of neutrino mass

Recall that in oscillation experiments we probe dispersion relations and not masses immediately Effective neutrino masses in oscillation experiments in beta decay in cosmology and bb-decay can be different

Usual neutrino masses can be strongly suppressed, e.g. by the seesaw, so that ”unusual contributions” dominate Slide5

4

.

Steriles – the key?

3. Mixing and CP-violation

Content:

2. Scales of new physics

1. Challenging the riddle

5. Some guesses Slide6

the riddle

are we asking right questions?

do we interpret the data correctly?

ChallengingSlide7

The riddle and the solution

It is not excluded that the correct solution (or the key to the solution) already exists among hundreds of approaches, models, mechanisms, schemes, etc.

The problem is then to identify the correct solution

Still something fundamental

can be missedSlide8

Smallness of mass?

Special

m

3 mt

~ 3 10-11

Normal?Neutrinos: no clear generation structure as well as the correspondence light flavor – light mass, especially if the mass hierarchy is inverted or spectrum is quasi-degenerate

m3 me ~ 3 10-6

me mt~ 3 10

-6

106Similar for other generations if spectrum is hierarchical

10310

1210910-3

10

0

mass,

eV

gap

comparing within generation:

?

due to neutrality of neutrinos?Slide9

Leptons & quarks

The riddle is formulated as comparison with masses (and mixing) of quarks

There is no solution of the riddle of quark masses

Yes, if

Can we solve the neutrino mass riddle?Do efforts make sense? neutrino mass generation and generation of the charged lepton and quark masses are independent

we will try to explain the difference of masses and mixing of neutrinos and quarks, and not masses and mixing completely we still hope (as it was before) that neutrinos will uncover something simple and insightful which will allow to solve the quark mass riddle

Higgs triplet

Radiative

mechanismsSeesaw type III, etc.Slide10

Masses and mixing

Should mixing be included in the riddle?

Quarks

Relation between masses and mixing

md mssin

qC ~

Leptons

Maximal mixing - quasi- degenerate mass states ?

Tri-Bi-Maximal mixing (TBM) no connection between masses and mixing (at least in the lowest order)

Realized in the residual symmetry approachIn 3 generations: Fritzsch ansatz

Form invariance of the mass matricesSlide11

Mixing: quarks and leptons

Completely

related

Partiallyrelated

Largely unrelatedHiggs tripletRadiative mechanisms

Seesaw type II and IIISeesaw type I, Quark-lepton unification

with the only difference that originates from Majorana nature of neutrinos, symmetriesGUT, seesaw type IISlide12

The riddle and Dark Universe

Dark Matter

Riddle

Dark EnergyRiddle

Neutrino massriddleSolution may come from unexpected side

Dark radiationBaryon asymmetry in the UniverseInflationSlide13

The riddle

New Physics

and scales of

The riddle of new physicsSlide14

CKM type

Two types of new physics

additional structures in lepton sector such as the see – saw

responsible for small quark mixing and hierarchical structure of the Dirac masses

common for quarks and leptons

responsible forsmallness of neutrino mass and large lepton mixing These two types are different but probably should somehow “know” about each other

Neutrino new physics

A guess

Counter example, seesaw with degenerate RH neutrinos

does not work in this framework Slide15

Scales

GUT - Planck

mass

sub-

eV

Electroweak –

LHC

High scale seesawQuark- lepton symmetry /analogyGUT

eV-Low scale seesaw,

radiative mechanisms, RPV, high dimensionaloperatorsScale of neutrino masses themselves Relation to dark energy, MAVAN?

m

V

EW

2

m

n

n

Unification

of new

Looking under the lamp

Neutrino mass itself is the fundamental scale of new physics

physics

28 orders of

magnitude

Spurious scale?Slide16

m

n

= - mD

T mD 1M

R MGUT

2 MPl

for the heaviest in the presence of mixingMGUT ~ 1016

GeVLeptogenesis

High scale seesaw, unificationN ~ 102

many heavy singlets (RH neutrinos)…string theory

q – l similarity: mD ~

mq ~ ml MR ~ 108

- 10

14

GeV

double seesaw

10

16

- 10

17

GeV

Gauge coupling unification

BICEP-II ?

In

favorSlide17

Natural, minimalistic, in principles

Realizes relations:

High scale seesaw, unification

Neutrality, zero charges

MajoranaNatureSmallness of mass – high mass scale

Large mixingTestable?

- Proton decay- Majorana massesFine tuning

“Neutrinoful Universe” Seesaw sector is responsible for inflation (scalar which breaks B-L and gives masses of RH neutrinos), dark matter, leptogenesis

T. Higaki et al, arViv:1405.0013Partial relation of the quark and neutrino propertiesSlide18

High scale line: the problem

<<

M

PlNew physics below Planck scale

dmH2 ~ MR2 log (q /MR)

H

H

nL

nR “Partial” SUSY?

Simplest seesaw implies new physical scale

MR ~ mD2 /mn

~ 10

14

GeV

n

R

F.

Vissani

hep-phl9709409

(Another indication: unification

of gauge couplings)

y

2

(2

p

)

2

~ log (

q /M

R

)

M

R

3

m

n

(2

p

v)

2

J Elias-

Miro

et al,

1112.3022 [

hep

-ph]

M

R

< 10

7

GeV

Small

Yukawas

,

Leptogenesis

?

Cancellation?

M.

Fabbrichesi

AYSSlide19

EW – LHC scale

Neutralino

as RH neutrino

Rp-SUSY

L-RnMSM

- No hierarchy problem (even without SUSY)

- testable at LHC, new particles at 0.1 – few

TeV

scale- LNV decays

Low scale seesaw

Radiative

Small VEV

Higgs

Triplet

New Higgs

doublets

0ne loop

Two loops

Three loops

Low scale

Inverse

seesaw

Radiative

seesaw

Connection to Dark Matter

High dimensional operatorsSlide20

n

MSM

L

R

Normal

Mass hierarchy

3 - 10 kev- warm dark matter -

radiative decays  3.5 kev line

Few 100 MeV – GeV

- generate light mass of neutrinos generate via oscillations lepton asymmetry in the Universe can be produced in B-decays (BR ~ 10-10 )

split ~

eV

M.

Shaposhnikov

et al

BAU

WDM

Everything below EW scale

 s

mall Yukawa couplings

EW seesaw

Higgs inflation

Nothing new below Planck scale

RH neutrino?

very

small

split

very small mixingSlide21

eV

- sub

eV

scale physicsMaybe related to Dark energy, MAVAN

Very light sector which may include eV scale Seesaw with RH neutrinos for sterile anomalies LSND/ MiniBooNE ....

- new scalar bosons, majorons, axions, - new fermions (sterile neutrinos, baryonic nu) , - new gauge bosons (e.g. Dark photons)

A. De GouveaTests:

5th force searches experimentsModification of dynamics of neutrino oscillations

Checks of standard oscillation formulas,searches for deviationsGenerate finite neutrino masses, usual Dirac masses can be suppressed by seesaw with MR = MPl

or multi singlet mechanism M. PospelovSlide22

Mixing and

CP-violationSlide23

H.

Minakata, A Y S

From charged leptons or

Dirac matrices of charged leptons and neutrinosRelated to mechanism of neutrino mass generation

U

PMNS = VCKM+ UX

C. Giunti, M. TanimotoCKM type new physics

New neutrino structure

PMNS & CKM

In a spirit two types of new physics and partial relationsIn general, has similar hierarchical structure determined (as in

Wolfenstein parametrization) by powers of

Related to (any) mechanism that explains smallness of neutrino mass Should be fixed to reproduce correct Lepton mixing angles

V

CKM

~ I

U

X

~ U

TBM

l

= sin

q

C

Slide24

H.

Minakata, A Y S……………………………….

Realized in QLC

(Quark-Lepton Complementarity)U

12 (qc) U23(p/2)

q13~ ½ qc

Prediction:

permutation - to

reduce the lepton mixing matrix to the standard form leads toUPMNS

= VCKM+ UX e.g. UX

= UBM, UTBM

C. Giunti, M. TanimotoPheno. level

U

X

=

U

23

(

p

/2) U

12

sin

2

q

13

~

½sin

2

q

C

can be obtained in the context of

if

TBM-

Cabibbo

scheme

S. F. King et al

q

13

~ ½

q

cSlide25

``Naturalness’’

, absence of fine tuning of mass matrix

Dm212 Dm322

O(1)

sin2q13

~ ½sin2qC

Quark-Lepton ComplementarityGUT, family symmetry, … ~ ½cos2 2

q23universal nm

- nt – symmetry violationThe same

value with completely different implications

Mixing anarchy> 0.025

1-3 mixing

¼

sin

2

q

12

sin

2

q

23

Analogy with quark mixing relation

q

13

= 2

1/2

(

p/4

-

q

23

)

Eby,Frampton

,

Matsuzaki

relation

implications

?Slide26

CP-phase prediction

B.

Dasgupta

, A.S.UPMNS

~ VCKM+ UX

If the only source of CP violation

No CPV

sinq13

sin dCP = (-cos q23) sinq13q

sindqsin dCP ~

l3/s13 ~ l2

~ 0.046 dq = 1.2 +/- 0.08 rad

d

CP

~ -

d

or

p

+

d

where

d

= (s

13

q

/s

13

) c

23

sin

d

q

New sources may have specific symmetries or structures which lead to particular values of

d

CP

e.g. -

p

/2, and q - l unification will give just small corrections

l

3

l

If the phase

d

CP

deviates substantially from 0 or

p

, new sources of CPV beyond CKM should exists (e.g. from the RH sector) or another framework

Slide27

In general

sin

d

CP = s13-1 [sin(am +

dX)Vud|Xe3| – sin ae |Vcd|Xm

3 ] neglecting terms of the order ~ l3

here am , dX

and ae are parameters of the RH neutrinos if X

e3 = 0 we have sin dCP ~ – sin ae

if ae =

p /2

Some special values of dCP can be obtained under certain assumptions dCP

~ 3

p

/2

One can find structure of the RH sector which lead to these conditionsSlide28

In the Seesaw type I

B

Dasgupta

A.SMX

= - mDdiag UR+ (MR)-1 U

R* mDdiag U

x is the matrix diagonalizes mD

= UL (mD diag) UR+

HereMinimal extension is the L- R symmetry:

UR = UL ~ VCKM*

and no CPV in MR

Seesaw can enhance this small CPV effect so that resulting phase in PMNS is largeCPV from U

R

In contrast to quarks for

Majorana

neutrinos the RH rotation that

diagonalizes

m

D

becomes relevant and contributes to PMNS

m

D

n

~

m

D

q

U

X

= U

R

U

S

In the LR symmetric basis

From seesawSlide29

Quark-lepton

universality

Normal

mass hierarhy, relation between masses and mixing

Flavor alignment in mass matrixSimilar structure of mass

matrices but with different expansion parametersinq13 ~ ½ sinq

12 sinq23 The same relations between coupling strength between generations

Vub = ½ Vus Vcb

Fritzsch Anzatz similar to quark sector, RH neutrinos with equal masses

A guess

l

l = 1 - lq

Realization:

Expectations:Slide30

Steriles

is the key?Slide31

New neutrino states

(2 – 4) 10

-3 eV

0.5 - 2 eV

5 - 10 keV Warm Dark matter Pulsar kick

- Solar neutrinos- Extra radiation in the Universe- LSND, MB

Reactor Ga anomalies - Extra radiationns

1

eV

1 keV

1 MeV

10-3 eV

mixing

d

m

~

q

aS

2

m

S

(1

–

2) 10

-8

eV

2 10

-11

10

-6

eV

q

aS

2

0.02

0.02

eV

10

-3

Compare with large elements of the mass matrix 0.02

eVSlide32

Effect of sterile neutrinos

m

n

= ma + dm

Original active mass matrix e.g. from see-sawdm can change structure (symmetries)

of the original mass matrix completely Induced mass matrix due to mixing with nu sterile

U

PMNSbe

origin of difference of VCKM

andon the 3n structureFor keV

ma

= 0.025 eV dm << m

a

Decouples from generation of the light neutrino masses argument that this is not RH neutrino

but has some other origin

For

eV

d

m ~ m

a

Not a small perturbation

For

meV

d

m << m

a

can be

be

considered as very small perturbation of the 3

n

system Slide33

New physics: neutrino portal

L H F

where F is the

fermionic

operator

nLnR

SSS

H

n

R

is the key to the solution of the riddle?

New structure (but physics is the same)

1

L

n

(F)

- 3/2

Neutrino new physics

Through this portal neutrino gets mass

S

S

S

S

s

s

s

s

Scale

symmetriesSlide34

Some

guessesSlide35

Two different types of new physics are involved in explanation of data: the CKM type common to quarks and leptons and physics responsible for smallness of neutrino mass and large lepton mixing. The latter may have certain symmetries

It makes sense to identify the second one which explains the difference between the quarks and leptons

Still generation of quark and neutrino masses can be essentially independent

High (GUT) scale new physics: still appealingEW scale: see LHC14 resultsSub eV –eV scale: interesting, worth to explore

New neutrino physics may have certain symmetries which leads to specific values of mixing angles and CP phase. Phase from CKM part is strongly suppressedSterile neutrinos may be the key to solution to a riddleSlide36

and your solution to the riddle?